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Document and Entity Information - USD ($)	12 Months Ended
Document and Entity Information - USD ($)	Dec. 31, 2017	Jan. 31, 2018	Jun. 30, 2017
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2017
Document Fiscal Year Focus	2017
Document Fiscal Period Focus	FY
Trading Symbol	MX
Entity Registrant Name	MAGNACHIP SEMICONDUCTOR Corp
Entity Central Index Key	0001325702
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		34,203,058
Entity Public Float			$ 260,362,764

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Current assets
Cash and cash equivalents	$ 128,575	$ 83,355
Restricted cash (Note 14)		18,251
Accounts receivable, net	92,026	61,775
Inventories, net	73,073	57,048
Other receivables (Note 19)	4,292	5,864
Prepaid expenses	9,250	8,137
Hedge collateral (Note 8)	7,600	3,150
Other current assets (Notes 1 and 2)	15,444	5,113
Total current assets	330,260	242,693
Property, plant and equipment, net	205,903	179,793
Intangible assets, net	4,061	3,085
Long-term prepaid expenses	12,791	9,556
Deferred income tax assets	264	193
Other non-current assets	5,510	6,632
Total assets	558,789	441,952
Current liabilities
Accounts payable	65,940	51,509
Other accounts payable	10,261	12,272
Accrued expenses	51,746	60,365
Deferred revenue	8,335	11,092
Deposits received (Note 14)		16,549
Other current liabilities	1,860	1,654
Total current liabilities	138,142	153,441
Long-term borrowings, net	303,416	221,082
Accrued severance benefits, net	148,905	129,225
Other non-current liabilities	7,963	10,318
Total liabilities	598,426	514,066
Commitments and contingencies (Note 19)
Stockholders' equity
Common stock, $0.01 par value, 150,000,000 shares authorized, 42,563,808 shares issued and 34,189,599 outstanding at December 31, 2017 and 41,627,103 shares issued and 35,048,338 outstanding at December 31, 2016	426	416
Additional paid-in capital	136,259	130,189
Accumulated deficit	(40,889)	(125,825)
Treasury stock, 8,374,209 shares at December 31, 2017 and 6,578,765 shares at December 31, 2016, respectively	(102,319)	(90,918)
Accumulated other comprehensive income (loss)	(33,114)	14,024
Total stockholders' deficit	(39,637)	(72,114)
Total liabilities and stockholders' equity	$ 558,789	$ 441,952

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	150,000,000	150,000,000
Common stock, shares issued	42,563,808	41,627,103
Common stock, shares outstanding	34,189,599	35,048,338
Treasury stock, shares	8,374,209	6,578,765

Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Statement [Abstract]
Net sales	$ 679,672	$ 687,969	$ 633,712
Cost of sales	491,779	531,743	498,848
Gross profit	187,893	156,226	134,864
Operating expenses
Selling, general and administrative expenses	81,775	83,549	94,378
Research and development expenses	70,523	72,180	83,420
Restructuring and other charges (gain), net	(17,010)	(6,480)
Early termination charges	13,369	4,240
Total operating expenses	148,657	153,489	177,798
Operating income (loss)	39,236	2,737	(42,934)
Interest expense	(21,559)	(16,238)	(16,268)
Foreign currency gain (loss), net	65,516	(15,360)	(42,531)
Other income, net	2,898	2,990	1,779
Income (loss) before income tax expenses	86,091	(25,871)	(99,954)
Income tax expenses (benefits)	1,155	3,744	(15,087)
Net income (loss)	$ 84,936	$ (29,615)	$ (84,867)
Earnings (loss) per common share-
Basic	$ 2.50	$ (0.85)	$ (2.47)
Diluted	$ 2.02	$ (0.85)	$ (2.47)
Weighted average number of shares-
Basic	33,943,264	34,833,967	34,380,517
Diluted	44,755,137	34,833,967	34,380,517

Consolidated Statements of Comprehensive Income/(Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 84,936	$ (29,615)	$ (84,867)
Other comprehensive income (loss)
Foreign currency translation adjustments	(52,873)	14,650	35,361
Derivative adjustments
Fair valuation of derivatives	7,736	(1,032)	(3,748)
Reclassification adjustment for loss (gain) on derivatives included in net loss	(2,001)	637	3,222
Total other comprehensive income (loss)	(47,138)	14,255	34,835
Total comprehensive income (loss)	$ 37,798	$ (15,360)	$ (50,032)

Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock Outstanding [Member]	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings (Deficit) [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Balance, beginning at Dec. 31, 2014	$ (18,502)		$ 406	$ 118,419	$ (11,343)	$ (90,918)	$ (35,066)
Balance, Shares beginning at Dec. 31, 2014		34,056,468
Stock-based compensation	2,768			2,768
Exercise of stock options	$ 3,436		5	3,431
Exercise of stock options, Shares	512,474	512,474
Other comprehensive income (loss), net	$ 34,835						34,835
Net income (loss)	(84,867)				(84,867)
Balance, ending at Dec. 31, 2015	(62,330)		411	124,618	(96,210)	(90,918)	(231)
Balance, Shares ending at Dec. 31, 2015		34,568,942
Stock-based compensation	3,843			3,843
Exercise of stock options	$ 1,733		3	1,730
Exercise of stock options, Shares	296,103	296,103
Settlement of restricted stock units			2	(2)
Settlement of restricted stock units, Shares		183,293
Acquisition of treasury stock			0
Other comprehensive income (loss), net	$ 14,255						14,255
Net income (loss)	(29,615)				(29,615)
Balance, ending at Dec. 31, 2016	$ (72,114)		416	130,189	(125,825)	(90,918)	14,024
Balance, Shares ending at Dec. 31, 2016	35,048,338	35,048,338
Stock-based compensation	$ 2,336			2,336
Exercise of stock options	$ 3,744		6	3,738
Exercise of stock options, Shares	539,183	539,183
Settlement of restricted stock units			4	(4)
Settlement of restricted stock units, Shares		397,522
Acquisition of treasury stock	$ (11,401)		0			(11,401)
Acquisition of treasury stock, Shares	(1,795,444)	(1,795,444)
Other comprehensive income (loss), net	$ (47,138)						(47,138)
Net income (loss)	84,936				84,936
Balance, ending at Dec. 31, 2017	$ (39,637)		$ 426	$ 136,259	$ (40,889)	$ (102,319)	$ (33,114)
Balance, Shares ending at Dec. 31, 2017	34,189,599	34,189,599

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash flows from operating activities
Net income (loss)	$ 84,936	$ (29,615)	$ (84,867)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities
Depreciation and amortization	28,146	25,416	26,490
Provision for severance benefits	24,373	14,432	15,289
Amortization of debt issuance costs and original issue discount	1,987	707	660
Loss (gain) on foreign currency, net	(77,600)	18,884	46,984
Restructuring gain and other	(17,010)	(7,785)
Stock-based compensation	2,336	3,843	2,768
Other	49	103	2,434
Changes in operating assets and liabilities
Accounts receivable, net	(22,210)	285	3,299
Inventories, net	(8,077)	(557)	12,929
Other receivables	3,981	19,125	(21,463)
Other current assets	2,318	5,000	11,339
Accounts payable	10,320	(4,163)	(12,605)
Other accounts payable	(12,141)	(6,603)	(10,892)
Accrued expenses	(12,020)	(16,305)	(1,679)
Deferred revenue	(3,949)	1,674	8,136
Other current liabilities	(1,281)	(5,331)	(1,210)
Other non-current liabilities	(760)	(1,574)	3,105
Payment of severance benefits	(21,506)	(15,352)	(11,394)
Other (Note 19)	(336)	5,447	700
Net cash provided by (used in) operating activities	(18,444)	7,631	(9,977)
Cash flows from investing activities
Proceeds from settlement of hedge collateral	10,615	6,317	10,841
Payment of hedge collateral	(14,839)	(3,552)	(17,182)
Proceeds from disposal of plant, property and equipment	18,834	688	9,886
Purchase of property, plant and equipment	(32,661)	(18,727)	(6,350)
Payment for intellectual property registration	(1,207)	(1,049)	(742)
Collection of guarantee deposits	1,462	619	636
Payment of guarantee deposits	(41)	(193)	(675)
Other	94	23	195
Net cash used in investing activities	(17,743)	(15,874)	(3,391)
Cash flows from financing activities
Proceeds from issuance of senior notes	86,250
Payment of debt issuance costs	(5,902)
Proceeds from exercise of stock options	3,744	1,732	3,436
Acquisition of treasury stock	(11,401)
Net cash provided by financing activities	72,691	1,732	3,436
Effect of exchange rates on cash and cash equivalents	8,716	(1,016)	(1,620)
Net increase (decrease) in cash and cash equivalents	45,220	(7,527)	(11,552)
Cash and cash equivalents
Beginning of the period	83,355	90,882	102,434
End of the period	128,575	83,355	90,882
Supplemental cash flow information
Cash paid for interest	17,590	14,906	15,181
Cash paid (refunded) for income taxes	1,027	693	(5,276)
Non-cash investing and financing activities
Property, plant and equipment additions in other accounts payable	$ 2,520	3,091	$ 3,348
Restricted cash received from sale of property, plant and equipment		$ (16,917)

Business, Basis of Presentation and Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2017

Accounting Policies [Abstract]

Business, Basis of Presentation and Summary of Significant Accounting Policies

1. Business, Basis of Presentation and Summary of Significant Accounting Policies

Business

MagnaChip Semiconductor Corporation (together with its subsidiaries, the “Company”) is a designer and manufacturer of analog and mixed-signal semiconductor platform solutions for communications, Internet of Things (“IoT”) applications, consumer, industrial and automotive applications. The Company provides technology platforms for analog, mixed signal, power, high voltage, non-volatile memory and Radio Frequency (“RF”) applications. The Company’s business is comprised of two operating segments: Foundry Services Group and Standard Products Group. The Company’s Foundry Services Group provides specialty analog and mixed-signal foundry services mainly for fabless and Integrated Device Manufacturer (“IDM”) semiconductor companies that primarily serve communications, IoT, consumer, industrial and automotive applications. The Company’s Standard Products Group is comprised of two business lines: Display Solutions and Power Solutions. The Company’s Display Solutions products provide panel display solutions to major suppliers of large and small rigid and flexible panel displays, and mobile, automotive applications and home appliances. The Company’s Power Solutions products include discrete and integrated circuit solutions for power management in communications, consumer and industrial applications.

Basis of Presentation

The consolidated financial statements are presented in accordance with accounting principles generally accepted in the United States of America (“US GAAP”).

Significant accounting policies followed by the Company in the preparation of the accompanying consolidated financial statements are summarized below.

Principles of Consolidation

The consolidated financial statements include the accounts of the Company including its wholly-owned subsidiaries. All intercompany transactions and balances are eliminated in consolidation.

Reclassifications

Certain charges related to the closure of the Company’s 6-inch fab and headcount reduction during 2016, previously included in selling, general and administrative expenses in the consolidated statements of operations, have been reclassified to restructuring and other charges (gain), net and early termination charges, respectively, to conform to the Company’s current year presentation. These reclassifications had no impact on the Company’s net income (loss), the consolidated balance sheets, the consolidated statements of comprehensive income (loss) and the consolidated statements of cash flows as previously reported.

Use of Estimates

The preparation of financial statements in accordance with US GAAP requires management to make estimates and assumptions about future events. These estimates and the underlying assumptions affect the amounts of assets and liabilities reported, disclosures about contingent assets and liabilities, and reported amounts of revenue and expenses. Such estimates include the valuation of accounts receivable, inventories, stock based compensation, property plant and equipment, intangible assets, other long-lived assets, long-term employee benefits, contingencies liabilities, estimated future cash flows and other assumptions used in long-lived asset impairment tests and calculation of income taxes and deferred tax valuation allowances, and assumptions used in the calculation of sales incentives, among others. Although these estimates and assumptions are based on management’s best knowledge of current events and actions that the Company may undertake in the future, actual results may be significantly different from the estimates. Changes in those estimates resulting from continuing changes in the economic environment will be reflected in the financial statements in future periods.

Foreign Currency Translation

The Company has assessed in accordance with Accounting Standards Codification (ASC) 830, “Foreign Currency Matters” (“ASC 830”), the functional currency of each of its subsidiaries in Luxembourg and the Netherlands and has designated the U.S. dollar to be their respective functional currencies. The Korean Won is the functional currency for the Company’s Korean subsidiary, which is the primary operating subsidiary of the Company. The Company and its other subsidiaries are utilizing their local currencies as their functional currencies. The financial statements of the subsidiaries in functional currencies other than the U.S. dollar are translated into the U.S. dollar in accordance with ASC 830. All the assets and liabilities are translated to the U.S. dollar at the end-of-period exchange rates. Capital accounts are determined to be of a permanent nature and are therefore translated using historical exchange rates. Revenues and expenses are translated using average exchange rates for the respective periods. Foreign currency translation adjustments arising from differences in exchange rates from period to period are included in the foreign currency translation adjustment account in accumulated other comprehensive income (loss) of stockholders’ equity. Gains and losses due to transactions in currencies other than the functional currency are included as a component of other income, net in the statement of operations.

Cash and Cash Equivalents

Cash equivalents consist of highly liquid investments with an original maturity date of three months or less when purchased.

Accounts Receivable Reserves

An allowance for doubtful accounts is provided based on the aggregate estimated uncollectability of the Company’s accounts receivable. The Company also records an estimate for sales returns, included within accounts receivable, net, based on the historical experience of the amount of goods that will be returned and refunded or replaced. In addition, the Company also includes in accounts receivable, an allowance for additional products that may have to be provided, free of charge, to compensate customers for products that do not meet previously agreed yield criteria, which the Company refers to as the low yield compensation reserve.

Sales of Accounts Receivable

The Company accounts for transfers of financial assets under ASC 860, “Transfers and Servicing,” as either sales or financings. Transfers of financial assets that result in sales accounting are those in which (1) the transfer legally isolates the transferred assets from the transferor, (2) the transferee has the right to pledge or exchange the transferred assets and no condition both constrains the transferee’s right to pledge or exchange the assets and provides more than a trivial benefit to the transferor, and (3) the transferor does not maintain effective control over the transferred assets. If the transfer does not meet these criteria, the transfer is accounted for as a financing. Financial assets that are treated as sales are removed from the Company’s accounts with any realized gain or loss reflected in earning during the period of sale.

Inventories

Inventories are stated at the lower of cost or net realizable value, using the first in, first out method (“FIFO”). If net realizable value is less than cost at the balance sheet date, the carrying amount is reduced to the realizable value, and the difference is recognized as a loss on valuation of inventories within cost of sales. Inventory reserves are established when conditions indicate that the net realizable value is less than costs due to physical deterioration, obsolescence, changes in price levels, or other causes based on individual facts and circumstances. The Company evaluates the sufficiency of inventory reserves and take into consideration historical usage, expected demand, anticipated sales price, new product development schedules, the effect new products might have on the sale of existing products, product age and other factors. Reserves are also established for excess inventory based on the Company’s current inventory levels and projected demand and its ability to sell those specific products. Situations that could cause these inventory reserves include a decline in business and economic conditions, decline in consumer confidence caused by changes in market conditions, sudden and significant decline in demand for our products, inventory obsolescence because of rapidly changing technology and consumer requirements, or failure to estimate end customer demand properly. A reduction of these inventory reserves may be recorded if previously reserved items are subsequently sold as a result of unexpected changes to certain aforementioned situations.

In addition, as prescribed in ASC 330, “Inventory,” once a reserve is established for a particular item based on the Company’s assessment as described above, it is maintained until the related item is sold or scrapped as a new cost basis has been established that cannot subsequently be marked up. In addition, the cost of inventories is determined based on the normal capacity of each fabrication facility. In case the capacity utilization is lower than a certain level that management believes to be normal, the fixed overhead costs per production unit which exceeds those under normal capacity are charged to cost of sales rather than capitalized as inventories.

Advances to Suppliers

The Company, from time to time, may make prepayments to suppliers to procure materials to meet its planned production. The Company recorded prepayments of $7,404 thousand and $ 1,390 thousand as other current assets as of December 31, 2017 and 2016, respectively.

Vendor Rebates

The Company, from time to time, enters into arrangements whereby rebates are obtained from vendors when the Company achieves certain levels of purchases. The vendor rebates are computed at an agreed upon amount or percentage of purchase levels. As these vendor rebates are impacted by actual and estimated purchases for the applicable agreed upon period, the Company periodically assesses the progress of its purchase levels and revises the estimates when necessary. The Company accounts for such rebates as a reduction of inventory until the Company sells the product, at which time such rebates are reflected as a reduction of cost of sales in its consolidated statements of operations. Vendor rebates recorded as a reduction of inventory were $0 and $359 thousand as of December 31, 2017 and 2016, respectively. Vendor rebates recorded as a reduction of cost of sales were $379 thousand and $4,044 thousand for the years ended December 31, 2017 and 2016, respectively.

Property, Plant and Equipment

Property, plant and equipment are stated at cost, less accumulated depreciation. Depreciation is computed using the straight-line method over the estimated useful lives of the assets as set forth below.


Buildings			30 - 40 years
Building related structures			10 - 20 years
Machinery and equipment			10 - 12 years
Others			3 - 10 years

Routine maintenance and repairs are charged to expense as incurred. Expenditures that enhance the value or significantly extend the useful lives of the related assets are capitalized.

Impairment of Long-Lived Assets

The Company reviews property, plant and equipment and other long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount may not be recoverable in accordance with ASC 360, “Property, Plant and Equipment”. Recoverability is measured by comparing its carrying amount with the future net undiscounted cash flows the assets are expected to generate. If such assets are considered to be impaired, the impairment is measured as the difference between the carrying amount of the assets and the fair value of assets using the present value of the future net cash flows generated by the respective long-lived assets.

Restructuring Charges

The Company recognizes restructuring charges in accordance with ASC 420, “Exit or Disposal Cost Obligations”. Certain costs and expenses related to exit or disposal activities are recorded as restructuring charges when liabilities for those costs and expenses are incurred.

Lease Transactions

The Company accounts for lease transactions as either operating leases or capital leases, depending on the terms of the underlying lease agreements. Machinery and equipment acquired under capital lease agreements are recorded at the lower of the present value of future minimum lease payments and estimated fair value of leased property and depreciated using the straight-line method over their estimated useful lives. In addition, the aggregate lease payments are recorded as capital lease obligations, net of unaccrued interest. Interest is amortized over the lease period using the effective interest rate method. Leases that do not qualify as capital leases are classified as operating leases, and the related rental payments are expensed on a straight-line basis over the shorter of the estimated useful lives of the leased property and the lease term.

Intangible Assets

Intangible assets other than intellectual property include technology and customer relationships which are amortized on a straight-line basis over periods ranging from one to five years. Intellectual property assets acquired represent rights under patents, trademarks and property use rights and are amortized over their respective periods of benefit, ranging up to ten years, on a straight-line basis.

Fair Value Disclosures of Financial Instruments

The Company follows ASC 820, “Fair Value Measurements and Disclosures” (“ASC 820”) for measurement and disclosures about fair value of its financial instruments. ASC 820 establishes a framework for measuring fair value in US GAAP, and expands disclosures about fair value measurements. To increase consistency and comparability in fair value measurements and related disclosures, ASC 820 establishes a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value into three broad levels. The fair value hierarchy gives the highest priority to quoted prices (unadjusted) in active markets for identical assets or liabilities and the lowest priority to unobservable inputs. The three levels of fair value hierarchy defined by ASC 820 are:

Level 1—Inputs are unadjusted, quoted prices in active markets for identical assets or liabilities at the measurement date.

Level 2—Inputs (other than quoted market prices included in Level 1) are either directly or indirectly observable for the asset or liability through correlation with market data at the measurement date and for the duration of the instrument’s anticipated life.

Level 3—Inputs reflect management’s best estimate of what market participants would use in pricing the asset or liability at the measurement date. Consideration is given to the risk inherent in the valuation technique and the risk inherent in the inputs to the model. Valuation of instruments includes unobservable inputs to the valuation methodology that are significant to the measurement of fair value of assets or liabilities.

As defined by ASC 820, the fair value of a financial instrument is the amount at which the instrument could be exchanged in a current transaction between willing parties, other than in a forced or liquidation sale, which was further clarified as the price that would be received to sell an asset or paid to transfer a liability (“an exit price”) in an orderly transaction between market participants at the measurement date. The carrying amounts of the Company’s financial assets and liabilities, such as cash equivalents, accounts receivable, other receivables, accounts payable and other accounts payable approximate their fair values because of the short maturity of these instruments.

Accrued Severance Benefits

The majority of accrued severance benefits is for employees in the Company’s Korean subsidiary, MagnaChip Semiconductor Ltd. Pursuant to the Employee Retirement Benefit Security Act of Korea, eligible employees and executive officers with one or more years of service are entitled to severance benefits upon the termination of their employment based on their length of service and rate of pay. As of December 31, 2017, 98% of all employees of the Company were eligible for severance benefits.

Accrued severance benefits are funded through a group severance insurance plan. The amounts funded under this insurance plan are classified as a reduction of the accrued severance benefits. Subsequent accruals are to be funded at the discretion of the Company.

In accordance with the National Pension Act of the Republic of Korea, a certain portion of accrued severance benefits is deposited with the National Pension Fund and deducted from the accrued severance benefits. The contributed amount is paid to employees from the National Pension Fund upon their retirement.

Revenue Recognition

Revenue is recognized when there is persuasive evidence of an arrangement, the price to the buyer is fixed or determinable, delivery has occurred and collectability of the sales price is reasonably assured. Revenue from the sale of products is recognized when title and risk of loss transfers to the customer, which is generally when the product is shipped to or accepted by the customer depending on the terms of the arrangement.

A portion of the Company’s sales are made through distributors for which revenue recognition criteria are usually met when the product is shipped to or accepted by the distributors, consistent with the principles described above. However, the risk of loss may not pass upon shipment of products to the distributor due to a variety of reasons, including the nature of the business arrangement with the distributor. For example, the financial condition of a distributor may indicate that payments by the distributor to the Company are contingent on resale of products to an end customer. In this situation, the Company defers recognition of revenue and cost of revenue on transactions with such distributor until the product has been resold to the end customer.

The Company recorded deferred revenue in the amount of $8,335 thousand as of December 31, 2017 and $11,092 thousand as of December 31, 2016 as the Company received cash from certain customers and distributors for the sale of products prior to risk of loss being transferred based on the terms of the arrangement.

In accordance with revenue recognition guidance, any tax assessed by a governmental authority that is directly imposed on a revenue-producing transaction between a seller and a customer is presented in the statements of operations on a net basis (excluded from revenues).

The Company provides a warranty, under which customers can return defective products. The Company estimates the costs related to those defective product returns and records them as a component of cost of sales.

In addition, the Company offers sales returns (other than those that relate to defective products under warranty), yield provisions, cash discounts for early payments and certain allowances to its customers, including distributors. The Company records reserves for those returns, discounts and allowances as a deduction from sales, based on historical experience and other quantitative and qualitative factors.

All amounts billed to a customer related to shipping and handling are classified as sales while all costs incurred by the Company for shipping and handling are classified as selling, general and administrative expenses. The amounts charged to selling, general and administrative expenses were $1,652 thousand, $1,631 thousand, and $2,394 thousand for the years ended December 31, 2017, 2016 and 2015, respectively.

Derivative Financial Instruments

The Company applies the provisions of ASC 815, “Derivatives and Hedging” (“ASC 815”). This Statement requires the recognition of all derivative instruments as either assets or liabilities measured at fair value.

Under the provisions of ASC 815, the Company may designate a derivative instrument as hedging the exposure to variability in expected future cash flows that are attributable to a particular risk (a “cash flow hedge”) or hedging the exposure to changes in the fair value of an asset or a liability (a “fair value hedge”). Special accounting for qualifying hedges allows the effective portion of a derivative instrument’s gains and losses to offset related results on the hedged item in the consolidated statements of operations and requires that a company formally document, designate and assess the effectiveness of the transactions that receive hedge accounting treatment. Both at the inception of a hedge and on an ongoing basis, a hedge must be expected to be highly effective in achieving offsetting changes in cash flows or fair value attributable to the underlying risk being hedged. If the Company determines that a derivative instrument is no longer highly effective as a hedge, it discontinues hedge accounting prospectively and future changes in the fair value of the derivative are recognized in current earnings. The Company assesses hedge effectiveness at the end of each quarter.

In accordance with ASC 815, changes in the fair value of derivative instruments that are cash flow hedges are recognized in accumulated other comprehensive income (loss) and reclassified into earnings in the period in which the hedged item affects earnings. Ineffective portions of a derivative instrument’s change in fair value are immediately recognized in earnings. Derivative instruments that do not qualify, or cease to qualify, as hedges must be adjusted to fair value and the adjustments are recorded through net income (loss).

The cash flows from derivative instruments receiving hedge accounting treatment are classified in the same categories as the hedged items in the consolidated statements of cash flows.

