View Filing Data

Selling, general and administrative

$ 71,285

$ 73,934

$ 67,352

$ 55,959

$ 48,546

$ 67,634

$ 62,733

^[1]

$ 52,620

$ 268,530

$ 231,533

$ 178,535

Cost of revenues

50,337

49,792

47,328

43,634

44,288

55,088

46,328

^[1]

43,545

191,091

189,249

153,204

Gross profit

20,948

24,142

20,024

12,325

4,258

12,546

16,405

9,075

77,439

42,284

25,331

Operating expenses:

Research and development

10,706

11,198

11,074

9,747

9,994

10,301

10,915

^[1]

10,929

42,725

42,139

40,130

12,631

13,309

13,191

12,254

12,160

12,952

13,487

^[1]

14,618

51,385

53,217

49,231

584

1,997

443

143

^[1]

3,980

2,668

4,658

2,917

Loss on sale of subsidiary

2,668

300

Gain on settlement of litigation

390

743

567

121

^[1]

1,219

761

421

(3,250)

Total operating expenses

24,311

24,621

24,324

24,741

23,164

23,411

24,915

29,585

97,997

101,075

89,449

Operating loss

(3,363)

(479)

(4,300)

(12,416)

(18,906)

(10,865)

(8,510)

(20,510)

(20,558)

(58,791)

(64,118)

Interest income, net

^[1]

107

302

386

691

Other income, net

155

228

(156)

(66)

(91)

209

^[1]

423

161

623

1,461

Loss before income taxes

(3,139)

(176)

(4,377)

(12,403)

(18,736)

(10,861)

(8,205)

(19,980)

(20,095)

(57,782)

(61,966)

Benefit from income taxes

(1,268)

101

(51)

308

(147)

202

^[1]

(207)

(910)

(99)

(26,420)

Net loss

$ (1,871)

$ (277)

$ (4,326)

$ (12,711)

$ (18,789)

$ (10,714)

$ (8,407)

$ (19,773)

$ (19,185)

$ (57,683)

$ (35,546)

Net loss per share:

Basic and diluted (usd per share)

$ (0.03)

$ 0.00

$ (0.08)

$ (0.23)

$ (0.34)

$ (0.20)

$ (0.16)

$ (0.37)

$ (0.34)

$ (1.06)

$ (0.70)

Weighted-average number of shares used in per share calculations:

Basic and diluted (shares)

56,472

56,297

55,812

55,050

54,608

54,437

54,105

53,664

55,908

54,204

50,551

[1]	In the second quarter of fiscal 2013, we recorded a $0.3 million loss on the sale of our subsidiary, TMMC. See Note 7, Fair Value, to the Notes to Consolidated Financial Statements for further details relating to the terms of the sale.

CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	12 Months Ended
	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Net loss	$ (19,185)	$ (57,683)	$ (35,546)
Other comprehensive loss, net of tax:
Foreign currency translation adjustments	(1,502)	(1,825)	(838)
Unrealized losses on available-for-sale marketable securities	(10)	(139)	(147)
Other comprehensive loss, net of tax	(1,512)	(1,964)	(985)
Comprehensive loss	$ (20,697)	$ (59,647)	$ (36,531)

