View Filing Data

Print Document View Excel Document

Document and Entity Information Document - USD ($)	12 Months Ended
Document and Entity Information Document - USD ($)	Dec. 26, 2015	Mar. 03, 2016	Jun. 26, 2015
Document and Entity Information [Abstract]
Entity Registrant Name	FORMFACTOR INC.
Entity Central Index Key	0001039399
Current Fiscal Year End Date	--12-26
Entity Filer Category	Accelerated Filer
Document Type	10-K
Document Period End Date	Dec. 26, 2015
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Common Stock, Shares Outstanding (in shares)		58,912,756
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 363,290,833

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 26, 2015	Dec. 27, 2014
Current assets:
Cash and cash equivalents	$ 146,264	$ 113,940
Marketable securities	41,325	49,897
Accounts receivable, net	36,725	45,152
Inventories, net	27,223	25,548
Deferred tax assets	0	2,036
Refundable income taxes	0	782
Prepaid expenses and other current assets	6,481	6,919
Total current assets	258,018	244,274
Restricted cash	435	435
Property, plant and equipment, net	23,853	25,498
Goodwill	30,731	30,731
Intangibles, net	25,552	38,689
Deferred tax assets	3,281	3,466
Other assets	853	1,150
Total assets	342,723	344,243
Current liabilities:
Accounts payable	18,072	20,274
Accrued liabilities	21,507	21,217
Income taxes payable	110	68
Deferred revenue	3,892	6,303
Total current liabilities	43,581	47,862
Long-term income taxes payable	1,069	1,094
Deferred tax liabilities	0	2,208
Deferred rent and other liabilities	3,392	3,643
Total liabilities	48,042	54,807
Commitments and contingencies (Note 9)
Stockholders' equity:
10,000,000 shares authorized; no shares issued and outstanding at December 26, 2015 and December 27, 2014	0	0
250,000,000 shares authorized; 58,088,969 and 56,518,428 shares issued and outstanding at December 26, 2015 and December 27, 2014, respectively	58	57
Additional paid-in capital	718,904	711,676
Accumulated other comprehensive loss	(2,222)	(1,761)
Accumulated deficit	(422,059)	(420,536)
Total stockholders' equity	294,681	289,436
Total liabilities and stockholders' equity	$ 342,723	$ 344,243

CONSOLIDATED BALANCE SHEETS (PARENTHETICAL) - $ / shares	Dec. 26, 2015	Dec. 27, 2014
Statement of Financial Position [Abstract]
Preferred Stock, Par or Stated Value (Per Share)	$ 0.001	$ 0.001
Preferred Stock, Shares Authorized (Shares)	10,000,000	10,000,000
Preferred Stock, Shares Issued	0	0
Preferred Stock, Shares Outstanding	0	0
Common Stock, Par or Stated Value Per Share	$ 0.001	$ 0.001
Common Stock, Shares Authorized	250,000,000	250,000,000
Common Stock, Shares, Issued	58,088,969	56,518,428
Common Stock, Shares, Outstanding	58,088,969	56,518,428

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Income Statement [Abstract]
Revenues	$ 282,358	$ 268,530	$ 231,533
Cost of revenues	196,620	191,091	189,249
Gross profit	85,738	77,439	42,284
Operating expenses:
Research and development	44,184	42,725	42,139
Selling, general and administrative	45,090	51,385	53,217
Restructuring charges, net	559	2,668	4,658
Loss on sale of subsidiary	0	0	300
Impairment of long-lived assets	8	1,219	761
Total operating expenses	89,841	97,997	101,075
Operating loss	(4,103)	(20,558)	(58,791)
Interest income, net	285	302	386
Other income, net	2,547	161	623
Loss before income taxes	(1,271)	(20,095)	(57,782)
Provision (benefit) from income taxes	252	(910)	(99)
Net loss	$ (1,523)	$ (19,185)	$ (57,683)
Net loss per share:
Basic and diluted (usd per share)	$ (0.03)	$ (0.34)	$ (1.06)
Weighted-average number of shares used in per share calculations:
Basic and diluted (in shares)	57,850	55,908	54,204

CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Statement of Comprehensive Income [Abstract]
Net loss	$ (1,523)	$ (19,185)	$ (57,683)
Foreign currency translation adjustments	(397)	(1,502)	(1,825)
Unrealized losses on available-for-sale marketable securities	(64)	(10)	(139)
Other comprehensive loss, net of tax	(461)	(1,512)	(1,964)
Comprehensive loss	$ (1,984)	$ (20,697)	$ (59,647)

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References + Details

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Balances at Dec. 29, 2012	$ 339,258	$ 54	$ 681,157	$ 1,715	$ (343,668)
Balances (in shares) at Dec. 29, 2012		53,286,703
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock pursuant to exercise of options for cash	106	$ 0	106	0	0
Issuance of common stock pursuant to exercise of options for cash (in shares)		20,000
Issuance of common stock pursuant to vesting of restricted stock units, net of stock withheld	(4)	$ 0	(4)	0	0
Issuance of common stock pursuant to vesting of restricted stock units, net of stock withheld (in shares)		759,724
Issuance of common stock under the Employee Stock Purchase Plan	2,502	$ 1	2,501	0	0
Issuance of common stock under the Employee Stock Purchase Plan (in shares)		583,173
Stock-based compensation	11,871	$ 0	11,871	0	0
Stock Issued During Period (in shares)		0
Components of other comprehensive income (loss):
Change in unrealized gain (loss) on marketable securities, net of tax	(139)	$ 0	0	(139)	0
Foreign currency translation adjustments	(1,825)	0	0	(1,825)	0
Net loss	(57,683)	0	0	0	(57,683)
Balances at Dec. 28, 2013	294,086	$ 55	695,631	(249)	(401,351)
Balances (in shares) at Dec. 28, 2013		54,649,600
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock pursuant to exercise of options for cash	0	$ 0	0	0	0
Issuance of common stock pursuant to exercise of options for cash (in shares)		0
Issuance of common stock pursuant to vesting of restricted stock units, net of stock withheld	1	$ 1	0	0	0
Issuance of common stock pursuant to vesting of restricted stock units, net of stock withheld (in shares)		1,282,442
Issuance of common stock under the Employee Stock Purchase Plan	2,812	$ 1	2,811	0	0
Issuance of common stock under the Employee Stock Purchase Plan (in shares)		586,386
Stock-based compensation	13,234	$ 0	13,234	0	0
Stock Issued During Period (in shares)		0
Components of other comprehensive income (loss):
Change in unrealized gain (loss) on marketable securities, net of tax	(10)	$ 0	0	(10)	0
Foreign currency translation adjustments	(1,502)	0	0	(1,502)	0
Net loss	(19,185)	0	0	0	(19,185)
Balances at Dec. 27, 2014	$ 289,436	$ 57	711,676	(1,761)	(420,536)
Balances (in shares) at Dec. 27, 2014	56,518,428	56,518,428
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock pursuant to exercise of options for cash	$ 209	$ 0	209	0	0
Issuance of common stock pursuant to exercise of options for cash (in shares)		24,607
Issuance of common stock pursuant to vesting of restricted stock units, net of stock withheld	2	$ 2	0	0	0
Issuance of common stock pursuant to vesting of restricted stock units, net of stock withheld (in shares)		1,993,603
Issuance of common stock under the Employee Stock Purchase Plan	3,206	$ 0	3,206	0	0
Purchase and retirement of common stock (in shares)		(1,013,162)
Purchase and retirement of common stock	(8,211)	$ (1)	(8,210)	0	0
Issuance of common stock under the Employee Stock Purchase Plan (in shares)		565,493
Stock-based compensation	12,023	$ 0	12,023	0	0
Stock Issued During Period (in shares)		0
Components of other comprehensive income (loss):
Change in unrealized gain (loss) on marketable securities, net of tax	(64)	$ 0	0	(64)	0
Foreign currency translation adjustments	(397)	0	0	(397)	0
Net loss	(1,523)	0	0	0	(1,523)
Balances at Dec. 26, 2015	$ 294,681	$ 58	$ 718,904	$ (2,222)	$ (422,059)
Balances (in shares) at Dec. 26, 2015	58,088,969

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Cash flows from operating activities:
Net loss	$ (1,523)	$ (19,185)	$ (57,683)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	23,771	30,491	28,909
(Accretion) amortization of discount on investments	(10)	208	463
Stock-based compensation expense	11,575	13,279	12,124
Deferred income tax (benefit) provision	(14)	230	445
Provision (recovery) for doubtful accounts receivable	18	1	(19)
Provision for excess and obsolete inventories	6,493	7,127	10,461
(Gain) loss on disposal and write-off of long-lived assets	(1,009)	(10)	365
Impairment of long-lived assets	8	1,219	761
Loss on sale of subsidiary	0	0	300
Non-cash restructuring	500	600	2,743
Foreign currency transaction (gains) losses	(275)	2,489	620
Changes in assets and liabilities:
Accounts receivable	8,261	(15,949)	(2,102)
Inventories	(8,167)	(11,975)	(7,980)
Prepaid expenses and other current assets	173	(822)	3,557
Refundable income taxes	782	0	5,143
Other assets	250	25	138
Accounts payable	(2,036)	4,155	(2,324)
Accrued liabilities	(333)	7,765	(2,474)
Income taxes payable	19	(1,511)	(346)
Deferred rent and other liabilities	52	248	83
Deferred revenues	(2,413)	(726)	1,014
Net cash provided by (used in) operating activities	36,122	17,659	(5,802)
Cash flows from investing activities:
Acquisition of property, plant and equipment	(8,640)	(5,670)	(8,530)
Proceeds (use of cash) from sale of subsidiary	53	115	(210)
Proceeds from sale of intellectual property and property, plant and equipment	1,200	1,114	61
Purchases of marketable securities	(66,234)	(31,693)	(91,338)
Proceeds from maturities of marketable securities	74,750	73,473	90,385
Proceeds from sale of marketable securities	0	0	2,000
Change in restricted cash	0	0	(118)
Net cash provided by (used in) investing activities	1,129	37,339	(7,750)
Cash flows from financing activities:
Proceeds from issuances of common stock	3,418	2,813	2,602
Purchase and retirement of common stock	(8,210)	0	0
Payments made on capital leases	0	(271)	(603)
Net cash (used in) provided by financing activities	(4,792)	2,542	1,999
Effect of exchange rate changes on cash and cash equivalents	(135)	(2,796)	(1,494)
Net increase (decrease) in cash and cash equivalents	32,324	54,744	(13,047)
Cash and cash equivalents, beginning of year	113,940	59,196	72,243
Cash and cash equivalents, end of year	146,264	113,940	59,196
Non-cash investing and financing activities:
Changes in accounts payable and accrued liabilities related to property, plant and equipment purchases	361	(122)	1,528
Supplemental disclosure of cash flow information:
Income and property taxes paid (refunded), net	$ 27	$ 950	$ (6,152)

Formation and Business of the Company	12 Months Ended
Formation and Business of the Company	Dec. 26, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Formation and Business of the Company	Formation and Business of the Company FormFactor, Inc. ("FormFactor" or the "Company" and also referred to as "we" or "our") was incorporated in Delaware on April 15, 1993 and designs, develops, manufactures, sells and supports precision, high performance advanced semiconductor probe card products. We are based in Livermore, California, which is our corporate office, research and development center, and one of our manufacturing locations. We have facilities in the United States, Singapore, Japan, Taiwan, South Korea, Germany, Italy and the People's Republic of China. Fiscal Year Our fiscal year ends on the last Saturday in December. The fiscal years ended on December 26, 2015, December 27, 2014 and December 28, 2013, respectively, consisted of 52 weeks each.

Summary of Significant Accounting Policies

12 Months Ended

Dec. 26, 2015

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

Basis of Consolidation and Foreign Currency Translation

The consolidated financial statements include our accounts and those of our wholly-owned subsidiaries. All intercompany balances and transactions have been eliminated.

The functional currencies of certain of our foreign subsidiaries are the local currencies and, accordingly, all assets and liabilities of these foreign operations are translated to U.S. Dollars at current period-end exchange rates, and revenues and expenses are translated to U.S. Dollars using average exchange rates in effect during the period. The gains and losses from the foreign currency translation of these subsidiaries' financial statements are included as a separate component of stockholders' equity under “Accumulated other comprehensive income (loss).”

Certain other of our foreign subsidiaries use the U.S. Dollar as their functional currency. Accordingly, monetary assets and liabilities in non-functional currencies of these subsidiaries are remeasured using exchange rates in effect at the end of the period. Revenues and costs in local currency are remeasured using average exchange rates for the period, except for costs related to those balance sheet items that are remeasured using historical exchange rates. The resulting remeasurement gains and losses are included in the Consolidated Statements of Operations as incurred.

Use of Estimates

The preparation of consolidated financial statements in conformity with accounting principles generally accepted in the United States of America ("GAAP") requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenues and expenses during the reporting period. Estimates may change as new information is obtained. We believe that the estimates, assumptions and judgments involved in revenue recognition, fair value of marketable securities, allowance for doubtful accounts, reserves for product warranty, valuation of obsolete and slow moving inventory, assets acquired and liabilities assumed in business combinations, legal contingencies, valuation of goodwill, the assessment of recoverability of long-lived assets, valuation and recognition of stock-based compensation, provision for income taxes and valuation of deferred tax assets have the greatest potential impact on our consolidated financial statements. Actual results could differ from those estimates.

Business Acquisitions

Our consolidated financial statements include the operations of an acquired business after the completion of the acquisition. We account for acquired businesses using the acquisition method of accounting. The acquisition method of accounting for acquired businesses requires, among other things, that assets acquired and liabilities assumed be recognized at their estimated fair values as of the acquisition date, and that the fair value of acquired intangibles including in-process research and development (IPR&D) be recorded on the balance sheet. Also, transaction costs are expensed as incurred. Any excess of the purchase price over the assigned fair values of the net assets acquired is recorded as goodwill.

Cash, Cash Equivalents and Marketable Securities

Cash and cash equivalents consist of deposits and financial instruments which are readily convertible into cash and have original maturities of 90 days or less at the time of acquisition. Marketable securities consist primarily of highly liquid investments with maturities of greater than 90 days when purchased. We generally classify our marketable securities at the date of acquisition as available-for-sale. These securities are reported at fair value with the related unrealized gains and losses included in "Accumulated other comprehensive income (loss)", a component of stockholder's equity, net of tax. Any unrealized losses which are considered to be other-than-temporary impairments are recorded in "Other income, net" in the Consolidated Statements of Operations. Realized gains (losses) on the sale of marketable securities are determined using the specific-identification method and recorded in "Other income, net" in the Consolidated Statements of Operations.

All of our available-for-sale investments are subject to a periodic impairment review. We record a charge to earnings when a decline in fair value is significantly below cost basis and judged to be other-than-temporary, or have other indicators of impairments. If the fair value of an available-for-sale investment is less than its amortized cost basis, an other-than-temporary impairment is triggered in circumstances where (1) we intend to sell the instrument, (2) it is more likely than not that we will be required to sell the instrument before recovery of its amortized cost basis or (3) a credit loss exists where we do not expect to recover the entire amortized cost basis of the instrument. If we intend to sell or it is more likely than not that we will be required to sell the available-for-sale investment before recovery of its amortized cost basis, we recognize an other-than- temporary impairment charge equal to the entire difference between the investment's amortized cost basis and its fair value.

Fair Value of Financial Instruments

We have evaluated the estimated fair value of financial instruments using available market information and valuations as provided by third-party sources. The use of different market assumptions and/or estimation methodologies could have a significant effect on the estimated fair value amounts. The fair value of the Company's cash, cash equivalents, accounts receivable, accounts payable and other current liabilities approximate their carrying amounts due to the relatively short maturity of these items. Estimates of fair value of our marketable securities are based on quoted market prices from active markets or third party, market-based pricing sources which we believe to be reliable. These estimates represent the third parties' good faith opinion as to what a buyer in the marketplace would pay for a security in a current sale.

Whenever possible, the fair values of our financial assets and liabilities are determined using quoted market prices of identical assets or quoted market prices of similar assets from active markets. The three levels of inputs that may be used to measure fair value are as follows:


•	Level 1 valuations are obtained from real-time quotes for transactions in active exchange markets involving identical assets;


•	Level 2 inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities, quoted prices near the reporting date in markets that are less active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities; and


•	Level 3 valuations are based on unobservable inputs to the valuation methodology and include our own data about assumptions market participants would use in pricing the asset or liability based on the best information available under the circumstances.

Each level of input has different levels of subjectivity and difficulty involved in determining fair value.

Foreign Exchange Management

We transact business in various foreign currencies. We enter into forward foreign exchange contracts in an effort to mitigate the risks associated with currency fluctuations on certain foreign currency balance sheet exposures. Gains and losses resulting from the impact of currency exchange rate movements on forward foreign exchange contracts designated to offset certain foreign currency balance sheet exposures are recognized as "Other income, net" in the Consolidated Statements of Operations in the period in which the exchange rates change. These gains and losses are intended to partially offset the foreign currency exchange gains and losses on the underlying exposures being hedged. We record the fair value of these contracts as of the end of our reporting period in the Consolidated Balance Sheet. We do not use derivative financial instruments for trading or speculative purposes.

Restricted Cash

Under the terms of one of our facility leases, we provide security to the landlord in the form of letters of credit. As of December 26, 2015 and December 27, 2014, restricted cash included $0.4 million, respectively, for letters of credit secured by a certificate of deposit.

Inventories

Inventories are stated at the lower of cost (principally standard cost which approximates actual cost on a first-in, first-out basis) or market value. The provision for potentially excess and obsolete inventory is made based on management's analysis of inventory levels and forecasted future sales. On a quarterly basis, we review inventory quantities on hand and on order under non-cancelable purchase commitments in comparison to our past usage and estimated forecast of product demand for the next six to twelve months to determine what inventory quantities, if any, may not be sellable. Based on this analysis, we write down the affected inventory value for estimated excess and obsolescence charges. Once the value is adjusted, the original cost of our inventory less the related inventory write-down represents the new cost basis of such products. Reversal of these write downs is recognized only when the related inventory has been scrapped or sold. Shipping and handling costs are classified as a component of "Cost of revenues" in the Consolidated Statements of Operations.

We design, manufacture and sell a fully custom product into a market that has been subject to cyclicality and significant demand fluctuations. Probe cards are complex products, custom to a specific chip design and have to be delivered on short lead-times. Probe cards are manufactured in low volumes, but for certain materials, the purchases are often subject to minimum order quantities in excess of the actual underlying probe card demand. It is not uncommon for us to acquire production materials and commence production activities based on estimated production yields and forecasted demand prior to or in excess of actual demand for our probe cards. These factors result in normal recurring inventory valuation adjustments to cost of revenues. Aggregate inventory write downs were $6.5 million, $7.1 million and $10.5 million for fiscal 2015, 2014 and 2013, respectively.

When our products have been delivered, but the revenue associated with that product is deferred because the related revenue recognition criteria have not been met, we may defer the related inventory costs. The deferred inventory costs do not exceed the deferred revenue amounts. The deferred inventory costs are classified as a component of "Prepaid expenses and other current assets" in the Consolidated Balance Sheet.

Property, Plant, and Equipment

Property and equipment is stated at cost less accumulated depreciation and amortization. Depreciation is provided on a straight-line method over the following estimated useful lives of the assets: 1 to 5 years for machinery and equipment, 1 to 5 years for computer equipment and software and 1 to 5 years for furniture and fixtures. Leasehold improvements are amortized over the shorter of the lease term or the estimated useful life of the related asset. Construction-in-progress assets are not depreciated until the assets are placed in service. Upon sale or retirement of assets, the cost and related accumulated depreciation or amortization, are removed from the balance sheet and the resulting gain or loss is reflected in operations.

Goodwill

Goodwill represents the excess of the purchase price over the fair value of identifiable assets acquired and liabilities assumed. Since our acquisition of MicroProbe in Fiscal 2012, we had historically operated in one reportable segment consisting of two operating segments and for the purposes of our goodwill impairment analysis, we had two reporting units, all of which related to our FormFactor and MicroProbe product groups. During the fourth quarter of fiscal 2015, we determined that we now operate in one reportable segment consisting of one operating segment and for the purposes of our goodwill impairment analysis, we further concluded that we now have one reporting unit, all of which relates to the design, development, manufacture and sale of high performance advanced probe cards as a result of the successful integration of the MicroProbe business into our overall consolidated operations.

The Company first assesses qualitative factors to determine whether it is necessary to perform a two-step quantitative goodwill impairment test. If an entity determines as a result of the qualitative assessment that it is more likely than not that the fair value of a reporting unit is less than its carrying amount, then the quantitative impairment test is required. Otherwise, no further testing is required.

The performance of the quantitative impairment test involves a two-step process. The first step of the impairment test involves comparing the fair value of the applicable reporting unit with its aggregate carrying value, including goodwill. We generally determine the fair value of our reporting unit using a combination of the income approach (that includes the use of the discounted cash flow method) and the market approach (guideline company approach) valuation methodologies. If the carrying amount of a reporting unit exceeds the fair value of that reporting unit, we perform the second step of the quantitative impairment test to determine the amount of impairment loss. The second step of the goodwill impairment test involves comparing the implied fair value of the affected reporting unit's goodwill with the carrying value of that goodwill.