Advertising

The Company expenses advertising costs as incurred. Advertising expense was approximately $95 thousand, $149 thousand and $144 thousand for the years ended December 31, 2017, 2016 and 2015, respectively.

Product Warranties

The Company records, in other current liabilities, warranty liabilities for the estimated costs that may be incurred under its basic limited warranty. The standard limited warranty period is one to two years for the majority of products. This warranty covers defective products, and related liabilities are accrued when product revenues are recognized. Factors that affect the Company’s warranty liability include historical and anticipated rates of warranty claims and repair or replacement costs per claim to satisfy the Company’s warranty obligation. As these factors are impacted by actual experience and future expectations, the Company periodically assesses the adequacy of its recorded warranty liabilities and adjusts the amounts when necessary.

Research and Development

Research and development costs are expensed as incurred and include wafers, masks, employee expenses, contractor fees, building costs, utilities and administrative expenses.

Licensed Patents and Technologies

The Company has entered into a number of royalty agreements to license patents and technology used in the design of its products. The Company carries two types of royalties: lump-sum and running basis. Lump-sum royalties, which require initial payments, usually paid in installments, represent a non-refundable commitment, such that the total present value of these payments is recorded as a prepaid expense and a liability upon execution of the agreements and the costs are amortized over the contract period using the straight-line method and charged to research and development expenses in the consolidated statements of operations.

Running royalties are paid based on the revenue of related products sold by the Company.

Stock-Based Compensation

The Company follows the provisions of ASC 718, “Compensation-Stock Compensation” (“ASC 718”). Under ASC 718, stock-based compensation cost is measured at the grant date, based on the fair value of the award, and is recognized as expense, net of the estimated forfeiture rate, over the requisite service period. As permitted under ASC 718, the Company elected to recognize compensation expense for all options with graded vesting based on the graded attribution method.

The Company uses the Black-Scholes option-pricing model to measure the grant-date-fair-value of options. The Black-Scholes model requires certain assumptions to determine an option’s fair value, including expected term, risk free interest rate, expected volatility and fair value of underlying common share. The expected term of each option grant was based on employees’ expected exercises and post-vesting employment termination behavior and the risk free interest rate was based on the U.S. Treasury yield curve for the period corresponding with the expected term at the time of grant. No dividends were assumed for this calculation of option value.

Earnings per Share

In accordance with ASC 260, “Earnings Per Share”, the Company computes basic earnings per share by dividing net income (loss) available to common stockholders by the weighted average number of common shares outstanding during the period. Diluted earnings per share reflect the dilution of potential common stock outstanding during the period including stock options and restricted stock units, using the treasury stock method (by using the average stock price for the period to determine the number of shares assumed to be purchased from the exercise of stock options and restricted stock units), and convertibles, using the if-converted method. In determining the hypothetical shares repurchased, the Company uses the average share price for the period. In the case that earnings are negative, any potential common stock equivalents would have the effect of being anti-dilutive in the computation of net loss per share.

Income Taxes

The Company accounts for income taxes in accordance with ASC 740, “Income Taxes” (“ASC 740”). ASC 740 requires recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been recognized in a company’s financial statements or tax returns. Under this method, deferred tax assets and liabilities are determined based upon the difference between the financial statement carrying amounts and the tax bases of assets and liabilities using enacted tax rates in effect in the years in which the differences are expected to reverse. Valuation allowances are established when it is necessary to reduce deferred tax assets to the amount expected to be realized. Income tax expense is the tax payable for the period and the change during the period in deferred tax assets and liabilities.

The Company recognizes and measures uncertain tax positions taken or expected to be taken in a tax return utilizing a two-step process. In the first step, recognition, the Company determines whether it is more-likely-than-not that a tax position will be sustained upon examination, including resolution of any related appeals or litigation processes, based on the technical merits of the position. The second step addresses measurement of a tax position that meets the more-likely-than-not criteria. The tax position is measured at the largest amount of benefit that has a likelihood of greater than 50 percent of being realized upon ultimate settlement.

Concentration of Credit Risk

The Company performs periodic credit evaluations of its customers’ financial condition and generally does not require collateral for customers on accounts receivable. The Company maintains reserves for potential credit losses, which are periodically reviewed.

Recent Accounting Pronouncements

In August 2017, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update No. 2017-12, “Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities” (“ASU 2017-12”). ASU 2017-12 provides new guidance about income statement classification and eliminates the requirement to separately measure and report hedge ineffectiveness. The entire change in fair value for qualifying hedge instruments included in the effectiveness will be recorded in other comprehensive income (OCI) and amounts deferred in OCI will be reclassified to earnings in the same income statement line item in which the earnings effect of the hedged item is reported. ASU 2017-12 is effective for interim and annual periods for the Company on January 1, 2019, with early adoption permitted. The Company is currently evaluating the impact of adoption of ASU 2017-12 on its consolidated financial statements.

In July 2017, the FASB issued Accounting Standards Update No. 2017-11, “Earnings Per Share (Topic 260); Distinguishing Liabilities from Equity (Topic 480); Derivatives and Hedging (Topic 815)” (“ASU 2017-11”), which addresses the complexity of accounting for certain financial instruments with down round features. Down round features are features of certain equity-linked instruments (or embedded features) that result in the strike price being reduced on the basis of the pricing of future equity offerings. Current accounting guidance creates cost and complexity for entities that issue financial instruments (such as warrants and convertible instruments) with down round features that require fair value measurement of the entire instrument or conversion option. For public business entities, the amendments in ASU 2017-11 are effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018. The Company is currently evaluating the impact of adoption of ASU 2017-11 on its consolidated financial statements.

In May 2017, the FASB issued Accounting Standards Update No. 2017-09, “Compensation-Stock Compensation (Topic 718): Scope of Modification Accounting” (“ASU 2017-09”). ASU 2017-09 provides clarity and reduces both (i) diversity in practice and (ii) cost and complexity when applying the guidance in Topic 718 to a change to the terms or conditions of a share-based payment award. The amendments in ASU 2017-09 provide guidance about which changes to the terms or conditions of a share-based payment award require an entity to apply modification accounting in Topic 718. ASU 2017-09 is effective for fiscal years beginning after December 15, 2017, and interim periods within those years and early adoption is permitted. The Company does not expect the adoption of ASU 2017-09 to have a material effect on the Company’s consolidated financial statements.

In August 2016, the FASB issued Accounting Standards Update No. 2016-15, “Statement of Cash Flows (Topic 230), Classification of Certain Cash Receipts and Cash Payments” (“ASU 2016-15”). ASU 2016-15 reduces the existing diversity in practice in financial reporting across all industries by clarifying certain existing principles in ASC 230, Statement of Cash Flows (“ASC 230”), including providing additional guidance on how and what an entity should consider in determining the classification of certain cash flows. In addition, in November 2016, the FASB issued ASU 2016-18, Statement of Cash Flows (Topic 230), Restricted Cash (“ASU 2016-18”). ASU 2016-18 clarifies certain existing principles in ASC 230, including providing additional guidance related to transfers between cash and restricted cash and how entities present, in their statement of cash flows, the cash receipts and cash payments that directly affect the restricted cash accounts. These ASUs are effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. Early adoption is permitted. The Company does not expect the adoption of ASU 2016-15 to have a material effect on the Company’s consolidated financial statements. The adoption of ASU 2016-18 will impact the Company’s current disclosures as it will require including restricted cash within cash and cash equivalents on the statement of cash flows. These ASUs will be adopted in the first quarter of 2018.

In February 2016, the FASB issued Accounting Standards Update No. 2016-02, “Leases (Topic 842)” (“ASU 2016-02”) in order to increase transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet for those leases classified as operating leases under US GAAP. ASU 2016-02 requires that a lessee should recognize a liability to make lease payments and a right-of-use asset representing its right to use the underlying asset for the lease term on the balance sheet. ASU 2016-02 is effective for fiscal years beginning after December 15, 2018, including interim periods within those reporting periods using a modified retrospective approach and early adoption is permitted. The Company is performing a preliminary review of its contracts that are expected to be applied under the new guidance.

In May 2014, the FASB issued Accounting Standards Update No. 2014-09, “Revenue from Contracts with Customers (Topic 606)” (“ASU 2014-09”). ASU 2014-09 supersedes the revenue recognition requirements in “Revenue Recognition (Topic 605)”, and requires entities to recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled to in exchange for those goods or services. ASU 2014-09 is effective for annual reporting periods beginning after December 15, 2017, including interim periods within that reporting period. Subsequently, the FASB approved a deferral included in ASU 2015-14 that permits public entities to apply the amendments in ASU 2014-09 for annual reporting periods beginning after December 15, 2017, including interim reporting periods therein, and that would also permit public entities to elect to adopt the amendments as of the original effective date as applicable to reporting periods beginning after December 15, 2016. The new guidance allows for the amendments to be applied either retrospectively to each prior reporting period presented (the “full retrospective method”) or retrospectively as a cumulative-effect adjustment as of the date of adoption (the “modified retrospective method”). In March 2016, the FASB issued ASU 2016-08, which clarifies the implementation guidance on principal versus agent considerations. In April 2016, the FASB issued ASU 2016-10, which clarifies identifying performance obligations and the licensing implementation guidance. In May 2016, the FASB issued ASU 2016-12, which improves certain aspects of ASC Topic 606 “Revenue from Contracts with Customers.” In December 2016, the FASB issued ASU 2016-20, which improves certain aspects of ASC Topic 606 “Revenue from Contracts with Customers.” The effective date and transition requirements for ASU 2016-08, ASU 2016-10, ASU 2016-12 and ASU 2016-20 are the same as the effective date and transition requirements of ASU 2014-09 (collectively, the “new revenue standard”).

The Company adopted the new revenue standard effective January 1, 2018 using the modified retrospective method. Based on our evaluation of the terms of revenue contracts and other arrangements, the most significant impact relates to the accounting for the Company’s foundry services revenue. The Company’s foundry services group manufactures products that have no alternative use since such products are made to specific customer orders, and has a legally enforceable right to payment for performance completed to date on these manufactured products including a reasonable profit. For those manufactured products, the Company will recognize revenue “over time” in proportion of wafer-manufacturing rather than at the time of shipment or delivery of the related products.

The Company will recognize the cumulative effect of initially applying the new revenue standard as an adjustment to the Company’s equity as of January 1, 2018. The estimated impact is based on assessments undertaken to date and the Company expects this adjustment to increase the Company’s beginning equity as of January 1, 2018 by less than $10 million.

Recently Adopted Accounting Pronouncements

In July 2015, the FASB issued Accounting Standards Update No. 2015-11, “Simplifying the Measurement of Inventory” (“ASU 2015-11”). Under ASU 2015-11, inventory will be measured at the lower of cost and net realizable value, and options that currently exist for market value will be eliminated. Net realizable value is defined as the estimated selling prices in the ordinary course of business, less reasonably predictable costs of completion, disposal, and transportation. No other changes were made to the current guidance on inventory measurement. The Company adopted ASU 2015-11 in the first quarter of 2017, and the adoption of ASU 2015-11 did not impact the Company’s consolidated financial statements.

In November 2015, the FASB issued Accounting Standards Update No. 2015-17, “Income Taxes (Topic 740): Balance Sheet Classification of Deferred Taxes” (“ASU 2015-17”). The amendments in ASU 2015-17 require an entity to classify all deferred tax assets and liabilities as noncurrent. The Company adopted ASU 2015-17 in the first quarter of 2017 prospectively and all current deferred tax assets and liabilities in the prior periods have not been reclassified as noncurrent.

In March 2016, the FASB issued Accounting Standards Update No. 2016-09, “Improvements to Employee Share-Based Payment Accounting” (“ASU 2016-09”). ASU 2016-09 simplifies several aspects of the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities and classification on the statement of cash flows. The primary impact of adoption is the recognition of excess tax benefits within income tax provision rather than within stockholders’ equity. The Company adopted ASU 2016-09 in the first quarter of 2017, and the adoption of ASU 2016-09 did not have a material impact to the Company’s consolidated financial statements.

Fair Value Measurements

12 Months Ended

Dec. 31, 2017

Fair Value Disclosures [Abstract]

Fair Value Measurements

2. Fair Value Measurements

ASC 820 defines fair value, establishes a consistent framework for measuring fair value and expands disclosure requirements about fair value measurements. ASC 820 requires, among other things, the Company’s valuation techniques used to measure fair value to maximize the use of observable inputs and minimize the use of unobservable inputs.

Fair Value of Financial Instruments

As of December 31, 2017, the following table represents the Company’s assets measured at fair value on a recurring basis and the basis for that measurement (in thousands):


	Carrying Value December 31, 2017		Fair Value Measurement December 31, 2017		Quoted Prices in Active Markets for Identical Asset (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets:
Derivative assets (other current assets)	$	5,179	$	5,179		—	$	5,179		—

As of December 31, 2016, the following table represents the Company’s liabilities measured at fair value on a recurring basis and the basis for that measurement (in thousands):


	Carrying Value December 31, 2016		Fair Value Measurement December 31, 2016		Quoted Prices in Active Markets for Identical Asset (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Liabilities:
Derivative liabilities (other current liabilities)	$	453	$	453		—	$	453		—

Items not reflected in the table above include cash equivalents, restricted cash, accounts receivable, other receivables, accounts payable, and other accounts payable, fair value of which approximate carrying values due to the short-term nature of these instruments. The fair value of assets and liabilities whose carrying value approximates fair value is determined using Level 2 inputs.

Fair Value of Long-term Borrowings


	December 31, 2017				December 31, 2016
	Carrying Value		Fair Value		Carrying Value		Fair Value
	(In thousands of US dollars)
Long-term Borrowings:
5.0% Exchangeable Senior Notes due March 2021 (Level 2)	$	81,576	$	127,617	$	—	$	—
6.625% senior notes due July 2021 (Level 2)	$	221,840	$	224,719	$	221,082	$	193,500

On January 17, 2017, the Company’s wholly-owned subsidiary, MagnaChip Semiconductor S.A., closed an offering (the “Exchangeable Notes Offering”) of 5.0% Exchangeable Senior Notes due March 1, 2021 (the “Exchangeable Notes”) of $86,250 thousand, which represents the principal amount, excluding $5,902 thousand of debt issuance costs. The Company estimates the fair value of the Exchangeable Notes using the market approach, which utilizes quoted market prices that fall under Level 2. For further description of the Exchangeable Notes, see Note 10, “Long-term Borrowings”.

On July 18, 2013, the Company issued 6.625% senior notes due July 15, 2021 (the “2021 Notes”) of $225.0 million, which represents the principal amount, excluding $1.1 million of original issue discount and $5.1 million of debt issuance costs. The Company estimates the fair value of the 2021 Notes using the market approach, which utilizes quoted market prices that fall under Level 2. For further description of the 2021 Notes, see Note 10, “Long-term Borrowings”.

Fair Values Measured on a Non-recurring Basis

The Company’s non-financial assets, such as property, plant and equipment, and intangible assets are recorded at fair value upon acquisition and are remeasured at fair value only if an impairment charge is recognized. As of December 31, 2017 and 2016, the Company did not have any assets or liabilities measured at fair value on a non-recurring basis.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Accounts Receivable

12 Months Ended

Dec. 31, 2017

Receivables [Abstract]

Accounts Receivable

3. Accounts Receivable

Accounts receivable as of December 31, 2017 and 2016 consisted of the following (in thousands):


	December 31,
	2017			2016
Accounts receivable	$	86,167		$	63,116
Notes receivable		7,425			281
Less:
Allowances for doubtful accounts		(94	)		(83	)
Sales return reserves		(628	)		(1,107	)
Low yield compensation reserve		(844	)		(432	)

Accounts receivable, net	$	92,026		$	61,775

Changes in allowance for doubtful accounts for the years ended December 31, 2017, 2016 and 2015 are as follows (in thousands):


	Year Ended December 31,
	2017			2016			2015
Beginning balance	$	(83	)	$	(236	)	$	(263	)
Reversal		—			148			3
Translation adjustments		(11	)		5			24

Ending balance	$	(94	)	$	(83	)	$	(236	)

Changes in sales return reserves for the years ended December 31, 2017, 2016 and 2015 are as follows (in thousands):


	Year Ended December 31,
	2017			2016			2015
Beginning balance	$	(1,107	)	$	(1,481	)	$	(787	)
Provision		(40	)		(26	)		(1,586	)
Usage		626			361			851
Translation adjustments		(107	)		39			41

Ending balance	$	(628	)	$	(1,107	)	$	(1,481	)

Changes in low yield compensation reserve for the years ended December 31, 2017, 2016 and 2015 are as follows (in thousands):


	Year Ended December 31,
	2017			2016			2015
Beginning balance	$	(432	)	$	(480	)	$	(1,100	)
Reversal (Provision)		(362	)		(29	)		69
Usage		22			63			512
Translation adjustments		(72	)		14			39

Ending balance	$	(844	)	$	(432	)	$	(480	)

The Company has entered into an agreement to sell selected trade accounts receivable to a financial institution from time to time since March 2012. After the sale, the Company does not retain any interest in the receivables and the applicable financial institution collects these accounts receivable directly from the customer. The proceeds from the sales of these accounts receivable totaled $18,973 thousand, $25,146 thousand and $57,185 for the years ended December 31, 2017, 2016 and 2015, respectively, and these sales resulted in pre-tax losses of $55 thousand, $78 thousand and $114 thousand for the years ended December 31, 2017, 2016 and 2015, respectively, which are included in selling, general and administrative expenses in the consolidated statements of operations. Net proceeds of the accounts receivable sale program are recognized in the consolidated statements of cash flows as part of operating cash flows.

The Company uses receivable discount programs with certain customers. These discount arrangements allow the Company to accelerate collection of customers’ receivables.

- Definition

The entire disclosure for claims held for amounts due a entity, excluding financing receivables. Examples include, but are not limited to, trade accounts receivables, notes receivables, loans receivables. Includes disclosure for allowance for credit losses.

+ References + Details

Inventories

12 Months Ended

Dec. 31, 2017

Inventory Disclosure [Abstract]

Inventories

4. Inventories

Inventories as of December 31, 2017 and 2016 consist of the following (in thousands):


	Year Ended December 31,
	2017			2016
Finished goods		13,737			7,867
Semi-finished goods and work-in-process		53,148			46,653
Raw materials		12,445			7,846
Materials in-transit		134			1,859
Less: inventory reserve		(6,391	)		(7,177	)

Inventories, net	$	73,073		$	57,048

Changes in inventory reserve for the years ended December 31, 2017, 2016 and 2015 are as follows (in thousands):


	Year Ended December 31,
	2017			2016			2015
Beginning balance	$	(7,177	)	$	(16,033	)	$	(47,488	)
Change in reserve
Inventory reserve charged to costs of sales		(4,789	)		(7,646	)		(13,635	)
Sale of previously reserved inventory		3,784			4,985			13,932

		(1,005	)		(2,661	)		297
Write off		2,620			11,384			29,146
Translation adjustments		(829	)		133			2,012

Ending balance	$	(6,391	)	$	(7,177	)	$	(16,033	)

Inventory reserve represents the Company’s best estimate in value lost due to excessive inventory level, physical deterioration, obsolescence, changes in price levels, or other causes based on individual facts and circumstances. Inventory reserve relates to inventory items including finished goods, semi-finished goods and work-in-process. Write off of this reserve is recognized only when the related inventory has been disposed or scrapped.

Property, Plant and Equipment

12 Months Ended

Dec. 31, 2017

Property, Plant and Equipment [Abstract]

Property, Plant and Equipment

5. Property, Plant and Equipment

Property, plant and equipment as of December 31, 2017 and 2016 are comprised of the following (in thousands):


	December 31,
	2017			2016
Buildings and related structures	$	69,958		$	64,939
Machinery and equipment		308,713			255,618
Others		42,497			29,492

		421,168			350,049
Less: accumulated depreciation		(231,356	)		(184,521	)
Land		16,091			14,265

Property, plant and equipment, net	$	205,903		$	179,793

Aggregate depreciation expenses totaled $27,498 thousand and $24,941 thousand for the years ended December 31, 2017 and 2016, respectively.

In December 2017, a portion of the Company’s real estate was pledged as collateral in connection with a payment plan for taxes and penalties assessed by the Korean National Tax Service (the “KNTS”) as a result of a tax audit. For further description of the tax audit, see Note 17, “Income Taxes—Other Matter”.

Intangible Assets

12 Months Ended

Dec. 31, 2017

Goodwill and Intangible Assets Disclosure [Abstract]

Intangible Assets

6. Intangible Assets

Intangible assets as of December 31, 2017 and 2016 are comprised of the following (in thousands):


	December 31, 2017
	Gross amount		Accumulated amortization			Net amount
Technology	$	20,194	$	(20,194	)	$	—
Customer relationships		29,002		(29,002	)		—
Intellectual property assets		11,319		(7,258	)		4,061

Intangible assets, net	$	60,515	$	(56,454	)	$	4,061


	December 31, 2016
	Gross amount		Accumulated amortization			Net amount
Technology	$	17,903	$	(17,903	)	$	—
Customer relationships		25,712		(25,712	)		—
Intellectual property assets		9,026		(5,941	)		3,085

Intangible assets, net	$	52,641	$	(49,556	)	$	3,085

Aggregate amortization expense for intangible assets totaled $ 648 thousand and $475 thousand for the years ended December 31, 2017 and 2016, respectively. The aggregate amortization expense of intangible assets for the next five years are estimated to be $751 thousand, $748 thousand, $727 thousand, $690 thousand and $582 thousand, for the years ended December 31, 2018, 2019, 2020, 2021 and 2022, respectively.

- Definition

The entire disclosure for the aggregate amount of goodwill and a description of intangible assets, which may include (a) for amortizable intangible assets (also referred to as finite-lived intangible assets), the carrying amount, the amount of any significant residual value, and the weighted-average amortization period, (b) for intangible assets not subject to amortization (also referred to as indefinite-lived intangible assets), the carrying amount, and (c) the amount of research and development assets acquired and written off in the period, including the line item in the income statement in which the amounts written off are aggregated, if not readily apparent from the income statement. Also discloses (a) for amortizable intangibles assets in total and by major class, the gross carrying amount and accumulated amortization, the total amortization expense for the period, and the estimated aggregate amortization expense for each of the five succeeding fiscal years, (b) for intangible assets not subject to amortization the carrying amount in total and by major class, and (c) for goodwill, in total and for each reportable segment, the changes in the carrying amount of goodwill during the period (including the aggregate amount of goodwill acquired, the aggregate amount of impairment losses recognized, and the amount of goodwill included in the gain (loss) on disposal of a reporting unit). If any part of goodwill has not been allocated to a reportable segment, discloses the unallocated amount and the reasons for not allocating. For each impairment loss recognized related to an intangible asset (excluding goodwill), discloses: (a) a description of the impaired intangible asset and the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method for determining fair value, (c) the caption in the income statement or the statement of activities in which the impairment loss is aggregated, and (d) the segment in which the impaired intangible asset is reported. For each goodwill impairment loss recognized, discloses: (a) a description of the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method of determining the fair value of the associated reporting unit, and (c) if a recognized impairment loss is an estimate not finalized and the reasons why the estimate is not final. May also disclose the nature and amount of any significant adjustments made to a previous estimate of an impairment loss.

+ References + Details

Accrued Expenses

12 Months Ended

Dec. 31, 2017

Payables and Accruals [Abstract]

Accrued Expenses

7. Accrued Expenses

Accrued expenses as of December 31, 2017 and 2016 are comprised of the following (in thousands):


	December 31,
	2017		2016
Payroll, benefits and related taxes, excluding severance benefits	$	16,724	$	24,982
Withholding tax attributable to intercompany interest income		18,138		15,573
Interest on senior notes		8,268		6,831
Outside service fees		1,942		4,423
Others		6,674		8,556

Accrued expenses	$	51,746	$	60,365

On December 10, 2015, it was determined that the Company was obligated to make an aggregate settlement payment of $23,500 thousand, which includes all attorneys’ fees, costs of administration and plaintiffs’ out-of-pocket expenses, lead plaintiff compensatory awards and disbursements. In connection with the securities class action complaints, the Company also settled with its insurers and obtained proceeds of $29,571 thousand in the first quarter of 2016, and disbursed the $23,500 thousand from the escrow account, recorded as restricted cash, in the third quarter of 2016. For more information on the accrued claim settlement, see Note 19, “Commitments and Contingencies”.

Payroll, benefits and related taxes payable as of December 31, 2016 in the table above included unpaid other termination benefits under the voluntary resignation program of $1,392 thousand, the remaining balance of the $4,241 thousand total aggregate expense for such benefits accrued during the second quarter of 2016 and being paid out in equal monthly installments over the twelve month period which began in May 2016.

Derivative Financial Instruments

12 Months Ended

Dec. 31, 2017

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Derivative Financial Instruments

8. Derivative Financial Instruments

The Company’s Korean subsidiary from time to time has entered into zero cost collar and forward contracts to hedge the risk of changes in the functional-currency-equivalent cash flows attributable to currency rate changes on U.S. dollar denominated revenues.