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

Summary of Significant Accounting Policies

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. 31, 2011	$ 346,652	$ 50	$ 652,024	$ 2,700	$ (308,122)
Balances (Shares) at Dec. 31, 2011		49,268,479
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 (Shares)		0
Fair value of stock issued in connection with the MicroProbe Acquisition	13,805	$ 3	13,802	0	0
Issuance of common stock pursuant to acquisitions of businesses (Shares)		3,020,944
Issuance of common stock pursuant to vesting of restricted stock units, net of stock withheld	(106)	$ 0	(106)	0	0
Issuance of common stock pursuant to vesting of restricted stock units, net of stock withheld (Shares)		464,203
Issuance of common stock under the Employee Stock Purchase Plan	2,358	$ 1	2,357	0	0
Issuance of common stock under the Employee Stock Purchase Plan (Shares)		533,077
Stock-based compensation	13,080	$ 0	13,080	0	0
Stock Issued During Period (Shares)		0
Components of other comprehensive income (loss):
Change in unrealized gain (loss) on marketable securities, net of tax	(147)	$ 0	0	(147)	0
Currency translation adjustments	(838)	0	0	(838)	0
Net loss	(35,546)	0	0	0	(35,546)
Balances at Dec. 29, 2012	339,258	$ 54	681,157	1,715	(343,668)
Balances (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 (Shares)		20,000
Fair value of stock issued in connection with the MicroProbe Acquisition	0
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 (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 (Shares)		583,173
Stock-based compensation	11,871	$ 0	11,871	0	0
Stock Issued During Period (Shares)		0
Components of other comprehensive income (loss):
Change in unrealized gain (loss) on marketable securities, net of tax	(139)	$ 0	0	(139)	0
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 (Shares) at Dec. 28, 2013	54,649,600	54,649,600
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Fair value of stock issued in connection with the MicroProbe Acquisition	$ 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 (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 (Shares)		586,386
Stock-based compensation	13,234	$ 0	13,234	0	0
Stock Issued During Period (Shares)		0
Components of other comprehensive income (loss):
Change in unrealized gain (loss) on marketable securities, net of tax	(10)	$ 0	0	(10)	0
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 (Shares) at Dec. 27, 2014	56,518,428	56,518,428

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Cash flows from operating activities:
Net loss	$ (19,185)	$ (57,683)	$ (35,546)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	30,491	28,909	16,901
Amortization of discount on investments	208	463	91
Stock-based compensation expense	13,279	12,124	13,049
Deferred income tax provision (benefit)	230	445	(24,460)
Provision (recovery) for doubtful accounts receivable	1	(19)	52
Provision for excess and obsolete inventories	7,127	10,461	7,232
(Gain) loss on disposal and write-off of long-lived assets	(10)	365	41
Gain on settlement of litigation	0	0	(3,250)
Impairment of long-lived assets	1,219	761	421
Loss on sale of subsidiary	0	300	0
Non-cash restructuring	600	2,743	462
Foreign currency transaction losses	2,489	620	1,267
Changes in assets and liabilities:
Accounts receivable	(15,949)	(2,102)	5,158
Inventories	(11,975)	(7,980)	(926)
Prepaid expenses and other current assets	(822)	3,557	821
Refundable income taxes	0	5,143	(27)
Other assets	25	138	426
Accounts payable	4,155	(2,324)	(5,903)
Accrued liabilities	7,765	(2,474)	(1,123)
Income taxes payable	(1,511)	(346)	(2,145)
Deferred rent and other liabilities	248	83	167
Deferred revenues	(726)	1,014	1,064
Net cash provided by (used in) operating activities	17,659	(5,802)	(26,228)
Cash flows from investing activities:
Acquisition of property, plant and equipment	(5,670)	(8,530)	(7,952)
Acquisition of MicroProbe, net of cash acquired	0	0	(96,652)
Proceeds (use of cash) from sale of subsidiary	115	(210)	0
Proceeds from sale of property, plant and equipment	1,114	61	0
Purchases of marketable securities	(31,693)	(91,338)	(82,437)
Proceeds from maturities of marketable securities	73,473	90,385	135,340
Proceeds from sale of marketable securities	0	2,000	11,000
Change in restricted cash	0	(118)	0
Net cash provided by (used in) investing activities	37,339	(7,750)	(40,701)
Cash flows from financing activities:
Proceeds from issuances of common stock	2,813	2,602	2,251
Payments made on capital leases	(271)	(603)	(112)
Net cash provided by financing activities	2,542	1,999	2,139
Effect of exchange rate changes on cash and cash equivalents	(2,796)	(1,494)	(2,016)
Net increase (decrease) in cash and cash equivalents	54,744	(13,047)	(66,806)
Cash and cash equivalents, beginning of year	59,196	72,243	139,049
Cash and cash equivalents, end of year	113,940	59,196	72,243
Non-cash investing and financing activities:
Fair value of stock issued in connection with the MicroProbe Acquisition	0	0	13,805
Changes in accounts payable and accrued liabilities related to property, plant and equipment purchases	(122)	1,528	2,215
Working capital adjustment	0	0	2,782
Supplemental disclosure of cash flow information:
Income and property taxes paid (refunded), net	$ 950	$ (6,152)	$ (40)