Intangible Assets

Intangible assets consist of acquisition related intangible assets and intellectual property. The intangible assets are being amortized over periods which reflect the pattern in which economic benefits of the assets are expected to be realized, over 1 to 10 years. We perform a review of intangible assets when facts and circumstances indicate that the useful life is shorter than originally estimated or that the carrying amount of assets may not be recoverable. Such facts and circumstances include significant adverse changes in the business climate or legal factors; current period cash flow or operating losses combined with a history of losses or a forecast of continuing losses associated with the use of the intangible assets; and current expectation that the intangible assets will more likely than not be sold or disposed of before the end of their estimated useful lives. We assess the recoverability of identified intangible assets by comparing the projected undiscounted net cash flows associated with the related asset or group of assets over their remaining lives against their respective carrying amounts. Impairments, if any, are based on the excess of the carrying amount over the fair value of those assets.

Impairment of Long-Lived Assets

We test long-lived assets or asset groups such as property, plant and equipment and intangible assets for recoverability when events or changes in circumstances indicate that their carrying amounts may not be recoverable. Circumstances which could trigger a review include, but are not limited to: significant decreases in the market price of the asset; significant adverse changes in the business climate or legal factors; accumulation of costs significantly in excess of the amount originally expected for the acquisition or construction of the asset; current period cash flow or operating losses combined with a history of losses or a forecast of continuing losses associated with the use of the asset; and current expectation that the asset will more likely than not be sold or disposed of before the end of its estimated useful life.

Recoverability is assessed based on the carrying amounts of the asset or asset group and the sum of the undiscounted cash flows expected to result from the use and the eventual disposal of the asset. An impairment loss is recognized when the carrying amount is not recoverable and exceeds fair value. Refer to Note 6 to Notes to Consolidated Financial Statements - Impairment of Long-lived Assets, for additional information.

Concentration of Credit Risk and Other Risks and Uncertainties

Financial instruments that potentially subject us to concentrations of credit risk consist primarily of cash equivalents, marketable securities and trade receivables. Our cash equivalents and marketable securities are held in safekeeping by large, credit worthy financial institutions. We invest our excess cash primarily in U.S. banks, government and agency bonds, money market funds and corporate obligations. We have established guidelines relative to credit ratings, diversification and maturities that seek to maintain safety and liquidity. Deposits in these banks may exceed the amounts of insurance provided on such deposits. To date, we have not experienced any losses on our deposits of cash and cash equivalents.

We market and sell our products to a narrow base of customers and generally do not require collateral. The following customers represented greater than 10% of our revenues in fiscal 2015, fiscal 2014 and fiscal 2013:



	Fiscal 2015		Fiscal 2014		Fiscal 2013
Intel	19.6	%	19.7	%	17.7	%
Samsung	14.6		*		*
SK hynix	14.3		16.9		16.5
Micron	11.7		15.0		11.7
Total	60.2	%	51.6	%	45.9	%

* Less than 10% of revenues

At December 26, 2015, one customer accounted for 29% of gross accounts receivable. At December 27, 2014, two customers accounted for 26% and 18% of gross accounts receivable. We operate in the intensely competitive semiconductor industry, including the Dynamic Random Access Memory, or DRAM, Flash memory, and System-on-Chip, or SoC markets, which have been characterized by price erosion, rapid technological change, short product life cycles and heightened foreign and domestic competition. Significant technological changes in the industry could adversely affect our operating results.

We are exposed to non-performance risk by counterparties on the currency forward exchange contracts used in hedging activities. We seek to minimize risk by diversifying our hedging program across multiple financial institutions. These counterparties are large international financial institutions, and to date no such counterparty has failed to meet its financial obligations to us.

Certain components for our wafer probe card products that meet our requirements are available only from a limited number of suppliers. The rapid rate of technological change and the necessity of developing and manufacturing products with short life cycles may intensify our reliance on such suppliers. The inability to obtain components as required, or to develop alternative sources, if and as required in the future, could result in delays or reductions in product shipments, which in turn could have a material adverse effect on our business, financial condition, results of operations or cash flows.

Revenue Recognition

We recognize revenue when persuasive evidence of a sales arrangement exists, title and risk of loss has transferred to the customer, the selling price is fixed or determinable and collection of the related receivable is reasonably assured. In instances where final acceptance of the deliverable is specified by the customer, revenue is deferred until all acceptance criteria have been met. Revenues from the licensing of our design and manufacturing technology, which have not been material to date, are recognized over the term of the license agreement or when the significant contractual obligations have been fulfilled.

Warranty Obligations

We offer warranties on certain products and record a liability for the estimated future costs associated with warranty claims at the time revenue is recognized. The warranty liability is based upon historical experience and our estimate of the level of future costs. While we engage in product quality programs and processes, our warranty obligation is affected by product failure rates, material usage and service delivery costs incurred in correcting a product failure. We continuously monitor product returns for warranty and maintain a reserve for the related expenses based upon our historical experience and any specifically identified field failures. As we sell new products to our customers, we must exercise considerable judgment in estimating the expected failure rates. This estimating process is based on historical experience of similar products, as well as various other assumptions that we believe to be reasonable under the circumstances.

We provide for the estimated cost of product warranties at the time revenue is recognized. Warranty costs are reflected in the Consolidated Statement of Operations as a cost of revenues. A reconciliation of the changes in our warranty liability is as follows (in thousands):



	Fiscal Years Ended
	December 26, 2015			December 27, 2014
Balance at beginning of year	$	1,592		$	691
Accruals	2,536			2,972
Settlements	(3,012		)	(2,071		)
Balance at end of year	$	1,116		$	1,592

Research and Development

Research and development expenses include expenses related to product development, engineering and material costs. All research and development costs are expensed as incurred.

Allowance for Doubtful Accounts

The majority of our trade receivables are derived from sales to large multinational semiconductor manufacturers throughout the world. In order to monitor potential credit losses, we perform ongoing credit evaluations of our customers' financial condition. An allowance for doubtful accounts is maintained based upon our assessment of the expected collectability of all accounts receivable. The allowance for doubtful accounts is reviewed and assessed for adequacy on a quarterly basis. We take into consideration (1) any circumstances of which we are aware of a customer's inability to meet its financial obligations and (2) our judgments as to prevailing economic conditions in the industry and their impact on our customers. If circumstances change, and the financial condition of our customers is adversely affected and they are unable to meet their financial obligations, we may need to take additional allowances, which would result in an increase in our operating expense.

The allowance for doubtful accounts receivable consisted of the following activity for fiscal years 2015, 2014 and 2013 (in thousands):



	Balance at Beginning of Year		Additions		Reductions			Balance at End of Year
Fiscal year ended December 28, 2013	$	289	$	—	$	(24	)	$	265
Fiscal year ended December 27, 2014	265		5		(4		)	266
Fiscal year ended December 26, 2015	$	266	$	20	$	(2	)	$	284

Restructuring Charges

Restructuring charges include costs related to employee termination benefits, cost of long-lived assets abandoned or impaired, as well as contract termination costs. The determination of when we accrue for employee termination benefits depends on whether the termination benefits are provided under a one-time benefit arrangement or under an on-going benefit arrangement. For restructuring charges recorded as an on-going benefit arrangement, a liability for post-employment benefits is recorded when payment is probable, the amount is reasonably estimable, and the obligation relates to rights that have vested or accumulated. For restructuring charges recorded as a one-time benefit arrangement, we recognize a liability for employee termination benefits when a plan of termination, approved by management and establishing the terms of the benefit arrangement, has been communicated to employees. The timing of the recognition of one-time employee termination benefits is dependent upon the period of time the employees are required to render service after communication. If employees are not required to render service in order to receive the termination benefits or if employees will not be retained to render service beyond the minimum legal notification period, a liability for the termination benefits is recognized at the communication date. In instances where employees will be retained to render service beyond the minimum legal notification period, the liability for employee termination benefits is measured initially at the communication date based on the fair value of the liability as of the termination date and is recognized ratably over the future service period. We continually evaluate the adequacy of the remaining liabilities under our restructuring initiatives.

We record charges related to long-lived assets to be abandoned when the assets cease to be used. When we cease using a building or other asset with remaining non-cancelable lease payments continuing beyond our use period, we record a liability for remaining payments under lease arrangements and contract termination costs that continue for the remaining term without economic benefit to us at the cease-use date. Given the significance of, and the timing of the execution of such activities, this process is complex and involves periodic reassessments of estimates made at the time the original decisions were made, including evaluating real estate market conditions for expected vacancy periods and sub-lease rents. Although we believe that these estimates accurately reflect the costs of our restructuring plans, actual results may differ, thereby requiring us to record additional provisions or reverse a portion of such provisions.

The Company recorded restructuring charges of $0.6 million, $2.7 million and $4.7 million for fiscal years 2015, 2014 and 2013, respectively. Refer to Note 4, Restructuring Charges in Notes to Consolidated Financial Statements for further details.

Income Taxes

We utilize the asset and liability method of accounting for income taxes, under which deferred taxes are determined based on the temporary differences between the financial statement and tax basis of assets and liabilities using tax rates expected to be in effect during the years in which the basis differences reverse and for operating losses and tax credit carryforwards. We estimate our provision for income taxes and amounts ultimately payable or recoverable in numerous tax jurisdictions around the world. Estimates involve interpretations of regulations and are inherently complex. Resolution of income tax treatments in individual jurisdictions may not be known for many years after completion of any fiscal year. We are required to evaluate the realizability of our deferred tax assets on an ongoing basis to determine whether there is a need for a valuation allowance with respect to such deferred tax assets. A valuation allowance is recorded when it is more likely than not that some or all of the deferred tax assets will not be realized. Significant management judgment is required in determining any valuation allowance recorded against deferred tax assets. In evaluating the ability to recover deferred tax assets, we consider all available positive and negative evidence giving greater weight to our recent cumulative losses and our ability to carryback losses against prior taxable income and, commensurate with objective verifiability, the forecast of future taxable income including the reversal of temporary differences and the implementation of feasible and prudent tax planning strategies.

We recognize and measure uncertain tax positions taken or expected to be taken in a tax return if it is more likely than not that the tax position will be sustained on examination by the taxing authorities, based on the technical merits of the position. The tax benefits recognized in the consolidated financial statements from such positions are then measured based on the largest benefit that has a greater than 50 percent likelihood of being realized upon ultimate settlement. We report a liability for unrecognized tax benefits resulting from uncertain tax positions taken or expected to be taken in a tax return. We adjust these reserves in light of changing facts and circumstances, such as the closing of a tax audit or the refinement of an estimate. To the extent that the final tax outcome of these matters is different than the amounts recorded, such differences will impact the provision for income taxes in the period in which such determination is made. The provision for income taxes includes the impact of reserve provisions and changes to reserves that are considered appropriate, as well as the related net interest. We recognize interest and penalties related to unrecognized tax benefits within the income tax provision. Accrued interest and penalties are included within the related tax liability caption line in the consolidated balance sheet.

We file annual income tax returns in multiple taxing jurisdictions around the world. A number of years may elapse before an uncertain tax position is audited and finally resolved. While it is often difficult to predict the final outcome or the timing of resolution of any particular uncertain tax position, we believe that our reserves for income taxes reflect the most likely outcome. We adjust these reserves, as well as the related interest, in light of changing facts and circumstances. Settlement of any particular position could require the use of cash.

Stock-Based Compensation

We recognize compensation expense for all stock-based awards based on the grant-date estimated fair values, net of an estimated forfeiture rate. The value of the portion of the award that is ultimately expected to vest is recognized as expense ratably over the requisite service periods in our Consolidated Statement of Operations. The fair value of stock options is measured using the Black-Scholes option pricing model while the fair value for restricted stock awards and restricted stock units is measured based on the closing market price of our common stock on the date of grant.

Net Loss Per Share

Basic net loss per share is computed by dividing net loss by the weighted-average number of common shares outstanding for the period. Diluted net loss per share is computed giving effect to all potential dilutive common stock, including stock options, restricted stock units and common stock subject to repurchase. Diluted loss per share was based only on the weighted-average number of shares outstanding during that period as the inclusion of any common stock equivalents would have been anti-dilutive.

A reconciliation of the numerator and denominator used in the calculation of basic and diluted net loss per share is as follows (in thousands):



	Fiscal Years Ended
	December 26, 2015			December 27, 2014			December 28, 2013
Numerator:
Net loss used in computing basic and diluted net loss per share	$	(1,523	)	$	(19,185	)	$	(57,683	)
Denominator:
Weighted-average shares used in computing basic net loss per share	57,850			55,908			54,204
Add potentially dilutive securities	—			—			—
Weighted-average shares used in computing basic and diluted net loss per share	57,850			55,908			54,204

The following securities were excluded from the calculation of diluted net loss per share because their effect would have been anti-dilutive for the periods presented (in thousands):



	Fiscal Years Ended
	December 26, 2015	December 27, 2014	December 28, 2013
Options to purchase common stock	2,320	2,874	3,805
Restricted stock units	2,578	—	373
Employee stock purchase plan	8	28	22
Total potentially dilutive securities	4,906	2,902	4,200

Accumulated Other Comprehensive Loss

Accumulated other comprehensive loss includes foreign currency translation adjustments and unrealized losses on available-for-sale securities net of tax, the impact of which has been excluded from earnings and reflected as components of stockholders' equity.

Components of accumulated other comprehensive loss was as follows (in thousands):



	December 26, 2015			December 27, 2014
Unrealized loss on marketable securities, net of tax of $428 in fiscal 2015 and fiscal 2014, respectively	$	(483	)	$	(419	)
Cumulative translation adjustments	(1,739		)	(1,342		)
Accumulated other comprehensive loss	$	(2,222	)	$	(1,761	)

Recent Adopted Accounting Standards

In November 2015, the FASB issued ASU 2015-17, Balance Sheet Classification of Deferred Taxes, related to balance sheet classification of deferred taxes. The ASU requires that deferred tax assets and liabilities be classified as noncurrent in the statement of financial position, thereby simplifying the current guidance that requires an entity to separate deferred assets and liabilities into current and noncurrent amounts. The ASU will be effective for us beginning in the first quarter of fiscal year 2018 though early adoption is permitted. We have early-adopted the ASU as of December 26, 2015 prospectively and our statement of financial position as of this date reflects the revised classification of current deferred tax assets and liabilities as noncurrent. No prior periods were retrospectively adjusted. There is no other impact on our financial statements of early-adopting the ASU.

Balance Sheet Components

12 Months Ended

Dec. 26, 2015

Balance Sheet Components [Abstract]

Balance Sheet Components

Marketable Securities

Marketable securities at December 26, 2015 consisted of the following (in thousands):



	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
U.S. Treasuries	$	18,896	$	1	$	(44	)	$	18,853
Agency securities (Federal)	22,484		—		(12		)	22,472
	$	41,380	$	1	$	(56	)	$	41,325

Marketable securities at December 27, 2014 consisted of the following (in thousands):



	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
U.S. Treasuries	$	42,386	$	13	$	(4	)	$	42,395
Agency securities (Federal)	7,502		—		—			7,502
	$	49,888	$	13	$	(4	)	$	49,897

We classify our marketable securities as available-for-sale. All marketable securities represent the investment of funds available for current operations, notwithstanding their contractual maturities. Such marketable securities are recorded at fair value and unrealized gains and losses are recorded in accumulated other comprehensive income until realized.

We typically invest in highly-rated securities with low probabilities of default. Our investment policy requires investments to be rated single-A or better, limits the types of acceptable investments, concentration as to security holder and duration of the investment. The gross unrealized losses on the Company's investments in fiscal 2015 and 2014, respectively, were caused primarily by changes in interest rates.

Our investment portfolio consists of both corporate and government securities that have a maximum maturity of three years. The longer the duration of these securities, the more susceptible they are to changes in market interest rates and bond yields. As yields increase, those securities with a lower yield-at-cost show a mark-to-market unrealized loss. We anticipate recovering the full cost of the securities either as market conditions improve, or as the securities mature. Accordingly, we believe that the unrealized losses are not other-than-temporary. When evaluating the investments for other-than-temporary impairment, we review factors such as the length of time and extent to which fair value has been below the amortized cost basis, review of current market liquidity, interest rate risk, the financial condition of the issuer, as well as credit rating downgrades. As of December 26, 2015 and December 27, 2014, none of our investments had been in a continuous loss position for 12 months or more.

The contractual maturities of marketable securities as of December 26, 2015 and December 27, 2014 were as follows (in thousands):



	December 26, 2015				December 27, 2014
	Amortized Cost		Fair Value		Amortized Cost		Fair Value
Due in one year or less	$	33,882	$	33,871	$	38,499	$	38,509
Due after one year to five years	7,498		7,454		11,389		11,388
	$	41,380	$	41,325	$	49,888	$	49,897

Realized gains on sales or maturities of marketable securities were immaterial for each of the fiscal years 2015, 2014, and 2013.

Asset Retirement Obligations

We account for the fair value of a liability for an asset retirement obligation to be recognized in the period in which it is incurred if a reasonable estimate of fair value can be made. The fair value of the liability is added to the carrying amount of the associated asset and this additional carrying amount is amortized over the life of the asset. Our asset retirement obligation is associated with our commitment to return property subject to operating leases in the People's Republic of China, Taiwan, South Korea, Singapore and Japan to their original condition upon lease termination. We have estimated that as of December 26, 2015, gross expected future cash flows of $0.9 million would be required to fulfill these obligations.

The carrying amount of a majority of the leasehold improvements resulting from asset retirement obligations were fully amortized by fiscal 2013 and over the original term of the related leases. Leasehold improvements amortization expense was immaterial for each of fiscal years 2015 and 2014.

The following is a reconciliation of the aggregate asset retirement liability associated with our commitment to return property to its original condition upon lease termination (in thousands):



	Fiscal Years Ended
	December 26, 2015		December 27, 2014
Asset retirement obligation beginning balance	$	903	$	988
Initial amount recorded for new asset retirement obligation	10		—
Currency translation	6		(85		)
Asset retirement obligation ending balance	$	919	$	903

The aggregate asset retirement liability was further classsified in the Consolidated Balance Sheets as (in thousands):



Other accrued liabilities, current	$	212	$	—
Deferred rent and other liabilities, non-current	707		903
	$	919	$	903

Inventories

Net inventories consisted of the following (in thousands):



	Fiscal Years Ended
	December 26, 2015		December 27, 2014
Raw materials	$	12,996	$	10,646
Work-in-progress	12,492		12,813
Finished goods	1,735		2,089
	$	27,223	$	25,548

Property, Plant and Equipment

Property, plant and equipment consisted of the following (in thousands):



	Fiscal Years Ended
	December 26, 2015			December 27, 2014
Machinery and equipment	150,983			145,995
Computer equipment and software	27,951			28,953
Furniture and fixtures	5,380			5,402
Leasehold improvements	67,121			66,821
Sub-total	251,435			247,171
Less: Accumulated depreciation and amortization	(232,005		)	(224,135		)
Net long-lived assets	19,430			23,036
Construction-in-progress	4,423			2,462
Total	$	23,853		$	25,498

In fiscal 2015 and 2014, we ceased use of fully depreciated assets with an acquired cost of $1.6 million and $6.6 million, respectively.

As discussed in Note 6 to the Notes to Consolidated Financial Statements - Impairment of Long-lived Assets, in fiscal 2015, long-lived asset impairment charges recorded were insignificant. In fiscal 2014 and 2013, we recorded impairment charges of $1.2 million and $0.8 million, respectively, for manufacturing assets and software that we no longer utilize.

Depreciation and amortization of property, plant and equipment, excluding the impairments charges discussed above, for the fiscal years 2015, 2014 and 2013 was $10.6 million, $11.7 million and $12.2 million, respectively.

Accrued Liabilities

Accrued liabilities consisted of the following (in thousands):



	Fiscal Years Ended
	December 26, 2015		December 27, 2014
Accrued compensation and benefits	$	12,286	$	12,431
Accrued indirect and other taxes	2,189		2,223
Accrued commissions	366		460
Accrued warranty	1,116		1,592
Deferred rent	325		216
Accrued restructuring	2		584
Other accrued expenses	5,223		3,711
	$	21,507	$	21,217

Restructuring Charges

12 Months Ended

Dec. 26, 2015

Restructuring Charges [Abstract]

Restructuring Charges

Restructuring charges include costs related to employee termination benefits, cost of long-lived assets abandoned or impaired, as well as contract termination costs. Restructuring charges are reflected separately as "Restructuring charges, net" in the Consolidated Statements of Operations. A summary of the actions we have taken during fiscal 2015, 2014, and 2013, the purpose of which were to improve operating efficiency, streamline and simplify our operations and reduce our operating costs, are discussed below.

2015 Restructuring Activities

During fiscal 2015, we recorded restructuring charges of approximately $0.6 million which included stock-based compensation expense of approximately $0.5 million relating to the modification of an equity-based award. All other restructuring charges recorded in fiscal 2015 were insignificant.

2014 Restructuring Activities

On January 27, 2014, we announced a global organizational restructuring and cost reduction plan. As part of the plan, the Company eliminated 52 full-time employees. In addition, we reduced our temporary workforce by 9 positions. We recorded $2.0 million of restructuring charges during the first quarter of fiscal 2014, which was comprised of $1.4 million in severance and related benefits and $0.6 million in impairment charges for certain equipment that would no longer be utilized. During the remainder of fiscal 2014, we further eliminated an additional 5 full-time positions and recorded $0.7 million in severance charges. The activities comprising these restructuring activities were substantially completed in fiscal 2014 and the remaining cash payments associated with these activities were paid in fiscal 2015.

2013 Restructuring Activities

In the first fiscal quarter of 2013, we implemented a restructuring plan which resulted in the reduction of our global workforce by 31 employees across the organization. In addition, we reduced our temporary workforce by approximately 20 positions. We also suspended development activities and engineering efforts for our next generation DRAM Matrix platform and terminated development activities for a certain SoC product platform. We recorded $4.0 million of restructuring charges during the first fiscal quarter of 2013, which was comprised of $1.3 million in severance and related benefits and $2.7 million in impairment charges for certain equipment that would no longer be utilized.