Details of derivative contracts as of December 31, 2017 are as follows (in thousands):


Date of transaction	Type of derivative	Total notional amount		Month of settlement
June 22, 2017	Zero cost collar	$	20,000	January 2018 to February 2018
September 28, 2017	Zero cost collar	$	54,000	January 2018 to June 2018
September 28, 2017	Forward	$	36,000	January 2018 to June 2018

Details of derivative contracts as of December 31, 2016 are as follows (in thousands):

Date of transaction

Type of derivative

Total notional amount

Month of settlement

November 11, 2016

Zero cost collar

18,000

March to August 2017

The zero cost collar and forward contracts qualify as cash flow hedges under ASC 815, “Derivatives and Hedging,” since at both the inception of the contracts and on an ongoing basis, the hedging relationship was and is expected to be highly effective in achieving offsetting cash flows attributable to the hedged risk during the term of the contracts. The Company is utilizing the “hypothetical derivative” method to measure the effectiveness by comparing the changes in value of the actual derivative versus the change in fair value of the “hypothetical derivative.”

The fair values of the Company’s outstanding zero cost collar and forward contracts recorded as assets and liabilities as of December 31, 2017 and 2016 are as follows (in thousands):


Derivatives designated as hedging instruments:		December 31,
Derivatives designated as hedging instruments:		2017		2016
Asset Derivatives:
Zero cost collars	Other current assets	$	2,827	$	—
Forward	Other current assets	$	2,352	$	—
Liability Derivatives:
Zero cost collars	Other current liabilities	$	—	$	453

Offsetting of derivative assets as of December 31, 2017 is as follows (in thousands):


As of December 31, 2017	Gross amounts of recognized assets		Gross amounts offset in the balance sheets		Net amounts of assets presented in the balance sheets		Gross amounts not offset in the balance sheets				Net amount
As of December 31, 2017	Gross amounts of recognized assets		Gross amounts offset in the balance sheets		Net amounts of assets presented in the balance sheets		Financial instruments		Cash collateral pledged		Net amount
Asset Derivatives:
Zero cost collars	$	2,827	$	—	$	2,827	$	—	$	—	$	2,827
Forward	$	2,352	$	—	$	2,352	$	—	$	—	$	2,352

Offsetting of derivative liabilities as of December 31, 2016 is as follows (in thousands):


As of December 31, 2016	Gross amounts of recognized liabilities		Gross amounts offset in the balance sheets		Net amounts of liabilities presented in the balance sheets		Gross amounts not offset in the balance sheets					Net amount
As of December 31, 2016	Gross amounts of recognized liabilities		Gross amounts offset in the balance sheets		Net amounts of liabilities presented in the balance sheets		Financial instruments		Cash collateral pledged			Net amount
Liability Derivatives:
Zero cost collars	$	453	$	—	$	453	$	—	$	(650	)	$	(197	)

For derivative instruments that are designated and qualify as cash flow hedges, the effective portion of the gain or loss on the derivative is reported as a component of accumulated other comprehensive income (“AOCI”) and reclassified into earnings in the same period or periods during which the hedged transaction affects earnings. Gains and losses on the derivative, representing either hedge ineffectiveness or hedge components excluded from the assessment of effectiveness, are recognized in current earnings.

The following table summarizes the impact of derivative instruments on the consolidated statement of operations for the years ended December 31, 2017 and 2016 (in thousands):


Derivatives in ASC 815 Cash Flow Hedging Relationships	Amount of Gain (Loss) Recognized in AOCI on Derivatives (Effective Portion)					Location of Gain (loss) Reclassified from AOCI into Statement of Operations (Effective Portion)		Amount of Gain (loss) Reclassified from AOCI into Statement of Operations (Effective Portion)					Location of Gain (loss) Recognized in Statement of Operations on Derivative (Ineffective Portion)		Amount of Gain (loss) Recognized in Statement of Operations on Derivatives (Ineffective Portion)
	2017		2016					2017		2016					2017			2016
Zero cost collars	$	4,692	$	(1,032	)		Net sales	$	1,501	$	(637	)		Other income, net	$	606		$	(272	)
Forwards	$	3,044	$	—			Net sales	$	500	$	—			Other income, net	$	(370	)	$	—

Total	$	$7,736	$	(1,032	)			$	2,001	$	—				$	236		$	(272	)

As of December 31, 2017, the amount expected to be reclassified from accumulated other comprehensive income into income within the next twelve months is $5,299 thousand.

The Company set aside $7,600 thousand and $2,500 thousand of cash deposits to the counterparty, Nomura Financial Investment (Korea) Co., Ltd. (“NFIK”) as required for the zero cost collar and forward contracts outstanding as of December 31, 2017 and 2016, respectively. These cash deposits are recorded as hedge collateral on the consolidated balance sheets.

The Company is required to deposit additional cash collateral with NFIK for any exposure in excess of $500 thousand, and no such cash collateral was required as of December 31, 2017. As of December 31, 2016, $650 thousand of additional cash collateral was required and recorded as hedge collateral on the consolidated balance sheets. These outstanding zero cost collar and forward contracts are subject to termination if the sum of qualified and unrestricted cash and cash equivalents held by the Company is less than $30,000 thousand on the last day of a fiscal quarter.

Product Warranties

12 Months Ended

Dec. 31, 2017

Guarantees and Product Warranties [Abstract]

Product Warranties

9. Product Warranties

Changes in accrued warranty liabilities for the years ended December 31, 2017, 2016 and 2015 are as follows (in thousands):


	Year Ended December 31,
	2017			2016			2015
Beginning balance	$	466		$	1,425		$	2,973
Change in provision		(224	)		(426	)		(648	)
Usage		(65	)		(527	)		(758	)
Translation adjustments		39			(6	)		(142	)

Ending balance	$	216		$	466		$	1,425

Long-term Borrowings

12 Months Ended

Dec. 31, 2017

Debt Disclosure [Abstract]

Long-term Borrowings

10. Long-term Borrowings

Long-term borrowings as of December 31, 2017 and 2016 are as follows (in thousands):


	December 31,
	2017			2016
5.0% Exchangeable Senior Notes due March 2021	$	86,250		$	—
6.625% senior notes due July 2021	$	225,000		$	225,000
Less: unamortized discount and debt issuance costs		(7,834	)		(3,918	)

Long-term borrowings, net of unamortized discount and debt issuance costs	$	303,416		$	221,082

5.0% Exchangeable Senior Notes

On January 17, 2017, MagnaChip Semiconductor S.A. closed the Exchangeable Notes Offering of $86,250 thousand aggregate principal amount of 5.0% Exchangeable Notes. Interest on the Exchangeable Notes accrues at a rate of 5.0% per annum, payable semi-annually on March 1 and September 1 of each year, beginning on March 1, 2017. The Exchangeable Notes will mature on March 1, 2021, unless earlier repurchased or converted. Holders may convert their notes at their option at any time prior to the close of business on the business day immediately preceding the stated maturity date.

The Company used a portion of the net proceeds from the issuance to repurchase 1,795,444 shares of common stock under its stock repurchase program at an aggregate cost of $11,401 thousand.

Upon conversion, the Company will deliver for each $1,000 principal amount of converted notes a number of shares equally to the exchange rate, which will initially be 121.1387 shares of common stock per $1,000 principal amount of Exchangeable Notes, equivalent to an initial exchange price of approximately $8.26 per share of common stock. The exchange rate will be subject to adjustment in some circumstances, but will not be adjusted for any accrued and unpaid interest. In addition, if a “make-whole fundamental change” (as defined in the Exchangeable Notes indenture (the “Exchangeable Notes Indenture”)) occurs prior to the stated maturity date, the Company will increase the exchange rate for a holder who elects to convert its notes in connection with such make-whole fundamental change in certain circumstances. MagnaChip Semiconductor S.A. may also, under certain circumstances, be required to pay additional amounts to holders of Exchangeable Notes if withholding or deduction is required in a relevant tax jurisdiction.

If the Company undergoes a fundamental change, subject to certain conditions, holders may require the Company to repurchase for cash all or part of their notes at a purchase price equal to 100% of the principal amount of the notes to be repurchased, plus accrued and unpaid interest to, but excluding, the fundamental change purchase date. In addition, upon certain events of default described in the Exchangeable Notes Indenture, the trustee or holders of at least 25% principal amount of the Exchangeable Notes may declare 100% of the then outstanding Exchangeable Notes due and payable in full, together with all accrued and unpaid interest thereon. Payment of principal on the Exchangeable Notes may also accelerate and become automatically due and payable upon certain events of default involving bankruptcy or insolvency proceedings involving the Company, MagnaChip Semiconductor S.A. and their significant subsidiaries. The Exchangeable Notes are not redeemable at the option of MagnaChip Semiconductor S.A. prior to the maturity date.

The Exchangeable Notes Indenture contains covenants that limit the ability of the Company, MagnaChip Semiconductor S.A. and the Company’s other restricted subsidiaries to: (i) declare or pay any dividend or make any payment or distribution on account of or purchase or redeem the Company’s capital stock or equity interests of the restricted subsidiaries; (ii) make any principal payment on, or redeem or repurchase, prior to any scheduled repayment or maturity, any subordinated indebtedness; (iii) make certain investments; (iv) incur additional indebtedness and issue certain types of capital stock; (v) create or incur any lien (except for permitted liens) that secures obligations under any indebtedness; (vi) merge with or into or sell all or substantially all of the Company’s assets to other companies; (vii) enter into certain types of transactions with affiliates; (viii) guarantee the payment of any indebtedness; and (ix) designate unrestricted subsidiaries.

These covenants are subject to a number of exceptions and qualifications. Certain of these restrictive covenants will terminate if the Exchangeable Notes are rated investment grade at any time.

The Company incurred debt issuance costs of $5,902 thousand related to the issuance of the Exchangeable Notes. The debt issuance costs are recorded as a direct deduction from the long-term borrowings in the consolidated balance sheets and amortized to interest expense using the effective interest method over the term of the Exchangeable Notes. Interest expense related to the Exchangeable Notes for year ended December 31, 2017 was $5,349 thousand.

6.625% Senior Notes

On July 18, 2013, the Company issued a $225,000,000 aggregate principal amount of the 2021 Notes at a price of 99.5%. Interest on the 2021 Notes accrues at a rate of 6.625% per annum, payable semi-annually on January 15 and July 15 of each year, beginning on January 15, 2014.

The Company can optionally redeem all or a part of the 2021 Notes according to the following schedule: on or after July 15, 2017, the Company may on any one or more occasions redeem all or a part of the 2021 Notes, at a redemption price equal to 103.313%, 101.656% and 100% of the principal amount of the notes redeemed on or after July 15, 2017, 2018 and 2019, respectively, plus accrued and unpaid interest and special interest, if any, on the notes redeemed, to the applicable date of redemption.

The Indenture relating to the 2021 Notes contains covenants that limit the ability of the Company and its restricted subsidiaries to: (i) declare or pay any dividend or make any payment or distribution on account of or purchase or redeem the Company’s capital stock or equity interests of the restricted subsidiaries; (ii) make any principal payment on, or redeem or repurchase, prior to any scheduled repayment or maturity, any subordinated indebtedness; (iii) make certain investments; (iv) incur additional indebtedness and issue certain types of capital stock; (v) create or incur any lien (except for permitted liens) that secures obligations under any indebtedness; (vi) merge with or into or sell all or substantially all of the Company’s assets to other companies; (vii) enter into certain types of transactions with affiliates; (viii) guarantee the payment of any indebtedness; (ix) enter into sale-leaseback transactions; (x) enter into agreements that would restrict the ability of the restricted subsidiaries to make distributions with respect to their equity to the Company or other restricted subsidiaries, to make loans to the Company or other restricted subsidiaries or to transfer assets to the Company or other restricted subsidiaries; and (xi) designate unrestricted subsidiaries.

These covenants are subject to a number of exceptions and qualifications. Certain of these restrictive covenants will terminate if the 2021 Notes are rated investment grade at any time.

The Company incurred original issue discount of $1,125 thousand and debt issuance costs of $5,120 thousand related to the issuance of the 2021 Notes. The original issue discount and the debt issuance costs are recorded as a direct deduction from the long-term borrowings in the consolidated balance sheets and amortized to interest expense using the effective interest method over the term of the 2021 Notes. Interest expenses related to the 2021 Notes for the year ended December 31, 2017 and 2016 were $15,664 thousand and $15,613 thousand, respectively.

Accrued Severance Benefits

12 Months Ended

Dec. 31, 2017

Postemployment Benefits [Abstract]

Accrued Severance Benefits

11. Accrued Severance Benefits

The majority of accrued severance benefits are for employees in the Company’s Korean subsidiary. Pursuant to the Employee Retirement Benefit Security Act of Korea, eligible employees and executive officers with one or more years of service are entitled to severance benefits upon the termination of their employment based on their length of service and rate of pay. As of December 31, 2017, 98% of all employees of the Company were eligible for severance benefits.

Changes in accrued severance benefits are as follows (in thousands):


	Year Ended December 31,
	2017			2016
Beginning balance	$	130,144		$	135,160
Provisions		24,373			14,432
Severance payments		(21,506	)		(15,352	)
Translation adjustments		16,785			(4,096	)

		149,796			130,144
Less: Cumulative contributions to the National Pension Fund		(259	)		(276	)
Group severance insurance plan		(632	)		(643	)

Accrued severance benefits, net	$	148,905		$	129,225

The severance benefits funded through the Company’s National Pension Fund and group severance insurance plan will be used exclusively for payment of severance benefits to eligible employees. These amounts have been deducted from the accrued severance benefit balance.

The Company is liable to pay the following future benefits to its non-executive employees upon their normal retirement age (in thousands):


	Severance Benefit
2018	$	—
2019		610
2020		1,094
2021		1,573
2022		1,584
2023 – 2027		20,541

The above amounts were determined based on the non-executive employees’ current salary rates and the number of service years that will be accumulated upon their retirement dates. These amounts do not include amounts that might be paid to non-executive employees that will cease working with the Company before their normal retirement ages.

The above table reflects an effect of a mandatory extension of retirement age in Korea from 57 to 60 under the Employment Promotion for the Aged Act effective from the beginning of 2016.

Common Stock

12 Months Ended

Dec. 31, 2017

Equity [Abstract]

Common Stock

12. Common Stock

Common stock par value $0.01 per share, was authorized in the amount of 150,000 thousand shares, of which 42,564 thousand shares were issued and 34,190 thousand shares were outstanding as of December 31, 2017.

Changes in common stock for each period are as follows (in thousands):


	Year Ended December 31,
	2017					2016
	Shares			Amount		Shares		Amount
Common stock at the beginning of the period		35,048,338		$	416		34,568,942	$	411
Exercise of stock options		539,183			6		296,103		3
Settlement of restricted stock units		397,522			4		183,293		2
Acquisitions of treasury stock		(1,795,444	)		—		—		—

Total common stock outstanding at the end of the period		34,189,599		$	426		35,048,338	$	416

Equity Incentive Plans

12 Months Ended

Dec. 31, 2017

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Equity Incentive Plans

13. Equity Incentive Plans

The Company adopted its 2009 Common Unit Plan, or the 2009 Plan, effective December 8, 2009, which is administered by the Compensation Committee of the Company’s Board of Directors (the “Compensation Committee”). The 2009 Plan terminated in connection with the Company’s initial public offering in March 2011, and no additional options or other equity awards may be granted under the 2009 Plan. However, options granted under the 2009 Plan prior to its termination will remain outstanding until they are either exercised or expire. The Company adopted its 2011 Equity Incentive Plan, or the 2011 Plan, in March 2010. The Company amended and restated the 2011 Plan in February 2011, and the Company’s stockholders approved the amendment in March 2011 to reflect that it became effective in 2011 in connection with the Company’s initial public offering in March 2011. The 2011 Plan was amended on October 23, 2017, to revise the clawback policy of the 2011 Plan. Awards may be granted under the 2011 Plan to the Company’s employees, officers, directors, or consultants or those of any present or future parent or subsidiary corporation or other affiliated entity. While the Company may grant incentive stock options only to employees, the Company may grant nonstatutory stock options, stock appreciation rights, restricted stock purchase rights or bonuses, restricted stock units, performance shares, performance units and cash-based awards or other stock-based awards to any eligible participant, subject to terms and conditions determined by the Compensation Committee. The term of options shall not exceed ten years from the date of grant. Restricted stock purchase rights shall be exercisable within a period established by the Compensation Committee, which shall in no event exceed thirty days from the effective date of the grant. As of December 31, 2017, an aggregate maximum of 7,975 thousand shares were authorized and 1,104 thousand shares were reserved for all future grants.

Stock options and stock appreciation rights must have exercise prices at least equal to the fair market value of the stock at the time of their grant pursuant to the 2011 Plan. The requisite service period, or the period during which a grantee is required to provide service in exchange for option grants, coincides with the vesting period. Stock options typically vest over one to three years following grant.

Restricted stock units granted under the 2011 Plan represent a right to receive shares of the Company’s common stock when the restricted stock unit vests. No monetary payment (other than applicable tax withholding) shall be required as a condition of receiving shares pursuant to a restricted stock unit, the consideration for which shall be services actually rendered to a participating company or for its benefit. Stock issued pursuant to any restricted stock unit may (but need not) be made subject to vesting conditions based upon the satisfaction of such service requirements, conditions, restrictions or performance criteria as shall be established by the Compensation Committee and set forth in the award agreement evidencing such award. Restricted stock units typically vest over one to three years following grant.

The purchase price for shares issuable under each restricted stock purchase right shall be established by the Compensation Committee in its discretion. No monetary payment (other than applicable tax withholding) shall be required as a condition of receiving shares pursuant to a restricted stock bonus, the consideration for which shall be services actually rendered to a participating company or for its benefit. Stock issued pursuant to any restricted stock award may (but need not) be made subject to vesting conditions based upon the satisfaction of such service requirements, conditions, restrictions or performance criteria as shall be established by the Compensation Committee and set forth in the award agreement evidencing such award. During any period in which stock acquired pursuant to a restricted stock award remain subject to vesting conditions, such stock may not be sold, exchanged, transferred, pledged, assigned or otherwise disposed of other than pursuant to an ownership change event or transfer by will or the laws of descent and distribution. The grantee shall have all of the rights of a stockholder of the Company holding stock, including the right to vote such stock and to receive all dividends and other distributions paid with respect to such stock; provided, however, that if so determined by the Compensation Committee and provided by the award agreement, such dividends and distributions shall be subject to the same vesting conditions as the stock subject to the restricted stock award with respect to which such dividends or distributions were paid. If a grantee’s service terminates for any reason, whether voluntary or involuntary (including the grantee’s death or disability), then (a) the Company (or its assignee) has the option to repurchase for the purchase price paid by the grantee any stock acquired by the grantee pursuant to a restricted stock purchase right which remain subject to vesting conditions as of the date of the grantee’s termination of service and (b) the grantee shall forfeit to the Company any stock acquired by the grantee pursuant to a restricted stock bonus which remain subject to vesting conditions as of the date of the grantee’s termination of service. The Company has the right to assign at any time any repurchase right it may have, whether or not such right is then exercisable, to one or more persons as may be selected by the Company.

The following summarizes restricted stock unit activities for the years ended December 31, 2017, 2016 and 2015.


	Number of Restricted Stock Units			Weighted Average Grant-Date Fair Value of Restricted Stock Units
Outstanding at January 1, 2015		—		$	—
Granted		265,332			7.68
Vested		(129,962	)		7.64

Outstanding at December 31, 2015		135,370		$	7.72

Granted		505,689			5.71
Vested		(101,240	)		7.09
Forfeited		(21,339	)		6.24

Outstanding at December 31, 2016		518,480		$	5.94

Granted		172,716			11.15
Vested		(368,555	)		5.72
Forfeited		(830	)		8.33

Outstanding at December 31, 2017		321,811		$	8.99

Total compensation expenses recorded for the restricted stock units were $1,601 thousand, $2,292 thousand and $1,400 thousand for the years ended December 31, 2017, 2016 and 2015, respectively. As of December 31, 2017, there was $ 1,364 thousand of total unrecognized compensation cost related to unvested restricted stock units, which is expected to be recognized over a weighted average future period of 0.8 years. Total fair value of restricted stock units vested were $2,107 thousand, $717 thousand and $993 thousand for the years ended December 31, 2017, 2016 and 2015, respectively.

The following summarizes stock option activities for the years ended December 31, 2017, 2016 and 2015. At the date of grant, all options had an exercise price not less than the fair value of common stock (aggregate intrinsic value in thousands):


	Number of Options			Weighted Average Exercise Price of Stock Options		Aggregate Intrinsic Value of Stock Options		Weighted Average Remaining Contractual Life of Stock Options
Outstanding at January 1, 2015		3,215,945		$	9.60	$	39,615		6.6 years
Granted		802,193			7.92		—		—
Forfeited		(325,765	)		9.88		—		—
Exercised		(512,474	)		6.70		692		—

Outstanding at December 31, 2015		3,179,899		$	9.61	$	—		6.7 years

Vested and expected to vest at December 31, 2015		3,155,828			9.62		—		6.7 years
Exercisable at December 31, 2015		2,547,902			9.63		—		6.0 years

Outstanding at January 1, 2016		3,179,899		$	9.61	$	—		6.7 years
Granted		827,406			6.04		—		—
Forfeited		(282,537	)		7.67		—		—
Exercised		(296,103	)		5.85		806		—

Outstanding at December 31, 2016		3,428,665		$	9.23	$	525		6.7 years

Vested and expected to vest at December 31, 2016		3,389,763			9.27		508		6.7 years
Exercisable at December 31, 2016		2,531,243			10.11		236		5.9 years

Outstanding at January 1, 2017		3,428,665		$	9.23	$	525		6.7 years
Granted		70,865			10.43		—		—
Forfeited		(88,443	)		12.77		—		—
Exercised		(539,183	)		6.94		1,540		—

Outstanding at December 31, 2017		2,871,904		$	9.59	$	6,073		6.2 years

Vested and expected to vest at December 31, 2017		2,865,475			9.59		6,050		6.2 years
Exercisable at December 31, 2017		2,395,979			10.11		4,603		5.7 years

Total compensation expenses recorded for the stock options were $734 thousand, $1,551 thousand and $1,368 thousand for the years ended December 31, 2017, 2016 and 2015, respectively. As of December 31, 2017, there was $339 thousand of total unrecognized compensation cost related to unvested stock options, which is expected to be recognized over a weighted average future period of 0.6 years. Total weighted average grant-date fair value of vested options was $794 thousand, $1,011 thousand and $1,361 thousand for the years ended December 31, 2017, 2016 and 2015, respectively.

The Company utilizes the Black-Scholes option-pricing model to measure the fair value of each option grant. The following summarizes the grant-date fair value of options granted for the years ended December 31, 2017, 2016 and 2015 and assumptions used in the Black-Scholes option-pricing model on a weighted average basis. For the year ended December 31, 2017, the expected volatility was estimated using historical volatility of the Company’s share prices. For the years ended December 31, 2016 and 2015, it was based on historical volatility of share prices of similar public entities:


	Year Ended December 31,
	2017			2016			2015
Grant-date fair value of option	$	5.02		$	1.54		$	1.67
Expected term		2.5 Years			2.7 Years			2.4 Years
Risk-free interest rate		1.2	%		1.0	%		0.8	%
Expected volatility		81.7	%		36.8	%		33.8	%
Expected dividends		—			—			—

The number and weighted average grant-date fair value of the unvested stock options are as follows:


	Year Ended December 31,
	2017					2016					2015
	Number			Weighted Average Grant- Date Fair Value		Number			Weighted Average Grant- Date Fair Value		Number			Weighted Average Grant- Date Fair Value
Unvested options at the beginning of the period		897,421		$	1.72		631,997		$	2.40		455,543		$	4.18
Granted options during the period		70,865			5.02		827,406			1.54		802,193			1.67
Vested options during the period		(455,301	)		1.74		(446,570	)		2.26		(532,682	)		2.56
Forfeited options during the period		(19,031	)		1.77		(85,934	)		1.88		(92,959	)		4.01
Exercised options during the period		(18,029	)		1.59		(29,478	)		1.24		(98	)		3.08

Unvested options at the end of the period		475,925		$	2.19		897,421		$	1.72		631,997		$	2.40

Restructuring and Other Charges (Gain), Net	12 Months Ended
Restructuring and Other Charges (Gain), Net	Dec. 31, 2017
Restructuring and Related Activities [Abstract]
Restructuring and Other Charges (Gain), Net	14. Restructuring and Other Charges (Gain), Net As of December 21, 2016, the Company entered into a purchase and sale agreement to sell a building located in Cheongju, South Korea. The building has historically been used to house the Company’s six-inch fabrication facility in Cheongju, South Korea (the “6-inch fab”) and became vacant upon the closure of the fabrication facility in February 2016. As of December 31, 2015, the building was fully impaired. The Company received proceeds of $18,204 thousand, including a $1,655 thousand value-added tax, for the sale of the building in December 2016. As the Company was obligated to perform certain removal construction work, it recorded the $18,204 thousand proceeds as restricted cash and $16,549 thousand as deposits received in its consolidated balance sheets as of December 31, 2016. During the first quarter of 2017, the Company completed all removal construction work necessary to transfer the title of the building, and the $18,204 thousand of restricted cash was fully released. Accordingly, the Company recorded $16,635 thousand as restructuring gain in the consolidated statements of operations for the three months ended March 31, 2017. In March 2017, the Company sold its sensor product business, which was included in and reported as part of Display Solutions line of its Standard Products Group, to a third party for proceeds of $1,295 thousand, in an effort to improve our overall profitability. The Company recorded $375 thousand net gain from this sale after deducting the book values of certain assets transferred to the buyer. During the first quarter of 2016, the Company completed all procedures necessary to sell all machineries in its closed 6-inch fab and recognized the $7,785 thousand of restructuring gain from the related deposit of $8,165 thousand received as of December 31, 2015, net of certain direct selling costs.