Formation and Business of the Company	12 Months Ended
Formation and Business of the Company	Dec. 27, 2014
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 and solutions. We are based in Livermore, California, our corporate office, one of our main research and development centers, and one of our manufacturing locations. We have facilities in the United States, Singapore, Japan, Taiwan, South Korea, Germany 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 27, 2014, December 28, 2013 and December 29, 2012, respectively, consisted of 52 weeks each. Reclassifications Certain reclassifications have been made to the prior year's Consolidated Balance Sheet to conform to the current year presentation.

Summary of Significant Accounting Policies

12 Months Ended

Dec. 27, 2014

Accounting Policies [Abstract]

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.


•	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 27, 2014 and December 28, 2013, restricted cash included $0.4 million each, 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 $7.1 million, $10.5 million and $7.2 million for fiscal 2014, 2013 and 2012, 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. We have determined that we operate in one reportable segment consisting of two operating segments relating to our FormFactor and MicroProbe product groups. We further have determined that for the purposes of our goodwill impairment analysis, we have two reporting units relating to our FormFactor and MicroProbe product groups and which are both associated with the design, development, manufacture, sale and support of precision, high performance advanced semiconductor probe card products and solutions.

The FASB, in order to simplify testing goodwill for impairment, allows an entity to first assess 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 values of the applicable reporting units with their aggregate carrying values, including goodwill. We generally determine the fair values of our reporting units 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.

We acquired Astria Semiconductor Holdings, Inc., including its major subsidiary Micro-Probe Incorporated (together "MicroProbe") which we refer to as the "MicroProbe Acquisition", and performed a fair value assessment as of the acquisition date, October 16, 2012, resulting in our current goodwill balance. We performed our annual goodwill impairment test for both reporting units in the fourth quarter of fiscal 2014 and 2013, respectively. No impairment charges associated with our goodwill were recorded during fiscal 2014 and fiscal 2013. Refer to note 8 to Notes to Consolidated Financial Statements - Goodwill and Intangible Assets for further details.

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.

In fiscal 2014, we did not experience events or changes in circumstances which would indicate that the carrying amounts of our long-lived assets or asset groups were not recoverable. During the fourth quarter of fiscal 2013, we reviewed the recoverability of our long-lived asset groups and we concluded that our business was able to fully recover the carrying amounts of our assets. We performed an enterprise-wide impairment test in the fourth fiscal quarter of 2012 and no enterprise-wide impairment charges were recorded. Refer to Note 6 to Notes to Consolidated Financial Statements - Impairment of Long-lived Assets, for additional information.

Long-Lived Assets Held For Sale

We classify long-lived assets as held for sale when certain criteria are met, including: management's commitment to a plan to sell the assets; the availability of the assets for immediate sale in their present condition; whether an active program to locate buyers and other actions to sell the assets has been initiated; whether the sale of the assets is probable and their transfer is expected to qualify for recognition as a completed sale within one year; whether the assets are being marketed at reasonable prices in relation to their fair value; and whether it is unlikely that significant changes will be made to the plan to sell the assets.

We measure long-lived assets to be disposed of by sale at the lower of the carrying amount or fair value less cost to sell. Fair value is determined using quoted market prices or the anticipated cash flows discounted at a rate commensurate with the risk involved. Changes to our estimated fair values of such assets are recorded in the periods in which such changes are identified.