In the fourth fiscal quarter of 2013, we implemented a restructuring plan which resulted in the reduction of our global workforce by 17 full-time employees across the organization. In addition, we reduced our temporary workforce by 17 positions. We recorded $0.4 million of restructuring charges during the fourth fiscal quarter of 2013 for severance and related benefits.

The above activities comprising the reduction in workforce were completed in fiscal 2013. The remaining cash payments as of December 28, 2013 associated with the various reductions in workforce were paid in fiscal 2014.

The following table summarizes the activities related to the restructuring actions from fiscal 2013 to 2015 (in thousands):



	Employee Severance and Benefits			Property and Equipment Impairment			Contract Termination and Other Costs			Total
Accrual at December 31, 2012	$	548		$	—		$	68		$	616
Restructuring charges	2,083			2,743			15			4,841
Asset impairments	—			(2,743		)	—			(2,743		)
Adjustments to restructuring charges	(178		)	(5		)	—			(183		)
Cash payments	(2,320		)	(32		)	(17		)	(2,369		)
Non-cash settlements	5			37			(66		)	(24		)
Accrual at December 28, 2013	138			—			—			138
Restructuring charges	2,068			600			—			2,668
Asset impairments	—			(600		)	—			(600		)
Cash payments	(1,620		)	—			—			(1,620		)
Non-cash settlements	(2		)	—			—			(2		)
Accrual at December 27, 2014	584			—			—			584
Restructuring charges	59			—			500			559
Cash payments	(641		)	—			—			(641		)
Non-cash settlements	—			—			(500		)	(500		)
Accrual at December 26, 2015	$	2		$	—		$	—		$	2

Derivative Financial Instruments

12 Months Ended

Dec. 26, 2015

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Derivative Financial Instruments

We operate and sell our products in various global markets. As a result, we are exposed to changes in foreign currency exchange rates. We utilize foreign currency forward contracts to hedge against future movements in foreign exchange rates that affect certain existing foreign currency denominated assets and liabilities. Under this program, our strategy is to have increases or decreases in our foreign currency exposures offset by gains or losses on the foreign currency forward contracts to mitigate the risks and volatility associated with foreign currency transaction gains or losses. We do not use derivative financial instruments for speculative or trading purposes. Our derivative instruments are not designated as hedging instruments for accounting purposes. Accordingly, changes in the fair value of these hedges are recorded in earnings to offset the changes in the fair value of the assets or liabilities being hedged. We record the fair value of these contracts as of the end of our reporting period to our Consolidated Balance Sheet with changes in fair value recorded within "Other income, net" in our Consolidated Statement of Operations for both realized and unrealized gains and losses.

As of December 26, 2015, there were three outstanding foreign exchange forward contracts, one contract to sell Japanese Yen and two contracts to buy Korean Won and Taiwan Dollars. The following tables provide information about our foreign currency forward contracts outstanding as of December 26, 2015 and December 27, 2014 (in thousands):



December 26, 2015		Contract Position	Contract Amount (Local Currency)		Contract Amount (U.S. Dollar)
			(In thousands)
Japanese Yen		Sell	3,328,268		$	27,635
Taiwan Dollar		Buy	(37,152	)	(1,136		)
Korean Won		Buy	(840,111	)	(718		)
	Total USD notional amount of outstanding foreign exchange contracts				$	25,781



December 27, 2014		Contract Position	Contract Amount (Local Currency)		Contract Amount (U.S. Dollar)
			(In thousands)
Japanese Yen		Sell	1,955,798		$	16,241
Taiwan Dollar		Buy	(30,886	)	(977		)
Korean Won		Buy	(1,763,054	)	(1,613		)
	Total USD notional amount of outstanding foreign exchange contracts				$	13,651

The contracts outstanding at December 26, 2015 were entered into on December 24, 2015 and matured on January 26, 2016 for the Japanese Yen, Korean Won and Taiwan Dollar. Our foreign currency contracts are classified within Level 2 of the fair value hierarchy as they are valued using pricing models that utilize observable market inputs. There was no change in the value of these contracts as of December 26, 2015. Additionally, no gains or losses relating to the outstanding derivative contracts as of December 26, 2015 and December 27, 2014 were recorded during their respective fiscal periods.

The location and amount of gains (losses) related to non-designated derivative instruments that matured in fiscal 2015 and 2014 in the Consolidated Statements of Operations are as follows (in thousands):



		Fiscal Years Ended
Derivatives Not Designated as Hedging Instruments	Location of Gain (Loss) Recognized on Derivatives	December 26, 2015			December 27, 2014
Foreign exchange forward contracts	Other Income, net	$	(310	)	$	1,768

- Definition

The entire disclosure for derivative instruments and hedging activities including, but not limited to, risk management strategies, non-hedging derivative instruments, assets, liabilities, revenue and expenses, and methodologies and assumptions used in determining the amounts.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6441202&loc=d3e80720-113993

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-URI http://asc.fasb.org/extlink&oid=56946850&loc=SL5624171-113959

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=56946850&loc=d3e41620-113959

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4B
-URI http://asc.fasb.org/extlink&oid=56946850&loc=SL5624163-113959

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=56946850&loc=SL5579240-113959

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4D
-URI http://asc.fasb.org/extlink&oid=56946850&loc=SL5624177-113959

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 30
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=35736893&loc=d3e80784-113994

Reference 8: 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=56946850&loc=d3e41641-113959

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=56946850&loc=SL5579245-113959

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4H
-URI http://asc.fasb.org/extlink&oid=56946850&loc=SL5624258-113959

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 30
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=35736893&loc=d3e80748-113994

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4K
-URI http://asc.fasb.org/extlink&oid=56946850&loc=SL5708775-113959

Reference 13: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4J
-URI http://asc.fasb.org/extlink&oid=56946850&loc=SL5708773-113959

Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4A
-URI http://asc.fasb.org/extlink&oid=56946850&loc=SL5618551-113959

Reference 15: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=56946850&loc=SL5580258-113959

Reference 16: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4E
-URI http://asc.fasb.org/extlink&oid=56946850&loc=SL5624181-113959

Reference 17: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 25
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6886632&loc=d3e76258-113986

Reference 18: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=56946850&loc=d3e41638-113959

Reference 19: 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.(n))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

+ Details

Impairment of Long-lived Assets

12 Months Ended

Dec. 26, 2015

Property, Plant and Equipment Impairment or Disposal [Abstract]

Impairment of Long-lived Assets

The following table summarizes the components of the impairments that we recorded in fiscal 2015, 2014 and 2013 (in thousands):



	Fiscal Years Ended
	December 26, 2015		December 27, 2014		December 28, 2013
Impairment of long-lived assets:
Assets held for sale	$	—	$	191	$	—
Assets to be disposed of other than by sale	8		1,028		761
Total	$	8	$	1,219	$	761

Assets held for sale

In fiscal 2015, we did not record any impairment charge on assets held for sale and there were no long-lived assets classified as held for sale as of December 26, 2015.

During fiscal 2014, we reclassified $0.6 million of building and $0.5 million of machinery and equipment from "Property, plant and equipment, net" to "Prepaid expenses and other current assets" in our Consolidated Balance Sheet as these assets were identified as held for sale. In the same fiscal year, we recorded a gain of $0.2 million and $52.0 thousand on the sale of the building and machinery and equipment, respectively. In addition, we also recorded a $0.2 million impairment charge related to machinery and equipment which was held for sale. There were no long-lived assets classified as held for sale as of December 27, 2014.

In fiscal 2013, we did not record any impairment charge on assets held for sale.

These impairments were included within "Impairment of long-lived assets" in the Consolidated Statement of Operations for their respective periods.

Assets to be disposed of other than by sale

In fiscal 2015, long-lived asset impairment charges recorded were insignificant. In fiscal 2014 and 2013, we recorded impairment charges of $1.2 million and $0.8 million, respectively, for manufacturing assets and software that we no longer utilize.

All of these charges are included in "Impairment of long-lived assets" in the Consolidated Statements of Operations for their respective periods.

Refer to Note 8 to the Notes to Consolidated Financial Statements - Goodwill and Intangible Assets for further details relating to our intangible long-lived assets.

Fair Value

12 Months Ended

Dec. 26, 2015

Fair Value Disclosures [Abstract]

Fair Value

We use fair value measurements to record adjustments to certain financial and non-financial assets and to determine fair value disclosures. The carrying amounts of certain of our financial instruments, including cash and cash equivalents, accounts receivable, accounts payable, accrued compensation and other accrued liabilities, approximate fair value because of their short maturities. Our marketable securities are financial assets recorded at fair value on a recurring basis.

The accounting standards for fair value defines fair value, establishes a framework for measuring fair value and requires disclosures about fair value measurements. Fair value is defined as the price that would be received from selling an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. When determining the fair value measurements for assets and liabilities required to be recorded at fair value, we consider the principal or most advantageous market in which we would transact and consider assumptions that market participants would use when pricing the asset or liability, such as inherent risk, transfer restrictions and risk of nonperformance. The accounting standard establishes a fair value hierarchy that requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. A financial instrument's categorization within the fair value hierarchy is based upon the lowest level of input that is significant to the fair value measurement. The standard describes a fair value hierarchy based on three levels of inputs, the first two of which are considered observable and the last unobservable. We apply the following fair value hierarchy, which prioritizes the inputs used in measuring fair value as follows:


•	Level 1—Quoted prices in active markets for identical assets or liabilities;


•	Level 2—Inputs, other than the quoted prices in active markets, such as quoted prices for similar assets or liabilities, quoted prices near the reporting date in markets that are less active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities; and


•	Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities.

We obtain the fair value of our Level 1 investments in certain money market funds, at the expected market price. These investments are expected to maintain a net asset value of $1 per share.

We determine the fair value of our Level 2 financial instruments from several third party asset managers, custodian banks, and the accounting service providers. Independently, these service providers use professional pricing services to gather pricing data, which may include quoted market prices for identical or comparable instruments or inputs other than quoted prices that are observable either directly or indirectly.

We utilize the market approach to measure the fair value of our fixed income securities. The market approach is a valuation technique that uses prices and other relevant information generated by market transactions involving identical or comparable assets or liabilities. The fair value of our fixed income securities is obtained using readily-available market prices from a variety of industry standard data providers, large financial institutions and other third-party sources for the identical underlying securities.

Our fair value processes include controls that are designed to ensure appropriate fair values are recorded. Such controls include model validation, review of key model inputs, analysis of period-over-period fluctuations and independent recalculation of prices.

Assets Measured at Fair Value on a Recurring Basis

We measure and report certain assets and liabilities at fair value on a recurring basis, including money market funds, U.S. Treasury securities, agency securities and foreign currency derivatives (refer to Note 5 to Notes to Consolidated Financial Statements - Derivative Financial Instruments for a discussion of fair value of foreign currency derivatives).

Fair values measured on a recurring basis as of December 26, 2015 (in thousands):



	Level 1		Level 2		Total
Assets:
Cash equivalents
Money market funds	$	82,935	$	—	$	82,935
Marketable securities
U.S. Treasuries	—		18,853		18,853
Agency securities (Federal)	—		22,472		22,472
Total	$	82,935	$	41,325	$	124,260

Fair values measured on a recurring basis as of December 27, 2014 (in thousands):



	Level 1		Level 2		Total
Assets:
Cash equivalents
Money market funds	$	65,303	$	—	$	65,303
Marketable securities
U.S. Treasuries	—		42,395		42,395
Agency securities (Federal)	—		7,502		7,502
Total	$	65,303	$	49,897	$	115,200

The Level 1 assets consist of our money market fund deposits. The Level 2 assets consist of our available-for-sale investment portfolio, which are valued utilizing a market approach. Our investments are priced by pricing vendors who provided observable inputs for their pricing without applying significant judgment. Broker pricing is used mainly when a quoted price is not available, the investment is not priced by our pricing vendors or when a broker price is more reflective of fair values in the market in which the investment trades. Our broker-priced investments are labeled as Level 2 investments because fair values of these investments are based on similar assets without applying significant judgments. In addition, all of our investments have a sufficient level of trading volume to demonstrate that the fair values used are appropriate for these investments.

We did not have any transfers of assets measured at fair value on a recurring basis to or from Level 1 and Level 2 during fiscal 2015 and 2014.

Assets Measured at Fair Value on a Non-recurring Basis

We measure and report goodwill and intangible assets at fair value on a non-recurring basis. Refer to Note 8 to Notes to Consolidated Financial Statements - Goodwill and Intangible Assets, for further details. There were no assets measured at fair value on a non-recurring basis during fiscal 2015.

- 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

Goodwill and Intangible Assets

12 Months Ended

Dec. 26, 2015

Goodwill and Intangible Assets Disclosure [Abstract]

Goodwill and Intangible Assets

Goodwill of $30.7 million as of December 26, 2015 remained unchanged from the amounts recorded as of December 27, 2014.

For the purposes of our goodwill impairment analysis and since our acquisition of MicroProbe in Fiscal 2012, we had historically two reporting units, all of which related to our FormFactor and MicroProbe product groups. During the fourth quarter of fiscal 2015, we determined that we now have one reporting unit relating to the design, development, manufacture and sale of high performance advanced probe cards as a result of the successful integration of the MicroProbe business into our overall consolidated operations.

During the fourth quarter of fiscal 2015, we performed our annual goodwill impairment test prior to and subsequent to the change in our reporting unit structure by assessing qualitative factors and we concluded that our goodwill was not impaired as of December 26, 2015. Our qualitative review included, among other factors, an assessment of our market capitalization which was significantly higher than our book value. During the fourth quarter of fiscal 2014, we also performed our annual goodwill impairment test by an assessment of qualitative factors and concluded that our goodwill was not impaired as December 27, 2014. Furthermore, the Company has not recorded any historical goodwill impairments as of December 26, 2015. The evaluation of goodwill and intangible assets for impairment requires the exercise of significant judgment. In the event of future changes in business conditions, we will be required to reassess and update our forecasts and estimates used in future impairment analyses. If the results of these analyses are lower than current estimates, a material impairment charge may result at that time.

The changes in intangible assets for fiscal 2015 and the net book value of intangible assets at December 26, 2015 and December 27, 2014 were as follows (in thousands):



	Intangible Assets, Gross Amount							Accumulated Amortization						Intangible Assets, Net				Weight Average Useful Life
Other Intangible Assets (1)	December 27, 2014		Additions/Disposals			December 26, 2015		December 27, 2014		Expense, net		December 26, 2015		December 27, 2014		December 26, 2015		December 26, 2015
Existing developed technologies (2)	$	45,300	$	6,900		$	52,200	$	29,097	$	10,484	$	39,581	$	16,203	$	12,619	2.0
Trade name	4,388		—			4,388		970		439		1,409		3,418		2,979		6.8
Customer relationships	17,000		—			17,000		4,832		2,214		7,046		12,168		9,954		4.8
Total finite-lived intangible assets	66,688		6,900			73,588		34,899		13,137		48,036		31,789		25,552
In-process research and development	6,900		(6,900		)	—		—		—		—		6,900		—
Total intangible assets	$	73,588	$	—		$	73,588	$	34,899	$	13,137	$	48,036	$	38,689	$	25,552



(1)	Excludes fully amortized intangible assets.
(2)	As of December 26, 2015, we excluded approximately $5.9 million of fully amortized existing developed technology intangible assets from gross intangible assets and accumulated amortization due to the sale of these intangible assets to MarTek Inc. These intangible assets were fully amortized as of December 27, 2014 but were in use until their sale to MarTek Inc. Refer to Note 9 in Notes to Consolidated Financial Statements-Commitments and Contingencies, for further details.

During the year ended December 26, 2015, purchased in-process research and development ("IPR&D") projects with carrying values of $6.9 million were completed and reclassified to finite-lived intangible assets, and are currently being amortized over their remaining estimated weighted average useful lives of 2.8 years as of December 26, 2015.

We recorded $13.1 million, $18.8 million and $16.7 million, in amortization expense related to our intangible assets in fiscal 2015, 2014, and 2013, respectively. Of the total amortization expense for fiscal 2015, 2014, and 2013, $10.4 million, $16.1 million, and $13.8 million were charged to cost of revenues, respectively, and $2.7 million, $2.7 million and $2.9 million were charged to selling, general and administrative expenses, respectively.

Based on the carrying value of the finite-lived intangible assets recorded as of December 26, 2015, and assuming no subsequent additions to or impairment of the underlying assets, the remaining estimated annual amortization expense is expected to be as follows (in thousands):



Fiscal Year	Amount
2016	$	10,060
2017	4,943
2018	4,666
2019	3,052
2020	2,045
and thereafter	786
Total	$	25,552

Commitments and Contingencies

12 Months Ended

Dec. 26, 2015

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

Leases

We lease facilities under non-cancellable operating leases with various expiration dates through 2021. The facilities generally require us to pay property taxes, insurance and maintenance costs. Further, several lease agreements contain rent escalation clauses or rent holidays. For purposes of recognizing minimum rental expenses on a straight-line basis over the terms of the leases, we use the date of initial possession to begin amortization. We have the option to extend or renew most of our leases which may increase the future minimum lease commitments.

Rent expense for the fiscal years 2015, 2014, and 2013 was $4.9 million, $4.8 million and $4.9 million, respectively.

As of December 26, 2015 and December 27, 2014, we did not lease any equipment under capital leases. The depreciation expense of certain equipment under capital leases was $0.2 million in fiscal 2014 and $0.5 million in fiscal 2013.

Future minimum payments under our non-cancelable operating leases are as follows as of December 26, 2015 (in thousands):



	Operating Leases
Fiscal years:
2016	$	3,994
2017-2018	7,194
2019-2020	7,064
Thereafter	2,505
Total	$	20,757

Other Contractual Obligations

The following table sets forth our commitments to settle other contractual obligations in cash as of December 26, 2015 (in thousands):



	Payments Due In Fiscal Years
	2016		2017-2018		2019-2020		After 2020		Total
	(In thousands)
Purchase obligations	$	20,899	$	9,580	$	30	$	—	$	30,509

Purchase obligations are primarily for purchases of inventory and manufacturing related service contracts. For the purposes of this table, purchase obligations are defined as agreements that are enforceable and legally binding and that specify all significant terms, including: fixed or minimum quantities to be purchased; fixed, minimum or variable price provisions; and the approximate timing of the transaction. The expected timing of payment of the obligations discussed above is estimated based on information available to us as of December 26, 2015. Timing of payments and actual amounts paid may be different depending on the time of receipt of goods or services or changes to agreed-upon amounts for some obligations.

The table above excludes our gross liability for unrecognized tax benefits, which totaled $17.0 million as of December 26, 2015. The timing of any payments which could result from these unrecognized tax benefits will depend upon a number of factors. Accordingly, the timing of payment cannot be estimated and has been excluded from the table above. As of December 26, 2015, the changes to our uncertain tax positions in the next 12 months, that are reasonably possible, are not expected to have a significant impact on our financial position or results of operations.

Environmental Matters

We are subject to U.S. Federal, State, local, and foreign governmental laws and regulations relating to the protection of the environment, including those governing the discharge of pollutants into the air and water, the management and disposal of hazardous substances and wastes, the clean-up of contaminated sites and the maintenance of a safe workplace. We believe that we comply in all material respects with the environmental laws and regulations that apply to us, including those of the California Department of Toxic Substances Control, the Bay Area Air Quality Management District, the City of Livermore Water Resources Division, County of Santa Clara Department of Environmental Health, County of San Diego Hazardous Materials Division and Encino Water District, and the California Division of Occupational Safety and Health. We did not receive any notices of violations of environmental laws and regulations in fiscal 2015, 2014 or 2013. In the future, we may receive notices of violations of environmental regulations, or otherwise learn of such violations. Environmental contamination or violations may negatively impact our business.

Indemnification Arrangements

We have entered, and may from time to time in the ordinary course of our business enter, into contractual arrangements with third parties that include indemnification obligations. Under these contractual arrangements, we have agreed to defend, indemnify and/or hold the third party harmless from and against certain liabilities. These arrangements include indemnities in favor of customers in the event that our products or services infringe a third party's intellectual property or cause property or other damages and indemnities in favor of our lessors in connection with facility leasehold liabilities that we may cause. In addition, we have entered into indemnification agreements with our directors and certain of our officers, and our bylaws contain indemnification obligations in favor of our directors, officers and agents. These indemnity arrangements may limit the type of the claim, the total amount that we can be required to be paid in connection with the indemnification obligation and the time within which an indemnification claim can be made. The duration of the indemnification obligation may vary, and for most arrangements, survives the agreement term and is indefinite. We believe that substantially all of our indemnity arrangements provide either for limitations on the maximum potential future payments we could be obligated to make, or for limitations on the types of claims and damages we could be obligated to indemnify, or both. However, it is not possible to determine or reasonably estimate the maximum potential amount of future payments under these indemnification obligations due to the varying terms of such obligations, a lack of history of prior indemnification claims, the unique facts and circumstances involved in each particular contractual arrangement and in each potential future claim for indemnification, and the contingency of any potential liabilities upon the occurrence of events that are not reasonably determinable. We have not had any material requests for indemnification under these arrangements. Our management believes that any liability for these indemnity arrangements would not be material to our accompanying consolidated financial statements. We have not recorded any liabilities for these indemnification arrangements on our consolidated balance sheet as of December 26, 2015.