Early Termination Charges	12 Months Ended
Early Termination Charges	Dec. 31, 2017
Restructuring and Related Activities [Abstract]
Early Termination Charges	15. Early Termination Charges As of February 22, 2017, the Company’s Board of Directors approved the implementation of a new headcount reduction plan (the “Headcount Reduction Plan”). As of June 30, 2017, 352 employees elected to resign from the Company during the period in which the Headcount Reduction Plan was offered. The total cash cost of approximately $31 million has been fully paid. The Company recorded in its consolidated statement of operations $11,107 thousand and $2,262 thousand in termination related charges as early termination charges for the three months ended March 31, 2017 and June 30, 2017, respectively. The remaining total estimated cost relates to statutory severance benefits, which are required by law and have already been fully accrued in the Company’s financial statements.

Foreign Currency Gain (Loss), Net	12 Months Ended
Foreign Currency Gain (Loss), Net	Dec. 31, 2017
Foreign Currency [Abstract]
Foreign Currency Gain (Loss), Net	16. Foreign Currency Gain (Loss), Net Net foreign currency gain or loss includes non-cash translation gain or loss associated with intercompany balances. A substantial portion of the Company’s net foreign currency gain or loss is non-cash translation gain or loss associated with intercompany long-term loans to our Korean subsidiary. The loans are denominated in U.S. dollars and are affected by changes in the exchange rate between the Korean won and the U.S. dollar. As of December 31, 2017, 2016 and 2015, the outstanding intercompany loan balances including accrued interest between the Korean subsidiary and the Dutch subsidiary were $677,267 thousand, $598,212 thousand and $591,388 thousand, respectively. The Korean won to U.S. dollar exchange rates were 1,071.4:1, 1,208.5:1 and 1,172.0:1 using the first base rate as of December 31, 2017, 2016 and 2015, respectively, as quoted by the KEB Hana Bank.

Income Taxes

12 Months Ended

Dec. 31, 2017

Income Tax Disclosure [Abstract]

Income Taxes

17. Income Taxes

The Company’s income tax expenses are composed of domestic and foreign income taxes depending on the relevant tax jurisdictions. Domestic income (loss) before taxes and income tax expenses are generated or incurred in the United States, where the parent company resides.

The components of income tax expense are as follows (in thousands):


	Year Ended December 31,
	2017			2016			2015
Income (loss) before income taxes
Domestic	$	27,461		$	(1,738	)	$	32,903
Foreign		58,630			(24,133	)		(132,857	)

	$	86,091		$	(25,871	)	$	(99,954	)

Current income taxes expense (benefit)
Domestic	$	(359	)	$	(6	)	$	25
Foreign		3,680			3,386			(14,301	)
Uncertain tax position liability (domestic)		(476	)		12			10
Uncertain tax position liability (foreign)		(1,635	)		339			(1,220	)

		1,210			3,731			(15,486	)

Deferred income taxes expense (benefit)
Foreign		(55	)		13			399

Total income tax expense (benefit)	$	1,155		$	3,744		$	(15,087	)

Effective tax rate		1.3	%		(14.5	)%		15.1	%

The differences between the annual effective tax rates and the U.S. federal statutory rate of 35.0% primarily result from the non-income based withholding tax attributable to intercompany interest income of the Company’s Dutch subsidiary, application of lower tax rates associated with certain earnings from the Company’s operations outside the U.S., the parent Company’s interest income, which is non-taxable for US tax purposes and the change of deferred tax assets and valuation allowance. The statutory income tax rate of the Company’s Korean operating subsidiary was approximately 24.2% in 2017, 2016 and 2015.

The decrease in income tax expense in 2017 was primarily attributable to a decrease in the Company’s uncertain tax positions. The significant increase in income tax expense in 2016 is related to the reversal of withholding tax payable with respect to the waiver of the accrued interest on the loans granted to our Korean subsidiary by our Dutch subsidiary in 2015. The Company’s Korean and Dutch subsidiaries agreed that the Company’s Dutch subsidiary waived and released a partial amount of unpaid interest of $174 million on its intercompany loans granted to the Company’s Korean subsidiary in order to decrease the cumulative losses of the Company’s Korean subsidiary to enhance the subsidiary’s credit standing under the local banking rules. This transaction created a taxable income for the Company’s Korean subsidiary but did not result in a liability because of the utilization of expired loss carryforwards, which is deductible only against gains from cancellation of debt. The loss was not tax deductible for the Company’s Dutch subsidiary. This transaction also resulted in taxable loss for the Company’s Luxemburg subsidiary and this tax benefit was offset by an increase in the change in valuation allowance. In connection with the waiver of unpaid interest, the related withholding tax was reversed, resulting in the recognition of income tax benefit of $17.8 million as of December 31, 2015.

The provision for domestic and foreign income taxes incurred is different from the amount calculated by applying the statutory tax rate to the net income before income taxes. The significant items causing this difference are as follows (in thousands):


	Year Ended December 31,
	2017			2016			2015
Provision computed at statutory rate	$	30,223		$	(9,055	)	$	(34,984	)
Change in statutory tax rates		13,438			—			—
Difference in foreign tax rates		(12,344	)		1,995			24,359
Permanent differences
Derivative assets adjustment		1,937			(149	)		(143	)
TPECs, hybrid and other interest		(7,526	)		(10,353	)		(27,273	)
Permanent impairment		—			—			(62,334	)
Thin capitalization		1,888			2,120			2,457
Permanent foreign currency gain (loss)		(838	)		(54	)		11,575
Penalty		4,001			689			—
Non-deductible bad debt expense		—			—			89
Other permanent differences		633			50			(69	)
Withholding tax		3,339			3,092			(14,457	)
Foreign exchange rate adjustment		16,075			(1,838	)		(8,954	)
Change in valuation allowance		(56,744	)		10,095			95,757
Tax credits claimed		(659	)		(706	)		(875	)
Tax credits expired		2,638			1,578			—
Uncertain tax positions liability		(2,111	)		351			(1,211	)
Change in net operating loss carry-forwards		6,878			—			—
Others		327			5,929			976

Income tax expense (benefit)	$	1,155		$	3,744		$	(15,087	)

The tax expense of $13,438 thousand in 2017 due to change in statutory tax rates was primarily related to a remeasurement of deferred tax assets and liabilities using the reduced U.S. federal statutory rate of 21.0% from 35.0% effective January 1, 2018. For further description of the rate change, see “United States Tax Reform” below.

The $4,001 thousand tax impact of the penalty in 2017 was related to the $3,000 thousand civil penalty imposed by the SEC as discussed in Note 19, “Commitments and Contingencies—SEC Enforcement Staff Review”, and certain taxes and penalties assessed by the KNTS as a result of a tax audit as discussed in “Other Matter” below. The change in net operating loss carry-forwards of $6,878 thousand in 2017 was attributable to the Company’s revised tax positions, which primarily related to periods with respect to which the Company previously restated its financial statements as a result of the independent investigation commenced by the Company’s Audit Committee in January 2014 (the “Restatement”).

The permanent differences above include non-taxable Tracking Preferred Equity Certificates (TPECs) and interest income from other financial instruments for US tax purposes and non-deductible interest expense according to the thin capitalization rule for Korean tax purposes. The permanent impairment of $62,334 thousand in 2015 was related to the loss recognized by the Company’s Luxemburg subsidiary in connection with the cancellation of debt as described above, which was not recognized for US tax purposes.

A summary of the composition of net deferred income tax assets (liabilities) as of December 31, 2017 and 2016 are as follows (in thousands):


	Year-Ended December 31,
	2017			2016
Deferred tax assets
Inventory reserves	$	1,630		$	1,822
Derivative assets		(1,253	)		110
Accrued expenses		2,826			2,803
Product warranties		52			113
Other reserves		356			372
Property, plant and equipment		9,759			13,314
Intangible assets		35			103
Accumulated severance benefits		36,245			31,478
Foreign currency translation losses		20,067			53,130
NOL carry-forwards		175,543			167,590
Tax credit		20,583			20,249
Other long-term payable		1,801			2,079
Others		3,546			4,885

Total deferred tax assets		271,190			298,048
Less: Valuation allowance		(251,132	)		(281,473	)

		20,058			16,575


Deferred tax liabilities
Foreign currency translation gains		18,187			14,338
Prepaid expense		1,464			1,644
Others		143			410

Total deferred tax liabilities		19,794			16,392

Net deferred tax assets	$	264		$	183

Reported as
Current deferred income tax assets	$	—		$	37
Non-current deferred income tax assets	$	264		$	193
Current deferred income tax liabilities	$	—		$	(46	)
Non-current deferred income tax liabilities	$	—		$	(1	)

The valuation allowances at December 31, 2017 and 2016 are primarily attributable to deferred tax assets for the uncertainty in taxable income at certain of the Company’s foreign subsidiaries, including its Korean operating subsidiary.

Changes in valuation allowance for deferred tax assets for the years ended December 31, 2017, 2016 and 2015 are as follows (in thousands):


	Year Ended December 31,
	2017			2016			2015
Beginning balance	$	281,473		$	279,867		$	194,739
Charged to expense		(54,816	)		10,095			95,757
NOL/tax credit claimed/expired		(1,928	)		(872	)		(1,197	)
Translation adjustments		26,403			(7,617	)		(9,432	)

Ending balance	$	251,132		$	281,473		$	279,867

The evaluation of the recoverability of the deferred tax asset and the need for a valuation allowance requires the Company to weigh all positive and negative evidence to reach a conclusion that it is more likely than not that all or some portion of the deferred tax asset will not be realized. The weight given to the evidence is commensurate with the extent to which it can be objectively verified. The more negative evidence that exists, the more positive evidence is necessary and the more difficult it is to support a conclusion that a valuation allowance is not needed. Realization of the future tax benefits related to the deferred tax assets is dependent on many factors, including the Company’s ability to generate future taxable income within the period during which the temporary differences reverse, the outlook for the economic environment in which the Company operates and the overall future industry outlook.

As of December 31, 2017, 2016 and 2015, the Company had net deferred tax assets of $264 thousand, $183 thousand and $171 thousand, respectively, related to the Company’s Japanese subsidiary. As of December 31, 2017, 2016 and 2015, the Company recorded a valuation allowance of $251,132 thousand, $281,473 thousand and $279,867 thousand on its deferred tax assets related to temporary differences, net operating loss carry-forwards and tax credits of domestic and foreign subsidiaries. The Company recorded these valuation allowances on deferred tax assets based on its assessment that the negative evidence of expected losses in early future years outweighs the positive evidence of historical income.

As of December 31, 2017, the Company had approximately $770,233 thousand of net operating loss carry-forwards available to offset future taxable income, of which $281,383 thousand is associated with the Company’s Korean subsidiary, which expires in part at various dates through 2026. The net operating loss of $310,975 thousand associated with the Company’s Luxembourg subsidiary is mainly attributable to certain expenses incurred in connection with its shareholding in the Company’s Dutch subsidiary. Although this net operating loss amount is carried forward indefinitely, it will be recaptured on future capital gain. The remaining net operating loss mainly relates to the US parent company and its domestic subsidiary, which expires in part at various dates through 2037. The Company utilized net operating loss of $417 thousand, $279 thousand and $121 thousand, for the years ended December 31, 2017, 2016 and 2015, respectively. The Company also has Korean, Dutch and U.S. tax credit carry-forwards of approximately $5,639 thousand, $14,936 thousand and $9 thousand, respectively, as of December 31, 2017. The Korean tax credits expire at various dates starting from 2018 to 2022, and the Dutch tax credits are carried forward to be used for an indefinite period of time.

United States Tax Reform

On December 22, 2017, H.R. 1, originally known as the Tax Cuts and Jobs Act in the U.S. was enacted (the “Tax Reform”). The Tax Reform reduces the U.S. federal statutory rate to 21.0% from 35.0% effective January 1, 2018. The Tax Reform contains several key provisions that might affect the Company’s assessment on its deferred taxes as of December 31, 2017, which include the remeasurement of deferred taxes, recognition of liabilities for taxes on mandatory deemed repatriation and certain other foreign income, and reassessment of the realizability of deferred tax assets. ASC 740 requires that the effects of changes in tax rates and laws are recognized in the period in which the new legislation is enacted.

As of December 31, 2017, the Company remeasured its deferred tax assets and liabilities at the reduced rate of 21.0%, assessed the realizability of remeasured deferred tax assets, which resulted in a reduction of its net deferred tax assets by $13,438 thousand. However, there was no net impact on the Company’s income tax expense due to a full allowance against the deferred tax assets. In addition, the Company recorded a tax benefit of $381 thousand due to certain minimum tax amounts being refundable under the Tax Reform. The Company is currently evaluating the newly enacted rule relating to the mandatory deemed repatriation tax.

Uncertainty in Income Taxes

The Company and its subsidiaries file income tax returns in Korea, Japan, Taiwan, the U.S. and in various other jurisdictions. The Company is subject to income- or non-income tax examinations by tax authorities of these jurisdictions for all open tax years.

A tabular reconciliation of the total amounts of unrecognized tax benefits at the beginning and end of each period is as follows (in thousands):


	Year Ended December 31,
	2017			2016			2015
Unrecognized tax benefits, balance at the beginning	$	2,459		$	2,139		$	3,495
Additions based on tax positions related to the current year		10			371			351
Additions (reductions) for tax positions of prior years		(676	)		317			(135	)
Lapse of statute of limitations		(735	)		(670	)		(1,318	)
Additions (reductions) of interest and penalties		(712	)		334			(108	)
Translation adjustments		137			(32	)		(146	)

Unrecognized tax benefits, balance at the ending	$	483		$	2,459		$	2,139

For the year ended December 31, 2017, the Company recorded $676 thousand income tax benefit by reversing a withholding tax payable related to interests on intercompany balances as a result of the tax audit as discussed in “Other Matter” below. The Company also recorded a reduction of $712 thousand of interest and penalties in 2017, primarily due to a change in certain tax regulations at the Company’s subsidiary in Taiwan. Total interest and penalties accrued as of December 31, 2017, 2016 and 2015 were $8 thousand, $691 thousand and $359 thousand, respectively.

A tabular reconciliation of the total amounts of uncertain tax positions at the beginning and end of each period is as follows (in thousands):


	Year Ended December 31,
	2017			2016			2015
Uncertain tax positions, balance at the beginning	$	11,894		$	13,330		$	14,969
Additions based on tax positions related to the current year		(366	)		942			1,789
Additions (reductions) for tax positions of prior years		(8,923	)		317			—
Lapse of statute of limitations		(2,218	)		(2,380	)		(2,142	)
Translation adjustments		675			(315	)		(1,287	)

Uncertain tax positions, balance at the ending	$	1,062		$	11,894		$	13,330

Other Matter

In September 2017, the Company’s Korean subsidiary was notified that the KNTS would be examining its income- and non-income-based taxes for its 2012 to 2014 tax years. The KNTS conducted its audit, primarily focusing on non-income-based VAT transactions associated with the Restatement periods.

As a result, the aggregate tax and penalty assessment by the KNTS was $6,030 thousand, of which $3,336 thousand had already been accrued by the Company in its financial statements in connection with the Restatement filed in 2015. Such amount also included $548 thousand related to employee withholding amounts and associated penalties, and to the extent any such tax obligation was that of the Company’s Korean subsidiary’s employees, the Company expects to seek reimbursement of the applicable amounts from those employees. In addition, KNTS assessed an administrative fine of $2,034 thousand in connection with the above-described tax audit.

During the fourth quarter of 2017, the Company recorded the $4,179 thousand related to this additional tax assessment and associated penalties and administrative fine as selling, general and administrative expenses in its consolidated statements of operations for the year ended December 31, 2017 and recorded the $548 thousand related to employee withholding amounts as other receivables in our consolidated balance sheets as of December 31, 2017 as the Company expects to seek reimbursement of the applicable amounts from those employees.

Geographic and Segment Information

12 Months Ended

Dec. 31, 2017

Segment Reporting [Abstract]

Geographic and Segment Information

18. Geographic and Segment Information

The Company had previously reported its results of operations under one operating segment. During the second quarter of 2015, organizational changes were made to (i) realign the Company’s businesses and organizational structure and (ii) streamline and consolidate certain business processes to achieve greater operating efficiencies. In furtherance of these objectives, the Company combined its Display Solutions and Power Solutions business lines into a new segment called Standard Products Group. Beginning in the second quarter of 2015, the Company began reporting its financial results in two operating segments: Semiconductor Manufacturing Services and Standard Products Group. During the third quarter of 2015, the Company changed the name of its Semiconductor Manufacturing Services segment to Foundry Services Group. The Company’s chief operating decision maker is its Chief Executive Officer who allocates resources and assesses performance of the business and other activities based on gross profit. The two newly established operating segments were managed prospectively and all prior period amounts related to the segment change have been retrospectively reclassified to conform to the new presentation.

The following sets forth information relating to the operating segments (in thousands):


	Year Ended December 31,
	2017		2016		2015
Net Sales
Foundry Services Group	$	320,089	$	273,961	$	290,775
Standard Products Group
Display Solutions		209,539		281,967		207,480
Power Solutions		149,836		131,468		134,814

Total Standard Products Group		359,375		413,435		342,294
All other		208		573		643

Total net sales	$	679,672	$	687,969	$	633,712


	Year Ended December 31,
	2017		2016			2015
Gross Profit
Foundry Services Group	$	95,458	$	69,412		$	66,175
Standard Products Group		92,227		87,194			68,094
All other		208		(380	)		595

Total gross profit	$	187,893	$	156,226		$	134,864

The following is a summary of net sales by geographic region, based on the location to which the products are billed (in thousands):


	Year Ended December 31,
	2017		2016		2015
Korea	$	279,883	$	219,618	$	241,715
Asia Pacific (other than Korea)		322,595		391,875		316,562
U.S.A.		35,089		33,201		51,164
Europe		41,109		42,274		23,461
Others		996		1,001		810

Total	$	679,672	$	687,969	$	633,712

Net sales from the Company’s top ten largest customers accounted for 57%, 64% and 64% for the years ended December 31, 2017, 2016 and 2015, respectively.

For the year ended December 31, 2017, the Company had one customer that represented 15.6% of its net sales. For the year ended December 31, 2016, the Company had two customers that represented 23.5% and 11.4% of its net sales, respectively. For the year ended December 31, 2015, the Company had two customers that represented 15.2% and 11.0% of its net sales, respectively.

97% of the Company’s property, plant and equipment are located in Korea as of December 31, 2017.

Commitments and Contingencies

12 Months Ended

Dec. 31, 2017

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

19. Commitments and Contingencies

Operating Agreements with SK Hynix

In connection with the acquisition of the non-memory semiconductor business from SK Hynix on October 4, 2004 (the “Original Acquisition”), the Company entered into several agreements with SK Hynix, including a non-exclusive cross license that provides the Company with access to certain of SK Hynix’s intellectual property for use in the manufacture and sale of non-memory semiconductor products. The Company also agreed to provide certain utilities and infrastructure support services to SK Hynix.

Upon the closing of the Original Acquisition, the Company’s Korean subsidiary and SK Hynix also entered into lease agreements under which the Company’s Korean subsidiary leases space to SK Hynix in several buildings, primarily warehouses and utility facilities, in Cheongju, Korea. These leases are generally for an initial term of 20 years plus an indefinite number of renewal terms of 10 years each. Each of the leases is cancelable upon 90 days’ notice by the lessee. The Company also leases certain land from SK Hynix located in Cheongju, Korea. The term of this lease is indefinite unless otherwise agreed by the parties, and as long as the buildings remain on the lease site and are owned and used by the Company for permitted uses.

Operating Leases

The Company leases land, office space and equipment under various operating lease agreements with various terms. Rental expenses were approximately $7,498 thousand, $8,898 thousand and $8,194 thousand for the years ended December 31, 2017, 2016 and 2015, respectively.

As of December 31, 2017, the minimum aggregate rental payments due under non-cancelable lease contracts are as follows (in thousands):


2018	$	6,724
2019		3,764
2020		3,459
2021		1,472
2022		1,316
2023 and thereafter		15,448

	$	32,183

Long-term Purchase Agreements

The Company purchases raw materials from a variety of vendors. During the normal course of business, in order to manage manufacturing lead times and help assure adequate supply, the Company from time to time may enter into multi-year purchase agreements, which specify future quantities and pricing of materials to be supplied by the vendors. The Company reviews the terms of the long-term supply agreements and assesses the need for any accrual for estimated losses, such as lower of cost or net realizable value that will not be recovered by future sales prices. No such accrual was required as of December 31, 2017.

SEC Enforcement Staff Review

In March 2014, the Company voluntarily reported to the Securities and Exchange Commission, or the SEC, that the Company’s Audit Committee had determined that the Company incorrectly recognized revenue on certain transactions and as a result would restate its financial statements, and that the Audit Committee had commenced an independent investigation. Over the course of 2014 and the first two quarters of 2015, the Company voluntarily produced documents to the SEC regarding the various accounting issues identified during the independent investigation, and whether the Company’s hiring of an accountant from the Company’s independent registered public accounting firm impacted that accounting firm’s independence. On July 22, 2014, the Staff of the SEC’s Division of Enforcement obtained a Formal Order of Investigation. On March 12, 2015, the SEC issued a subpoena for documents to the Company in connection with its investigation. On May 1, 2017, the SEC announced that it had reached a final settlement with the Company, resolving the SEC’s investigation. In that connection, the Company has consented, without admitting or denying the SEC’s findings, to the entry of an administrative order by the SEC directing that the Company cease and desist from committing or causing any violations of certain provisions of the federal securities laws and related SEC regulations. The SEC’s administrative order was entered on May 1, 2017. The SEC imposed a monetary penalty of $3,000 thousand on the Company. In the first quarter ended March 31, 2017, the Company established a reserve in that amount for the potential settlement of this matter. The reserved monetary penalty of $3,000 thousand was paid to the SEC during the second quarter of 2017. The Company also agreed to an undertaking to cooperate fully with the SEC in any and all investigations, litigations or other proceedings relating to or arising from the matters described in the SEC’s order. In connection with the settlement, the SEC considered remedial acts promptly undertaken by the Company and its cooperation with the SEC staff during the course of the investigation. Among other things, as previously disclosed in the Company’s filings with the SEC, the Audit Committee of the Company self-investigated and self-reported the accounting errors, selected new management and implemented various additional controls designed to prevent similar errors going forward.

Securities Class Action Complaints

On March 12, 2014, a purported class action was filed against the Company and certain of the Company’s now-former officers. On April 21, 2015, a related purported class action lawsuit (Okla. Police Pension & Retirement Sys. v. MagnaChip Semiconductor Corp., et al., No. 3:15-cv-01797) was filed against the Company, certain of the Company’s current directors and former and now-former officers, a shareholder of the Company, and certain financial firms that acted as underwriters of the Company’s public stock offerings. On June 15, 2015, these two class action lawsuits were consolidated. On June 26, 2015, an amended complaint was filed in the consolidated action, against the Company, certain of the Company’s current directors and former officers, a shareholder of the Company, and certain financial firms that acted as underwriters of the Company’s public stock offerings on behalf of a putative class consisting of all persons other than the defendants who purchased or acquired the Company’s securities between February 1, 2012 and February 12, 2015 and a putative subclass consisting of all purchasers of the Company’s common stock pursuant to or traceable to a shelf registration statement and prospectus issued in connection with the Company’s February 6, 2013 public stock offering. The consolidated amended complaint asserted claims on behalf of the putative class for (i) alleged violations of Section 10(b) of the Exchange Act and Rule 10b-5 promulgated thereunder by the Company and certain of the Company’s current directors and former officers, (ii) alleged violations of Section 20(a) of the Exchange Act by certain of the Company’s current directors and former officers, and (iii) alleged violations of Sections 20(a) and 20(A) of the Exchange Act by a shareholder. The consolidated amended complaint also asserted claims on behalf the subclass for (i) alleged violations of Section 11 of the Securities Act by the Company, certain of the Company’s current directors and former officers, and certain financial firms that acted as underwriters of the Company’s public stock offerings, (ii) alleged violations of Section 12 of the Securities Act by the Company, certain of the Company’s current directors and former officers, a shareholder of the Company, and certain financial firms that acted as underwriters of the Company’s public stock offerings, (iii) alleged violations of Section 15 of the Securities Act by the Company, certain of the Company’s former officers, and a shareholder of the Company.