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 2014, fiscal 2013 and fiscal 2012:



	Fiscal 2014		Fiscal 2013		Fiscal 2012
Intel	19.7	%	17.7	%	* %
SK hynix	16.9		16.5		29.4
Micron	15.0		11.7		13.3
Samsung	*		*		12.4
Total	51.6	%	45.9	%	55.1	%

* Less than 10% of revenues

At December 27, 2014, two customers accounted for 26% and 18% of gross accounts receivable. At December 28, 2013, three customers accounted for 21%, 15% and 11% 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, cyclical market patterns 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 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 27, 2014			December 28, 2013
Balance at beginning of year	$	691		$	734
Accruals	2,972			1,916
Settlements	(2,071		)	(1,959		)
Balance at end of year	$	1,592		$	691

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 2014, 2013 and 2012 (in thousands):



	Balance at Beginning of Year		Additions		Reductions			Balance at End of Year
Fiscal year ended December 29, 2012	$	238	$	202	$	(151	)	$	289
Fiscal year ended December 28, 2013	289		—		(24		)	265
Fiscal year ended December 27, 2014	$	265	$	5	$	(4	)	$	266

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 $2.7 million, $4.7 million and $2.9 million for fiscal years 2014, 2013 and 2012, 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 27, 2014			December 28, 2013			December 29, 2012
Numerator:
Net loss used in computing basic and diluted net loss per share	$	(19,185	)	$	(57,683	)	$	(35,546	)
Denominator:
Weighted-average shares used in computing basic net loss per share	55,908			54,204			50,551
Add potentially dilutive securities	—			—			—
Weighted-average shares used in computing basic and diluted net loss per share	55,908			54,204			50,551

The following table sets forth the weighted-average number of potentially dilutive securities excluded from the computation in the table above because their effect would have been anti-dilutive (in thousands):



	Fiscal Years Ended
	December 27, 2014	December 28, 2013	December 29, 2012
Options to purchase common stock	2,874	3,805	4,430
Restricted stock units	—	373	1,246
Employee stock purchase plan	28	22	39
Total potentially dilutive securities	2,902	4,200	5,715

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 27, 2014			December 28, 2013
Unrealized loss on marketable securities, net of tax of $428 in fiscal 2014 and fiscal 2013, respectively	$	(419	)	$	(409	)
Cumulative translation adjustments	(1,342		)	160
Accumulated other comprehensive loss	$	(1,761	)	$	(249	)

Balance Sheet Components

12 Months Ended

Dec. 27, 2014

Balance Sheet Components [Abstract]

Balance Sheet Components

Marketable Securities

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

Marketable securities at December 28, 2013 consisted of the following (in thousands):



	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
U.S. Treasuries	$	48,991	$	33	$	(10	)	$	49,014
Commercial paper	11,623		—		—			11,623
Agency securities (Federal)	31,261		1		(4		)	31,258
	$	91,875	$	34	$	(14	)	$	91,895

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 2014 and 2013, 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 do not have a foreseeable need to liquidate the portfolio and 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. We do not have a foreseeable need to liquidate the portfolio and anticipate recovering the full cost of the securities either as market conditions improve or as the securities mature.

As of December 27, 2014 and December 28, 2013, 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 27, 2014 and December 28, 2013 were as follows (in thousands):



	December 27, 2014				December 28, 2013
	Amortized Cost		Fair Value		Amortized Cost		Fair Value
Due in one year or less	$	38,499	$	38,509	$	59,888	$	59,894
Due after one year to five years	11,389		11,388		31,987		32,001
	$	49,888	$	49,897	$	91,875	$	91,895

Realized gains on sales or maturities of marketable securities were immaterial for each of the fiscal years 2014, 2013, and 2012, respectively.

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 Taiwan, South Korea, Singapore and Japan to their original condition upon lease termination. We have estimated that as of December 27, 2014, gross expected future cash flows of $0.9 million would be required to fulfill these obligations.