Legal Matters

From time to time, we may be subject to legal proceedings and claims in the ordinary course of business. For the year ended December 26, 2015, we were not involved in any material legal proceedings. We identify below in "Other Litigation", a proceeding filed in fiscal 2013, which, if not resolved amicably, either (i) includes allegations that could potentially result in a material legal proceeding, or (ii) the cost to defend the allegations through trial could be material. In the future we may become a party to additional legal proceedings that may require us to spend significant resources, including proceedings designed to protect our intellectual property rights. Litigation can be expensive and disruptive to normal business operations. Moreover, the results of legal proceedings are difficult to predict, and the costs incurred in litigation can be substantial, regardless of outcome.

In March 2014, we filed a lawsuit against MarTek, Inc. ("MarTek"), asserting breach of contract, copyright infringement and related claims arising out of a licensing agreement we entered into with MarTek for the use by MarTek of certain intellectual property assets (the “IP”). MarTek asserted counterclaims against us for breach of contract and related claims regarding that license.

On July 13, 2015, we entered into an agreement with MarTek under which the parties agreed to dismiss the pending litigation and release each other from any and all claims relating to the license agreement. As part of the agreement, we agreed to sell the IP to MarTek for $2 million, of which $1.2 million was received on July 17, 2015, and the remaining $0.8 million is in the form of a promissory note secured by the IP and scheduled to be repaid by MarTek in two equal tranches on the first and second anniversary of the settlement. We recognized a net gain of approximately $1.0 million (which was classified in our Consolidated Statement of Operations under Other Income, net) from the agreement proceeds of $1.2 million received on July 17, 2015.

Other Litigation

In August 2013, a former employee filed a class action lawsuit against the Company in the Superior Court of California, alleging violations of California’s wage and hour laws and unfair business practices on behalf of himself and all other similarly situated current and former employees at the Company’s Livermore facilities from August 21, 2009, to the present. On January 4, 2016, the court certified the plaintiff class. The lawsuit is currently proceeding to notice to class members and merits discovery. The Company denies the allegations contained in the lawsuit, and, based on available information, believes it has significant defenses to the allegations of the lawsuit. The Company currently believes that any settlement reached would be an amount that is not material to the Company's financial statements. If the matter is not settled, the Company could incur material attorneys’ fees in defending the lawsuit.

Stockholders' Equity

12 Months Ended

Dec. 26, 2015

Stockholders' Equity Note [Abstract]

Stockholders' Equity

Preferred Stock

We have authorized 10,000,000 shares of undesignated preferred stock, $0.001 par value, none of which is issued and outstanding. Our Board of Directors shall determine the rights, preferences, privileges and restrictions of the preferred stock, including dividends rights, conversion rights, voting rights, terms of redemption, liquidation preferences, sinking fund terms and the number of shares constituting any series or the designation of any series.

Common Stock

Each share of common stock has the right to one vote. The holders of common stock are also entitled to receive dividends whenever funds are legally available and when declared by the Board of Directors, subject to the prior rights of holders of all classes of stock outstanding having priority rights as to dividends. No dividends have been declared or paid as of December 26, 2015.

Common Stock Repurchase Program

On April 16, 2015, our Board of Directors authorized a program to repurchase up to $25.0 million of outstanding common stock. Under the authorized stock repurchase program, we may repurchase shares from time-to-time on the open market. The pace of repurchase activity will depend on levels of cash generation, current stock price and other factors. The stock repurchase program was announced on April 16, 2015 and expires on April 15, 2016. The program may be modified or discontinued at any time. During fiscal 2015, under this repurchase authorization, we repurchased and retired 1,013,162 shares of common stock for approximately $8.2 million.

Repurchased shares are retired upon the settlement of the related trade transactions. Our policy related to repurchases of our common stock is to charge the excess of cost over par value to additional paid-in capital. All repurchases were made in compliance with Rule 10b-18 under the Securities Exchange Act of 1934, as amended.

Equity Incentive Plan

We currently grant equity-based awards under our Equity Incentive Plan (the "2012 Plan") which was approved by our stockholders at our Annual Meeting of Stockholders on April 18, 2012. On May 1, 2015, at our Annual Meeting of Stockholders, our stockholders further approved the amended and restated 2012 Plan which increased the maximum number of shares of common stock authorized for issuance by an additional 4.5 million shares and prohibited the cashing out of stock appreciation rights. Refer to the 2015 Proxy Statement filed with the Securities and Exchange Commission on March 19, 2015 for further details.

Restricted stock and restricted stock units granted under the 2012 Plan will generally vest over four years in annual tranches though we also have granted and will continue to grant such awards over a shorter vest term for employee retention purposes. Additionally, restricted shares reduce the shares available for issuance at 1.70 shares for every one share issued.

The 2012 Plan also provides for the grant of incentive stock options, nonqualified stock options and stock appreciation rights. The incentive stock options may be granted to our employees and the nonqualified stock options, and all awards other than incentive stock options may be granted to employees, directors and consultants. The exercise price of incentive stock options must be at least equal to the fair market value of common stock on the date of grant. All options granted under the 2012 Plan will generally vest over four years and have a term of ten years, unless otherwise determined by the Compensation Committee of the Board of Directors. Stock appreciation rights granted under the 2012 Plan will generally vest over four years in annual tranches. We have not granted any incentive stock options or stock appreciation rights during fiscal 2015 and 2014.

At December 26, 2015, there were 5.8 million shares available for grant under the 2012 Plan.

Stock Options

Stock option activity is set forth below:



	Outstanding Options
	Number of Shares		Weighted Average Exercise Price		Weighted Average Remaining Contractual Life in Years	Aggregate Intrinsic Value
Outstanding at December 27, 2014	2,571,376		10.72
Options granted	456,000		8.42
Options exercised	(24,607	)	8.61
Options canceled	(682,574	)	13.75
Outstanding at December 26, 2015	2,320,195		$	9.40	2.70	$	1,146,680
Vested and expected to vest at December 26, 2015	2,320,195		$	9.40	2.70	$	1,146,680
Exercisable at December 26, 2015	1,864,861		$	9.64	1.86	$	833,552

On February 9, 2015, we granted 450,000 stock options to our Chief Executive Officer with a grant-date fair value of approximately $1.7 million which will be recognized as stock compensation expense ratably over the service period. The following weighted average assumptions were used in the estimated grant-date fair value calculations using the Black-Scholes option pricing model:



Stock Options:
Dividend yield	—	%
Expected volatility	47.5	%
Risk-free interest rate	1.6	%
Expected term (in years)	5.5

Restricted Stock Units

Restricted stock units are converted into shares of our common stock upon vesting on a one-for-one basis. The vesting of restricted stock units is subject to the employee's continuing service to us. Restricted stock unit activity is set forth below:



	Number of Shares		Weighted Average Grant Date Fair Value
Restricted stock units at December 29, 2012	2,228,946		$	7.66
Granted	1,708,000		5.04
Vested	(760,590	)	8.44
Canceled	(246,717	)	8.18
Restricted stock units at December 28, 2013	2,929,639		5.88
Granted	1,900,000		6.52
Vested	(1,282,442	)	6.30
Canceled	(297,151	)	6.17
Restricted stock units at December 27, 2014	3,250,046		6.07
Granted	1,540,250		8.64
Vested	(1,993,603	)	6.00
Canceled	(218,555	)	6.36
Restricted stock units at December 26, 2015	2,578,138		$	7.63

On May 28, 2015, we issued 195,000 RSUs to seven senior executives of our company that will vest based on certain market performance criteria. The performance criteria are based on a metric called our Total Shareholder Return (TSR) for the period from April 1, 2015 to March 31, 2017 relative to the TSR of the companies identified as being part of the S&P Semiconductor Select Industry Index (FormFactor peer companies), as of April 1, 2015. The total stock-based compensation cost of approximately $1.5 million will be recognized ratably over the requisite service period.

On May 5, 2014, we issued 350,000 RSUs to seven senior executives of our company that will vest based on certain market performance criteria. The performance criteria are based on our TSR for the period from April 1, 2014 to March 31, 2016 relative to the TSR of the companies identified as being part of the S&P Semiconductor Select Industry Index (FormFactor peer companies), as of April 1, 2014. The total stock-based compensation cost of approximately $1.8 million will be recognized ratably over the requisite service period.

On May 6, 2013, we issued 355,000 RSUs to seven senior executives and one non-executive of our company that would vest based on certain market performance criteria. The performance criteria were based on our TSR for the period from April 1, 2013 to March 31, 2015 relative to the TSR of the companies identified as being part of the S&P Semiconductor Select Industry Index (FormFactor peer companies), as of April 1, 2013. On April 8, 2015, upon the review of the market performance criteria, our Compensation Committee certified a total earn out of 443,750 RSUs which immediately vested as of that date.

The total fair value of restricted stock units vested during fiscal 2015, 2014 and 2013 was $18.1 million, $8.2 million and $3.9 million, respectively.

Employee Stock Purchase Plan

Under the 2012 Employee Stock Purchase Plan ("ESPP"), the offering periods are 12 months commencing on February 1 of each calendar year and ending on January 31 of the subsequent calendar year, and a six month fixed offering period commencing on August 1 of each calendar year and ending on January 31 of the subsequent calendar year. The 12 month offering period consists of two six-month purchase periods and the six month offering period consists of one six month purchase period. The price of the common stock purchased is 85% of the lesser of the fair market value of the common stock on the first day of the applicable offering period or the last day of each purchase period.

During fiscal 2015, 2014, and 2013, employees purchased 565,493 shares, 586,386 shares and 583,173 shares under this program at a weighted average exercise price of $5.67, $4.80 and $4.29, respectively.

- Definition

The entire disclosure for shareholders' equity comprised of portions attributable to the parent entity and noncontrolling interest, including other comprehensive income. Includes, but is not limited to, balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings, accumulated balance for each classification of other comprehensive income and amount of comprehensive income.

+ References

Reference 1: 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.(d),(e))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21484-112644

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB TOPIC 4.E)
-URI http://asc.fasb.org/extlink&oid=27010918&loc=d3e74512-122707

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21488-112644

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.29-31)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SAB TOPIC 4.C)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187143-122770

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21506-112644

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 30
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6405834&loc=d3e23285-112656

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21475-112644

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Preferred Stock
-URI http://asc.fasb.org/extlink&oid=6521494

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

Reference 13: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21564-112644

Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 4
-Section E

Reference 15: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 4
-Section C

+ Details

Stock-Based Compensation

12 Months Ended

Dec. 26, 2015

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

Stock-Based Compensation

We account for all stock-based compensation to employees and directors, including grants of restricted stock units and stock options, as stock-based compensation costs in the Consolidated Financial Statements based on the fair value measured as of the date of grant. These costs are recognized as an expense in the Consolidated Statements of Operations over the requisite service period and increase additional paid-in capital.

The table below shows the stock-based compensation expense included in the Consolidated Statement of Operations (in thousands):



	Fiscal Years Ended
	December 26, 2015		December 27, 2014		December 28, 2013
Stock-based compensation expense included in:
Cost of revenues	$	2,651	$	2,433	$	2,436
Research and development	3,490		3,529		3,440
Selling, general and administrative	5,434		7,317		6,248
Total stock-based compensation	11,575		13,279		12,124
Tax effect on stock-based compensation	—		—		—
Total stock-based compensation, net of tax	$	11,575	$	13,279	$	12,124

During fiscal 2015, we recorded stock-based compensation expense of approximately $0.5 million relating to a full-time employee who was impacted by our restructuring activities. Hence, we classified this stock-based compensation expense as a restructuring expense. The table above does not include this expense. Refer to Note 4 to Notes to Consolidated Financial Statements - Restructuring Charges for further details.

Restricted Stock Units

The fair value of restricted stock units is determined using the market closing price of our common stock on the grant date and compensation cost is recognized over the vesting period on a straight line basis. The restricted stock units generally vest over four years though we also have granted and will continue to grant such awards over a shorter vest term for employee retention purposes.

During fiscal 2015, 2014 and 2013, we granted 1,540,250 shares, 1,900,000 shares and 1,708,000 shares of restricted stock units with the weighted average grant-date fair values of $8.64, $6.52 and $5.04 per share, respectively. As of December 26, 2015, the unamortized stock-based compensation balance related to restricted stock units was $11.8 million after estimated forfeitures, which will be recognized over an estimated period of 2.03 years based on the weighted average days to vest.

Stock Options

The exercise price of each stock option equals the market price of our stock on the date of grant. Most options are scheduled to vest over three to four years and expire five to ten years from the grant date. The fair value of each option grant is estimated on the date of grant using the Black-Scholes option pricing model. In addition, we estimate forfeitures when recognizing compensation expense, and adjust our estimates of forfeitures over the requisite service period based on the extent to which actual forfeitures differ, or are expected to differ, from such estimates. Changes in estimated forfeitures are recognized as a change in estimate in the period of change and will also impact the amount of compensation expense to be recognized in future periods.

The following weighted-average assumptions were used in the estimated grant-date fair value calculations for stock options granted in fiscal 2015. There were no options granted in fiscal 2014 and 2013.



Stock Options:
Dividend yield	—	%
Expected volatility	47.5	%
Risk-free interest rate	1.6	%
Expected life (in years)	5.5

During fiscal 2015, we granted 456,000 stock options under our approved plans with a weighted average grant-date fair value of $3.78 per share. Our computation of expected volatility was based on a combination of historical and market-based implied volatility from traded options on our common stock. We believe that including market-based implied volatility in the calculation of expected volatility results in a more accurate measure of the volatility expected in future periods. Risk-free interest rates are yields for zero-coupon U.S. Treasury notes maturing approximately at the end of the expected option life. We determine the expected term by considering several factors, including historical option exercise behavior, post vesting turnover rates, contractual terms and vesting periods of the options granted.

As of December 26, 2015, the unamortized stock-based compensation balance related to stock options was $1.3 million after estimated forfeitures, which will be recognized over an estimated period of 3.1 years based on the weighted average days to vest.

Employee Stock Purchase Plan

During fiscal 2015, we issued 565,493 shares under our approved employee stock purchase plans. As of December 26, 2015, we had $0.1 million of total unrecognized stock-based compensation expense, which will be recognized over the weighted average period of approximately one month. Compensation expense is calculated using the fair value of the employees' purchase rights under the Black-Scholes model.

The following assumptions were used in estimating the fair value of employees' purchase rights under the approved employee stock purchase plans:



	Fiscal Years Ended
	December 26, 2015		December 27, 2014		December 28, 2013
Employee Stock Purchase Plan:
Dividend yield	—	%	—	%	—	%
Expected volatility	51.78	%	41.71	%	39.80	%
Risk-free interest rate	0.12	%	0.09	%	0.13	%
Expected life (in years)	0.7		0.7		0.7

Income Taxes

12 Months Ended

Dec. 26, 2015

Income Tax Disclosure [Abstract]

Income Taxes

The components of loss before income taxes were as follows (in thousands):



	Fiscal Years Ended
	December 26, 2015			December 27, 2014			December 28, 2013
United States	$	(3,069	)	$	(23,230	)	$	(60,447	)
Foreign	1,798			3,135			2,665
	$	(1,271	)	$	(20,095	)	$	(57,782	)

The components of the provision for income taxes are as follows (in thousands):



	Fiscal Years Ended
	December 26, 2015			December 27, 2014			December 28, 2013
Current provision (benefit):
Federal	$	(3	)	$	(983	)	$	(770	)
State	72			(386		)	76
Foreign	198			234			287
	267			(1,135		)	(407		)
Deferred provision (benefit):
Federal	—			—			—
State	—			—			—
Foreign	(15		)	225			308
	(15		)	225			308
Total provision (benefit) from income taxes	$	252		$	(910	)	$	(99	)

The following is a reconciliation of the difference between income taxes computed by applying the federal statutory rate of 35% and the provision (benefit) from income taxes for fiscal 2015, 2014 and 2013 (in thousands):



	Fiscal Years Ended
	December 26, 2015			December 27, 2014			December 28, 2013
U.S. statutory federal tax rate	$	(445	)	$	(7,033	)	$	(20,224	)
State taxes and credits, net of Federal benefit	17			(186		)	(345		)
Amortization of stock-based compensation	907			686			923
Research and development credits	(1,872		)	(1,183		)	(560		)
Foreign taxes at rates different than the U.S.	(66		)	(84		)	162
Other permanent differences	238			(972		)	(378		)
Change in valuation allowance	1,457			7,886			20,505
Other	16			(24		)	(182		)
Total	$	252		$	(910	)	$	(99	)

Deferred tax assets and liabilities are recognized for the future tax consequences of differences between the carrying amounts of assets and liabilities and their respective tax bases using enacted tax rates in effect for the year in which the differences are expected to be reversed. Significant deferred tax assets and liabilities consist of the following (in thousands):



	Fiscal Years Ended
	December 26, 2015			December 27, 2014
Tax credits	$	30,968		$	28,458
Inventory reserve	14,010			16,612
Unrealized investment gains	20			—
Other reserves and accruals	5,953			7,610
Non-statutory stock options	4,936			18,096
Depreciation and amortization	13,440			14,037
Net operating loss carryforwards	119,327			120,110
Gross deferred tax assets	188,654			204,923
Valuation allowance	(176,196		)	(187,759		)
Total deferred tax assets	12,458			17,164
Acquired intangibles & fixed assets	(9,177		)	(13,867		)
Unrealized investment gains	—			(3		)
Total deferred tax liabilities	(9,177		)	(13,870		)
Net deferred tax assets	$	3,281		$	3,294

We are required to evaluate the realizability of our deferred tax assets in both our U.S. and non-U.S. jurisdictions on an ongoing basis to determine whether there is a need for a valuation allowance with respect to such deferred tax assets. During fiscal 2015 and 2014, we maintained a valuation allowance against our U.S. deferred tax assets. We intend to maintain a valuation allowance until sufficient positive evidence exists to support the realization of such deferred tax assets.

The valuation allowance against deferred tax assets consisted of the following activity for the fiscal years 2015, 2014 and 2013 (in thousands):



Description	Balance at Beginning of Year		Additions		Reduction			Balance at End of Year
Allowance against deferred tax assets
Year ended December 31, 2015	$	187,759	$	—	$	(11,563	)	$	176,196
Year ended December 31, 2014	180,913		6,846		—			187,759
Year ended December 31, 2013	$	163,265	$	17,648	$	—		$	180,913

At December 26, 2015, we had Federal research and development tax credit, net operating loss, and foreign tax credit carryforwards of $21.0 million, $298.7 million and $2.0 million, respectively, which will expire at various dates from 2016 through 2035. We had alternative minimum tax credits of $2.4 million which do not expire. We had California research credit and net operating loss carryforwards of $28.4 million and $270.7 million, respectively. The California research credit can be carried forward indefinitely while California net operating loss carryforwards will expire at various dates from 2016 through 2035. We had Japan and Singapore net operating loss carryforwards of approximately $0.3 million and $10.0 million, respectively. Japan net operating loss carryforwards will expire in 2022 while Singapore net operating loss carryforwards can be carried forward indefinitely.

We have not provided U.S. Federal and State income taxes, nor foreign withholding taxes, on approximately $5.4 million of undistributed earnings for certain non-US subsidiaries, because such earnings are intended to be indefinitely reinvested. If these earnings were distributed to the U.S. in the form of dividends or otherwise, or if the shares of the relevant foreign subsidiaries were sold or otherwise transferred, we would be subject to additional U.S. income taxes (subject to an adjustment for foreign tax credits) and foreign withholding taxes, of approximately $0.4 million. Determination of the amount of unrecognized deferred tax liability for temporary differences related to investment in these non-U.S. subsidiaries that are essentially permanent in duration is not practicable.

During fiscal 2015, there is $6.3 million tax benefit associated with the exercise of employee stock options and other employee stock programs. During fiscal 2014 and 2013, there were no tax benefits associated with the exercise of employee stock options and other employee stock programs.

The following table reflects changes in the unrecognized tax benefits (in thousands):



	Fiscal Years Ended
	December 26, 2015			December 27, 2014			December 28, 2013
Unrecognized tax benefit beginning balance	$	16,333		$	16,972		$	17,181
Additions based on tax positions related to the current year	667			498			307
Additions based on tax position from prior year	163			324			—
Reductions for tax positions of prior years	(18		)	(1,109		)	(60		)
Reductions to unrecognized tax benefits due to lapse of the applicable statute of limitations	(112		)	(352		)	(456		)
Unrecognized tax benefit ending balance	$	17,033		$	16,333		$	16,972

At December 26, 2015, we had total tax-effected unrecognized tax benefits of $17.0 million of which $1.1 million, if recognized, would impact the effective tax rate.

We recognize interest (benefit) charges and penalties related to uncertain tax positions as part of the income tax provision. We recognized interest (benefit) charges and penalties of $50 thousand, $(0.1) million and $(0.2) million in fiscal 2015, 2014, and 2013, respectively. As of December 26, 2015 and December 27, 2014, we have accrued total interest charges and penalties of $0.2 million and $0.1 million, respectively, related to uncertain tax positions.

The amount of income taxes we pay is subject to ongoing audits by Federal, State and foreign tax authorities which might result in proposed assessments. Our estimate for the potential outcome for any uncertain tax issue is judgmental in nature. However, we believe we have adequately provided for any reasonably foreseeable outcome related to those matters. Our future results may include favorable or unfavorable adjustments to our estimated tax liabilities in the period the assessments are made or resolved or when statutes of limitation on potential assessments expire. As of December 26, 2015 changes to our uncertain tax positions in the next 12 months that are reasonably possible are not expected to have a significant impact on our financial position or results of operations.