On December 10, 2015, the Company and certain of its current and former officers and directors entered into a Memorandum of Understanding with the plaintiffs’ representatives to memorialize an agreement in principle to settle the consolidated securities class action lawsuit, Thomas, et al. v. MagnaChip Semiconductor Corp. et al., Civil Action No. 3:14-CV-01160-JST, pending in the United States District Court for the Northern District of California (the “Class Action Litigation”). On February 5, 2016, the plaintiffs in the consolidated securities class action filed a motion for preliminary approval of the settlement, as well as the stipulation and agreement of settlement and related exhibits. The stipulation and agreement of settlement provided that all claims asserted against all defendants in the Class Action Litigation except for Avenue Capital Management II, L.P. would be released. The stipulation and agreement of settlement also provided for an aggregate settlement payment by the Company of $23,500 thousand, which would include all attorneys’ fees, costs of administration and plaintiffs’ out-of-pocket expenses, lead plaintiff compensatory awards and disbursements. The settlement also included the dismissal of all claims against the Company and the named individuals in the Class Action Litigation without any liability or wrongdoing attributed to them.

On April 13, 2016, the plaintiffs filed a renewed motion for preliminary approval of the settlement. On July 18, 2016, the court granted plaintiffs’ renewed motion for preliminary approval of the settlement. On October 17, 2016, plaintiffs filed their motions for final approval of the settlement and plan of allocation of the settlement and for an award of attorneys’ fees, reimbursement of litigation expenses, and reimbursement of the costs and expenses of Lead Plaintiff Keith Thomas. On December 1, 2016, following a hearing on November 21, 2016 and an order dated November 21, 2016, the court entered a supplemental order and final judgment (the “Judgment”) granting final approval of the settlement. The Judgment was not appealed within the applicable appeals period (on or before January 3, 2017). The settlement therefore became effective after the expiration of the appeals period. The settlement was fully funded by insurance proceeds.

The Company recorded the $23,500 thousand of the settlement obligation for the Class Action Litigation as accrued expenses in the consolidated balance sheets as of December 31, 2015 and as selling, general and administrative expenses in the consolidated statements of operations for the year ended December 31, 2015. The Company recorded $29,571 thousand of the proceeds from the insurers as other receivables in the consolidated balance sheets as of December 31, 2015 and as a deduction of the selling, general and administrative expenses in the consolidated statements of operations for the year ended December 31, 2015. The proceeds from the insurers of $29,571 thousand were deposited into the Company’s escrow account during the first quarter of 2016 and the Company reclassified the $29,571 thousand deposits recorded in other receivables into restricted cash. During the third quarter of 2016, the Company disbursed the aggregate settlement payment of $23,500 thousand after the court granted plaintiffs’ renewed motion for preliminary approval of the settlement in July 2016. Upon the settlement payment, $6,114 thousand of the insurance proceeds remained in the Company’s escrow account. For subsequent treatment of the escrow amount, see “Shareholder Derivative Complaints” below.

Shareholder Derivative Complaints

A shareholder derivative action, styled Hemmingson et al. v. Elkins et al., Case No. 1-15-cv-278614, was filed in the Superior Court of the State of California in and for Santa Clara County on March 25, 2015, naming as defendants certain of the Company’s current directors and former and now-former officers, as well as a shareholder of the Company, and naming the Company as a nominal defendant. The complaint in this action asserted claims for (i) alleged breaches of fiduciary duty by certain of the Company’s current directors and former and now-former officers for purportedly knowingly failing to maintain adequate internal controls over its accounting and reporting functions and disseminating to shareholders certain alleged materially false and misleading statements, (ii) alleged breaches of fiduciary duty by certain of the Company’s current directors and a current shareholder of the Company for purported insider trading, and (iii) alleged unjust enrichment by a shareholder of the Company for purported insider trading.

On June 1, 2015, a shareholder derivative action was filed in the Superior Court of the State of California, Santa Clara County styled Bushansky v. Norby, et al., No. 1-15-CV-281284 (PHK) (Cal. Super. Ct. Santa Clara Cnty.). The complaint names as defendants certain of the Company’s current directors and former officers, and a shareholder of the Company, with the Company being named as a nominal defendant. The complaint asserted claims for (i) alleged breaches of fiduciary duties by certain of the Company’s current directors and former officers for knowingly failing to maintain adequate internal controls over the Company’s accounting and reporting functions and disseminating to shareholders certain alleged materially false and misleading statements; and (ii) alleged aiding and abetting of such breaches of fiduciary duties by all defendants.

On January 22, 2016, the Company and the plaintiffs in the Hemmingson and Bushansky actions entered into and filed a stipulation of settlement with the Superior Court of the State of California, Santa Clara County. The settlement provided for the resolution of all of the pending claims in both shareholder derivative actions against the Company and the individual defendants, without any liability or wrongdoing attributed to them. The settlement also provided for an aggregate payment from the Company defendants’ directors and officers insurance policies of $3,000 thousand to be made to an escrow account, which would be remitted to the Company once the settlement becomes final, less (i) any applicable costs of such escrow account, (ii) any amount awarded by the court to the plaintiff’s counsel for attorney’s fees and litigation expenses and (iii) the cost of providing notice of the settlement to the Company’s stockholders. The proposed settlement also required that the Company implement certain corporate governance measures. The $3,000 thousand settlement payment was included in the insurance proceeds of $29,571 thousand as discussed in “Securities Class Action Complaints” above.

On February 22, 2016, the plaintiffs filed an unopposed motion for preliminary approval of the proposed derivative settlement. On June 10, 2016, the court granted plaintiffs’ motion for preliminary approval of the proposed settlement. On October 18, 2016, after a hearing held on October 14, 2016, the court entered its order and final judgment (the “Shareholder Derivative Judgment”) granting final approval of the proposed settlement and awarding plaintiffs’ counsel $750 thousand for attorneys’ fees and litigation expenses. The Shareholder Derivative Judgment was not appealed within the applicable appeals period (on or before December 19, 2016). The settlement therefore became effective after the expiration of the appeals period and $2,258 thousand ($2,250 thousand plus applicable interest) was paid to the Company from the escrow account, previously recorded as restricted cash, in December 2016. The remaining restricted cash related to insurance proceeds of $3,078 thousand was also released in December 2016.

Related Party Transactions	12 Months Ended
Related Party Transactions	Dec. 31, 2017
Related Party Transactions [Abstract]
Related Party Transactions	20. Related Party Transactions Engaged Capital Flagship Master Fund, LP (“Engaged Capital Flagship Master Fund”), a fund for whom Engaged Capital, LLC (“Engaged Capital”) serves as investment advisor, and a managed account for which Engaged Capital serves as investment adviser (the “Engaged Capital Account”) purchased $4,496,288 and $503,712 principal amount of the Exchangeable Notes in the Exchangeable Notes Offering, respectively. Based on information contained in an Amendment No. 6 to Schedule 13D filed with the SEC on January 13, 2017 by Engaged Capital and certain affiliates, as of March 31, 2017, funds managed by Engaged Capital beneficially owned approximately 11.9% of the Company’s common stock (subject to certain blocker provisions in the Exchangeable Notes that may limit conversion to an aggregate of 9.99% of the Company’s common stock). In connection with the Exchangeable Notes Offering, the Company also repurchased 347,850 and 52,150 shares of the Company’s common stock from Engaged Capital Flagship Master Fund and the Engaged Capital Account, respectively, at an aggregate purchase price of $2,209 thousand and $331 thousand, respectively. On November 7, 2017, Engaged Capital filed with the SEC a Schedule 13D/A reporting beneficial ownership of less than 5% of the Company’s common stock.

Accumulated Other Comprehensive Income (Loss)

12 Months Ended

Dec. 31, 2017

Equity [Abstract]

Accumulated Other Comprehensive Income (Loss)

21. Accumulated Other Comprehensive Income (Loss)

Accumulated other comprehensive income (loss) consists of the following at December 31, 2017 and 2016, respectively (in thousands):


	Year Ended December 31,
	2017			2016
Foreign currency translation adjustments	$	(38,413	)	$	14,460
Derivative adjustments		5,299			(436	)

Total	$	(33,114	)	$	14,024

Changes in accumulated other comprehensive income (loss) for the years ended December 31, 2017, 2016 and 2015 are as follows (in thousands):


Year Ended December 31, 2017	Foreign currency translation adjustments			Derivative adjustments			Unrealized gain on investments		Total
Beginning balance	$	14,460		$	(436	)	$	—	$	14,024

Other comprehensive income (loss) before reclassifications		(52,873	)		7,736			—		(45,137	)
Amounts reclassified from accumulated other comprehensive income		—			(2,001	)		—		(2,001	)

Net current-period other comprehensive income (loss)		(52,873	)		5,735			—		(47,138	)

Ending balance	$	(38,413	)	$	5,299		$	—	$	(33,114	)


Year Ended December 31, 2016	Foreign currency translation adjustments			Derivative adjustments			Unrealized gain on investments		Total
Beginning balance	$	(190	)	$	(41	)	$	—	$	(231	)

Other comprehensive income (loss) before reclassifications		14,650			(1,032	)		—		13,618
Amounts reclassified from accumulated other comprehensive loss		—			637			—		637

Net current-period other comprehensive income (loss)		14,650			(395	)		—		14,255

Ending balance	$	14,460		$	(436	)	$	—	$	14,024


Year Ended December 31, 2015	Foreign currency translation adjustments			Derivative adjustments			Unrealized gain on investments		Total
Beginning balance	$	(35,551	)	$	485		$	—	$	(35,066	)

Other comprehensive income (loss) before reclassifications		35,361			(3,748	)		—		31,613
Amounts reclassified from accumulated other comprehensive loss		—			3,222			—		3,222

Net current-period other comprehensive income (loss)		35,361			(526	)		—		34,835

Ending balance	$	(190	)	$	(41	)	$	—	$	(231	)

Earnings (Loss) per Share

12 Months Ended

Dec. 31, 2017

Earnings Per Share [Abstract]

Earnings (Loss) per Share

22. Earnings (Loss) per Share

The following table illustrates the computation of basic and diluted loss per common share:


	Year Ended December 31,
	2017		2016			2015
	(In thousands of US dollars, except share data)
Basic Earnings per Share
Net income (loss)	$	84,936	$	(29,615	)	$	(84,867	)

Basic weighted average common stock outstanding		33,943,264		34,833,967			34,380,517
Basic earnings (loss) per share	$	2.50	$	(0.85	)	$	(2.47	)

Diluted Earnings per Share
Net income (loss)	$	84,936	$	(29,615	)	$	(84,867	)
Add back: Interest expense on Exchangeable Notes		5,349		—			—
Net income (loss) allocated to common stockholders	$	90,285	$	(29,615	)	$	(84,867	)

Basic weighted average common stock outstanding		33,943,264		34,833,967			34,380,517
Net effect of dilutive equity awards		821,664		—			—
Net effect of assumed conversion of 5.0% Exchangeable Notes to common stock		9,990,209		—			—

Diluted weighted average common stock outstanding		44,755,137		34,833,967			34,380,517
Diluted earnings (loss) per share	$	2.02	$	(0.85	)	$	(2.47	)

The following outstanding instruments were excluded from the computation of diluted loss per share, as they would have an anti-dilutive effect on the calculation:


	Year Ended December 31,
	2017		2016		2015
Options		835,572		3,428,665		3,179,899
Restricted Stock Units		—		518,480		135,370

Unaudited Quarterly Financial Results

12 Months Ended

Dec. 31, 2017

Quarterly Financial Information Disclosure [Abstract]

Unaudited Quarterly Financial Results

23. Unaudited Quarterly Financial Results

The following tables present selected unaudited Consolidated Statements of Operations for each quarter of the years ended December 31, 2017 and 2016.


	Fiscal Year 2017
	First Quarter		Second Quarter			Third Quarter		Fourth Quarter
	(In thousands of US dollars, except share data)
Net sales	$	161,710	$	166,685		$	176,697	$	174,580
Gross profit		41,570		46,662			50,310		49,351
Operating income		6,367		9,742			15,490		7,637
Net income (loss)	$	43,738	$	(8,059	)	$	5,604	$	43,653
Earnings (loss) per share:
Basic	$	1.30	$	(0.24	)	$	0.16	$	1.28
Diluted	$	1.05	$	(0.24	)	$	0.15	$	0.99
Weighted average common stock outstanding:
Basic		33,662,297		33,952,574			34,103,029		34,176,812
Diluted		42,892,044		33,952,574			45,542,418		45,573,889

	Fiscal Year 2016
	First Quarter		Second Quarter			Third Quarter		Fourth Quarter
	(In thousands of US dollars, except share data)
Net sales	$	148,105	$	167,106		$	192,296	$	180,462
Gross profit		34,249		36,749			39,139		46,089
Operating income (loss)		4,267		(7,377	)		618		5,229
Net income (loss)	$	8,125	$	(17,816	)	$	29,866	$	(49,790	)
Earnings (loss) per share:
Basic	$	0.23	$	(0.51	)	$	0.86	$	(1.42	)
Diluted	$	0.23	$	(0.51	)	$	0.85	$	(1.42	)
Weighted average common stock outstanding:
Basic		34,698,904		34,716,081			34,849,805		35,068,330
Diluted		34,918,568		34,716,081			35,302,706		35,068,330

Business, Basis of Presentation and Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2017

Accounting Policies [Abstract]

Business

Business

Basis of Presentation

Basis of Presentation

The consolidated financial statements are presented in accordance with accounting principles generally accepted in the United States of America (“US GAAP”).

Significant accounting policies followed by the Company in the preparation of the accompanying consolidated financial statements are summarized below.

Principles of Consolidation

Principles of Consolidation

The consolidated financial statements include the accounts of the Company including its wholly-owned subsidiaries. All intercompany transactions and balances are eliminated in consolidation.

Reclassifications

Reclassifications

Use of Estimates

Use of Estimates

Foreign Currency Translation

Foreign Currency Translation

Cash and Cash Equivalents

Cash and Cash Equivalents

Cash equivalents consist of highly liquid investments with an original maturity date of three months or less when purchased.

Accounts Receivable Reserves

Accounts Receivable Reserves

Sales of Accounts Receivable

Sales of Accounts Receivable

Inventories

Inventories

Advances to Suppliers

Advances to Suppliers

Vendor Rebates

Vendor Rebates

Property, Plant and Equipment

Property, Plant and Equipment


Buildings			30 - 40 years
Building related structures			10 - 20 years
Machinery and equipment			10 - 12 years
Others			3 - 10 years

Routine maintenance and repairs are charged to expense as incurred. Expenditures that enhance the value or significantly extend the useful lives of the related assets are capitalized.

Impairment of Long-Lived Assets

Impairment of Long-Lived Assets

Restructuring Charges

Restructuring Charges

Lease Transactions

Lease Transactions

Intangible Assets

Intangible Assets

Fair Value Disclosures of Financial Instruments

Fair Value Disclosures of Financial Instruments

Level 1—Inputs are unadjusted, quoted prices in active markets for identical assets or liabilities at the measurement date.

Accrued Severance Benefits

Accrued Severance Benefits

Revenue Recognition

Revenue Recognition

Derivative Financial Instruments

Derivative Financial Instruments

The cash flows from derivative instruments receiving hedge accounting treatment are classified in the same categories as the hedged items in the consolidated statements of cash flows.

Advertising

Advertising

Product Warranties

Product Warranties

Research and Development

Research and Development

Research and development costs are expensed as incurred and include wafers, masks, employee expenses, contractor fees, building costs, utilities and administrative expenses.

Licensed Patents and Technologies

Licensed Patents and Technologies

Running royalties are paid based on the revenue of related products sold by the Company.

Stock-Based Compensation

Stock-Based Compensation

Earnings per Share

Earnings per Share

Income Taxes

Income Taxes

Concentration of Credit Risk

Concentration of Credit Risk

Recent Accounting Pronouncements

Recent Accounting Pronouncements

Recently Adopted Accounting Pronouncements - Improvements to Employee Share-Based Payment Accounting

Recently Adopted Accounting Pronouncements

Business, Basis of Presentation and Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2017

Accounting Policies [Abstract]

Estimated Useful Lives of Assets

Depreciation is computed using the straight-line method over the estimated useful lives of the assets as set forth below.


Buildings			30 - 40 years
Building related structures			10 - 20 years
Machinery and equipment			10 - 12 years
Others			3 - 10 years

Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2017

Fair Value Disclosures [Abstract]

Financial Assets and Liabilities Measured at Fair Value on Recurring Basis

As of December 31, 2017, the following table represents the Company’s assets measured at fair value on a recurring basis and the basis for that measurement (in thousands):


	Carrying Value December 31, 2017		Fair Value Measurement December 31, 2017		Quoted Prices in Active Markets for Identical Asset (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets:
Derivative assets (other current assets)	$	5,179	$	5,179		—	$	5,179		—

As of December 31, 2016, the following table represents the Company’s liabilities measured at fair value on a recurring basis and the basis for that measurement (in thousands):


	Carrying Value December 31, 2016		Fair Value Measurement December 31, 2016		Quoted Prices in Active Markets for Identical Asset (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Liabilities:
Derivative liabilities (other current liabilities)	$	453	$	453		—	$	453		—

Schedule of Fair Value of Long-term Borrowings

Fair Value of Long-term Borrowings


	December 31, 2017				December 31, 2016
	Carrying Value		Fair Value		Carrying Value		Fair Value
	(In thousands of US dollars)
Long-term Borrowings:
5.0% Exchangeable Senior Notes due March 2021 (Level 2)	$	81,576	$	127,617	$	—	$	—
6.625% senior notes due July 2021 (Level 2)	$	221,840	$	224,719	$	221,082	$	193,500

- Definition

Tabular disclosure of financial instruments measured at fair value, including those classified in shareholders' equity measured on a recurring or nonrecurring basis. Disclosures include, but are not limited to, fair value measurements recorded and the reasons for the measurements, level within the fair value hierarchy in which the fair value measurements are categorized and transfers between levels 1 and 2. Nonrecurring fair value measurements are those that are required or permitted in the statement of financial position in particular circumstances.

+ References + Details

Accounts Receivable (Tables)

12 Months Ended

Dec. 31, 2017

Schedule of Accounts Receivable

Accounts receivable as of December 31, 2017 and 2016 consisted of the following (in thousands):


	December 31,
	2017			2016
Accounts receivable	$	86,167		$	63,116
Notes receivable		7,425			281
Less:
Allowances for doubtful accounts		(94	)		(83	)
Sales return reserves		(628	)		(1,107	)
Low yield compensation reserve		(844	)		(432	)

Accounts receivable, net	$	92,026		$	61,775

Allowance for Doubtful Accounts [Member]

Schedule of Changes in Receivables and Reserves

Changes in allowance for doubtful accounts for the years ended December 31, 2017, 2016 and 2015 are as follows (in thousands):


	Year Ended December 31,
	2017			2016			2015
Beginning balance	$	(83	)	$	(236	)	$	(263	)
Reversal		—			148			3
Translation adjustments		(11	)		5			24

Ending balance	$	(94	)	$	(83	)	$	(236	)

Sales Return Reserve [Member]

Schedule of Changes in Receivables and Reserves

Changes in sales return reserves for the years ended December 31, 2017, 2016 and 2015 are as follows (in thousands):


	Year Ended December 31,
	2017			2016			2015
Beginning balance	$	(1,107	)	$	(1,481	)	$	(787	)
Provision		(40	)		(26	)		(1,586	)
Usage		626			361			851
Translation adjustments		(107	)		39			41

Ending balance	$	(628	)	$	(1,107	)	$	(1,481	)

Low Yield Compensation Reserve [Member]

Schedule of Changes in Receivables and Reserves

Changes in low yield compensation reserve for the years ended December 31, 2017, 2016 and 2015 are as follows (in thousands):


	Year Ended December 31,
	2017			2016			2015
Beginning balance	$	(432	)	$	(480	)	$	(1,100	)
Reversal (Provision)		(362	)		(29	)		69
Usage		22			63			512
Translation adjustments		(72	)		14			39

Ending balance	$	(844	)	$	(432	)	$	(480	)

Inventories (Tables)

12 Months Ended

Dec. 31, 2017

Inventory Disclosure [Abstract]

Summary of Inventories

Inventories as of December 31, 2017 and 2016 consist of the following (in thousands):


	Year Ended December 31,
	2017			2016
Finished goods		13,737			7,867
Semi-finished goods and work-in-process		53,148			46,653
Raw materials		12,445			7,846
Materials in-transit		134			1,859
Less: inventory reserve		(6,391	)		(7,177	)

Inventories, net	$	73,073		$	57,048

Changes in Inventory Reserve

Changes in inventory reserve for the years ended December 31, 2017, 2016 and 2015 are as follows (in thousands):


	Year Ended December 31,
	2017			2016			2015
Beginning balance	$	(7,177	)	$	(16,033	)	$	(47,488	)
Change in reserve
Inventory reserve charged to costs of sales		(4,789	)		(7,646	)		(13,635	)
Sale of previously reserved inventory		3,784			4,985			13,932

		(1,005	)		(2,661	)		297
Write off		2,620			11,384			29,146
Translation adjustments		(829	)		133			2,012

Ending balance	$	(6,391	)	$	(7,177	)	$	(16,033	)

Property, Plant and Equipment (Tables)

12 Months Ended

Dec. 31, 2017

Property, Plant and Equipment [Abstract]

Summary of Property, Plant and Equipment

Property, plant and equipment as of December 31, 2017 and 2016 are comprised of the following (in thousands):


	December 31,
	2017			2016
Buildings and related structures	$	69,958		$	64,939
Machinery and equipment		308,713			255,618
Others		42,497			29,492

		421,168			350,049
Less: accumulated depreciation		(231,356	)		(184,521	)
Land		16,091			14,265

Property, plant and equipment, net	$	205,903		$	179,793

Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2017

Goodwill and Intangible Assets Disclosure [Abstract]

Summary of Intangible Assets

Intangible assets as of December 31, 2017 and 2016 are comprised of the following (in thousands):


	December 31, 2017
	Gross amount		Accumulated amortization			Net amount
Technology	$	20,194	$	(20,194	)	$	—
Customer relationships		29,002		(29,002	)		—
Intellectual property assets		11,319		(7,258	)		4,061

Intangible assets, net	$	60,515	$	(56,454	)	$	4,061


	December 31, 2016
	Gross amount		Accumulated amortization			Net amount
Technology	$	17,903	$	(17,903	)	$	—
Customer relationships		25,712		(25,712	)		—
Intellectual property assets		9,026		(5,941	)		3,085

Intangible assets, net	$	52,641	$	(49,556	)	$	3,085

Accrued Expenses (Tables)

12 Months Ended

Dec. 31, 2017

Payables and Accruals [Abstract]

Summary of Accrued Expenses

Accrued expenses as of December 31, 2017 and 2016 are comprised of the following (in thousands):


	December 31,
	2017		2016
Payroll, benefits and related taxes, excluding severance benefits	$	16,724	$	24,982
Withholding tax attributable to intercompany interest income		18,138		15,573
Interest on senior notes		8,268		6,831
Outside service fees		1,942		4,423
Others		6,674		8,556

Accrued expenses	$	51,746	$	60,365

Derivative Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2017

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Details of Derivative Contracts

Details of derivative contracts as of December 31, 2017 are as follows (in thousands):


Date of transaction	Type of derivative	Total notional amount		Month of settlement
June 22, 2017	Zero cost collar	$	20,000	January 2018 to February 2018
September 28, 2017	Zero cost collar	$	54,000	January 2018 to June 2018
September 28, 2017	Forward	$	36,000	January 2018 to June 2018

Details of derivative contracts as of December 31, 2016 are as follows (in thousands):

Date of transaction

Type of derivative

Total notional amount

Month of settlement

November 11, 2016

Zero cost collar

18,000

March to August 2017

Fair Values of Outstanding Zero Cost Collar and Forward Contracts Recorded as Assets and Liabilities

The fair values of the Company’s outstanding zero cost collar and forward contracts recorded as assets and liabilities as of December 31, 2017 and 2016 are as follows (in thousands):


Derivatives designated as hedging instruments:		December 31,
Derivatives designated as hedging instruments:		2017		2016
Asset Derivatives:
Zero cost collars	Other current assets	$	2,827	$	—
Forward	Other current assets	$	2,352	$	—
Liability Derivatives:
Zero cost collars	Other current liabilities	$	—	$	453

Offsetting of Derivative Assets and Liabilities

Offsetting of derivative assets as of December 31, 2017 is as follows (in thousands):