The carrying amount 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 2013 and 2012.

The following is a reconciliation of the aggregate retirement liability associated with our commitment to return property to its original condition upon lease termination included in non-current "Deferred rent and other liabilities" in the Consolidated Balance Sheets (in thousands):



	Fiscal Years Ended
	December 27, 2014			December 28, 2013
Asset retirement obligation beginning balance	$	988		$	1,292
Liabilities settled	—			(169		)
Currency translation	(85		)	(135		)
Asset retirement obligation ending balance	$	903		$	988

Inventories

Net inventories consisted of the following (in thousands):



	Fiscal Years Ended
	December 27, 2014		December 28, 2013
Raw materials	$	10,646	$	7,411
Work-in-progress	12,813		10,531
Finished goods	2,089		2,765
	$	25,548	$	20,707

Property, Plant and Equipment

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



	Fiscal Years Ended
	December 27, 2014			December 28, 2013
Building	$	—		$	790
Machinery and equipment	145,995			143,463
Computer equipment and software	28,953			34,547
Capital leases	—			866
Furniture and fixtures	5,402			5,495
Leasehold improvements	66,821			67,384
Sub-total	247,171			252,545
Less: Accumulated depreciation and amortization	(224,135		)	(221,346		)
Net long-lived assets	23,036			31,199
Construction-in-progress	2,462			3,991
Total	$	25,498		$	35,190

In fiscal 2014, we ceased use of fully depreciated assets with an acquired cost of $6.6 million. In fiscal 2013, we did not cease use any fully depreciated assets.

As discussed in Note 6 to the Notes to Consolidated Financial Statements - Impairment of Long-lived Assets, in fiscal 2014, 2013 and 2012, we recorded aggregated impairment charges of $1.2 million, $0.8 million and $0.4 million in our long-lived assets, respectively.

Depreciation and amortization of property, plant and equipment, excluding the impairments charges discussed above, for the fiscal years 2014, 2013 and 2012 was $11.7 million, $12.2 million and $10.3 million, respectively.

Accrued Liabilities

Accrued liabilities consisted of the following (in thousands):



	Fiscal Years Ended
	December 27, 2014		December 28, 2013
Accrued compensation and benefits	$	12,431	$	7,975
Accrued indirect and other taxes	2,223		1,400
Accrued commissions	460		448
Accrued warranty	1,592		691
Deferred rent	216		154
Accrued restructuring	584		138
Other accrued expenses	3,711		3,179
	$	21,217	$	13,985

Restructuring Charges

12 Months Ended

Dec. 27, 2014

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 2014, 2013, and 2012, the purpose of which were to improve operating efficiency, streamline and simplify our operations and reduce our operating costs, are discussed below.

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 employees and recorded $0.7 million in severance charges.

The liabilities we accrued represent our best estimate of the obligations we expect to incur and could be subject to adjustment as market conditions change. The activities comprising these restructuring activities were substantially completed in fiscal 2014 and the remaining cash payments associated with these activities are expected to be paid by the end of the first fiscal quarter of 2015.

2013 Restructuring Activities

In the first fiscal quarter of 2013, we implemented a restructuring plan (the "Q1 2013 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 (the "Q4 2013 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.

2012 Restructuring Activities

In the second fiscal quarter of 2012, we recorded $0.1 million in charges for severance and related benefits related to restructuring activities. This resulted in the reduction of our global workforce by one full-time employee across the organization. The activities comprising this restructuring activity were completed in fiscal 2012.

In the third fiscal quarter of 2012, we implemented a restructuring plan (the "Q3 2012 Restructuring Plan") which resulted in the reduction of our global workforce by 44 employees across the organization. In conjunction with this action, we also initiated a plan to cease our memory product assembly and test manufacturing operations in Japan. We recorded $1.8 million in severance and related benefits, $0.2 million in charges for contract termination, and other costs related to restructuring activities during the quarter related to this plan, and $0.4 million in impairment charges for certain equipment and leasehold improvements that would no longer be utilized. The activities comprising this reduction in workforce were completed by the end of fiscal 2012.