We and our subsidiaries file income tax returns in the U.S. Federal jurisdiction, various states and non U.S jurisdictions. The material income tax jurisdictions are the United States (Federal), California, Singapore, China and Japan. The audit of income tax returns for Federal and California for the tax years 2010 to 2012 stub period and 2010 to 2011, respectively, have been settled. However, as a result of net operating loss carryforwards, we are subject to audit for tax years 2007 and forward for Federal purposes and 2008 and forward for California purposes. For Singapore, China and Japan purposes, we are subject to audit for tax years after 2011.

On December 18, 2015, Protecting Americans from Tax Hikes Act of 2015 (PATH Act) was signed into law, which retroactively reinstated and made permanent the federal research tax credit provisions from January 1, 2015 through December 31, 2015. Since the Company has a full valuation allowance in the U.S., there is no income tax benefit recognized for federal research and development tax credit.

Employee Benefit Plans	12 Months Ended
Employee Benefit Plans	Dec. 26, 2015
Compensation and Retirement Disclosure [Abstract]
Employee Benefit Plans	Employee Benefit Plans We have an employee savings plan that qualifies as a deferred salary arrangement under Section 401(k) of the Internal Revenue Code. We match up to 50% of an eligible employee's contributions to a maximum of the first 1.5% of the eligible employee's contributions through a fiscal year. We also provide a tax-qualified profit sharing retirement plan for the benefit of eligible employees in the U.S. The plan is designed to provide employees with an accumulation of funds for retirement on a tax-deferred basis and provide for annual discretionary employer contributions. The total charge to operations under the 401(k) and the profit sharing retirement plans for fiscal 2015, 2014 and 2013 aggregated $1.1 million, $1.0 million and $1.0 million, respectively.

Operating Segment and Geographic Information

12 Months Ended

Dec. 26, 2015

Segment Reporting [Abstract]

Operating Segment and Geographic Information

Operating Segments and Geographic Information

Since our acquisition of MicroProbe in Fiscal 2012, we had historically operated in one reportable segment consisting of two operating segments related to our FormFactor and MicroProbe product groups. During the fourth quarter of fiscal 2015, we determined that we now operate in one reportable segment consisting of one operating segment relating to the design, development, manufacture and sale of high performance advanced probe cards as a result of the successful integration of the MicroProbe business into our overall consolidated operations. Our chief operating decision maker is the Chief Executive Officer, who reviews operating results to make decisions about allocating resources and assessing performance for the entire company.

The following table summarizes revenue by country as a percentage of total revenues based upon ship-to location:



	Fiscal Years Ended
	December 26, 2015		December 27, 2014		December 28, 2013
South Korea	25.2	%	19.6	%	19.8	%
North America	23.4		28.1		27.2
Taiwan	21.9		18.4		27.9
Asia-Pacific (1)	11.1		12.9		9.2
Japan	9.4		9.6		7.3
Europe	9.0		11.4		8.6
Total Revenues	100.0	%	100.0	%	100.0	%

(1) Asia-Pacific includes all countries in the region except Taiwan, Japan and South Korea, which are disclosed separately.

The following table summarizes revenue by product group (in thousands):



	Fiscal Years Ended
	December 26, 2015		December 27, 2014		December 28, 2013
SoC	$	145,839	$	142,360	$	115,597
DRAM	125,512		110,800		92,603
Flash	11,007		15,370		23,333
Total revenues	$	282,358	$	268,530	$	231,533

Long-lived assets, comprising of net property, plant and equipment, goodwill and net intangibles assets are reported based on the location of the asset. Long-lived assets by geographic location are as follows (in thousands):



	December 26, 2015		December 27, 2014
North America	$	77,257	$	91,862
South Korea	1,128		1,578
Asia-Pacific (1)	689		935
Japan	295		358
Singapore	112		172
Europe	655		13
Total	$	80,136	$	94,918


(1)	Asia-Pacific includes all countries in the region except South Korea, Singapore, and Japan, which are disclosed separately.

The following customers represented greater than 10% of our revenues in fiscal 2015, fiscal 2014 and fiscal 2013:



	Fiscal 2015		Fiscal 2014		Fiscal 2013
Intel	19.6	%	19.7	%	17.7	%
Samsung	14.6		*		*
SK hynix	14.3		16.9		16.5
Micron	11.7		15.0		11.7
Total	60.2	%	51.6	%	45.9	%

* Less than 10% of revenues

- Definition

The entire disclosure for reporting segments including data and tables. Reportable segments include those that meet any of the following quantitative thresholds a) it's reported revenue, including sales to external customers and intersegment sales or transfers is 10 percent or more of the combined revenue, internal and external, of all operating segments b) the absolute amount of its reported profit or loss is 10 percent or more of the greater, in absolute amount of 1) the combined reported profit of all operating segments that did not report a loss or 2) the combined reported loss of all operating segments that did report a loss c) its assets are 10 percent or more of the combined assets of all operating segments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 34
-URI http://asc.fasb.org/extlink&oid=51669610&loc=d3e8981-108599

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 41
-URI http://asc.fasb.org/extlink&oid=51669610&loc=d3e9038-108599

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=51669610&loc=d3e8971-108599

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=51669610&loc=d3e8595-108599

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=51669610&loc=d3e8380-108599

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-URI http://asc.fasb.org/extlink&oid=51669610&loc=d3e8933-108599

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 26
-URI http://asc.fasb.org/extlink&oid=51669610&loc=d3e8844-108599

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 35
-URI http://asc.fasb.org/extlink&oid=51669610&loc=d3e8984-108599

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 40
-URI http://asc.fasb.org/extlink&oid=51669610&loc=d3e9031-108599

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 42
-URI http://asc.fasb.org/extlink&oid=51669610&loc=d3e9054-108599

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=51669610&loc=d3e8538-108599

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 29
-URI http://asc.fasb.org/extlink&oid=51669610&loc=d3e8864-108599

Reference 13: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 31
-URI http://asc.fasb.org/extlink&oid=51669610&loc=d3e8924-108599

Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 30
-URI http://asc.fasb.org/extlink&oid=51669610&loc=d3e8906-108599

+ Details

Selected Quarterly Financial Data (Unaudited)

12 Months Ended

Dec. 26, 2015

Quarterly Financial Information Disclosure [Abstract]

Selected Quarterly Financial Data (Unaudited)

The following selected quarterly financial data should be read in conjunction with our consolidated financial statements and the related notes and "Item 7: Management's Discussion and Analysis of Financial Condition and Results of Operations." This information has been derived from our unaudited consolidated financial statements that, in our opinion, reflect all recurring adjustments necessary to fairly present this information when read in conjunction with our consolidated financial statements and the related notes appearing in the section entitled "Consolidated Financial Statements." The results of operations for any quarter are not necessarily indicative of the results to be expected for any future period.



	Fiscal Quarters Ended
	Dec. 26, 2015			Sep. 26, 2015 (2)			June. 27, 2015		March 28, 2015 (1)			Dec. 27, 2014			Sep. 27, 2014			June. 28, 2014			March 29, 2014
	(in thousands, except per share data)
Revenues	$	71,782		$	65,862		$	73,885	$	70,829		$	71,285		$	73,934		$	67,352		$	55,959
Cost of revenues	50,591			47,407			50,582		48,040			50,337			49,792			47,328			43,634
Gross profit	21,191			18,455			23,303		22,789			20,948			24,142			20,024			12,325
Operating Expenses:
Research and development	11,236			10,645			11,217		11,086			10,706			11,198			11,074			9,747
Selling, general and administrative	10,719			11,108			11,381		11,882			12,631			13,309			13,191			12,254
Restructuring charges, net	(3		)	59			—		503			584			28			59			1,997
Impairment of long-lived assets	—			—			8		—			390			86			—			743
Total operating expenses	21,952			21,812			22,606		23,471			24,311			24,621			24,324			24,741
Operating income (loss)	(761		)	(3,357		)	697		(682		)	(3,363		)	(479		)	(4,300		)	(12,416		)
Interest income, net	70			65			65		85			69			75			79			79
Other income (expense), net	(36		)	982			100		1,501			155			228			(156		)	(66		)
Income (loss) before income taxes	(727		)	(2,310		)	862		904			(3,139		)	(176		)	(4,377		)	(12,403		)
Provision (benefit) for income taxes	(108		)	215			24		121			(1,268		)	101			(51		)	308
Net income (loss)	$	(619	)	$	(2,525	)	$	838	$	783		$	(1,871	)	$	(277	)	$	(4,326	)	$	(12,711	)
Net income (loss) per share:
Basic	$	(0.01	)	$	(0.04	)	$	0.01	$	0.01		$	(0.03	)	$	0.00		$	(0.08	)	$	(0.23	)
Diluted	$	(0.01	)	$	(0.04	)	$	0.01	$	0.01		$	(0.03	)	$	0.00		$	(0.08	)	$	(0.23	)
Weighted average number of shares used in per share calculations:
Basic	58,128			58,209			58,109		56,594			56,472			56,297			55,812			55,050
Diluted	58,128			58,209			59,094		58,838			56,472			56,297			55,812			55,050


(1)	In the first quarter of fiscal 2015, we recorded a $1.5 million gain from a business interruption insurance claim relating to a factory fire at a customer. See Note 16, Business Interruption Insurance Claim Recovery, to the Notes to Consolidated Financial Statements for further details.


(2)	In the third quarter of fiscal 2015, we recorded a $1.0 million net gain from the sale of intellectual property. See Note 9, Commitments and contingencies, to the Notes to Consolidated Financial Statements for further details.

Business Interruption Insurance Claim Recovery	12 Months Ended
Business Interruption Insurance Claim Recovery	Dec. 26, 2015
Extraordinary and Unusual Items [Abstract]
Business Interruption Insurance Claim Recovery	Business Interruption Insurance Claim Recovery During fiscal 2015, we received approximately $1.5 million as a result of a payment from our insurer arising from a business interruption insurance claim related to a factory fire at a customer during the second half of fiscal 2013. We recorded this cash receipt within “Other income, net” in our Consolidated Statements of Operations.

Subsequent Events	12 Months Ended
Subsequent Events	Dec. 26, 2015
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events Cascade Microtech Acquisition On February 3, 2016, we entered into an Agreement and Plan of Merger under which we agreed to acquire Cascade Microtech through the merger of a wholly owned subsidiary with and into Cascade Microtech. Subject to the terms of the merger agreement, at the effective time of the merger, each outstanding share of Cascade Microtech common stock will be cancelled and converted into the right to receive (a) $16.00 in cash, without interest, and (b) 0.6534 shares of FormFactor common stock. Cascade Microtech is an Oregon corporation that designs, develops, manufactures and markets advanced wafer probing, thermal and reliability solutions for the electrical measurement and testing of high performance semiconductor devices. Subject to the terms of the merger agreement, at the effective time of the merger all of the outstanding and vested equity awards of Cascade Microtech will be cancelled and converted into the right to receive an amount in cash in respect of the merger consideration the shares of Cascade Microtech common stock underlying the awards would have received, and all of the outstanding and unvested equity awards of Cascade Microtech will be assumed on substantially the same terms, except that the number of shares of our common stock that will underlie the assumed award and the exercise price of any assumed option will be determined pursuant to a formula intended to preserve the intrinsic value of the original award. Completion of the merger is subject to customary closing conditions, including approval by Cascade Microtech’s shareholders and expiration of the applicable waiting period under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended, among others, and therefore has not been reflected in the financial statements included in this Annual Report on Form 10-K. There is no financing condition to our obligations under the merger agreement. We expect the merger to be completed in mid-2016. To finance a portion of the consideration for the proposed merger, we entered into a commitment letter with certain lenders to provide a senior secured term loan facility in an aggregate amount of $150 million. The funding of the term loan facility is subject to certain conditions, including the execution of definitive financing documentation, the consummation of the merger in accordance with the merger agreement, the absence of a Company Material Adverse Effect (as defined in the merger agreement), a minimum liquidity condition and other customary closing conditions. The above description of the merger agreement and the proposed merger is a summary and is qualified in its entirety by reference to the merger agreement included as Exhibit 2.1 to our Current Report on Form 8-K, filed with the SEC on February 9, 2016.

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 26, 2015

Accounting Policies [Abstract]

Fiscal Year

Our fiscal year ends on the last Saturday in December. The fiscal years ended on December 26, 2015, December 27, 2014 and December 28, 2013, respectively, consisted of 52 weeks each.

Basis of Consolidation

Basis of Consolidation and Foreign Currency Translation

The consolidated financial statements include our accounts and those of our wholly-owned subsidiaries. All intercompany balances and transactions have been eliminated.

Foreign Currency Translation

Use of Estimates

Business Aquisitions

Business Acquisitions

Cash and Cash Equivalents

Cash, Cash Equivalents and Marketable Securities

Cash and cash equivalents consist of deposits and financial instruments which are readily convertible into cash and have original maturities of 90 days or less at the time of acquisition.

Marketable Securities

Marketable securities consist primarily of highly liquid investments with maturities of greater than 90 days when purchased. We generally classify our marketable securities at the date of acquisition as available-for-sale. These securities are reported at fair value with the related unrealized gains and losses included in "Accumulated other comprehensive income (loss)", a component of stockholder's equity, net of tax. Any unrealized losses which are considered to be other-than-temporary impairments are recorded in "Other income, net" in the Consolidated Statements of Operations. Realized gains (losses) on the sale of marketable securities are determined using the specific-identification method and recorded in "Other income, net" in the Consolidated Statements of Operations.

Fair Value of Financial Instruments


•	Level 1 valuations are obtained from real-time quotes for transactions in active exchange markets involving identical assets;


•	Level 2 inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities, quoted prices near the reporting date in markets that are less active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities; and


•	Level 3 valuations are based on unobservable inputs to the valuation methodology and include our own data about assumptions market participants would use in pricing the asset or liability based on the best information available under the circumstances.

Each level of input has different levels of subjectivity and difficulty involved in determining fair value.

Foreign Exchange Management

Restricted Cash

Under the terms of one of our facility leases, we provide security to the landlord in the form of letters of credit.

Inventories

Property, Plant, and Equipment

Goodwill

Intangible Assets

Impairment of Long-Lived Assets

Concentration of Credit Risk and Other Risk and Uncertainties

Concentration of Credit Risk and Other Risks and Uncertainties

Revenue Recognition

Warranty Obligations

We provide for the estimated cost of product warranties at the time revenue is recognized. Warranty costs are reflected in the Consolidated Statement of Operations as a cost of revenues

Research and Development

Research and development expenses include expenses related to product development, engineering and material costs. All research and development costs are expensed as incurred

Allowance for Doubtful Accounts

Restructuring Charges

Income Taxes

Stock-based Compensation

Stock-Based Compensation

Net Loss Per Share

Accumulated Other Comprehensive Loss

Recent Adopted Accounting Standards

Derivative Financial Instruments

We do not use derivative financial instruments for speculative or trading purposes. Our derivative instruments are not designated as hedging instruments for accounting purposes. Accordingly, changes in the fair value of these hedges are recorded in earnings to offset the changes in the fair value of the assets or liabilities being hedged. We record the fair value of these contracts as of the end of our reporting period to our Consolidated Balance Sheet with changes in fair value recorded within "Other income, net" in our Consolidated Statement of Operations for both realized and unrealized gains and losses.

Fair Value Measurement


•	Level 1—Quoted prices in active markets for identical assets or liabilities;


•	Level 2—Inputs, other than the quoted prices in active markets, such as quoted prices for similar assets or liabilities, quoted prices near the reporting date in markets that are less active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities; and


•	Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities.

Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 26, 2015

Accounting Policies [Abstract]

Schedules of Concentration of Risk, by Customer

The following customers represented greater than 10% of our revenues in fiscal 2015, fiscal 2014 and fiscal 2013:



	Fiscal 2015		Fiscal 2014		Fiscal 2013
Intel	19.6	%	19.7	%	17.7	%
Samsung	14.6		*		*
SK hynix	14.3		16.9		16.5
Micron	11.7		15.0		11.7
Total	60.2	%	51.6	%	45.9	%

* Less than 10% of revenues

Schedule of Product Warranty Liability

A reconciliation of the changes in our warranty liability is as follows (in thousands):



	Fiscal Years Ended
	December 26, 2015			December 27, 2014
Balance at beginning of year	$	1,592		$	691
Accruals	2,536			2,972
Settlements	(3,012		)	(2,071		)
Balance at end of year	$	1,116		$	1,592

Schedule of Allowance for Doubtful Accounts

The allowance for doubtful accounts receivable consisted of the following activity for fiscal years 2015, 2014 and 2013 (in thousands):



	Balance at Beginning of Year		Additions		Reductions			Balance at End of Year
Fiscal year ended December 28, 2013	$	289	$	—	$	(24	)	$	265
Fiscal year ended December 27, 2014	265		5		(4		)	266
Fiscal year ended December 26, 2015	$	266	$	20	$	(2	)	$	284

Schedule of Calculation of Numerator and Denominator in Earnings Per Share

A reconciliation of the numerator and denominator used in the calculation of basic and diluted net loss per share is as follows (in thousands):



	Fiscal Years Ended
	December 26, 2015			December 27, 2014			December 28, 2013
Numerator:
Net loss used in computing basic and diluted net loss per share	$	(1,523	)	$	(19,185	)	$	(57,683	)
Denominator:
Weighted-average shares used in computing basic net loss per share	57,850			55,908			54,204
Add potentially dilutive securities	—			—			—
Weighted-average shares used in computing basic and diluted net loss per share	57,850			55,908			54,204

Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share

The following securities were excluded from the calculation of diluted net loss per share because their effect would have been anti-dilutive for the periods presented (in thousands):



	Fiscal Years Ended
	December 26, 2015	December 27, 2014	December 28, 2013
Options to purchase common stock	2,320	2,874	3,805
Restricted stock units	2,578	—	373
Employee stock purchase plan	8	28	22
Total potentially dilutive securities	4,906	2,902	4,200

Schedule of Accumulated Other Comprehensive Loss

Components of accumulated other comprehensive loss was as follows (in thousands):



	December 26, 2015			December 27, 2014
Unrealized loss on marketable securities, net of tax of $428 in fiscal 2015 and fiscal 2014, respectively	$	(483	)	$	(419	)
Cumulative translation adjustments	(1,739		)	(1,342		)
Accumulated other comprehensive loss	$	(2,222	)	$	(1,761	)

Balance Sheet Components (Tables)

12 Months Ended

Dec. 26, 2015

Balance Sheet Components [Abstract]

Schedule of Available-for-sale Securities Reconciliation

Marketable securities at December 26, 2015 consisted of the following (in thousands):



	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
U.S. Treasuries	$	18,896	$	1	$	(44	)	$	18,853
Agency securities (Federal)	22,484		—		(12		)	22,472
	$	41,380	$	1	$	(56	)	$	41,325

Marketable securities at December 27, 2014 consisted of the following (in thousands):



	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
U.S. Treasuries	$	42,386	$	13	$	(4	)	$	42,395
Agency securities (Federal)	7,502		—		—			7,502
	$	49,888	$	13	$	(4	)	$	49,897

Investments Classified by Contractual Maturity Date

The contractual maturities of marketable securities as of December 26, 2015 and December 27, 2014 were as follows (in thousands):



	December 26, 2015				December 27, 2014
	Amortized Cost		Fair Value		Amortized Cost		Fair Value
Due in one year or less	$	33,882	$	33,871	$	38,499	$	38,509
Due after one year to five years	7,498		7,454		11,389		11,388
	$	41,380	$	41,325	$	49,888	$	49,897

Schedule of Asset Retirement Obligations

The following is a reconciliation of the aggregate asset retirement liability associated with our commitment to return property to its original condition upon lease termination (in thousands):



	Fiscal Years Ended
	December 26, 2015		December 27, 2014
Asset retirement obligation beginning balance	$	903	$	988
Initial amount recorded for new asset retirement obligation	10		—
Currency translation	6		(85		)
Asset retirement obligation ending balance	$	919	$	903

The aggregate asset retirement liability was further classsified in the Consolidated Balance Sheets as (in thousands):



Other accrued liabilities, current	$	212	$	—
Deferred rent and other liabilities, non-current	707		903
	$	919	$	903

Schedule of Inventory, Current

Net inventories consisted of the following (in thousands):



	Fiscal Years Ended
	December 26, 2015		December 27, 2014
Raw materials	$	12,996	$	10,646
Work-in-progress	12,492		12,813
Finished goods	1,735		2,089
	$	27,223	$	25,548

Property, plant and equipment Including Construction-in-progress

Property, plant and equipment consisted of the following (in thousands):



	Fiscal Years Ended
	December 26, 2015			December 27, 2014
Machinery and equipment	150,983			145,995
Computer equipment and software	27,951			28,953
Furniture and fixtures	5,380			5,402
Leasehold improvements	67,121			66,821
Sub-total	251,435			247,171
Less: Accumulated depreciation and amortization	(232,005		)	(224,135		)
Net long-lived assets	19,430			23,036
Construction-in-progress	4,423			2,462
Total	$	23,853		$	25,498

Schedule of Accrued Liabilities

Accrued liabilities consisted of the following (in thousands):



	Fiscal Years Ended
	December 26, 2015		December 27, 2014
Accrued compensation and benefits	$	12,286	$	12,431
Accrued indirect and other taxes	2,189		2,223
Accrued commissions	366		460
Accrued warranty	1,116		1,592
Deferred rent	325		216
Accrued restructuring	2		584
Other accrued expenses	5,223		3,711
	$	21,507	$	21,217

Restructuring Charges (Tables)

12 Months Ended

Dec. 26, 2015

Restructuring Charges [Abstract]

Schedule of Restructuring Actions

The following table summarizes the activities related to the restructuring actions from fiscal 2013 to 2015 (in thousands):