As of December 31, 2017	Gross amounts of recognized assets		Gross amounts offset in the balance sheets		Net amounts of assets presented in the balance sheets		Gross amounts not offset in the balance sheets				Net amount
As of December 31, 2017	Gross amounts of recognized assets		Gross amounts offset in the balance sheets		Net amounts of assets presented in the balance sheets		Financial instruments		Cash collateral pledged		Net amount
Asset Derivatives:
Zero cost collars	$	2,827	$	—	$	2,827	$	—	$	—	$	2,827
Forward	$	2,352	$	—	$	2,352	$	—	$	—	$	2,352

Offsetting of derivative liabilities as of December 31, 2016 is as follows (in thousands):


As of December 31, 2016	Gross amounts of recognized liabilities		Gross amounts offset in the balance sheets		Net amounts of liabilities presented in the balance sheets		Gross amounts not offset in the balance sheets					Net amount
As of December 31, 2016	Gross amounts of recognized liabilities		Gross amounts offset in the balance sheets		Net amounts of liabilities presented in the balance sheets		Financial instruments		Cash collateral pledged			Net amount
Liability Derivatives:
Zero cost collars	$	453	$	—	$	453	$	—	$	(650	)	$	(197	)

Impact of Derivative Instruments on Consolidated Statement of Operations

The following table summarizes the impact of derivative instruments on the consolidated statement of operations for the years ended December 31, 2017 and 2016 (in thousands):


Derivatives in ASC 815 Cash Flow Hedging Relationships	Amount of Gain (Loss) Recognized in AOCI on Derivatives (Effective Portion)					Location of Gain (loss) Reclassified from AOCI into Statement of Operations (Effective Portion)		Amount of Gain (loss) Reclassified from AOCI into Statement of Operations (Effective Portion)					Location of Gain (loss) Recognized in Statement of Operations on Derivative (Ineffective Portion)		Amount of Gain (loss) Recognized in Statement of Operations on Derivatives (Ineffective Portion)
	2017		2016					2017		2016					2017			2016
Zero cost collars	$	4,692	$	(1,032	)		Net sales	$	1,501	$	(637	)		Other income, net	$	606		$	(272	)
Forwards	$	3,044	$	—			Net sales	$	500	$	—			Other income, net	$	(370	)	$	—

Total	$	$7,736	$	(1,032	)			$	2,001	$	—				$	236		$	(272	)

- Definition

Tabular disclosure of pertinent information about a derivative or group of derivatives on a disaggregated basis, such as for individual instruments, or small groups of similar instruments. May include a combination of the type of instrument, risks being hedged, notional amount, hedge designation, related hedged item, inception date, maturity date, or other relevant item.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=84234895&loc=d3e41641-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
-Topic 815
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-Name Accounting Standards Codification
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Reference 6: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
-Topic 815
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-Name Accounting Standards Codification
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-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
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-Paragraph 1
-Subparagraph (SX 210.4-08.(n)(2))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

+ Details

Product Warranties (Tables)

12 Months Ended

Dec. 31, 2017

Guarantees and Product Warranties [Abstract]

Schedule of Changes in Accrued Warranty Liabilities

Changes in accrued warranty liabilities for the years ended December 31, 2017, 2016 and 2015 are as follows (in thousands):


	Year Ended December 31,
	2017			2016			2015
Beginning balance	$	466		$	1,425		$	2,973
Change in provision		(224	)		(426	)		(648	)
Usage		(65	)		(527	)		(758	)
Translation adjustments		39			(6	)		(142	)

Ending balance	$	216		$	466		$	1,425

Long-term Borrowings (Tables)

12 Months Ended

Dec. 31, 2017

Debt Disclosure [Abstract]

Components of Long-term Borrowings

Long-term borrowings as of December 31, 2017 and 2016 are as follows (in thousands):


	December 31,
	2017			2016
5.0% Exchangeable Senior Notes due March 2021	$	86,250		$	—
6.625% senior notes due July 2021	$	225,000		$	225,000
Less: unamortized discount and debt issuance costs		(7,834	)		(3,918	)

Long-term borrowings, net of unamortized discount and debt issuance costs	$	303,416		$	221,082

- Definition

Tabular disclosure of long-debt instruments or arrangements, including identification, terms, features, collateral requirements and other information necessary to a fair presentation. These are debt arrangements that originally required repayment more than twelve months after issuance or greater than the normal operating cycle of the entity, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22)
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Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
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-URI http://asc.fasb.org/extlink&oid=84159872&loc=d3e21475-112644

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-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(e),(f))
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+ Details

Accrued Severance Benefits (Tables)

12 Months Ended

Dec. 31, 2017

Postemployment Benefits [Abstract]

Changes in Accrued Severance Benefits

Changes in accrued severance benefits are as follows (in thousands):


	Year Ended December 31,
	2017			2016
Beginning balance	$	130,144		$	135,160
Provisions		24,373			14,432
Severance payments		(21,506	)		(15,352	)
Translation adjustments		16,785			(4,096	)

		149,796			130,144
Less: Cumulative contributions to the National Pension Fund		(259	)		(276	)
Group severance insurance plan		(632	)		(643	)

Accrued severance benefits, net	$	148,905		$	129,225

Future Benefits Payments to Employees

The Company is liable to pay the following future benefits to its non-executive employees upon their normal retirement age (in thousands):


	Severance Benefit
2018	$	—
2019		610
2020		1,094
2021		1,573
2022		1,584
2023 – 2027		20,541

Common Stock (Tables)

12 Months Ended

Dec. 31, 2017

Equity [Abstract]

Schedule of Changes in Common Stock

Changes in common stock for each period are as follows (in thousands):


	Year Ended December 31,
	2017					2016
	Shares			Amount		Shares		Amount
Common stock at the beginning of the period		35,048,338		$	416		34,568,942	$	411
Exercise of stock options		539,183			6		296,103		3
Settlement of restricted stock units		397,522			4		183,293		2
Acquisitions of treasury stock		(1,795,444	)		—		—		—

Total common stock outstanding at the end of the period		34,189,599		$	426		35,048,338	$	416

- Definition

Tabular disclosure of an entity's stock, including par or stated value per share, number and dollar amount of share subscriptions, shares authorized, shares issued, shares outstanding, number and dollar amount of shares held in an employee trust, dividend per share, total dividends, share conversion features, par value plus additional paid in capital, the value of treasury stock and other information necessary to a fair presentation, and EPS information. Stock by class includes common, convertible, and preferred stocks which are not redeemable or redeemable solely at the option of the issuer. Includes preferred stock with redemption features that are solely within the control of the issuer and mandatorily redeemable stock if redemption is required to occur only upon liquidation or termination of the reporting entity. If more than one issue is outstanding, state the title of each issue and the corresponding dollar amount; dollar amount of any shares subscribed but unissued and the deduction of subscriptions receivable there from; number of shares authorized, issued, and outstanding.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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+ Details

Equity Incentive Plans (Tables)

12 Months Ended

Dec. 31, 2017

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Summary of Restricted Stock Unit Activities

The following summarizes restricted stock unit activities for the years ended December 31, 2017, 2016 and 2015.


	Number of Restricted Stock Units			Weighted Average Grant-Date Fair Value of Restricted Stock Units
Outstanding at January 1, 2015		—		$	—
Granted		265,332			7.68
Vested		(129,962	)		7.64

Outstanding at December 31, 2015		135,370		$	7.72

Granted		505,689			5.71
Vested		(101,240	)		7.09
Forfeited		(21,339	)		6.24

Outstanding at December 31, 2016		518,480		$	5.94

Granted		172,716			11.15
Vested		(368,555	)		5.72
Forfeited		(830	)		8.33

Outstanding at December 31, 2017		321,811		$	8.99

Summary of Stock Option Activities


	Number of Options			Weighted Average Exercise Price of Stock Options		Aggregate Intrinsic Value of Stock Options		Weighted Average Remaining Contractual Life of Stock Options
Outstanding at January 1, 2015		3,215,945		$	9.60	$	39,615		6.6 years
Granted		802,193			7.92		—		—
Forfeited		(325,765	)		9.88		—		—
Exercised		(512,474	)		6.70		692		—

Outstanding at December 31, 2015		3,179,899		$	9.61	$	—		6.7 years

Vested and expected to vest at December 31, 2015		3,155,828			9.62		—		6.7 years
Exercisable at December 31, 2015		2,547,902			9.63		—		6.0 years

Outstanding at January 1, 2016		3,179,899		$	9.61	$	—		6.7 years
Granted		827,406			6.04		—		—
Forfeited		(282,537	)		7.67		—		—
Exercised		(296,103	)		5.85		806		—

Outstanding at December 31, 2016		3,428,665		$	9.23	$	525		6.7 years

Vested and expected to vest at December 31, 2016		3,389,763			9.27		508		6.7 years
Exercisable at December 31, 2016		2,531,243			10.11		236		5.9 years

Outstanding at January 1, 2017		3,428,665		$	9.23	$	525		6.7 years
Granted		70,865			10.43		—		—
Forfeited		(88,443	)		12.77		—		—
Exercised		(539,183	)		6.94		1,540		—

Outstanding at December 31, 2017		2,871,904		$	9.59	$	6,073		6.2 years

Vested and expected to vest at December 31, 2017		2,865,475			9.59		6,050		6.2 years
Exercisable at December 31, 2017		2,395,979			10.11		4,603		5.7 years

Assumptions used in Black-Scholes Option-Pricing Model on Weighted Average Basis

The following summarizes the grant-date fair value of options granted for the years ended December 31, 2017, 2016 and 2015 and assumptions used in the Black-Scholes option-pricing model on a weighted average basis. For the year ended December 31, 2017, the expected volatility was estimated using historical volatility of the Company’s share prices. For the years ended December 31, 2016 and 2015, it was based on historical volatility of share prices of similar public entities:


	Year Ended December 31,
	2017			2016			2015
Grant-date fair value of option	$	5.02		$	1.54		$	1.67
Expected term		2.5 Years			2.7 Years			2.4 Years
Risk-free interest rate		1.2	%		1.0	%		0.8	%
Expected volatility		81.7	%		36.8	%		33.8	%
Expected dividends		—			—			—

Number and Weighted Average Grant-Date Fair Value of Unvested Stock Options

The number and weighted average grant-date fair value of the unvested stock options are as follows:


	Year Ended December 31,
	2017					2016					2015
	Number			Weighted Average Grant- Date Fair Value		Number			Weighted Average Grant- Date Fair Value		Number			Weighted Average Grant- Date Fair Value
Unvested options at the beginning of the period		897,421		$	1.72		631,997		$	2.40		455,543		$	4.18
Granted options during the period		70,865			5.02		827,406			1.54		802,193			1.67
Vested options during the period		(455,301	)		1.74		(446,570	)		2.26		(532,682	)		2.56
Forfeited options during the period		(19,031	)		1.77		(85,934	)		1.88		(92,959	)		4.01
Exercised options during the period		(18,029	)		1.59		(29,478	)		1.24		(98	)		3.08

Unvested options at the end of the period		475,925		$	2.19		897,421		$	1.72		631,997		$	2.40

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2017

Income Tax Disclosure [Abstract]

Components of Income Tax Expense

The components of income tax expense are as follows (in thousands):


	Year Ended December 31,
	2017			2016			2015
Income (loss) before income taxes
Domestic	$	27,461		$	(1,738	)	$	32,903
Foreign		58,630			(24,133	)		(132,857	)

	$	86,091		$	(25,871	)	$	(99,954	)

Current income taxes expense (benefit)
Domestic	$	(359	)	$	(6	)	$	25
Foreign		3,680			3,386			(14,301	)
Uncertain tax position liability (domestic)		(476	)		12			10
Uncertain tax position liability (foreign)		(1,635	)		339			(1,220	)

		1,210			3,731			(15,486	)

Deferred income taxes expense (benefit)
Foreign		(55	)		13			399

Total income tax expense (benefit)	$	1,155		$	3,744		$	(15,087	)

Effective tax rate		1.3	%		(14.5	)%		15.1	%

Difference Between Provision for Domestic and Foreign Income Taxes and Amount Calculated by Statutory Tax Rate to Net Income Before Income Taxes


	Year Ended December 31,
	2017			2016			2015
Provision computed at statutory rate	$	30,223		$	(9,055	)	$	(34,984	)
Change in statutory tax rates		13,438			—			—
Difference in foreign tax rates		(12,344	)		1,995			24,359
Permanent differences
Derivative assets adjustment		1,937			(149	)		(143	)
TPECs, hybrid and other interest		(7,526	)		(10,353	)		(27,273	)
Permanent impairment		—			—			(62,334	)
Thin capitalization		1,888			2,120			2,457
Permanent foreign currency gain (loss)		(838	)		(54	)		11,575
Penalty		4,001			689			—
Non-deductible bad debt expense		—			—			89
Other permanent differences		633			50			(69	)
Withholding tax		3,339			3,092			(14,457	)
Foreign exchange rate adjustment		16,075			(1,838	)		(8,954	)
Change in valuation allowance		(56,744	)		10,095			95,757
Tax credits claimed		(659	)		(706	)		(875	)
Tax credits expired		2,638			1,578			—
Uncertain tax positions liability		(2,111	)		351			(1,211	)
Change in net operating loss carry-forwards		6,878			—			—
Others		327			5,929			976

Income tax expense (benefit)	$	1,155		$	3,744		$	(15,087	)

Summary of Composition of Net Deferred Income Tax Assets (Liabilities)

A summary of the composition of net deferred income tax assets (liabilities) as of December 31, 2017 and 2016 are as follows (in thousands):


	Year-Ended December 31,
	2017			2016
Deferred tax assets
Inventory reserves	$	1,630		$	1,822
Derivative assets		(1,253	)		110
Accrued expenses		2,826			2,803
Product warranties		52			113
Other reserves		356			372
Property, plant and equipment		9,759			13,314
Intangible assets		35			103
Accumulated severance benefits		36,245			31,478
Foreign currency translation losses		20,067			53,130
NOL carry-forwards		175,543			167,590
Tax credit		20,583			20,249
Other long-term payable		1,801			2,079
Others		3,546			4,885

Total deferred tax assets		271,190			298,048
Less: Valuation allowance		(251,132	)		(281,473	)

		20,058			16,575


Deferred tax liabilities
Foreign currency translation gains		18,187			14,338
Prepaid expense		1,464			1,644
Others		143			410

Total deferred tax liabilities		19,794			16,392

Net deferred tax assets	$	264		$	183

Reported as
Current deferred income tax assets	$	—		$	37
Non-current deferred income tax assets	$	264		$	193
Current deferred income tax liabilities	$	—		$	(46	)
Non-current deferred income tax liabilities	$	—		$	(1	)

Changes in Valuation Allowance for Deferred Tax Assets

Changes in valuation allowance for deferred tax assets for the years ended December 31, 2017, 2016 and 2015 are as follows (in thousands):


	Year Ended December 31,
	2017			2016			2015
Beginning balance	$	281,473		$	279,867		$	194,739
Charged to expense		(54,816	)		10,095			95,757
NOL/tax credit claimed/expired		(1,928	)		(872	)		(1,197	)
Translation adjustments		26,403			(7,617	)		(9,432	)

Ending balance	$	251,132		$	281,473		$	279,867

Reconciliation of Total Amounts of Unrecognized Tax Benefits

A tabular reconciliation of the total amounts of unrecognized tax benefits at the beginning and end of each period is as follows (in thousands):


	Year Ended December 31,
	2017			2016			2015
Unrecognized tax benefits, balance at the beginning	$	2,459		$	2,139		$	3,495
Additions based on tax positions related to the current year		10			371			351
Additions (reductions) for tax positions of prior years		(676	)		317			(135	)
Lapse of statute of limitations		(735	)		(670	)		(1,318	)
Additions (reductions) of interest and penalties		(712	)		334			(108	)
Translation adjustments		137			(32	)		(146	)

Unrecognized tax benefits, balance at the ending	$	483		$	2,459		$	2,139

Reconciliation of Total Amounts of UncertainTax Positions

A tabular reconciliation of the total amounts of uncertain tax positions at the beginning and end of each period is as follows (in thousands):


	Year Ended December 31,
	2017			2016			2015
Uncertain tax positions, balance at the beginning	$	11,894		$	13,330		$	14,969
Additions based on tax positions related to the current year		(366	)		942			1,789
Additions (reductions) for tax positions of prior years		(8,923	)		317			—
Lapse of statute of limitations		(2,218	)		(2,380	)		(2,142	)
Translation adjustments		675			(315	)		(1,287	)

Uncertain tax positions, balance at the ending	$	1,062		$	11,894		$	13,330

Geographic and Segment Information (Tables)

12 Months Ended

Dec. 31, 2017

Segment Reporting [Abstract]

Schedule of Operating Segments

The following sets forth information relating to the operating segments (in thousands):


	Year Ended December 31,
	2017		2016		2015
Net Sales
Foundry Services Group	$	320,089	$	273,961	$	290,775
Standard Products Group
Display Solutions		209,539		281,967		207,480
Power Solutions		149,836		131,468		134,814

Total Standard Products Group		359,375		413,435		342,294
All other		208		573		643

Total net sales	$	679,672	$	687,969	$	633,712


	Year Ended December 31,
	2017		2016			2015
Gross Profit
Foundry Services Group	$	95,458	$	69,412		$	66,175
Standard Products Group		92,227		87,194			68,094
All other		208		(380	)		595

Total gross profit	$	187,893	$	156,226		$	134,864

Net Sales by Region, Based on Location of Products are Billed

The following is a summary of net sales by geographic region, based on the location to which the products are billed (in thousands):


	Year Ended December 31,
	2017		2016		2015
Korea	$	279,883	$	219,618	$	241,715
Asia Pacific (other than Korea)		322,595		391,875		316,562
U.S.A.		35,089		33,201		51,164
Europe		41,109		42,274		23,461
Others		996		1,001		810

Total	$	679,672	$	687,969	$	633,712

Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2017

Commitments and Contingencies Disclosure [Abstract]

Schedule of Minimum Aggregate Rental Payments Due Under Non-Cancelable Lease Contracts

As of December 31, 2017, the minimum aggregate rental payments due under non-cancelable lease contracts are as follows (in thousands):


2018	$	6,724
2019		3,764
2020		3,459
2021		1,472
2022		1,316
2023 and thereafter		15,448

	$	32,183

Accumulated Other Comprehensive Income (Loss) (Tables)

12 Months Ended

Dec. 31, 2017

Equity [Abstract]

Schedule of Accumulated Other Comprehensive Income (Loss)

Accumulated other comprehensive income (loss) consists of the following at December 31, 2017 and 2016, respectively (in thousands):


	Year Ended December 31,
	2017			2016
Foreign currency translation adjustments	$	(38,413	)	$	14,460
Derivative adjustments		5,299			(436	)

Total	$	(33,114	)	$	14,024

Changes in Accumulated Other Comprehensive Income (Loss)

Changes in accumulated other comprehensive income (loss) for the years ended December 31, 2017, 2016 and 2015 are as follows (in thousands):


Year Ended December 31, 2017	Foreign currency translation adjustments			Derivative adjustments			Unrealized gain on investments		Total
Beginning balance	$	14,460		$	(436	)	$	—	$	14,024

Other comprehensive income (loss) before reclassifications		(52,873	)		7,736			—		(45,137	)
Amounts reclassified from accumulated other comprehensive income		—			(2,001	)		—		(2,001	)

Net current-period other comprehensive income (loss)		(52,873	)		5,735			—		(47,138	)

Ending balance	$	(38,413	)	$	5,299		$	—	$	(33,114	)


Year Ended December 31, 2016	Foreign currency translation adjustments			Derivative adjustments			Unrealized gain on investments		Total
Beginning balance	$	(190	)	$	(41	)	$	—	$	(231	)

Other comprehensive income (loss) before reclassifications		14,650			(1,032	)		—		13,618
Amounts reclassified from accumulated other comprehensive loss		—			637			—		637

Net current-period other comprehensive income (loss)		14,650			(395	)		—		14,255

Ending balance	$	14,460		$	(436	)	$	—	$	14,024


Year Ended December 31, 2015	Foreign currency translation adjustments			Derivative adjustments			Unrealized gain on investments		Total
Beginning balance	$	(35,551	)	$	485		$	—	$	(35,066	)

Other comprehensive income (loss) before reclassifications		35,361			(3,748	)		—		31,613
Amounts reclassified from accumulated other comprehensive loss		—			3,222			—		3,222

Net current-period other comprehensive income (loss)		35,361			(526	)		—		34,835

Ending balance	$	(190	)	$	(41	)	$	—	$	(231	)

Earnings (Loss) per Share (Tables)

12 Months Ended

Dec. 31, 2017

Earnings Per Share [Abstract]

Schedule of Computation of Basic and Diluted Earnings (Loss) Per Common Share

The following table illustrates the computation of basic and diluted loss per common share:


	Year Ended December 31,
	2017		2016			2015
	(In thousands of US dollars, except share data)
Basic Earnings per Share
Net income (loss)	$	84,936	$	(29,615	)	$	(84,867	)

Basic weighted average common stock outstanding		33,943,264		34,833,967			34,380,517
Basic earnings (loss) per share	$	2.50	$	(0.85	)	$	(2.47	)

Diluted Earnings per Share
Net income (loss)	$	84,936	$	(29,615	)	$	(84,867	)
Add back: Interest expense on Exchangeable Notes		5,349		—			—
Net income (loss) allocated to common stockholders	$	90,285	$	(29,615	)	$	(84,867	)

Basic weighted average common stock outstanding		33,943,264		34,833,967			34,380,517
Net effect of dilutive equity awards		821,664		—			—
Net effect of assumed conversion of 5.0% Exchangeable Notes to common stock		9,990,209		—			—

Diluted weighted average common stock outstanding		44,755,137		34,833,967			34,380,517
Diluted earnings (loss) per share	$	2.02	$	(0.85	)	$	(2.47	)

Schedule of Antidilutive Securities Excluded from the Computation of Loss Per Common Share

The following outstanding instruments were excluded from the computation of diluted loss per share, as they would have an anti-dilutive effect on the calculation:


	Year Ended December 31,
	2017		2016		2015
Options		835,572		3,428,665		3,179,899
Restricted Stock Units		—		518,480		135,370

Unaudited Quarterly Financial Results (Tables)

12 Months Ended

Dec. 31, 2017

Quarterly Financial Information Disclosure [Abstract]

Schedule of Selected Consolidated Statements of Operations

The following tables present selected unaudited Consolidated Statements of Operations for each quarter of the years ended December 31, 2017 and 2016.