In the fourth fiscal quarter of 2012, we implemented a restructuring plan (the "Q4 2012 Restructuring Plan") which resulted in the reduction of our global workforce by four employees across the organization. We recorded $0.4 million in severance and related benefits related to restructuring activities. The activities comprising this reduction in workforce were completed in fiscal 2013.

The following table summarizes the activities related to the restructuring actions from fiscal 2012 to 2014 (in thousands):



	Employee Severance and Benefits			Property and Equipment Impairment			Contract Termination and Other Costs			Total
Accrual at December 31, 2011	$	200		$	—		$	—		$	200
Restructuring charges	2,261			462			194			2,917
Adjustments to restructuring charges	—			—			31			31
Cash payments	(1,913		)	—			(157		)	(2,070		)
Non-cash settlements	—			(462		)	—			(462		)
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

Derivative Financial Instruments

12 Months Ended

Dec. 27, 2014

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 27, 2014, 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 27, 2014 and December 28, 2013 (in thousands):



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



December 28, 2013		Contract Position	Contract Amount (Local Currency)		Contract Amount (U.S. Dollar)
			(In thousands)
Japanese Yen		Sell	439,328		$	4,174
Taiwan Dollar		Buy	(13,772	)	(462		)
Korean Won		Buy	(1,034,319	)	(983		)
	Total USD notional amount of outstanding foreign exchange contracts				$	2,729

The contracts outstanding at December 27, 2014 were entered into on December 26, 2014 and matured on January 27, 2015 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 27, 2014. Additionally, no gains or losses relating to the outstanding derivative contracts as of December 27, 2014 and December 28, 2013 were recorded during their respective fiscal periods.

The location and amount of gains (losses) related to non-designated derivative instruments that matured in fiscal 2014 and 2013 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 27, 2014		December 28, 2013
Foreign exchange forward contracts	Other Income, net	$	1,768	$	(5	)

Property, Plant and Equipment Impairment or Disposal [Abstract]

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=35706170&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=35706170&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=35706170&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=35706170&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=35706170&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=35706170&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=35706170&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=35706170&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=35706170&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=35706170&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=35706170&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=35706170&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=35706170&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=35706170&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. 27, 2014

Impairment of Long-lived Assets

The following table summarizes the components of the impairments that we recorded in fiscal 2014, 2013 and 2012 (in thousands):



	Fiscal Years Ended
	December 27, 2014		December 28, 2013		December 29, 2012
Impairment of long-lived assets:
Assets held for sale	$	191	$	—	$	168
Assets to be disposed of other than by sale	1,028		761		253
Total	$	1,219	$	761	$	421

Assets held for sale

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 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. In fiscal 2012, we recorded a $0.2 million charge related to certain assets which were previously held for sale that were determined to be no longer saleable and used for internal purposes.

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 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. In fiscal 2012, we recorded $0.2 million of charges related to the termination of on-going construction-in-progress projects.

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. 27, 2014

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.


•	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.

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, commercial paper and foreign currency derivatives (refer to Note 5 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 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

Fair values measured on a recurring basis as of December 28, 2013 (in thousands):



	Level 1		Level 2		Total
Assets:
Cash equivalents
Money market funds	$	27,943	$	—	$	27,943
Marketable securities
Commercial paper	—		11,623		11,623
U.S. Treasuries	—		49,014		49,014
Agency securities (Federal)	—		31,258		31,258
Total	$	27,943	$	91,895	$	119,838

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 2014 and 2013.

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-Goodwill and Intangible Assets, for further details. There were no assets measured at fair value on a non-recurring basis during fiscal 2014.