	Employee Severance and Benefits			Property and Equipment Impairment			Contract Termination and Other Costs			Total
Accrual at December 31, 2012	$	548		$	—		$	68		$	616
Restructuring charges	2,083			2,743			15			4,841
Asset impairments	—			(2,743		)	—			(2,743		)
Adjustments to restructuring charges	(178		)	(5		)	—			(183		)
Cash payments	(2,320		)	(32		)	(17		)	(2,369		)
Non-cash settlements	5			37			(66		)	(24		)
Accrual at December 28, 2013	138			—			—			138
Restructuring charges	2,068			600			—			2,668
Asset impairments	—			(600		)	—			(600		)
Cash payments	(1,620		)	—			—			(1,620		)
Non-cash settlements	(2		)	—			—			(2		)
Accrual at December 27, 2014	584			—			—			584
Restructuring charges	59			—			500			559
Cash payments	(641		)	—			—			(641		)
Non-cash settlements	—			—			(500		)	(500		)
Accrual at December 26, 2015	$	2		$	—		$	—		$	2

Derivative Financial Instruments (Tables)

12 Months Ended

Dec. 26, 2015

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Schedule of outstanding foreign currency forward contracts

The following tables provide information about our foreign currency forward contracts outstanding as of December 26, 2015 and December 27, 2014 (in thousands):



December 26, 2015		Contract Position	Contract Amount (Local Currency)		Contract Amount (U.S. Dollar)
			(In thousands)
Japanese Yen		Sell	3,328,268		$	27,635
Taiwan Dollar		Buy	(37,152	)	(1,136		)
Korean Won		Buy	(840,111	)	(718		)
	Total USD notional amount of outstanding foreign exchange contracts				$	25,781



December 27, 2014		Contract Position	Contract Amount (Local Currency)		Contract Amount (U.S. Dollar)
			(In thousands)
Japanese Yen		Sell	1,955,798		$	16,241
Taiwan Dollar		Buy	(30,886	)	(977		)
Korean Won		Buy	(1,763,054	)	(1,613		)
	Total USD notional amount of outstanding foreign exchange contracts				$	13,651

Schedule of non-designated derivative gains (losses)



		Fiscal Years Ended
Derivatives Not Designated as Hedging Instruments	Location of Gain (Loss) Recognized on Derivatives	December 26, 2015			December 27, 2014
Foreign exchange forward contracts	Other Income, net	$	(310	)	$	1,768

Impairment of Long-lived Assets (Tables)

12 Months Ended

Dec. 26, 2015

Property, Plant and Equipment Impairment or Disposal [Abstract]

Schedule Of Impairment of Long Lived Assets

The following table summarizes the components of the impairments that we recorded in fiscal 2015, 2014 and 2013 (in thousands):



	Fiscal Years Ended
	December 26, 2015		December 27, 2014		December 28, 2013
Impairment of long-lived assets:
Assets held for sale	$	—	$	191	$	—
Assets to be disposed of other than by sale	8		1,028		761
Total	$	8	$	1,219	$	761

Fair Value (Tables)

12 Months Ended

Dec. 26, 2015

Fair Value Disclosures [Abstract]

Fair Value Measured on Recurring Basis

Fair values measured on a recurring basis as of December 26, 2015 (in thousands):



	Level 1		Level 2		Total
Assets:
Cash equivalents
Money market funds	$	82,935	$	—	$	82,935
Marketable securities
U.S. Treasuries	—		18,853		18,853
Agency securities (Federal)	—		22,472		22,472
Total	$	82,935	$	41,325	$	124,260

Fair values measured on a recurring basis as of December 27, 2014 (in thousands):



	Level 1		Level 2		Total
Assets:
Cash equivalents
Money market funds	$	65,303	$	—	$	65,303
Marketable securities
U.S. Treasuries	—		42,395		42,395
Agency securities (Federal)	—		7,502		7,502
Total	$	65,303	$	49,897	$	115,200

Goodwill and Intangible Assets (Tables)

12 Months Ended

Dec. 26, 2015

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of Intangible Assets

The changes in intangible assets for fiscal 2015 and the net book value of intangible assets at December 26, 2015 and December 27, 2014 were as follows (in thousands):



	Intangible Assets, Gross Amount							Accumulated Amortization						Intangible Assets, Net				Weight Average Useful Life
Other Intangible Assets (1)	December 27, 2014		Additions/Disposals			December 26, 2015		December 27, 2014		Expense, net		December 26, 2015		December 27, 2014		December 26, 2015		December 26, 2015
Existing developed technologies (2)	$	45,300	$	6,900		$	52,200	$	29,097	$	10,484	$	39,581	$	16,203	$	12,619	2.0
Trade name	4,388		—			4,388		970		439		1,409		3,418		2,979		6.8
Customer relationships	17,000		—			17,000		4,832		2,214		7,046		12,168		9,954		4.8
Total finite-lived intangible assets	66,688		6,900			73,588		34,899		13,137		48,036		31,789		25,552
In-process research and development	6,900		(6,900		)	—		—		—		—		6,900		—
Total intangible assets	$	73,588	$	—		$	73,588	$	34,899	$	13,137	$	48,036	$	38,689	$	25,552



(1)	Excludes fully amortized intangible assets.
(2)	As of December 26, 2015, we excluded approximately $5.9 million of fully amortized existing developed technology intangible assets from gross intangible assets and accumulated amortization due to the sale of these intangible assets to MarTek Inc. These intangible assets were fully amortized as of December 27, 2014 but were in use until their sale to MarTek Inc. Refer to Note 9 in Notes to Consolidated Financial Statements-Commitments and Contingencies, for further details.

Schedule of Remaining Estimated Amortization Expense



Fiscal Year	Amount
2016	$	10,060
2017	4,943
2018	4,666
2019	3,052
2020	2,045
and thereafter	786
Total	$	25,552

Commitments and Contingencies (Tables)

12 Months Ended

Dec. 26, 2015

Commitments and Contingencies Disclosure [Abstract]

Schedule Of Capital and Operating Leases

Future minimum payments under our non-cancelable operating leases are as follows as of December 26, 2015 (in thousands):



	Operating Leases
Fiscal years:
2016	$	3,994
2017-2018	7,194
2019-2020	7,064
Thereafter	2,505
Total	$	20,757

Schedule of Purchase Obligations

The following table sets forth our commitments to settle other contractual obligations in cash as of December 26, 2015 (in thousands):



	Payments Due In Fiscal Years
	2016		2017-2018		2019-2020		After 2020		Total
	(In thousands)
Purchase obligations	$	20,899	$	9,580	$	30	$	—	$	30,509

Stockholders' Equity (Tables)

12 Months Ended

Dec. 26, 2015

Stockholders' Equity Note [Abstract]

Schedule of Stock Option Activity

Stock option activity is set forth below:



	Outstanding Options
	Number of Shares		Weighted Average Exercise Price		Weighted Average Remaining Contractual Life in Years	Aggregate Intrinsic Value
Outstanding at December 27, 2014	2,571,376		10.72
Options granted	456,000		8.42
Options exercised	(24,607	)	8.61
Options canceled	(682,574	)	13.75
Outstanding at December 26, 2015	2,320,195		$	9.40	2.70	$	1,146,680
Vested and expected to vest at December 26, 2015	2,320,195		$	9.40	2.70	$	1,146,680
Exercisable at December 26, 2015	1,864,861		$	9.64	1.86	$	833,552

Schedule of Weighted Average Assumptions

The following weighted average assumptions were used in the estimated grant-date fair value calculations using the Black-Scholes option pricing model:



Stock Options:
Dividend yield	—	%
Expected volatility	47.5	%
Risk-free interest rate	1.6	%
Expected term (in years)	5.5



Stock Options:
Dividend yield	—	%
Expected volatility	47.5	%
Risk-free interest rate	1.6	%
Expected life (in years)	5.5

Schedule of Restricted Stock Unit Activity

Restricted stock unit activity is set forth below:



	Number of Shares		Weighted Average Grant Date Fair Value
Restricted stock units at December 29, 2012	2,228,946		$	7.66
Granted	1,708,000		5.04
Vested	(760,590	)	8.44
Canceled	(246,717	)	8.18
Restricted stock units at December 28, 2013	2,929,639		5.88
Granted	1,900,000		6.52
Vested	(1,282,442	)	6.30
Canceled	(297,151	)	6.17
Restricted stock units at December 27, 2014	3,250,046		6.07
Granted	1,540,250		8.64
Vested	(1,993,603	)	6.00
Canceled	(218,555	)	6.36
Restricted stock units at December 26, 2015	2,578,138		$	7.63

Stock-Based Compensation (Tables)

12 Months Ended

Dec. 26, 2015

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

Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs

The table below shows the stock-based compensation expense included in the Consolidated Statement of Operations (in thousands):



	Fiscal Years Ended
	December 26, 2015		December 27, 2014		December 28, 2013
Stock-based compensation expense included in:
Cost of revenues	$	2,651	$	2,433	$	2,436
Research and development	3,490		3,529		3,440
Selling, general and administrative	5,434		7,317		6,248
Total stock-based compensation	11,575		13,279		12,124
Tax effect on stock-based compensation	—		—		—
Total stock-based compensation, net of tax	$	11,575	$	13,279	$	12,124

Schedule of Weighted Average Assumptions

The following weighted average assumptions were used in the estimated grant-date fair value calculations using the Black-Scholes option pricing model:



Stock Options:
Dividend yield	—	%
Expected volatility	47.5	%
Risk-free interest rate	1.6	%
Expected term (in years)	5.5



Stock Options:
Dividend yield	—	%
Expected volatility	47.5	%
Risk-free interest rate	1.6	%
Expected life (in years)	5.5

Schedule of Share-based Payment Award, Employee Stock Purchase Plan, Valuation Assumptions

The following assumptions were used in estimating the fair value of employees' purchase rights under the approved employee stock purchase plans:



	Fiscal Years Ended
	December 26, 2015		December 27, 2014		December 28, 2013
Employee Stock Purchase Plan:
Dividend yield	—	%	—	%	—	%
Expected volatility	51.78	%	41.71	%	39.80	%
Risk-free interest rate	0.12	%	0.09	%	0.13	%
Expected life (in years)	0.7		0.7		0.7

Income Taxes (Tables)

12 Months Ended

Dec. 26, 2015

Income Tax Disclosure [Abstract]

Schedule of Income before Income Tax, Domestic and Foreign

The components of loss before income taxes were as follows (in thousands):



	Fiscal Years Ended
	December 26, 2015			December 27, 2014			December 28, 2013
United States	$	(3,069	)	$	(23,230	)	$	(60,447	)
Foreign	1,798			3,135			2,665
	$	(1,271	)	$	(20,095	)	$	(57,782	)

Schedule of Components of Income Tax Expense (Benefit)

The components of the provision for income taxes are as follows (in thousands):



	Fiscal Years Ended
	December 26, 2015			December 27, 2014			December 28, 2013
Current provision (benefit):
Federal	$	(3	)	$	(983	)	$	(770	)
State	72			(386		)	76
Foreign	198			234			287
	267			(1,135		)	(407		)
Deferred provision (benefit):
Federal	—			—			—
State	—			—			—
Foreign	(15		)	225			308
	(15		)	225			308
Total provision (benefit) from income taxes	$	252		$	(910	)	$	(99	)

Schedule of Effective Income Tax Rate Reconciliation



	Fiscal Years Ended
	December 26, 2015			December 27, 2014			December 28, 2013
U.S. statutory federal tax rate	$	(445	)	$	(7,033	)	$	(20,224	)
State taxes and credits, net of Federal benefit	17			(186		)	(345		)
Amortization of stock-based compensation	907			686			923
Research and development credits	(1,872		)	(1,183		)	(560		)
Foreign taxes at rates different than the U.S.	(66		)	(84		)	162
Other permanent differences	238			(972		)	(378		)
Change in valuation allowance	1,457			7,886			20,505
Other	16			(24		)	(182		)
Total	$	252		$	(910	)	$	(99	)

Schedule of Deferred Tax Assets and Liabilities

Significant deferred tax assets and liabilities consist of the following (in thousands):



	Fiscal Years Ended
	December 26, 2015			December 27, 2014
Tax credits	$	30,968		$	28,458
Inventory reserve	14,010			16,612
Unrealized investment gains	20			—
Other reserves and accruals	5,953			7,610
Non-statutory stock options	4,936			18,096
Depreciation and amortization	13,440			14,037
Net operating loss carryforwards	119,327			120,110
Gross deferred tax assets	188,654			204,923
Valuation allowance	(176,196		)	(187,759		)
Total deferred tax assets	12,458			17,164
Acquired intangibles & fixed assets	(9,177		)	(13,867		)
Unrealized investment gains	—			(3		)
Total deferred tax liabilities	(9,177		)	(13,870		)
Net deferred tax assets	$	3,281		$	3,294

Summary of Valuation Allowance

The valuation allowance against deferred tax assets consisted of the following activity for the fiscal years 2015, 2014 and 2013 (in thousands):



Description	Balance at Beginning of Year		Additions		Reduction			Balance at End of Year
Allowance against deferred tax assets
Year ended December 31, 2015	$	187,759	$	—	$	(11,563	)	$	176,196
Year ended December 31, 2014	180,913		6,846		—			187,759
Year ended December 31, 2013	$	163,265	$	17,648	$	—		$	180,913

Schedule of Unrecognized Tax Benefits Roll Forward

The following table reflects changes in the unrecognized tax benefits (in thousands):



	Fiscal Years Ended
	December 26, 2015			December 27, 2014			December 28, 2013
Unrecognized tax benefit beginning balance	$	16,333		$	16,972		$	17,181
Additions based on tax positions related to the current year	667			498			307
Additions based on tax position from prior year	163			324			—
Reductions for tax positions of prior years	(18		)	(1,109		)	(60		)
Reductions to unrecognized tax benefits due to lapse of the applicable statute of limitations	(112		)	(352		)	(456		)
Unrecognized tax benefit ending balance	$	17,033		$	16,333		$	16,972

Operating Segment and Geographic Information (Tables)

12 Months Ended

Dec. 26, 2015

Segment Reporting [Abstract]

Schedule of Revenue by Country as a Percentage of Total Revenues

The following table summarizes revenue by country as a percentage of total revenues based upon ship-to location:



	Fiscal Years Ended
	December 26, 2015		December 27, 2014		December 28, 2013
South Korea	25.2	%	19.6	%	19.8	%
North America	23.4		28.1		27.2
Taiwan	21.9		18.4		27.9
Asia-Pacific (1)	11.1		12.9		9.2
Japan	9.4		9.6		7.3
Europe	9.0		11.4		8.6
Total Revenues	100.0	%	100.0	%	100.0	%

(1) Asia-Pacific includes all countries in the region except Taiwan, Japan and South Korea, which are disclosed separately.

Schedule of Revenue by Product Group

The following table summarizes revenue by product group (in thousands):



	Fiscal Years Ended
	December 26, 2015		December 27, 2014		December 28, 2013
SoC	$	145,839	$	142,360	$	115,597
DRAM	125,512		110,800		92,603
Flash	11,007		15,370		23,333
Total revenues	$	282,358	$	268,530	$	231,533

Schedule of Long-Lived Assets, by Geographical Location



	December 26, 2015		December 27, 2014
North America	$	77,257	$	91,862
South Korea	1,128		1,578
Asia-Pacific (1)	689		935
Japan	295		358
Singapore	112		172
Europe	655		13
Total	$	80,136	$	94,918


(1)	Asia-Pacific includes all countries in the region except South Korea, Singapore, and Japan, which are disclosed separately.

Schedule of Major Customers With Revenues Greater Than 10%

The following customers represented greater than 10% of our revenues in fiscal 2015, fiscal 2014 and fiscal 2013:



	Fiscal 2015		Fiscal 2014		Fiscal 2013
Intel	19.6	%	19.7	%	17.7	%
Samsung	14.6		*		*
SK hynix	14.3		16.9		16.5
Micron	11.7		15.0		11.7
Total	60.2	%	51.6	%	45.9	%

* Less than 10% of revenues

Selected Quarterly Financial Data (Unaudited) (Tables)

12 Months Ended

Dec. 26, 2015

Quarterly Financial Information Disclosure [Abstract]

Schedule of Quarterly Financial Information

The results of operations for any quarter are not necessarily indicative of the results to be expected for any future period.



	Fiscal Quarters Ended
	Dec. 26, 2015			Sep. 26, 2015 (2)			June. 27, 2015		March 28, 2015 (1)			Dec. 27, 2014			Sep. 27, 2014			June. 28, 2014			March 29, 2014
	(in thousands, except per share data)
Revenues	$	71,782		$	65,862		$	73,885	$	70,829		$	71,285		$	73,934		$	67,352		$	55,959
Cost of revenues	50,591			47,407			50,582		48,040			50,337			49,792			47,328			43,634
Gross profit	21,191			18,455			23,303		22,789			20,948			24,142			20,024			12,325
Operating Expenses:
Research and development	11,236			10,645			11,217		11,086			10,706			11,198			11,074			9,747
Selling, general and administrative	10,719			11,108			11,381		11,882			12,631			13,309			13,191			12,254
Restructuring charges, net	(3		)	59			—		503			584			28			59			1,997
Impairment of long-lived assets	—			—			8		—			390			86			—			743
Total operating expenses	21,952			21,812			22,606		23,471			24,311			24,621			24,324			24,741
Operating income (loss)	(761		)	(3,357		)	697		(682		)	(3,363		)	(479		)	(4,300		)	(12,416		)
Interest income, net	70			65			65		85			69			75			79			79
Other income (expense), net	(36		)	982			100		1,501			155			228			(156		)	(66		)
Income (loss) before income taxes	(727		)	(2,310		)	862		904			(3,139		)	(176		)	(4,377		)	(12,403		)
Provision (benefit) for income taxes	(108		)	215			24		121			(1,268		)	101			(51		)	308
Net income (loss)	$	(619	)	$	(2,525	)	$	838	$	783		$	(1,871	)	$	(277	)	$	(4,326	)	$	(12,711	)
Net income (loss) per share:
Basic	$	(0.01	)	$	(0.04	)	$	0.01	$	0.01		$	(0.03	)	$	0.00		$	(0.08	)	$	(0.23	)
Diluted	$	(0.01	)	$	(0.04	)	$	0.01	$	0.01		$	(0.03	)	$	0.00		$	(0.08	)	$	(0.23	)
Weighted average number of shares used in per share calculations:
Basic	58,128			58,209			58,109		56,594			56,472			56,297			55,812			55,050
Diluted	58,128			58,209			59,094		58,838			56,472			56,297			55,812			55,050


(1)	In the first quarter of fiscal 2015, we recorded a $1.5 million gain from a business interruption insurance claim relating to a factory fire at a customer. See Note 16, Business Interruption Insurance Claim Recovery, to the Notes to Consolidated Financial Statements for further details.


(2)	In the third quarter of fiscal 2015, we recorded a $1.0 million net gain from the sale of intellectual property. See Note 9, Commitments and contingencies, to the Notes to Consolidated Financial Statements for further details.