	Fiscal Year 2017
	First Quarter		Second Quarter			Third Quarter		Fourth Quarter
	(In thousands of US dollars, except share data)
Net sales	$	161,710	$	166,685		$	176,697	$	174,580
Gross profit		41,570		46,662			50,310		49,351
Operating income		6,367		9,742			15,490		7,637
Net income (loss)	$	43,738	$	(8,059	)	$	5,604	$	43,653
Earnings (loss) per share:
Basic	$	1.30	$	(0.24	)	$	0.16	$	1.28
Diluted	$	1.05	$	(0.24	)	$	0.15	$	0.99
Weighted average common stock outstanding:
Basic		33,662,297		33,952,574			34,103,029		34,176,812
Diluted		42,892,044		33,952,574			45,542,418		45,573,889

	Fiscal Year 2016
	First Quarter		Second Quarter			Third Quarter		Fourth Quarter
	(In thousands of US dollars, except share data)
Net sales	$	148,105	$	167,106		$	192,296	$	180,462
Gross profit		34,249		36,749			39,139		46,089
Operating income (loss)		4,267		(7,377	)		618		5,229
Net income (loss)	$	8,125	$	(17,816	)	$	29,866	$	(49,790	)
Earnings (loss) per share:
Basic	$	0.23	$	(0.51	)	$	0.86	$	(1.42	)
Diluted	$	0.23	$	(0.51	)	$	0.85	$	(1.42	)
Weighted average common stock outstanding:
Basic		34,698,904		34,716,081			34,849,805		35,068,330
Diluted		34,918,568		34,716,081			35,302,706		35,068,330

Business, Basis of Presentation and Summary of Significant Accounting Policies - Additional Information (Detail)	3 Months Ended	12 Months Ended
	Jun. 30, 2015 Segments	Dec. 31, 2017 USD ($) Segments Business_Lines	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Jan. 01, 2018 USD ($)
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of operating segments \| Segments	2	2
Cash equivalents, highly liquid investments original maturity date		Three months or less
Vendor rebates recorded as a reduction of inventory		$ 0	$ 359,000
Vendor rebates recorded as a reduction of cost of sales		$ 379,000	4,044,000
Percentage of employees eligible for severance benefits		98.00%
Recorded deferred revenue		$ 8,335,000	11,092,000
Advertising expense		$ 95,000	149,000	$ 144,000
Standard limited warranty period		The standard limited warranty period is one to two years for the majority of products.
Dividends		$ 0
Percentage of tax benefit realized upon settlement		50.00%
Other Current Assets [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Prepayments to suppliers		$ 7,404,000	1,390,000
Selling, General and Administrative Expenses [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Shipping and handling cost		$ 1,652,000	$ 1,631,000	$ 2,394,000
Minimum [Member] \| Technology [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Estimated useful life of Intangible assets		1 year
Minimum [Member] \| Customer Relationships [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Estimated useful life of Intangible assets		1 year
Maximum [Member] \| Technology [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Estimated useful life of Intangible assets		5 years
Maximum [Member] \| Customer Relationships [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Estimated useful life of Intangible assets		5 years
Maximum [Member] \| Intellectual Property Assets [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Estimated useful life of Intangible assets		10 years
Maximum [Member] \| Accounting Standards Update 2014-09 [Member] \| Subsequent Event [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Adjustment to increase the equity					$ 10,000,000
Standard Products Group [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of business lines \| Business_Lines		2

Business, Basis of Presentation and Summary of Significant Accounting Policies - Estimated Useful Lives of Assets (Detail)	12 Months Ended
	Dec. 31, 2017
Minimum [Member] \| Buildings [Member]
Property, Plant and Equipment [Line Items]
Property plant and equipment, estimated useful lives	30 years
Minimum [Member] \| Buildings and Related Structures [Member]
Property, Plant and Equipment [Line Items]
Property plant and equipment, estimated useful lives	10 years
Minimum [Member] \| Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property plant and equipment, estimated useful lives	10 years
Minimum [Member] \| Others [Member]
Property, Plant and Equipment [Line Items]
Property plant and equipment, estimated useful lives	3 years
Maximum [Member] \| Buildings [Member]
Property, Plant and Equipment [Line Items]
Property plant and equipment, estimated useful lives	40 years
Maximum [Member] \| Buildings and Related Structures [Member]
Property, Plant and Equipment [Line Items]
Property plant and equipment, estimated useful lives	20 years
Maximum [Member] \| Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property plant and equipment, estimated useful lives	12 years
Maximum [Member] \| Others [Member]
Property, Plant and Equipment [Line Items]
Property plant and equipment, estimated useful lives	10 years

Fair Value Measurements - Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Carrying Value [Member] \| Other Current Liabilities [Member]
Liabilities:
Derivative liabilities		$ 453
Carrying Value [Member] \| Other Current Assets [Member]
Assets:
Derivative assets	$ 5,179
Estimate of Fair Value Measurement [Member] \| Other Current Liabilities [Member]
Liabilities:
Derivative liabilities		453
Estimate of Fair Value Measurement [Member] \| Other Current Assets [Member]
Assets:
Derivative assets	5,179
Significant Other Observable Inputs (Level 2) [Member] \| Other Current Liabilities [Member]
Liabilities:
Derivative liabilities		$ 453
Significant Other Observable Inputs (Level 2) [Member] \| Other Current Assets [Member]
Assets:
Derivative assets	$ 5,179

Fair Value Measurements - Schedule of Fair Value of Long-term Borrowings (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Long-term Borrowings:
Carrying amount of senior notes	$ 303,416	$ 221,082
5.0% Exchangeable Senior Notes due March 2021 [Member] \| Exchangeable Senior Notes [Member] \| Significant Other Observable Inputs (Level 2) [Member]
Long-term Borrowings:
Carrying amount of senior notes	81,576
Estimated fair value of senior notes	127,617
6.625% Senior Notes Due 2021 [Member] \| Senior Notes [Member] \| Significant Other Observable Inputs (Level 2) [Member]
Long-term Borrowings:
Carrying amount of senior notes	221,840	221,082
Estimated fair value of senior notes	$ 224,719	$ 193,500

Fair Value Measurements - Schedule of Fair Value of Long-term Borrowings (Parenthetical) (Detail)			12 Months Ended
	Jan. 17, 2017	Jul. 18, 2013	Dec. 31, 2017	Dec. 31, 2016
5.0% Exchangeable Senior Notes due March 2021 [Member] \| Exchangeable Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate	5.00%		5.00%
Due date	Mar. 01, 2021		Mar. 01, 2021
6.625% Senior Notes Due 2021 [Member] \| Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate		6.625%	6.625%	6.625%
Due date		Jul. 15, 2021	Jul. 15, 2021	Jul. 15, 2021

Fair Value Measurements - Additional Information (Detail) - USD ($)			12 Months Ended
	Jan. 17, 2017	Jul. 18, 2013	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt issuance costs paid			$ 5,902,000
6.625% Senior Notes Due 2021 [Member] \| Senior Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate		6.625%	6.625%	6.625%
Due date		Jul. 15, 2021	Jul. 15, 2021	Jul. 15, 2021
Aggregate principal amount		$ 225,000,000
Debt issuance costs paid		5,120,000
Original debt issue discount		$ 1,125,000
5.0% Exchangeable Senior Notes due March 2021 [Member] \| Exchangeable Senior Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate	5.00%		5.00%
Due date	Mar. 01, 2021		Mar. 01, 2021
Aggregate principal amount	$ 86,250,000
Debt issuance costs paid	$ 5,902,000		$ 5,902,000
Other Asset Class [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets fair value on non-recurring basis			0	$ 0
Liabilities fair value on non-recurring basis			$ 0	$ 0

Accounts Receivable - Schedule of Accounts Receivable (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Receivables [Abstract]
Accounts receivable	$ 86,167	$ 63,116
Notes receivable	7,425	281
Allowances for doubtful accounts	(94)	(83)	$ (236)	$ (263)
Sales return reserves	(628)	(1,107)	(1,481)	(787)
Low yield compensation reserve	(844)	(432)	$ (480)	$ (1,100)
Accounts receivable, net	$ 92,026	$ 61,775

Accounts Receivable - Schedule of Changes in Allowance for Doubtful Accounts (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Receivables [Abstract]
Beginning balance	$ (83)	$ (236)	$ (263)
Reversal		148	3
Translation adjustments	(11)	5	24
Ending balance	$ (94)	$ (83)	$ (236)

Accounts Receivable - Schedule of Changes in Sales Return Reserve (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Receivables [Abstract]
Beginning balance	$ (1,107)	$ (1,481)	$ (787)
Provision	(40)	(26)	(1,586)
Usage	626	361	851
Translation adjustments	(107)	39	41
Ending balance	$ (628)	$ (1,107)	$ (1,481)

Accounts Receivable - Schedule of Changes in Low Yield Compensation Reserve (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Receivables [Abstract]
Beginning balance	$ (432)	$ (480)	$ (1,100)
Reversal (Provision)	(362)	(29)	69
Usage	22	63	512
Translation adjustments	(72)	14	39
Ending balance	$ (844)	$ (432)	$ (480)

Accounts Receivable - Additional Information (Detail) - Trade Accounts Receivable [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds from sale of accounts receivable	$ 18,973	$ 25,146	$ 57,185
Selling, General and Administrative Expenses [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Pre-tax losses on accounts receivable	$ 55	$ 78	$ 114

Inventories - Summary of Inventories (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Inventory Disclosure [Abstract]
Finished goods	$ 13,737	$ 7,867
Semi-finished goods and work-in-process	53,148	46,653
Raw materials	12,445	7,846
Materials in-transit	134	1,859
Less: inventory reserve	(6,391)	(7,177)	$ (16,033)	$ (47,488)
Inventories, net	$ 73,073	$ 57,048

Inventories - Changes in Inventory Reserve (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Inventory Disclosure [Abstract]
Beginning balance	$ (7,177)	$ (16,033)	$ (47,488)
Change in reserve
Inventory reserve charged to costs of sales	(4,789)	(7,646)	(13,635)
Sale of previously reserved inventory	3,784	4,985	13,932
Change in reserve	(1,005)	(2,661)	297
Write off	2,620	11,384	29,146
Translation adjustments	(829)	133	2,012
Ending balance	$ (6,391)	$ (7,177)	$ (16,033)

Property, Plant and Equipment - Summary of Property, Plant and Equipment (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 421,168	$ 350,049
Less: accumulated depreciation	(231,356)	(184,521)
Property, plant and equipment, net	205,903	179,793
Buildings and Related Structures [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	69,958	64,939
Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	308,713	255,618
Others [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	42,497	29,492
Land [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, net	$ 16,091	$ 14,265

Property, Plant and Equipment - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Abstract]
Depreciation expenses	$ 27,498	$ 24,941

Intangible Assets - Summary of Intangible Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Intangible asset, Gross amount	$ 60,515	$ 52,641
Accumulated amortization	(56,454)	(49,556)
Intangible asset, Net amount	4,061	3,085
Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible asset, Gross amount	20,194	17,903
Accumulated amortization	(20,194)	(17,903)
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible asset, Gross amount	29,002	25,712
Accumulated amortization	(29,002)	(25,712)
Intellectual Property Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible asset, Gross amount	11,319	9,026
Accumulated amortization	(7,258)	(5,941)
Intangible asset, Net amount	$ 4,061	$ 3,085

Intangible Assets - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization expense for intangible assets	$ 648	$ 475
Estimated aggregate amortization expense of intangible assets in 2017	751
Estimated aggregate amortization expense of intangible assets in 2018	748
Estimated aggregate amortization expense of intangible assets in 2019	727
Estimated aggregate amortization expense of intangible assets in 2020	690
Estimated aggregate amortization expense of intangible assets in 2021	$ 582

Accrued Expenses - Summary of Accrued Expenses (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Payables and Accruals [Abstract]
Payroll, benefits and related taxes, excluding severance benefits	$ 16,724	$ 24,982
Withholding tax attributable to intercompany interest income	18,138	15,573
Interest on senior notes	8,268	6,831
Outside service fees	1,942	4,423
Others	6,674	8,556
Accrued expenses	$ 51,746	$ 60,365

Accrued Expenses - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 10, 2015
Securities Class Action Complaints [Member]
Other Accrued Liabilities [Line Items]
Proceeds from insurance settlement			$ 29,571
Disbursements of accrued claims and settlements	$ 23,500
Securities Class Action Complaints [Member] \| Accrued Expense [Member]
Other Accrued Liabilities [Line Items]
Accrued claim settlement					$ 23,500	$ 23,500
Voluntary Resignation Program [Member]
Other Accrued Liabilities [Line Items]
Unpaid other termination benefits under the voluntary resignation program, current				$ 1,392
Aggregate other termination benefits expense under the voluntary resignation program		$ 4,241

Derivative Financial Instruments - Details of Derivative Contracts (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Zero Cost Collar One [Member]
Derivative [Line Items]
Date of transaction	Jun. 22, 2017	Nov. 11, 2016
Type of derivative	Zero cost collar
Total notional amount	$ 20,000,000	$ 18,000,000
Month of settlement, start	2018-01	2017-03
Month of settlement, end	2018-02	2017-08
Zero Cost Collar Two [Member]
Derivative [Line Items]
Date of transaction	Sep. 28, 2017
Type of derivative	Zero cost collar
Total notional amount	$ 54,000,000
Month of settlement, start	2018-01
Month of settlement, end	2018-06
Forward [Member]
Derivative [Line Items]
Date of transaction	Sep. 28, 2017
Type of derivative	Forward
Total notional amount	$ 36,000,000
Month of settlement, start	2018-01
Month of settlement, end	2018-06

Derivative Financial Instruments - Fair Values of Outstanding Zero Cost Collar and Forward Contracts Recorded as Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Zero Cost Collars [Member]
Asset Derivatives:
Derivatives designated as hedging instruments, Asset	$ 2,827
Liability Derivatives:
Derivatives designated as hedging instruments, Liability		$ 453
Forward [Member]
Asset Derivatives:
Derivatives designated as hedging instruments, Asset	2,352
Other Current Assets [Member] \| Zero Cost Collars [Member]
Asset Derivatives:
Derivatives designated as hedging instruments, Asset	2,827
Other Current Assets [Member] \| Forward [Member]
Asset Derivatives:
Derivatives designated as hedging instruments, Asset	$ 2,352
Other Current Liabilities [Member] \| Zero Cost Collars [Member]
Liability Derivatives:
Derivatives designated as hedging instruments, Liability		$ 453

Derivative Financial Instruments - Offsetting of Derivative Assets (Detail) $ in Thousands	Dec. 31, 2017 USD ($)
Zero Cost Collars [Member]
Derivative [Line Items]
Asset Derivatives, Gross amounts of recognized assets	$ 2,827
Asset Derivatives, Gross amounts offset in the balance sheets	0
Asset Derivatives, Net amounts of assets presented in the balance sheets	2,827
Asset Derivatives, Gross amounts not offset in the balance sheets, Financial instruments	0
Asset Derivatives, Gross amounts not offset in the balance sheets, Cash collateral pledged	0
Asset Derivatives, Net amount	2,827
Forward [Member]
Derivative [Line Items]
Asset Derivatives, Gross amounts of recognized assets	2,352
Asset Derivatives, Gross amounts offset in the balance sheets	0
Asset Derivatives, Net amounts of assets presented in the balance sheets	2,352
Asset Derivatives, Gross amounts not offset in the balance sheets, Financial instruments	0
Asset Derivatives, Gross amounts not offset in the balance sheets, Cash collateral pledged	0
Asset Derivatives, Net amount	$ 2,352

Derivative Financial Instruments - Offsetting of Derivative Liabilities (Detail) - Zero Cost Collars [Member] $ in Thousands	Dec. 31, 2016 USD ($)
Derivative [Line Items]
Liability Derivatives, Gross amounts of recognized liabilities	$ 453
Liability Derivatives, Gross amounts offset in the balance sheets	0
Liability Derivatives, Net amounts of liabilities presented in the balance sheets	453
Liability Derivatives, Gross amounts not offset in the balance sheets, Financial instruments	0
Liability Derivatives, Gross amounts not offset in the balance sheets, Cash collateral pledged	(650)
Liability Derivatives, Net amount after master netting	$ (197)

Derivative Financial Instruments - Impact of Derivative Instruments on Consolidated Statement of Operations (Detail) - Cash Flow Hedging [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Derivative [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivatives (Effective Portion)	$ 7,736	$ (1,032)
Other Income, Net [Member]
Derivative [Line Items]
Amount of Gain (loss) Recognized in Statement of Operations on Derivatives (Ineffective Portion)	236	(272)
Net Sales [Member]
Derivative [Line Items]
Amount of Gain (loss) Reclassified from AOCI into Statement of Operations (Effective Portion)	2,001
Zero Cost Collars [Member]
Derivative [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivatives (Effective Portion)	4,692	(1,032)
Zero Cost Collars [Member] \| Other Income, Net [Member]
Derivative [Line Items]
Amount of Gain (loss) Recognized in Statement of Operations on Derivatives (Ineffective Portion)	606	(272)
Zero Cost Collars [Member] \| Net Sales [Member]
Derivative [Line Items]
Amount of Gain (loss) Reclassified from AOCI into Statement of Operations (Effective Portion)	1,501	$ (637)
Forward [Member]
Derivative [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivatives (Effective Portion)	3,044
Forward [Member] \| Other Income, Net [Member]
Derivative [Line Items]
Amount of Gain (loss) Recognized in Statement of Operations on Derivatives (Ineffective Portion)	(370)
Forward [Member] \| Net Sales [Member]
Derivative [Line Items]
Amount of Gain (loss) Reclassified from AOCI into Statement of Operations (Effective Portion)	$ 500

Derivative Financial Instruments - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Derivative [Line Items]
Estimated amount reclassified from accumulated other comprehensive income into income, period	12 months
Estimated amount reclassified from accumulated other comprehensive income into income	$ 5,299,000
Zero Cost Collars [Member] \| Nomura Financial Investment (Korea) Co., Ltd. [Member]
Derivative [Line Items]
Deposit with counterparty		$ 2,500,000
Cash collateral for credit exposure in derivatives		$ 650,000
Zero Cost Collar and Forward Contracts [Member] \| Nomura Financial Investment (Korea) Co., Ltd. [Member]
Derivative [Line Items]
Deposit with counterparty	7,600,000
Threshold amount of cash collateral	500,000
Cash collateral for credit exposure in derivatives	0
Termination provisions for cash and cash equivalents	$ 30,000,000

Product Warranties - Schedule of Changes in Accrued Warranty Liabilities (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Beginning balance	$ 466	$ 1,425	$ 2,973
Change in provision	(224)	(426)	(648)
Usage	(65)	(527)	(758)
Translation adjustments	39	(6)	(142)
Ending balance	$ 216	$ 466	$ 1,425

Long-term Borrowings - Components of Long-term Borrowings (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Less: unamortized discount and debt issuance costs	$ (7,834)	$ (3,918)
Long-term borrowings, net of unamortized discount and debt issuance costs	303,416	221,082
Exchangeable Senior Notes [Member] \| 5.0% Exchangeable Senior Notes due March 2021 [Member]
Debt Instrument [Line Items]
Long-term borrowings	86,250
Senior Notes [Member] \| 6.625% Senior Notes Due 2021 [Member]
Debt Instrument [Line Items]
Long-term borrowings	$ 225,000	$ 225,000

Long-term Borrowings - Components of Long-term Borrowings (Parenthetical) (Detail)			12 Months Ended
	Jan. 17, 2017	Jul. 18, 2013	Dec. 31, 2017	Dec. 31, 2016
5.0% Exchangeable Senior Notes due March 2021 [Member] \| Exchangeable Senior Notes [Member]
Debt Instrument [Line Items]
Interest rate	5.00%		5.00%
Due date	Mar. 01, 2021		Mar. 01, 2021
6.625% Senior Notes Due 2021 [Member] \| Senior Notes [Member]
Debt Instrument [Line Items]
Interest rate		6.625%	6.625%	6.625%
Due date		Jul. 15, 2021	Jul. 15, 2021	Jul. 15, 2021

Long-Term Borrowings - Additional Information (Detail) - USD ($)			12 Months Ended
	Jan. 17, 2017	Jul. 18, 2013	Dec. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Repurchase of common stock, shares			1,795,444
Repurchase of common stock			$ 11,401,000
Debt issuance costs paid			5,902,000
Interest expense related to the Exchangeable Notes			$ 5,349,000
6.625% Senior Notes Due 2021 [Member] \| Senior Notes [Member]
Debt Instrument [Line Items]
Aggregate principal amount		$ 225,000,000
Interest rate		6.625%	6.625%	6.625%
Due date		Jul. 15, 2021	Jul. 15, 2021	Jul. 15, 2021
Aggregate principal amount of senior notes pricing		99.50%
Debt issuance costs paid		$ 5,120,000
Interest expense related to the Exchangeable Notes			$ 15,664,000	$ 15,613,000
Original debt issue discount		$ 1,125,000
6.625% Senior Notes Due 2021 [Member] \| Senior Notes [Member] \| 2017 [Member]
Debt Instrument [Line Items]
Redemption price plus accrued, unpaid interest and special interest to the date of redemption			103.313%
6.625% Senior Notes Due 2021 [Member] \| Senior Notes [Member] \| 2018 [Member]
Debt Instrument [Line Items]
Redemption price plus accrued, unpaid interest and special interest to the date of redemption			101.656%
6.625% Senior Notes Due 2021 [Member] \| Senior Notes [Member] \| 2019 [Member]
Debt Instrument [Line Items]
Redemption price plus accrued, unpaid interest and special interest to the date of redemption			100.00%
5.0% Exchangeable Senior Notes due March 2021 [Member] \| Exchangeable Senior Notes [Member]
Debt Instrument [Line Items]
Aggregate principal amount	$ 86,250,000
Interest rate	5.00%		5.00%
Due date	Mar. 01, 2021		Mar. 01, 2021
Aggregate principal amount of senior notes pricing	5.00%
Convertible notes principal amount denomination value			$ 1,000
Conversion of converted notes, shares issued			121.1387
Exchange price			$ 8.26
Redemption price plus accrued, unpaid interest and special interest to the date of redemption			100.00%
Minimum required percentage of holders to declare repurchase of notes			25.00%
Percentage of notes to repurchased on declaration by minimum required holders			100.00%
Debt issuance costs paid	$ 5,902,000		$ 5,902,000
Interest expense related to the Exchangeable Notes			$ 5,349,000

Accrued Severance Benefits - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2017
Percentage of employees eligible for severance benefits	98.00%
Korea [Member] \| Minimum [Member]
Retirement age of employees	57 years
Korea [Member] \| Maximum [Member]
Retirement age of employees	60 years

Accrued Severance Benefits - Changes in Accrued Severance Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Postemployment Benefits [Abstract]
Beginning balance	$ 130,144	$ 135,160
Provisions	24,373	14,432	$ 15,289
Severance payments	(21,506)	(15,352)	(11,394)
Translation adjustments	16,785	(4,096)
Ending balance	149,796	130,144	$ 135,160
Less: Cumulative contributions to the National Pension Fund	(259)	(276)
Group severance insurance plan	(632)	(643)
Accrued severance benefits, net	$ 148,905	$ 129,225

Accrued Severance Benefits - Future Benefits Payments to Employees (Detail) $ in Thousands	Dec. 31, 2017 USD ($)
Retirement Benefits [Abstract]
2018	$ 0
2019	610
2020	1,094
2021	1,573
2022	1,584
2023 - 2027	$ 20,541

Common Stock - Additional Information (Detail) - $ / shares	Dec. 31, 2017	Dec. 31, 2016
Equity [Abstract]
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	150,000,000	150,000,000
Common stock, shares issued	42,563,808	41,627,103
Common stock, shares outstanding	34,189,599	35,048,338

Common Stock - Schedule of Changes in Common Stock (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Class of Stock [Line Items]
Balance, Shares beginning	35,048,338
Exercise of stock options, Shares	539,183	296,103	512,474
Acquisition of treasury stock, Shares	(1,795,444)
Balance, Shares ending	34,189,599	35,048,338
Balance, beginning	$ (72,114)	$ (62,330)	$ (18,502)
Exercise of stock options	3,744	1,733	3,436
Acquisitions of treasury stock	11,401
Balance, ending	(39,637)	(72,114)	(62,330)
Common Stock [Member]
Class of Stock [Line Items]
Balance, beginning	416	411	406
Exercise of stock options	6	3	5
Settlement of restricted stock units	4	2
Acquisitions of treasury stock	0	0
Balance, ending	$ 426	$ 416	$ 411
Common Stock Outstanding [Member]
Class of Stock [Line Items]
Balance, Shares beginning	35,048,338	34,568,942	34,056,468
Exercise of stock options, Shares	539,183	296,103	512,474
Settlement of restricted stock units, Shares	397,522	183,293
Acquisition of treasury stock, Shares	(1,795,444)
Balance, Shares ending	34,189,599	35,048,338	34,568,942

Equity Incentive Plans - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options period shall not exceed from the date of grant	10 years
Number of shares authorized	7,975,000
Number of shares reserved for future issuance	1,104,000
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated share based compensation expense	$ 1,601	$ 2,292	$ 1,400
Unrecognized compensation cost related to unvested restricted stock units	$ 1,364
Unrecognized compensation cost, period for recognition	9 months 18 days
Fair value of restricted stock units vested	$ 2,107	717	993
Restricted Stock Units [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock vesting period	1 year
Restricted Stock Units [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock vesting period	3 years
Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated share based compensation expense	$ 734	1,551	1,368
Unrecognized compensation cost, period for recognition	7 months 6 days
Unrecognized compensation cost related to stock options	$ 339
Weighted average grant-date fair value of vested options	$ 794	$ 1,011	$ 1,361
Options [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock vesting period	1 year
Options [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock vesting period	3 years

Equity Incentive Plans - Summary of Restricted Stock Unit Activities (Detail) - Restricted Stock Units [Member] - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Restricted Stock Units, Outstanding Beginning Balance	518,480	135,370
Number of Restricted Stock Units, Granted	172,716	505,689	265,332
Number of Restricted Stock Units, Vested	(368,555)	(101,240)	(129,962)
Number of Restricted Stock Units, Forfeited	(830)	(21,339)
Number of Restricted Stock Units, Outstanding Ending Balance	321,811	518,480	135,370
Weighted Average Grant-Date Fair Value of Restricted Stock Units, Outstanding Beginning Balance	$ 5.94	$ 7.72
Weighted Average Grant-Date Fair Value of Restricted Stock Units, Granted	11.15	5.71	$ 7.68
Weighted Average Grant-Date Fair Value of Restricted Stock Units, Vested	5.72	7.09	7.64
Weighted Average Grant-Date Fair Value of Restricted Stock Units, Forfeited	8.33	6.24
Weighted Average Grant-Date Fair Value of Restricted Stock Units, Outstanding Ending Balance	$ 8.99	$ 5.94	$ 7.72