Formation and Business of the Company - Fiscal Year (Details)	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of weeks In fiscal year	P52W	P52W	P52W

Summary of Significant Accounting Policies - Restricted Cash (Details) - USD ($) $ in Thousands	Dec. 26, 2015	Dec. 27, 2014
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash	$ 435	$ 435
Letter of Credit
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash	$ 400	$ 0

Summary of Significant Accounting Policies - Inventories (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Accounting Policies [Abstract]
Aggregate inventory write downs.	$ 6,493	$ 7,127	$ 10,461

Summary of Significant Accounting Policies - Property, Plant, and Equipment (Details)	12 Months Ended
	Dec. 26, 2015
Machinery & Equipment
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	5 years
Machinery & Equipment \| Minimum
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	1 year
Computer equipment & Software \| Minimum
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	1 year
Computer equipment & Software \| Maximum
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	5 years
Furniture & Fixtures \| Minimum
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	1 year
Furniture & Fixtures \| Maximum
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	5 years

Summary of Significant Accounting Policies - Goodwill (Details)	3 Months Ended	12 Months Ended
	Dec. 26, 2015 unit segment	Dec. 26, 2015 segment	Dec. 29, 2012 unit segment
Goodwill and Intangible Assets Disclosure [Abstract]
Number of Reportable Segments	1	1	1
Number of Operating Segments	1	2	2
Number of Reporting Units \| unit	1		2

Summary of Significant Accounting Policies - Intangibles (Details)	12 Months Ended
	Dec. 26, 2015
Minimum
Acquired Finite-Lived Intangible Assets [Line Items]
Weight Average Useful Life	1 year
Maximum
Acquired Finite-Lived Intangible Assets [Line Items]
Weight Average Useful Life	10 years

Summary of Significant Accounting Policies - Concentration of Credit Risk and Other Risks and Uncertainties (Details) - Customer Concentration Risk - Customer	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Sales Revenue, Goods, Net
Concentration Risk [Line Items]
Percentage of concentration of risk	60.20%	51.60%	45.90%
Accounts Receivable
Concentration Risk [Line Items]
Number of major customers.	1	2
Intel \| Sales Revenue, Goods, Net
Concentration Risk [Line Items]
Percentage of concentration of risk	14.60%
Samsung \| Sales Revenue, Goods, Net
Concentration Risk [Line Items]
Percentage of concentration of risk	19.60%	19.70%	17.70%
SK hynix \| Sales Revenue, Goods, Net
Concentration Risk [Line Items]
Percentage of concentration of risk	14.30%	16.90%	16.50%
Micron \| Sales Revenue, Goods, Net
Concentration Risk [Line Items]
Percentage of concentration of risk	11.70%	15.00%	11.70%
Major Customer 1 \| Accounts Receivable
Concentration Risk [Line Items]
Percentage of concentration of risk	29.00%	26.00%
Major Customer 2 \| Accounts Receivable
Concentration Risk [Line Items]
Percentage of concentration of risk		18.00%

Summary of Significant Accounting Policies - Warrany Obligations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014
Movement in Standard Product Warranty Accrual [Roll Forward]
Warranty Accrual beginning balance	$ 1,592	$ 691
Accruals	2,536	2,972
Settlements	(3,012)	(2,071)
Warranty Accrual ending balance	$ 1,116	$ 1,592

Summary of Significant Accounting Policies - Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Allowance for Doubtful Accounts Receivable [Roll Forward]
Balance at Beginning of Year	$ 266	$ 265	$ 289
Additions	20	5	0
Reductions	(2)	(4)	(24)
Balance at End of Year	$ 284	$ 266	$ 265

Summary of Significant Accounting Policies - Restructuring Charges (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Restructuring and Related Activities [Abstract]
Restructuring charges, net	$ 559	$ 2,668	$ 4,658

Summary of Significant Accounting Policies - Net Loss per Share (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 26, 2015	Sep. 26, 2015	Jun. 27, 2015	Mar. 28, 2015	Dec. 27, 2014	Sep. 27, 2014	Jun. 28, 2014	Mar. 29, 2014	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Accounting Policies [Abstract]
Net loss	$ (619)	$ (2,525)	$ 838	$ 783	$ (1,871)	$ (277)	$ (4,326)	$ (12,711)	$ (1,523)	$ (19,185)	$ (57,683)
Weighted-average shares used in computing basic net loss per share (in shares)	58,128	58,209	58,109	56,594	56,472	56,297	55,812	55,050	57,850	55,908	54,204
Add potentially dilutive securities (in shares)									0	0	0
Weighted-average shares used in computing basic and diluted net loss per share (in shares)									57,850	55,908	54,204

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References + Details

Summary of Significant Accounting Policies - Net Loss Per Share Weighted-Average Dilutive Securities (Details) - shares shares in Thousands	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities excluded from computation of earnings per share	4,906	2,902	4,200
Stock Options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities excluded from computation of earnings per share	2,320	2,874	3,805
Restricted Stock Units (RSUs)
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities excluded from computation of earnings per share	2,578	0	373
Employee stock purchase plan
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities excluded from computation of earnings per share	8	28	22

Summary of Significant Accounting Policies - Comprehensive Loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014
Accounting Policies [Abstract]
Tax on marketable securities	$ 428	$ 428
Unrealized loss on marketable securities, net of tax of $428 in fiscal 2015 and fiscal 2014, respectively	(483)	(419)
Cumulative translation adjustments	(1,739)	(1,342)
Accumulated other comprehensive loss	$ (2,222)	$ (1,761)

- Definition

Accumulated change in equity from transactions and other events and circumstances from non-owner sources, net of tax effect, at period end. Excludes Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge.

+ References + Details

Balance Sheet Components - Marketable Securities (Details) - USD ($)	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014
Available-for-sale Securities [Abstract]
Amortized Cost	$ 41,380,000	$ 49,888,000
Available-for-sale Securities, Gross Unrealized Gains	1,000	13,000
Available-for-sale Securities, Gross Unrealized Losses	(56,000)	(4,000)
Available-for-sale Securities Fair Value	$ 41,325,000	49,897,000
Maximum Remaining Maturity of Foreign Currency Derivatives	3 years
Continuous Unrealized Loss Position, 12 Months or More, Fair Value	$ 0	0
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Fiscal Year Maturity [Abstract]
Due in one year or less - Amortized Cost	33,882,000	38,499,000
Due in one year to five years - Amortized Cost	7,498,000	11,389,000
Amortized Cost	41,380,000	49,888,000
Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Due in one year or less - Fair Value	33,871,000	38,509,000
Due in one year to five years - Fair Value	7,454,000	11,388,000
Available-for-sale Securities Fair Value	41,325,000	49,897,000
U.S. Treasuries
Available-for-sale Securities [Abstract]
Amortized Cost	18,896,000	42,386,000
Available-for-sale Securities, Gross Unrealized Gains	1,000	13,000
Available-for-sale Securities, Gross Unrealized Losses	(44,000)	(4,000)
Available-for-sale Securities Fair Value	18,853,000	42,395,000
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Fiscal Year Maturity [Abstract]
Amortized Cost	18,896,000	42,386,000
Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Available-for-sale Securities Fair Value	18,853,000	42,395,000
Agency securities (Federal)
Available-for-sale Securities [Abstract]
Amortized Cost	22,484,000	7,502,000
Available-for-sale Securities, Gross Unrealized Gains	0	0
Available-for-sale Securities, Gross Unrealized Losses	(12,000)	0
Available-for-sale Securities Fair Value	22,472,000	7,502,000
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Fiscal Year Maturity [Abstract]
Amortized Cost	22,484,000	7,502,000
Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Available-for-sale Securities Fair Value	$ 22,472,000	$ 7,502,000

Balance Sheet Components - Asset Retirement Obligation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Asset retirement obligation beginning balance	$ 903	$ 988
Initial amount recorded for new asset retirement obligation	10	0
Currency translation	6	(85)
Asset retirement obligation ending balance	919	903
Other Current Liabilities
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Asset retirement obligation beginning balance	0
Asset retirement obligation ending balance	212	0
Other Noncurrent Liabilities
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Asset retirement obligation beginning balance	903
Asset retirement obligation ending balance	$ 707	$ 903

Balance Sheet Components - Inventory (Details) - USD ($) $ in Thousands	Dec. 26, 2015	Dec. 27, 2014
Balance Sheet Components [Abstract]
Raw materials	$ 12,996	$ 10,646
Work-in-progress	12,492	12,813
Finished goods	1,735	2,089
Inventory, Net	$ 27,223	$ 25,548

Balance Sheet Components - Property Plant and Equipment (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 26, 2015	Sep. 26, 2015	Jun. 27, 2015	Mar. 28, 2015	Dec. 27, 2014	Sep. 27, 2014	Jun. 28, 2014	Mar. 29, 2014	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Property, Plant and Equipment [Line Items]
Property Plant And Equipment Gross, Excludes Construction in Progress Gross	$ 251,435				$ 247,171				$ 251,435	$ 247,171
Less: Accumulated depreciation and amortization	(232,005)				(224,135)				(232,005)	(224,135)
Net long-lived assets	19,430				23,036				19,430	23,036
Construction-in-progress	4,423				2,462				4,423	2,462
Property, plant and equipment, net	23,853				25,498				23,853	25,498
Fully depreciated assets	1,600				6,600				1,600	6,600
Impairment of long-lived assets	0	$ 0	$ 8	$ 0	390	$ 86	$ 0	$ 743	8	1,219	$ 761
Depreciation, excluding impairments									10,600	11,700	$ 12,200
Machinery & Equipment
Property, Plant and Equipment [Line Items]
Property Plant And Equipment Gross, Excludes Construction in Progress Gross	150,983				145,995				150,983	145,995
Computer equipment & Software
Property, Plant and Equipment [Line Items]
Property Plant And Equipment Gross, Excludes Construction in Progress Gross	27,951				28,953				27,951	28,953
Furniture & Fixtures
Property, Plant and Equipment [Line Items]
Property Plant And Equipment Gross, Excludes Construction in Progress Gross	5,380				5,402				5,380	5,402
Leasehold Improvements
Property, Plant and Equipment [Line Items]
Property Plant And Equipment Gross, Excludes Construction in Progress Gross	$ 67,121				$ 66,821				$ 67,121	$ 66,821

Balance Sheet Components - Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 26, 2015	Dec. 27, 2014
Accrued Liabilities, Current [Abstract]
Accrued compensation and benefits	$ 12,286	$ 12,431
Accrued indirect and other taxes	2,189	2,223
Accrued commissions	366	460
Accrued warranty	1,116	1,592
Deferred rent	325	216
Accrued restructuring	2	584
Other accrued expense	5,223	3,711
Total	$ 21,507	$ 21,217

Restructuring Charges - Restructuring Actions (Details) - USD ($) $ in Thousands	3 Months Ended										9 Months Ended	12 Months Ended
	Dec. 26, 2015	Sep. 26, 2015	Jun. 27, 2015	Mar. 28, 2015	Dec. 27, 2014	Sep. 27, 2014	Jun. 28, 2014	Mar. 29, 2014	Dec. 28, 2013	Mar. 30, 2013	Dec. 27, 2014	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Restructuring Reserve [Roll Forward]
Restructuring reserve				$ 584				$ 138		$ 616		$ 584	$ 138	$ 616
Restructuring charges, net	$ (3)	$ 59	$ 0	503	$ 584	$ 28	$ 59	1,997	$ 400	4,000		559	2,668	4,841
Asset impairments													(600)	(2,743)
Adjustments to restructuring charges														(183)
Cash payments												(641)	(1,620)	(2,369)
Non-cash settlements												(500)	(2)	(24)
Restructuring reserve	2				584				138		$ 584	2	584	138
Employee Severance and Benefits
Restructuring Reserve [Roll Forward]
Restructuring reserve				584				138		548		584	138	548
Restructuring charges, net								1,400		1,300	700	59	2,068	2,083
Asset impairments													0	0
Adjustments to restructuring charges														(178)
Cash payments												(641)	(1,620)	(2,320)
Non-cash settlements												0	(2)	5
Restructuring reserve	2				584				138		584	2	584	138
Property and Equipment Impairment
Restructuring Reserve [Roll Forward]
Restructuring reserve				0				0		0		0	0	0
Restructuring charges, net												0	600	2,743
Asset impairments													(600)	(2,743)
Adjustments to restructuring charges														(5)
Cash payments												0	0	(32)
Non-cash settlements												0	0	37
Restructuring reserve	0				0				0		0	0	0	0
Contract Termination and Other Costs
Restructuring Reserve [Roll Forward]
Restructuring reserve				$ 0				$ 0		$ 68		0	0	68
Restructuring charges, net												500	0	15
Asset impairments													0	0
Adjustments to restructuring charges														0
Cash payments												0	0	(17)
Non-cash settlements												(500)	0	(66)
Restructuring reserve	$ 0				$ 0				$ 0		$ 0	$ 0	$ 0	$ 0

Restructuring Charges - Additional Information (Details) $ in Thousands		3 Months Ended										9 Months Ended	12 Months Ended
	Jan. 27, 2014 Employee positions	Dec. 26, 2015 USD ($)	Sep. 26, 2015 USD ($)	Jun. 27, 2015 USD ($)	Mar. 28, 2015 USD ($)	Dec. 27, 2014 USD ($)	Sep. 27, 2014 USD ($)	Jun. 28, 2014 USD ($)	Mar. 29, 2014 USD ($)	Dec. 28, 2013 USD ($) Employee positions	Mar. 30, 2013 USD ($) Employee positions	Dec. 27, 2014 USD ($) positions	Dec. 26, 2015 USD ($)	Dec. 27, 2014 USD ($)	Dec. 28, 2013 USD ($)
Restructuring Cost and Reserve [Line Items]
Restructuring charges, net													$ 559	$ 2,668	$ 4,658
Restructuring costs, positions eliminated \| Employee	52									17	31
Restructuring costs, additional positions eliminated \| positions	9									17	20	5
Restructuring charges, net		$ (3)	$ 59	$ 0	$ 503	$ 584	$ 28	$ 59	$ 1,997	$ 400	$ 4,000		559	2,668	4,841
Share-based Compensation Expense
Restructuring Cost and Reserve [Line Items]
Restructuring charges, net													500
Employee Severance and Benefits
Restructuring Cost and Reserve [Line Items]
Restructuring charges, net									1,400		1,300	$ 700	59	2,068	2,083
Property and Equipment Impairment
Restructuring Cost and Reserve [Line Items]
Restructuring charges, net													$ 0	$ 600	$ 2,743
Impairment charges									$ 600		$ 2,700

Derivative Financial Instruments (Details) - Not Designated as Hedging Instrument - Foreign Exchange Forward ₩ in Thousands, ¥ in Thousands, $ in Thousands, $ in Thousands	12 Months Ended
	Dec. 26, 2015 USD ($)	Dec. 27, 2014 USD ($)	Dec. 26, 2015 KRW (₩)	Dec. 26, 2015 TWD ($)	Dec. 26, 2015 JPY (¥)	Dec. 27, 2014 KRW (₩)	Dec. 27, 2014 TWD ($)	Dec. 27, 2014 JPY (¥)
Derivatives, Fair Value [Line Items]
Notional amount of foreign currency derivatives	$ 25,781	$ 13,651
Other Income, net
Derivatives, Fair Value [Line Items]
Foreign exchange forward contracts gain (loss)	(310)	1,768
Japanese Yen
Derivatives, Fair Value [Line Items]
Notional amount of foreign currency derivatives	27,635	16,241			¥ 3,328,268			¥ 1,955,798
Taiwan Dollar
Derivatives, Fair Value [Line Items]
Notional amount of foreign currency derivatives	1,136	977		$ 37,152			$ 30,886
Korean Won
Derivatives, Fair Value [Line Items]
Notional amount of foreign currency derivatives	$ 718	$ 1,613	₩ 840,111			₩ 1,763,054

Impairment of Long-lived Assets - Asset Impairment (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 26, 2015	Sep. 26, 2015	Jun. 27, 2015	Mar. 28, 2015	Dec. 27, 2014	Sep. 27, 2014	Jun. 28, 2014	Mar. 29, 2014	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Impairment of long-lived assets:
Assets held for sale									$ 0	$ 191	$ 0
Assets to be disposed of other than by sale									8	1,028	761
Total	$ 0	$ 0	$ 8	$ 0	$ 390	$ 86	$ 0	$ 743	$ 8	$ 1,219	$ 761

Impairment of Long-lived Assets - Assets Held for Sale (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 26, 2015	Sep. 26, 2015	Jun. 27, 2015	Mar. 28, 2015	Dec. 27, 2014	Sep. 27, 2014	Jun. 28, 2014	Mar. 29, 2014	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Long Lived Assets Held-for-sale [Line Items]
Impairment of long-lived assets									$ 8,000	$ 1,219,000	$ 761,000
Gain on sale of property and equipment									1,009,000	10,000	(365,000)
Impairment of long-lived assets	$ 0	$ 0	$ 8,000	$ 0	$ 390,000	$ 86,000	$ 0	$ 743,000	$ 8,000	1,219,000	$ 761,000
Long-lived assets classified as held for sale					$ 0					0
Assets previously held for sale
Long Lived Assets Held-for-sale [Line Items]
Impairment of long-lived assets										200,000
Building
Long Lived Assets Held-for-sale [Line Items]
Impairment of long-lived assets										600,000
Gain on sale of property and equipment										200,000
Machinery & Equipment
Long Lived Assets Held-for-sale [Line Items]
Impairment of long-lived assets										500,000
Gain on sale of property and equipment										$ 52,000

Impairment of Long-lived Assets - Assets to be disposed of other than sale (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 26, 2015	Sep. 26, 2015	Jun. 27, 2015	Mar. 28, 2015	Dec. 27, 2014	Sep. 27, 2014	Jun. 28, 2014	Mar. 29, 2014	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Property, Plant and Equipment Impairment or Disposal [Abstract]
Impairment of long-lived assets	$ 0	$ 0	$ 8	$ 0	$ 390	$ 86	$ 0	$ 743	$ 8	$ 1,219	$ 761

Fair Value - Asset Measured at Fair Value (Details) - USD ($) $ / shares in Units, $ in Thousands	Dec. 26, 2015	Dec. 27, 2014
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable securities	$ 41,325	$ 49,897
Total	124,260	115,200
Money market funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents	82,935	65,303
U.S. Treasuries
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable securities	18,853	42,395
Agency securities (Federal)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable securities	22,472	7,502
Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total	$ 82,935	65,303
Level 1 \| Money market funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Net asset value (per share)	$ 1
Cash equivalents	$ 82,935	65,303
Level 1 \| U.S. Treasuries
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable securities	0	0
Level 1 \| Agency securities (Federal)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable securities	0	0
Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total	41,325	49,897
Level 2 \| Money market funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents	0	0
Level 2 \| U.S. Treasuries
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable securities	18,853	42,395
Level 2 \| Agency securities (Federal)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable securities	$ 22,472	$ 7,502

Goodwill and Intangible Assets - Goodwill (Details) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 26, 2015 USD ($) unit	Dec. 29, 2012 unit	Dec. 27, 2014 USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill \| $	$ 30,731		$ 30,731
Number of Reporting Units \| unit	1	2

Goodwill and Intangible Assets - Indefinite and Finite-Lived Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Finite-lived Intangible Assets [Roll Forward]
Intangible Assets, Gross Amount, Beginning Balance	$ 66,688
Additions/Disposals	6,900
Intangible Assets, Gross Amount, Ending Balance	73,588	$ 66,688
Accumulated Amortization, Beginning Balance	34,899
Expense, net	13,137	18,800	$ 16,700
Accumulated Amortization, Ending Balance	48,036	34,899
Intangible Assets, Net	25,552	31,789
Intangible Assets Net Excluding Goodwill [Roll Forward]
Intangible Assets Net Excluding Goodwill Gross	73,588
Intangible Assets Net Excluding Goodwill Acquired During Period	0
Intangible Assets Net Excluding Goodwill Gross	73,588	73,588
Intangible Assets, Net (Excluding Goodwill)	25,552	38,689
Existing Developed Technologies
Finite-lived Intangible Assets [Roll Forward]
Intangible Assets, Gross Amount, Beginning Balance	45,300
Additions/Disposals	6,900
Intangible Assets, Gross Amount, Ending Balance	52,200	45,300
Accumulated Amortization, Beginning Balance	29,097
Expense, net	10,484
Accumulated Amortization, Ending Balance	39,581	29,097
Intangible Assets, Net	$ 12,619	16,203
Weight Average Useful Life	2 years
Trade name
Finite-lived Intangible Assets [Roll Forward]
Intangible Assets, Gross Amount, Beginning Balance	$ 4,388
Additions/Disposals	0
Intangible Assets, Gross Amount, Ending Balance	4,388	4,388
Accumulated Amortization, Beginning Balance	970
Expense, net	439
Accumulated Amortization, Ending Balance	1,409	970
Intangible Assets, Net	$ 2,979	3,418
Weight Average Useful Life	6 years 9 months 6 days
Customer relationships
Finite-lived Intangible Assets [Roll Forward]
Intangible Assets, Gross Amount, Beginning Balance	$ 17,000
Additions/Disposals	0
Intangible Assets, Gross Amount, Ending Balance	17,000	17,000
Accumulated Amortization, Beginning Balance	4,832
Expense, net	2,214
Accumulated Amortization, Ending Balance	7,046	4,832
Intangible Assets, Net	$ 9,954	12,168
Weight Average Useful Life	4 years 9 months 6 days
In Process Research and Development
Finite-lived Intangible Assets [Roll Forward]
Additions/Disposals	$ 6,900
Weight Average Useful Life	2 years 9 months 6 days
Indefinite-lived Intangible Assets [Roll Forward]
Indefinite-lived Intangible Assets, Beginning Balance	$ 6,900
Indefinite-lived Intangible Assets, Additions/Disposals During Period	(6,900)
Indefinite-lived Intangible Assets, Ending balance	0	$ 6,900
Intangible Assets Disposed of by Sale \| Existing Developed Technologies
Finite-lived Intangible Assets [Roll Forward]
Additions/Disposals	$ 5,900

Goodwill and Intangible Assets - Amortization Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Property, Plant and Equipment [Line Items]
Amortization of intangible assets	$ 13,137	$ 18,800	$ 16,700
Finite-Lived Intangible Assets, Net, Amortization Expense, Rolling Maturity [Abstract]
2016	10,060
2017	4,943
2018	4,666
2019	3,052
2020	2,045
and thereafter	786
Total	25,552
Intellectual Property \| Cost of Sales
Property, Plant and Equipment [Line Items]
Amortization of intangible assets	10,400	16,100	13,800
Intellectual Property \| Selling, General and Administrative Expenses
Property, Plant and Equipment [Line Items]
Amortization of intangible assets	$ 2,700	$ 2,700	$ 2,900

Commitments and Contingencies - Additional Information (Details) $ in Thousands			3 Months Ended	12 Months Ended
	Jul. 17, 2015 USD ($)	Jul. 13, 2015 USD ($) tranche	Sep. 26, 2015 USD ($)	Dec. 26, 2015 USD ($)	Dec. 27, 2014 USD ($)	Dec. 28, 2013 USD ($)	Dec. 29, 2012 USD ($)
Loss Contingencies [Line Items]
Rent Expense				$ 4,900	$ 4,800	$ 4,900
Depreciation expense under capital leases					200	500
Unrecognized Tax Benefits				$ 17,033	$ 16,333	$ 16,972	$ 17,181
MarTek
Loss Contingencies [Line Items]
Litigation settlement amount		$ 2,000
Receivable from legal settlement, number of equal tranches \| tranche		2
MarTek \| Other Income, net \| Settled Litigation
Loss Contingencies [Line Items]
Gain related to legal settlement			$ 1,000
MarTek \| Cash
Loss Contingencies [Line Items]
Litigation settlement amount	$ 1,200
MarTek \| Notes Receivable
Loss Contingencies [Line Items]
Litigation settlement amount	$ 800

Commitments and Contingencies - Operating Lease (Details) $ in Thousands	Dec. 26, 2015 USD ($)
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2016	$ 3,994
2017-2018	7,194
2019-2020	7,064
Thereafter	2,505
Total	$ 20,757

Commitments and Contingencies - Other Contractual Obligations (Details) $ in Thousands	Dec. 26, 2015 USD ($)
Commitments and Contingencies Disclosure [Abstract]
2016	$ 20,899
2017-2018	9,580
2019-2020	30
After 2020	0
Total	$ 30,509

Stockholders' Equity - Preferred Stock (Details) - $ / shares	Dec. 26, 2015	Dec. 27, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Preferred Stock, Shares Authorized (Shares)	10,000,000	10,000,000
Preferred Stock, Par or Stated Value (Per Share)	$ 0.001	$ 0.001
Preferred Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Preferred Stock, Shares Authorized (Shares)	10,000,000
Preferred Stock, Par or Stated Value (Per Share)	$ 0.001

Stockholders' Equity - Common Stock (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 26, 2015	Apr. 16, 2015
Class of Stock [Line Items]
Stock repurchased during the period, amount	$ 8,211
Common Stock
Class of Stock [Line Items]
Stock repurchase program authorized amount		$ 25,000
Stock repurchased during the period (in shares)	1,013,162
Stock repurchased during the period, amount	$ 8,200

Stockholders' Equity - Equity Incentive Plans (Details) - USD ($)		12 Months Ended
	Feb. 09, 2015	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013	May 01, 2015	Jan. 01, 2015
Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total amount of shares authorized (in shares)					4,500,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Number of Shares Outstanding		2,571,376
Stock options granted (in shares)		456,000	0	0
Options exercised (Shares)		(24,607)
Options canceled (Shares)		(682,574)
Number of Shares Outstanding		2,320,195	2,571,376
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Weighted Average Exercise Price Outstanding (Per Share)		$ 10.72
Weighted Average Exercise Price, Options granted (Per Share)		8.42
Weighted Average Exercise Price, Options exercised (Per Share)		8.61
Weighted Average Exercise Price, Options canceled (Per Share)		13.75
Weighted Average Exercise Price Outstandin (Per Share)		$ 9.40	$ 10.72
Weighted Average Remaining Contractual Life in Years		2 years 8 months 12 days
Aggregate Intrinsic Value		$ 1,146,680
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest [Abstract]
Vested and expected to vest at December 27, 2014 (Shares)		2,320,195
Weighted Average Exercise Price, Vested and expected to vest at December 27, 2014 (Per Share)		$ 9.40
Weighted Average Remaining Contractual Term		2 years 8 months 12 days
Aggregate Intrinsic Value		$ 1,146,680
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Exercisable at December 27, 2014 (Shares)		1,864,861
Weighted average exercise price, exercisable (Per Share)		$ 9.64
Weighted Average Remaining Contractual Term		1 year 10 months 8 days
Aggregate Intrinsic Value		$ 833,552
Stock Options \| Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock conversion rate						1.70
Stock option vesting period		4 years
Stock Options Granted, Expiration Period		10 years
Shares available for grant (in shares)		5,800,000
Stock Appreciation Rights (SARs) \| Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option vesting period		4 years
Chief Executive Officer \| Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted	450,000
Stock-based compensation expense	$ 1,700,000

Stockholders' Equity - Weighted Average Assumptions (Details)	12 Months Ended
	Dec. 26, 2015
Statement of Stockholders' Equity [Abstract]
Dividend yield	0.00%
Expected volatility	47.50%
Risk-free interest rate	1.60%
Expected term (in years)	5 years 6 months 6 days

Stockholders' Equity - Restricted Stock Units (Details) - Restricted Stock Units (RSUs) $ / shares in Units, $ in Millions					12 Months Ended
	May 28, 2015 USD ($) executive shares	Apr. 08, 2015 shares	May 05, 2014 USD ($) executive shares	May 06, 2013 executive shares	Dec. 26, 2015 USD ($) $ / shares shares	Dec. 27, 2014 USD ($) $ / shares shares	Dec. 28, 2013 USD ($) $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Vested (Shares)		(443,750)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Stock options granted	195,000		350,000	355,000
Number of recipients \| executive	7		7	7
Stock-based compensation expense \| $	$ 1.5		$ 1.8
Fair value of restricted stock units vested during the period \| $					$ 18.1	$ 8.2	$ 3.9
Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Restricted stock units (Shares)					3,250,046	2,929,639	2,228,946
Granted (in shares)					1,540,250	1,900,000	1,708,000
Vested (Shares)					(1,993,603)	(1,282,442)	(760,590)
Canceled (Shares)					(218,555)	(297,151)	(246,717)
Restricted stock units (Shares)					2,578,138	3,250,046	2,929,639
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Restricted stock units (Per Share) \| $ / shares					$ 6.07	$ 5.88	$ 7.66
Granted (in dollars per share) \| $ / shares					8.64	6.52	5.04
Vested (Per Share) \| $ / shares					6.00	6.30	8.44
Canceled (Per Share) \| $ / shares					6.36	6.17	8.18
Restricted stock units (Per Share) \| $ / shares					$ 7.63	$ 6.07	$ 5.88

Stockholders' Equity - Employee Stock Purchase Plan (Details)	12 Months Ended
	Dec. 26, 2015 purchase_period $ / shares shares	Dec. 27, 2014 $ / shares shares	Dec. 28, 2013 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Discount from market price, offering date	85.00%
Employee Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of purchase periods, 12 months offering period	2
Number of purchase periods, 6 months offering period	1
Issuance of common stock under the Employee Stock Purchase Plan (in shares) \| shares	565,493	586,386	583,173
Weighted average exercise price, exercisable (Per Share) \| $ / shares	$ 5.67	$ 4.80	$ 4.29

Stock-Based Compensation - Included in Consolidated Statement of Operations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Tax effect on stock-based compensation	$ (6,300)
Employee Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	11,575	$ 13,279	$ 12,124
Tax effect on stock-based compensation	0	0	0
Total stock-based compensation, net of tax	11,575	13,279	12,124
Employee Stock \| Cost of Sales
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	2,651	2,433	2,436
Employee Stock \| Research and Development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	3,490	3,529	3,440
Employee Stock \| Selling, General and Administrative Expenses
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 5,434	$ 7,317	$ 6,248

Stock-Based Compensation - Valuation Assumptions (Details)	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend yield	0.00%
Expected volatility	47.50%
Risk-free interest rate	1.60%
Expected life (in years)	5 years 6 months 6 days
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend yield	0.00%
Expected volatility	47.50%
Risk-free interest rate	1.60%
Expected life (in years)	5 years 6 months 6 days
Employee Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend yield	0.00%	0.00%	0.00%
Expected volatility	51.78%	41.71%	39.80%
Risk-free interest rate	0.12%	0.09%	0.13%
Expected life (in years)	8 months	8 months	8 months

Stock-Based Compensation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended										12 Months Ended
	Dec. 26, 2015	Sep. 26, 2015	Jun. 27, 2015	Mar. 28, 2015	Dec. 27, 2014	Sep. 27, 2014	Jun. 28, 2014	Mar. 29, 2014	Dec. 28, 2013	Mar. 30, 2013	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restructuring charges, net	$ (3)	$ 59	$ 0	$ 503	$ 584	$ 28	$ 59	$ 1,997	$ 400	$ 4,000	$ 559	$ 2,668	$ 4,841
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unamortized stock-based compensation balance	1,300										$ 1,300
Amortization period for stock-based compensation balance											3 years 1 month 6 days
Employee Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Amortization period for stock-based compensation balance											1 month
Issuance of common stock under the Employee Stock Purchase Plan (in shares)											565,493	586,386	583,173
Total compensation cost not yet recognized, other than options	100										$ 100
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Amortization period for stock-based compensation balance											2 years 11 days
Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted (in shares)											456,000	0	0
Equity Incentive Plan \| Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option vesting period											4 years
Weighted average fair value (in dollars per share)											$ 3.78
Equity Incentive Plan \| Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total compensation cost not yet recognized, other than options	$ 11,800										$ 11,800
Ristricted stock units granted (in shares)											1,540,250	1,900,000	1,708,000
Weighted average grant value (in dollars per share)											$ 8.64	$ 6.52	$ 5.04
Minimum \| Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option vesting period											3 years
Stock option expiration date											5 years
Maximum \| Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option vesting period											4 years
Stock option expiration date											10 years
Share-based Compensation Expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restructuring charges, net											$ 500

Income Taxes - Components (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 26, 2015	Sep. 26, 2015	Jun. 27, 2015	Mar. 28, 2015	Dec. 27, 2014	Sep. 27, 2014	Jun. 28, 2014	Mar. 29, 2014	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest [Abstract]
United States									$ (3,069)	$ (23,230)	$ (60,447)
Foreign									1,798	3,135	2,665
Loss before income taxes	$ (727)	$ (2,310)	$ 862	$ 904	$ (3,139)	$ (176)	$ (4,377)	$ (12,403)	$ (1,271)	$ (20,095)	$ (57,782)

Income Taxes - Provision for Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 26, 2015	Sep. 26, 2015	Jun. 27, 2015	Mar. 28, 2015	Dec. 27, 2014	Sep. 27, 2014	Jun. 28, 2014	Mar. 29, 2014	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Current provision (benefit):
Federal									$ (3)	$ (983)	$ (770)
State									72	(386)	76
Foreign									198	234	287
Total									267	(1,135)	(407)
Deferred provision (benefit):
Federal									0	0	0
State									0	0	0
Foreign									(15)	225	308
Deferred income tax provision (benefit)									(15)	225	308
Total provision (benefit) from income taxes	$ (108)	$ 215	$ 24	$ 121	$ (1,268)	$ 101	$ (51)	$ 308	$ 252	$ (910)	$ (99)

Income Taxes - Federal Statutory Rate (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 26, 2015	Sep. 26, 2015	Jun. 27, 2015	Mar. 28, 2015	Dec. 27, 2014	Sep. 27, 2014	Jun. 28, 2014	Mar. 29, 2014	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Income Tax Disclosure [Abstract]
Federal statutory rate									35.00%	35.00%	35.00%
Income Tax Reconciliation, Other Reconciling Items [Abstract]
U.S. statutory federal tax rate									$ (445)	$ (7,033)	$ (20,224)
State taxes and credits, net of Federal benefit									17	(186)	(345)
Amortization of stock-based compensation									907	686	923
Research and development credits									(1,872)	(1,183)	(560)
Foreign taxes at rates different than the U.S.									(66)	(84)	162
Other permanent differences									238	(972)	(378)
Change in valuation allowance									1,457	7,886	20,505
Other									16	(24)	(182)
Total provision (benefit) from income taxes	$ (108)	$ 215	$ 24	$ 121	$ (1,268)	$ 101	$ (51)	$ 308	$ 252	$ (910)	$ (99)

Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Deferred Tax Assets, Net, Classification [Abstract]
Tax credits	$ 30,968	$ 28,458
Inventory reserve	14,010	16,612
Unrealized investment gains, asset	20	0
Other reserves and accruals	5,953	7,610
Non-statutory stock options	4,936	18,096
Depreciation and amortization	13,440	14,037
Net operating loss carryforwards	119,327	120,110
Gross deferred tax assets	188,654	204,923
Valuation allowance	(176,196)	(187,759)	$ (180,913)	$ (163,265)
Total deferred tax assets	12,458	17,164
Deferred Tax Liabilities, Net, Classification [Abstract]
Acquired intangibles & fixed assets	(9,177)	(13,867)
Unrealized investment gains, liability	0	(3)
Total deferred tax liabilities	(9,177)	(13,870)
Net deferred tax assets	$ 3,281	$ 3,294

Income Taxes - Valuation Allowance Against Deferred Tax Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Tax Credit Carryforward [Line Items]
Tax effect on stock-based compensation	$ (6,300)
Deferred Tax Assets Valuation Allowance [Roll Forward]
Balance at Beginning of Year	187,759	$ 180,913	$ 163,265
Additions	0	6,846	17,648
Reduction	(11,563)	0	0
Balance at End of Year	176,196	$ 187,759	$ 180,913
Federal
Deferred Tax Assets Valuation Allowance [Roll Forward]
Federal research and development tax credit, carryforwards.	21,000
Federal foreign tax credit carryforwards.	298,700
Federal foreign tax credit carryforwards.	2,000
Alternative minimum tax credits.	2,400
California
Deferred Tax Assets Valuation Allowance [Roll Forward]
Federal foreign tax credit carryforwards.	270,700
California research credit carryforwards.	28,400
Japan
Deferred Tax Assets Valuation Allowance [Roll Forward]
Singapore net operating loss carryforwards.	300
Singapore
Deferred Tax Assets Valuation Allowance [Roll Forward]
Singapore net operating loss carryforwards.	$ 10,000

Income Taxes - Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Income Tax Disclosure [Abstract]
Repatriation of earnings of foreign subsidiaries.	$ 5,400
Deferred tax liability, amount of unrecognized deferred tax liability, undistributed earnings of foreign subsidiaries	400
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefit beginning balance	16,333	$ 16,972	$ 17,181
Additions based on tax positions related to the current year	667	498	307
Additions based on tax position from prior year	163	324	0
Reductions for tax positions of prior years	(18)	(1,109)	(60)
Reductions to unrecognized tax benefits due to lapse of the applicable statute of limitations	(112)	(352)	(456)
Unrecognized tax benefit ending balance	17,033	16,333	16,972
Amount of unrecognized tax benefit if recognized, would impact the effective tax rate.	1,100
As part of the income tax provision we recognized interest charges (benefit) and penalties.	50	(100)	$ (200)
Amount of accrued interest charges and penalties.	$ 200	$ 100

Employee Benefit Plans (Details) - USD ($) $ in Millions	12 Months Ended
Employee Benefit Plans (Details) - USD ($) $ in Millions	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Employees maximum annual contribution (percent)	50.00%
Cost recognized under defined contribution plans	$ 1.1	$ 1.0	$ 1.0
Maximum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Employer matching contribution, (percent)	1.50%

Operating Segment and Geographic Information - Schedule of Revenue by Country as a Percent of Total Revenues (Details) - segment

3 Months Ended

12 Months Ended

Dec. 26, 2015

Dec. 27, 2014

Dec. 28, 2013

Dec. 29, 2012

Product Information [Line Items]

Number of Reportable Segments

Number of Operating Segments

Geographic Concentration Risk | Sales Revenue, Goods, Net

Product Information [Line Items]

Percentage of concentration of risk

100.00%

Geographic Concentration Risk | Sales Revenue, Goods, Net | South Korea

Product Information [Line Items]

Percentage of concentration of risk

25.20%

19.60%

19.80%

Geographic Concentration Risk | Sales Revenue, Goods, Net | North America

Product Information [Line Items]

Percentage of concentration of risk

23.40%

28.10%

27.20%

Geographic Concentration Risk | Sales Revenue, Goods, Net | Taiwan

Product Information [Line Items]

Percentage of concentration of risk

21.90%

18.40%

27.90%

Geographic Concentration Risk | Sales Revenue, Goods, Net | Asia-Pacific

Product Information [Line Items]

Percentage of concentration of risk

^[1]

11.10%

12.90%

9.20%

Geographic Concentration Risk | Sales Revenue, Goods, Net | Japan

Product Information [Line Items]

Percentage of concentration of risk

9.40%

9.60%

7.30%

Geographic Concentration Risk | Sales Revenue, Goods, Net | Europe

Product Information [Line Items]

Percentage of concentration of risk

9.00%

11.40%

8.60%

[1]	Asia-Pacific includes all countries in the region except Taiwan, Japan and South Korea, which are disclosed separately.

Operating Segment and Geographic Information - Schedule of Revenue by Product Group (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 26, 2015	Sep. 26, 2015	Jun. 27, 2015	Mar. 28, 2015	Dec. 27, 2014	Sep. 27, 2014	Jun. 28, 2014	Mar. 29, 2014	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Revenue from External Customers [Line Items]
Revenues	$ 71,782	$ 65,862	$ 73,885	$ 70,829	$ 71,285	$ 73,934	$ 67,352	$ 55,959	$ 282,358	$ 268,530	$ 231,533
SoC
Revenue from External Customers [Line Items]
Revenues									145,839	142,360	115,597
DRAM
Revenue from External Customers [Line Items]
Revenues									125,512	110,800	92,603
Flash
Revenue from External Customers [Line Items]
Revenues									$ 11,007	$ 15,370	$ 23,333

Operating Segment and Geographic Information - Schedule of Long-Lived Assets by Geographical Location (Details) - USD ($)
$ in Thousands

Dec. 26, 2015

Dec. 27, 2014

Long-Lived Assets [Line Items]

Long-Lived Assets

$ 80,136

$ 94,918

North America

Long-Lived Assets [Line Items]

Long-Lived Assets

77,257

91,862

South Korea

Long-Lived Assets [Line Items]

Long-Lived Assets

1,128

1,578

Asia-Pacific

Long-Lived Assets [Line Items]

Long-Lived Assets

^[1]

689

935

Japan

Long-Lived Assets [Line Items]

Long-Lived Assets

295

358

Singapore

Long-Lived Assets [Line Items]

Long-Lived Assets

112

172

Europe

Long-Lived Assets [Line Items]

Long-Lived Assets

$ 655

$ 13

[1]	Asia-Pacific includes all countries in the region except South Korea, Singapore, and Japan, which are disclosed separately.

Operating Segment and Geographic Information - Schedule of Major Customers With Revenues Greater Than 10% (Details) - Customer Concentration Risk - Sales Revenue, Goods, Net	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Revenue, Major Customer [Line Items]
Percentage of concentration of risk	60.20%	51.60%	45.90%
Samsung
Revenue, Major Customer [Line Items]
Percentage of concentration of risk	19.60%	19.70%	17.70%
Intel
Revenue, Major Customer [Line Items]
Percentage of concentration of risk	14.60%
SK hynix
Revenue, Major Customer [Line Items]
Percentage of concentration of risk	14.30%	16.90%	16.50%
Micron
Revenue, Major Customer [Line Items]
Percentage of concentration of risk	11.70%	15.00%	11.70%

Selected Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended										12 Months Ended
	Dec. 26, 2015	Sep. 26, 2015	Jun. 27, 2015	Mar. 28, 2015	Dec. 27, 2014	Sep. 27, 2014	Jun. 28, 2014	Mar. 29, 2014	Dec. 28, 2013	Mar. 30, 2013	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Quarterly Financial Data [Abstract]
Revenues	$ 71,782	$ 65,862	$ 73,885	$ 70,829	$ 71,285	$ 73,934	$ 67,352	$ 55,959			$ 282,358	$ 268,530	$ 231,533
Cost of revenues	50,591	47,407	50,582	48,040	50,337	49,792	47,328	43,634			196,620	191,091	189,249
Gross profit	21,191	18,455	23,303	22,789	20,948	24,142	20,024	12,325			85,738	77,439	42,284
Research and development	11,236	10,645	11,217	11,086	10,706	11,198	11,074	9,747			44,184	42,725	42,139
Selling, general and administrative	10,719	11,108	11,381	11,882	12,631	13,309	13,191	12,254			45,090	51,385	53,217
Restructuring charges, net	(3)	59	0	503	584	28	59	1,997	$ 400	$ 4,000	559	2,668	4,841
Impairment of long-lived assets	0	0	8	0	390	86	0	743			8	1,219	761
Total operating expenses	21,952	21,812	22,606	23,471	24,311	24,621	24,324	24,741			89,841	97,997	101,075
Operating income (loss)	(761)	(3,357)	697	(682)	(3,363)	(479)	(4,300)	(12,416)			(4,103)	(20,558)	(58,791)
Interest income, net	70	65	65	85	69	75	79	79			285	302	386
Other income, net	(36)	982	100	1,501	155	228	(156)	(66)			2,547	161	623
Income (loss) before income taxes	(727)	(2,310)	862	904	(3,139)	(176)	(4,377)	(12,403)			(1,271)	(20,095)	(57,782)
Provision (benefit) from income taxes	(108)	215	24	121	(1,268)	101	(51)	308			252	(910)	(99)
Net loss	$ (619)	$ (2,525)	$ 838	$ 783	$ (1,871)	$ (277)	$ (4,326)	$ (12,711)			$ (1,523)	$ (19,185)	$ (57,683)
Net loss per share: Basic (usd per share)	$ (0.01)	$ (0.04)	$ 0.01	$ 0.01	$ (0.03)	$ 0.00	$ (0.08)	$ (0.23)
Net loss per share: Diluted (usd per share)	$ (0.01)	$ (0.04)	$ 0.01	$ 0.01	$ (0.03)	$ 0.00	$ (0.08)	$ (0.23)
Weighted average number of shares used in per share calculations: Basic (in shares)	58,128	58,209	58,109	56,594	56,472	56,297	55,812	55,050			57,850	55,908	54,204
Weighted average number of shares used in per share calculations: Diluted (in shares)	58,128	58,209	59,094	58,838	56,472	56,297	55,812	55,050
Other Nonoperating Income (Expense)
Loss Contingencies [Line Items]
Proceeds from business interruption insurance recovery				$ 1,500							$ 1,500
Settled Litigation \| MarTek \| Other Income, net
Loss Contingencies [Line Items]
Gain related to legal settlement		$ 1,000

Business Interruption Insurance Claim Recovery (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 28, 2015	Dec. 26, 2015
Other Nonoperating Income (Expense)
Business Interruption Loss [Line Items]
Proceeds from business interruption insurance recovery	$ 1.5	$ 1.5

Subsequent Events (Details) - Subsequent Event $ / shares in Units, $ in Millions	Feb. 03, 2016 USD ($) $ / shares shares
Subsequent Event [Line Items]
Cash paid to acquire business (in usd per share) \| $ / shares	$ 16.00
Shares issued to acquire business (in shares) \| shares	0.6534
Senior Secured Term Loan
Subsequent Event [Line Items]
Senior secured loan to finance merger \| $	$ 150