Equity Incentive Plans - Summary of Stock Option Activities (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Outstanding Beginning Balance, Number of Options	3,428,665	3,179,899	3,215,945
Granted, Number of Options	70,865	827,406	802,193
Forfeited, Number of Options	(88,443)	(282,537)	(325,765)
Exercised, Number of Options	(539,183)	(296,103)	(512,474)
Outstanding Ending Balance, Number of Options	2,871,904	3,428,665	3,179,899	3,215,945
Vested and expected to vest, Number of Options	2,865,475	3,389,763	3,155,828
Exercisable, Number of Options	2,395,979	2,531,243	2,547,902
Outstanding Beginning Balance, Weighted Average Exercise Price of Stock Options	$ 9.23	$ 9.61	$ 9.60
Granted, Weighted Average Exercise Price of Stock Options	10.43	6.04	7.92
Forfeited, Weighted Average Exercise Price of Stock Options	12.77	7.67	9.88
Exercised, Weighted Average Exercise Price of Stock Options	6.94	5.85	6.70
Outstanding Ending Balance, Weighted Average Exercise Price of Stock Options	9.59	9.23	9.61	$ 9.60
Vested and expected to vest, Weighted Average Exercise Price of Stock Options	9.59	9.27	9.62
Exercisable, Weighted Average Exercise Price of Stock Options	$ 10.11	$ 10.11	$ 9.63
Outstanding Beginning Balance, Aggregate Intrinsic Value of Stock Options	$ 525		$ 39,615
Exercised, Aggregate Intrinsic Value of Stock Options	1,540	$ 806	$ 692
Outstanding Ending Balance, Aggregate Intrinsic Value of Stock Options	6,073	525		$ 39,615
Vested and expected to vest, Aggregate Intrinsic Value of Stock Options	6,050	508
Exercisable, Aggregate Intrinsic Value of Stock Options	$ 4,603	$ 236
Outstanding, Weighted Average Remaining Contractual Life of Stock Options	6 years 2 months 12 days	6 years 8 months 12 days	6 years 8 months 12 days	6 years 7 months 6 days
Vested and expected to vest, Weighted Average Remaining Contractual Life of Stock Options	6 years 2 months 12 days	6 years 8 months 12 days	6 years 8 months 12 days
Exercisable, Weighted Average Remaining Contractual Life of Stock Options	5 years 8 months 12 days	5 years 10 months 25 days	6 years
Outstanding, Weighted Average Remaining Contractual Life of Stock Options	6 years 2 months 12 days	6 years 8 months 12 days	6 years 8 months 12 days	6 years 7 months 6 days

Equity Incentive Plans - Assumptions used in Black-Scholes Option-Pricing Model on Weighted Average Basis (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Grant-date fair value of option	$ 5.02	$ 1.54	$ 1.67
Expected term	2 years 6 months	2 years 8 months 12 days	2 years 4 months 24 days
Risk-free interest rate	1.20%	1.00%	0.80%
Expected volatility	81.70%	36.80%	33.80%
Expected dividends	0.00%	0.00%	0.00%

Equity Incentive Plans - Number and Weighted Average Grant-Date Fair Value of Unvested Stock Options (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Outstanding Beginning Balance, Number of Options	897,421	631,997	455,543
Granted options during the period, Number	70,865	827,406	802,193
Vested options during the period, Number	(455,301)	(446,570)	(532,682)
Forfeited options during the period, Number	(19,031)	(85,934)	(92,959)
Exercised options during the period, Number	(18,029)	(29,478)	(98)
Outstanding Ending Balance, Number of Options	475,925	897,421	631,997
Unvested options at the beginning of the period, Weighted Average Grant-Date Fair Value	$ 1.72	$ 2.40	$ 4.18
Granted options during the period, Weighted Average Grant-Date Fair Value	5.02	1.54	1.67
Vested options during the period, Weighted Average Grant-Date Fair Value	1.74	2.26	2.56
Forfeited options during the period, Weighted Average Grant-Date Fair Value	1.77	1.88	4.01
Exercised options during the period, Weighted Average Grant-Date Fair Value	1.59	1.24	3.08
Unvested options at the end of the period, Weighted Average Grant-Date Fair Value	$ 2.19	$ 1.72	$ 2.40

Restructuring and Other Charges (Gain), Net - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended		3 Months Ended		12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Restructuring Cost and Reserve [Line Items]
Restricted cash		$ 18,251				$ 18,251
Deposits received		16,549				16,549
Gain on sale of machinery and building as part of restructuring					$ 17,010	6,480
Sensor Business [Member]
Restructuring Cost and Reserve [Line Items]
Proceeds from sale of business	$ 1,295
Net gain on sale of business	$ 375
Korea [Member] \| Buildings [Member]
Restructuring Cost and Reserve [Line Items]
Gross proceeds from sale of building		18,204
Value-added tax, for sale of the building		1,655				1,655
Restricted cash		18,204				18,204
Deposits received		$ 16,549				$ 16,549
Decrease in restricted cash due to release			$ 18,204
Korea [Member] \| Buildings [Member] \| Restructuring Gain [Member]
Restructuring Cost and Reserve [Line Items]
Gain on sale of machinery and building as part of restructuring			$ 16,635
6-inch Fabrication Facility Closure [Member]
Restructuring Cost and Reserve [Line Items]
Gain on sale of machinery and building as part of restructuring				$ 7,785
Restructuring related deposits							$ 8,165

Early Termination Charges - Additional Information (Detail) $ in Thousands	3 Months Ended		12 Months Ended
	Jun. 30, 2017 USD ($) Employee_Position	Mar. 31, 2017 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Restructuring Cost and Reserve [Line Items]
Early termination charges			$ 13,369	$ 4,240
Headcount Reduction Plan [Member]
Restructuring Cost and Reserve [Line Items]
Cash payments			$ 31,000
Early termination charges	$ 2,262	$ 11,107
Number of employees elected to resign \| Employee_Position	352

Foreign Currency Gain (Loss), Net - Additional Information (Detail) $ in Thousands	Dec. 31, 2017 USD ($) ₩ / $	Dec. 31, 2016 USD ($) ₩ / $	Dec. 31, 2015 USD ($) ₩ / $
Foreign Currency Transaction [Abstract]
Exchange rates using first base rate \| ₩ / $	1,071.4	1,208.5	1,172.0
Intercompany loan balances \| $	$ 677,267	$ 598,212	$ 591,388

Income Taxes - Components of Income Tax Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income (loss) before income taxes
Domestic	$ 27,461	$ (1,738)	$ 32,903
Foreign	58,630	(24,133)	(132,857)
Income (loss) before income tax expenses	86,091	(25,871)	(99,954)
Current income taxes expense (benefit)
Domestic	(359)	(6)	25
Foreign	3,680	3,386	(14,301)
Uncertain tax position liability	(2,111)	351	(1,211)
Current income taxes expense	1,210	3,731	(15,486)
Deferred income taxes expense (benefit)
Foreign	(55)	13	399
Income tax expense (benefit)	$ 1,155	$ 3,744	$ (15,087)
Effective tax rate	1.30%	(14.50%)	15.10%
Domestic [Member]
Current income taxes expense (benefit)
Uncertain tax position liability	$ (476)	$ 12	$ 10
Foreign [Member]
Current income taxes expense (benefit)
Uncertain tax position liability	$ (1,635)	$ 339	$ (1,220)

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands			3 Months Ended		12 Months Ended
	Sep. 30, 2017	Dec. 31, 2015	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Contingency [Line Items]
Statutory income tax rate						35.00%
Partial unpaid interest amount waiver on intercompany loan								$ 174,000
Income tax benefit recognized		$ 17,800
Tax expense due to change in statutory tax rates, TCJA						$ 13,438
Penalty						4,001	$ 689
Change in net operating loss carry-forwards						6,878
Permanent impairment								(62,334)
Net deferred tax assets		171	$ 264			264	183	171
Deferred tax assets, valuation allowance amount		279,867	251,132			251,132	281,473	279,867	$ 194,739
Net operating loss carry-forwards			770,233			770,233
Net operating loss utilized						$ 417	279	121
Net operating loss expiration date						2037
Income tax benefit, minimum tax amounts refundable, TCJA						$ 381
Income tax expenses (benefits)						1,155	3,744	(15,087)
Recognized interest and penalties as income tax expense						(712)
Total interest and penalties accrued		$ 359	8			8	$ 691	$ 359
Income tax penalties	$ 6,030
Accrued tax penalties	3,336
Employee withholding amounts	548
Administrative fine related to tax audit	$ 2,034
Selling, General and Administrative Expenses [Member]
Income Tax Contingency [Line Items]
Income tax penalties			4,179
Other Receivable [Member]
Income Tax Contingency [Line Items]
Employee withholding amounts			548
Securities and Exchange Commission Actions [Member]
Income Tax Contingency [Line Items]
Settlement charge				$ 3,000		3,000
Scenario, Forecast [Member]
Income Tax Contingency [Line Items]
Statutory income tax rate					21.00%
KNTS Audit [Member]
Income Tax Contingency [Line Items]
Income tax expenses (benefits)						676
Luxembourg Subsidiary [Member]
Income Tax Contingency [Line Items]
Net operating loss carry-forwards			310,975			310,975
Korean Statutory Tax Rate [Member]
Income Tax Contingency [Line Items]
Tax credit carry-forwards			5,639			$ 5,639
Net operating loss carry-forwards, expiration period						The Korean tax credits expire at various dates starting from 2018 to 2022
Dutch [Member]
Income Tax Contingency [Line Items]
Tax credit carry-forwards			14,936			$ 14,936
Net operating loss carry-forwards, expiration period						Indefinite period of time
U.S [Member]
Income Tax Contingency [Line Items]
Tax credit carry-forwards			9			$ 9
Korean Subsidiary [Member]
Income Tax Contingency [Line Items]
Statutory income tax rate						24.20%	24.20%	24.20%
Net operating loss carry-forwards			$ 281,383			$ 281,383
Net operating loss expiration date						2026

Income Taxes - Difference Between Provision for Domestic and Foreign Income Taxes and Amount Calculated by Statutory Tax Rate to Net Income Before Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Provision computed at statutory rate	$ 30,223	$ (9,055)	$ (34,984)
Change in statutory tax rates	13,438
Difference in foreign tax rates	(12,344)	1,995	24,359
Permanent differences
Derivative assets adjustment	1,937	(149)	(143)
TPECs, hybrid and other interest	(7,526)	(10,353)	(27,273)
Permanent impairment			(62,334)
Thin capitalization	1,888	2,120	2,457
Permanent foreign currency gain (loss)	(838)	(54)	11,575
Penalty	4,001	689
Non-deductible bad debt expense			89
Other permanent differences	633	50	(69)
Withholding tax	3,339	3,092	(14,457)
Foreign exchange rate adjustment	16,075	(1,838)	(8,954)
Change in valuation allowance	(56,744)	10,095	95,757
Tax credits claimed	(659)	(706)	(875)
Tax credits expired	2,638	1,578
Uncertain tax positions liability	(2,111)	351	(1,211)
Change in net operating loss carry-forwards	6,878
Others	327	5,929	976
Income tax expense (benefit)	$ 1,155	$ 3,744	$ (15,087)

Income Taxes - Summary of Composition of Net Deferred Income Tax Assets (Liabilities) (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Deferred tax assets
Inventory reserves	$ 1,630	$ 1,822
Derivative assets		110
Derivative liabilities	(1,253)
Accrued expenses	2,826	2,803
Product warranties	52	113
Other reserves	356	372
Property, plant and equipment	9,759	13,314
Intangible assets	35	103
Accumulated severance benefits	36,245	31,478
Foreign currency translation losses	20,067	53,130
NOL carry-forwards	175,543	167,590
Tax credit	20,583	20,249
Other long-term payable	1,801	2,079
Others	3,546	4,885
Total deferred tax assets	271,190	298,048
Less: Valuation allowance	(251,132)	(281,473)	$ (279,867)	$ (194,739)
Deferred tax assets, net	20,058	16,575
Deferred tax liabilities
Foreign currency translation gains	18,187	14,338
Prepaid expense	1,464	1,644
Others	143	410
Total deferred tax liabilities	19,794	16,392
Net deferred tax assets	264	183	171
Reported as
Current deferred income tax assets		37
Non-current deferred income tax assets	264	193
Current deferred income tax liabilities		(46)
Non-current deferred income tax liabilities		(1)
Net deferred tax assets	$ 264	$ 183	$ 171

Income Taxes - Changes in Valuation Allowance for Deferred Tax Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Beginning balance	$ 281,473	$ 279,867	$ 194,739
Charged to expense	(54,816)	10,095	95,757
NOL/tax credit claimed/expired	(1,928)	(872)	(1,197)
Translation adjustments	26,403	(7,617)	(9,432)
Ending balance	$ 251,132	$ 281,473	$ 279,867

Income Taxes - Reconciliation of Total Amounts of Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Unrecognized tax benefits, balance at the beginning	$ 2,459	$ 2,139	$ 3,495
Additions based on tax positions related to the current year	10	371	351
Additions for tax positions of prior years		317
Reductions for tax positions of prior years	(676)		(135)
Lapse of statute of limitations	(735)	(670)	(1,318)
Additions (reductions) of interest and penalties	(712)	334	(108)
Translation adjustments	137	(32)	(146)
Unrecognized tax benefits, balance at the ending	$ 483	$ 2,459	$ 2,139

Income Taxes - Reconciliation of Total Amounts of Uncertain Tax Positions (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Uncertain tax positions, balance at the beginning	$ 11,894	$ 13,330	$ 14,969
Additions based on tax positions related to the current year	(366)	942	1,789
Additions (reductions) for tax positions of prior years	(8,923)	317
Lapse of statute of limitations	(2,218)	(2,380)	(2,142)
Translation adjustments	675	(315)	(1,287)
Uncertain tax positions, balance at the ending	$ 1,062	$ 11,894	$ 13,330

Geographic and Segment Information - Additional Information (Detail)	3 Months Ended		12 Months Ended
	Jun. 30, 2015 Segments	Mar. 31, 2015 Segments	Dec. 31, 2017 Customer Segments	Dec. 31, 2016 Customer	Dec. 31, 2015 Customer
Revenues from External Customers and Long-Lived Assets [Line Items]
Number of operating segments \| Segments	2		2
As Previously Reported [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Number of operating segments \| Segments		1
Customer Concentration Risk [Member] \| Net Sales [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Number of customers greater than ten percent threshold \| Customer			1	2	2
Customer Concentration Risk [Member] \| Net Sales [Member] \| Top Ten Customers [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk, percentage			57.00%	64.00%	64.00%
Number of customers \| Customer			10	10	10
Customer Concentration Risk [Member] \| Net Sales [Member] \| Top Customer One [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk, percentage			15.60%	23.50%	15.20%
Customer Concentration Risk [Member] \| Net Sales [Member] \| Top Customer Two [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk, percentage				11.40%	11.00%
Geographic Concentration Risk [Member] \| Property, Plant and Equipment [Member] \| Korea [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk, percentage			97.00%

Geographic and Segment Information - Schedule of Operating Segment (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Total net sales	$ 174,580	$ 176,697	$ 166,685	$ 161,710	$ 180,462	$ 192,296	$ 167,106	$ 148,105	$ 679,672	$ 687,969	$ 633,712
Total gross profit	$ 49,351	$ 50,310	$ 46,662	$ 41,570	$ 46,089	$ 39,139	$ 36,749	$ 34,249	187,893	156,226	134,864
Operating Segments [Member] \| Foundry Services Group [Member]
Segment Reporting Information [Line Items]
Total net sales									320,089	273,961	290,775
Total gross profit									95,458	69,412	66,175
Operating Segments [Member] \| Standard Products Group [Member]
Segment Reporting Information [Line Items]
Total net sales									359,375	413,435	342,294
Total gross profit									92,227	87,194	68,094
Operating Segments [Member] \| Standard Products Group [Member] \| Display Solutions [Member]
Segment Reporting Information [Line Items]
Total net sales									209,539	281,967	207,480
Operating Segments [Member] \| Standard Products Group [Member] \| Power Solutions [Member]
Segment Reporting Information [Line Items]
Total net sales									149,836	131,468	134,814
All Other [Member]
Segment Reporting Information [Line Items]
Total net sales									208	573	643
Total gross profit									$ 208	$ (380)	$ 595

Geographic and Segment Information - Net Sales by Region, Based on Location of Products are Billed (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenues from External Customers and Long-Lived Assets [Line Items]
Total net sales	$ 174,580	$ 176,697	$ 166,685	$ 161,710	$ 180,462	$ 192,296	$ 167,106	$ 148,105	$ 679,672	$ 687,969	$ 633,712
Korea [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total net sales									279,883	219,618	241,715
Asia Pacific (Other Than Korea) [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total net sales									322,595	391,875	316,562
U.S.A. [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total net sales									35,089	33,201	51,164
Europe [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total net sales									41,109	42,274	23,461
Others [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total net sales									$ 996	$ 1,001	$ 810

Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Thousands			3 Months Ended				12 Months Ended
	Oct. 18, 2016	Feb. 05, 2016	Jun. 30, 2017	Mar. 31, 2017	Sep. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 10, 2015
Loss Contingencies [Line Items]
Initial term of leases							20 years
Renewal terms of leases							10 years
Notice period upon cancellation of leases							90 days
Rental expenses							$ 7,498	$ 8,898	$ 8,194
Restricted cash								18,251
Shareholder Derivative Actions [Member]
Loss Contingencies [Line Items]
Attorneys' fee and litigation expenses	$ 750
Settlement charge paid								2,258
Proceeds from insurance settlement						$ 3,000
Insurance proceeds in restricted cash reclassified from other receivables								(3,078)
Settlement charge paid, portion excluding interest								$ 2,250
Securities Class Action Complaints [Member]
Loss Contingencies [Line Items]
Damages sought		$ 23,500
Proceeds from insurance settlement						29,571
Insurance proceeds in restricted cash reclassified from other receivables						$ 29,571
Disbursements of accrued claims and settlements					$ 23,500
Restricted cash					$ 6,114
Securities Class Action Complaints [Member] \| Accrued Expense [Member]
Loss Contingencies [Line Items]
Accrued claim settlement									23,500	$ 23,500
Securities Class Action Complaints [Member] \| Other Receivables [Member]
Loss Contingencies [Line Items]
Insurance receivable									$ 29,571
Securities and Exchange Commission Actions [Member]
Loss Contingencies [Line Items]
Attorneys' fee and litigation expenses				$ 3,000			$ 3,000
Settlement charge paid			$ 3,000

Commitments and Contingencies - Schedule of Minimum Aggregate Rental Payments Due Under Non-Cancelable Lease Contracts (Detail) $ in Thousands	Dec. 31, 2017 USD ($)
Commitments and Contingencies Disclosure [Abstract]
2018	$ 6,724
2019	3,764
2020	3,459
2021	1,472
2022	1,316
2023 and thereafter	15,448
Minimum aggregate rental payments due under non-cancelable lease contracts	$ 32,183

Related Party Transactions - Additional Information (Detail) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2017	Nov. 07, 2017
Related Party Transaction [Line Items]
Stock repurchased, shares		1,795,444
Stock repurchased, value		$ 11,401,000
Engaged Capital, LLC [Member]
Related Party Transaction [Line Items]
Common stock outstanding affiliated percentage	11.90%
Maximum percentage of exchangeable notes conversion	9.99%
Engaged Capital, LLC [Member] \| Maximum [Member]
Related Party Transaction [Line Items]
Common stock outstanding affiliated percentage			5.00%
Engaged Capital Flagship Master Fund, LP [Member]
Related Party Transaction [Line Items]
Aggregate principal amount	$ 4,496,288
Stock repurchased, shares	347,850
Stock repurchased, value	$ 2,209,000
Engaged Capital Account [Member]
Related Party Transaction [Line Items]
Aggregate principal amount	$ 503,712
Stock repurchased, shares	52,150
Stock repurchased, value	$ 331,000

Accumulated Other Comprehensive Income (Loss) - Schedule of Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Equity [Abstract]
Foreign currency translation adjustments	$ (38,413)	$ 14,460
Derivative adjustments	5,299	(436)
Total	$ (33,114)	$ 14,024

Accumulated Other Comprehensive Income (Loss) - Changes in Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning	$ (72,114)	$ (62,330)	$ (18,502)
Total other comprehensive income (loss)	(47,138)	14,255	34,835
Balance, ending	(39,637)	(72,114)	(62,330)
Foreign Currency Translation Adjustments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning	14,460	(190)	(35,551)
Other comprehensive income (loss) before reclassifications	(52,873)	14,650	35,361
Total other comprehensive income (loss)	(52,873)	14,650	35,361
Balance, ending	(38,413)	14,460	(190)
Derivative Adjustments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning	(436)	(41)	485
Other comprehensive income (loss) before reclassifications	7,736	(1,032)	(3,748)
Amounts reclassified from accumulated other comprehensive income (loss)	(2,001)	637	3,222
Total other comprehensive income (loss)	5,735	(395)	(526)
Balance, ending	5,299	(436)	(41)
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning	14,024	(231)	(35,066)
Other comprehensive income (loss) before reclassifications	(45,137)	13,618	31,613
Amounts reclassified from accumulated other comprehensive income (loss)	(2,001)	637	3,222
Total other comprehensive income (loss)	(47,138)	14,255	34,835
Balance, ending	$ (33,114)	$ 14,024	$ (231)

Earnings (Loss) per Share - Schedule of Computation of Basic and Diluted Earnings (Loss) Per Common Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Earnings Per Share [Abstract]
Net income (loss)	$ 43,653	$ 5,604	$ (8,059)	$ 43,738	$ (49,790)	$ 29,866	$ (17,816)	$ 8,125	$ 84,936	$ (29,615)	$ (84,867)
Basic weighted average common stock outstanding	34,176,812	34,103,029	33,952,574	33,662,297	35,068,330	34,849,805	34,716,081	34,698,904	33,943,264	34,833,967	34,380,517
Basic earnings (loss) per share	$ 1.28	$ 0.16	$ (0.24)	$ 1.30	$ (1.42)	$ 0.86	$ (0.51)	$ 0.23	$ 2.50	$ (0.85)	$ (2.47)
Diluted Earnings per Share
Net income (loss)	$ 43,653	$ 5,604	$ (8,059)	$ 43,738	$ (49,790)	$ 29,866	$ (17,816)	$ 8,125	$ 84,936	$ (29,615)	$ (84,867)
Add back: Interest expense on Exchangeable Notes									5,349
Net income (loss) allocated to common stockholders									$ 90,285	$ (29,615)	$ (84,867)
Basic weighted average common stock outstanding	34,176,812	34,103,029	33,952,574	33,662,297	35,068,330	34,849,805	34,716,081	34,698,904	33,943,264	34,833,967	34,380,517
Net effect of dilutive equity awards									821,664
Net effect of assumed conversion of 5.0% Exchangeable Notes to common stock									9,990,209
Diluted weighted average common stock outstanding	45,573,889	45,542,418	33,952,574	42,892,044	35,068,330	35,302,706	34,716,081	34,918,568	44,755,137	34,833,967	34,380,517
Diluted earnings (loss) per share	$ 0.99	$ 0.15	$ (0.24)	$ 1.05	$ (1.42)	$ 0.85	$ (0.51)	$ 0.23	$ 2.02	$ (0.85)	$ (2.47)

Earnings (Loss) per Share - Schedule of Computation of Basic and Diluted Earnings (Loss) Per Common Share (Parenthetical) (Detail)	Dec. 31, 2017	Jan. 17, 2017
5.0% Exchangeable Senior Notes due March 2021 [Member] \| Exchangeable Senior Notes [Member]
Earnings Per Share [Line Items]
Conversion of exchangeable notes to common stock rate	5.00%	5.00%

Earnings (Loss) per Share - Schedule of Antidilutive Securities Excluded from the Computation of Loss Per Common Share (Detail) - shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Outstanding units and warrants excluded from computation of diluted loss per share/unit	835,572	3,428,665	3,179,899
Restricted Stock Units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Outstanding units and warrants excluded from computation of diluted loss per share/unit		518,480	135,370

Quarterly Financial Result - Schedule of Selected Consolidated Statements of Operations (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Quarterly Financial Information Disclosure [Abstract]
Net sales	$ 174,580	$ 176,697	$ 166,685	$ 161,710	$ 180,462	$ 192,296	$ 167,106	$ 148,105	$ 679,672	$ 687,969	$ 633,712
Gross profit	49,351	50,310	46,662	41,570	46,089	39,139	36,749	34,249	187,893	156,226	134,864
Operating income (loss)	7,637	15,490	9,742	6,367	5,229	618	(7,377)	4,267	39,236	2,737	(42,934)
Net income (loss)	$ 43,653	$ 5,604	$ (8,059)	$ 43,738	$ (49,790)	$ 29,866	$ (17,816)	$ 8,125	$ 84,936	$ (29,615)	$ (84,867)
Earnings (loss) per share:
Basic	$ 1.28	$ 0.16	$ (0.24)	$ 1.30	$ (1.42)	$ 0.86	$ (0.51)	$ 0.23	$ 2.50	$ (0.85)	$ (2.47)
Diluted	$ 0.99	$ 0.15	$ (0.24)	$ 1.05	$ (1.42)	$ 0.85	$ (0.51)	$ 0.23	$ 2.02	$ (0.85)	$ (2.47)
Weighted average common stock outstanding:
Basic	34,176,812	34,103,029	33,952,574	33,662,297	35,068,330	34,849,805	34,716,081	34,698,904	33,943,264	34,833,967	34,380,517
Diluted	45,573,889	45,542,418	33,952,574	42,892,044	35,068,330	35,302,706	34,716,081	34,918,568	44,755,137	34,833,967	34,380,517