As of December 28, 2013, our financial asset that was recorded at fair value on a non-recurring basis comprised of note receivable from The MicroManipulator Company (TMMC), a wholly-owned subsidiary of MicroProbe based in Carson City, Nevada. TMMC manufactures manual, analytical probe stations and accessories. As of June 29, 2013, TMMC's assets were sold to its management team for a purchase consideration of $1.0 million, of which $0.2 million was received in cash and $0.8 million in the form of a note receivable to be repaid over 7 years at a 5% interest rate. We intend to hold this note receivable until its maturity. We classified this note receivable at a Level 3 category in the fair value hierarchy and determined its fair value utilizing the income approach by applying a weighted average cost of capital discount rate to arrive at the net present value of the note receivable of approximately $0.5 million which approximates its amortized cost.

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, and analysis of period-over-period fluctuations and independent recalculation of prices.

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.

Goodwill and Intangible Assets Disclosure [Abstract]

Goodwill and Intangible Assets

12 Months Ended

Dec. 27, 2014

Goodwill and Intangible Assets

Goodwill recorded from the MicroProbe Acquisition on October 16, 2012 was $30.7 million as of December 27, 2014 and remained unchanged from the amounts recorded as of December 28, 2013. During the fourth quarter of fiscal 2014, we performed our annual goodwill impairment test by an assessment of qualitative factors and concluded that our goodwill was not impaired as of December 27, 2014. Furthermore, the Company has not recorded any historical goodwill impairments as of December 27, 2014.

At the time of our fiscal 2013 annual goodwill impairment test, we faced increasing operational and financial challenges, including manufacturing overcapacity and weak operating performance which led to a deterioration in market conditions. As a result, we performed the first step of the two-step goodwill impairment test relating to our two reporting units to ascertain if the carrying values of the net assets exceeded fair values. We utilized an equal weighting of both the discounted cash flow method of the income approach and the guideline company method of the market approach to estimate the fair value of our two reporting units. The results of the first step of the impairment test indicated that the goodwill of the FormFactor and MicroProbe reporting units were not impaired, as the estimated fair values in excess of carrying values were approximately $32 million and $41 million, respectively, or 16% and 39%, over the carrying value of the reporting units, respectively. As a result, we did not record any impairment to our goodwill as of December 28, 2013.

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 2014 and the net book value of intangible assets at December 27, 2014 and December 28, 2013 were as follows (in thousands):



	Intangible Assets, Gross Amount						Accumulated Amortization						Intangible Assets, Net				Weight Average Useful Life
Other Intangible Assets (1)	December 28, 2013		Additions/Disposals		December 27, 2014		December 28, 2013		Expense, net		December 27, 2014		December 28, 2013		December 27, 2014		December 27, 2014
Existing developed technologies	$	51,248	$	—	$	51,248	$	18,955	$	16,090	$	35,045	$	32,293	$	16,203	1.8
Trade name	4,388		—		4,388		530		440		970		3,858		3,418		7.8
Customer relationships	17,000		—		17,000		2,581		2,251		4,832		14,419		12,168		5.8
Total finite-lived intangible assets	72,636		—		72,636		22,066		18,781		40,847		50,570		31,789
In-process research and development	6,900		—		6,900		—		—		—		6,900		6,900
Total intangible assets	$	79,536	$	—	$	79,536	$	22,066	$	18,781	$	40,847	$	57,470	$	38,689

(1) Excludes fully amortized intangible assets

During the year ended December 28, 2013, purchased in-process research and development (IPR&D) projects from the MicroProbe Acquisition with a carrying value of $14.2 million were completed and reclassified as finite-lived intangible assets, and are currently being amortized over their estimated useful lives. There were no such reclassifications during the year ended December 27, 2014.

The IPR&D assets are classified as indefinite lived intangible assets that are not currently subject to amortization but are reviewed for impairment annually or whenever events or changes in circumstances indicate that the carrying value of such assets may not be recoverable. The IPR&D assets will be subject to amortization upon completion of their respective research projects and at the start of commercialization. The fair values assigned to IPR&D assets were determined using the income approach based on estimates and judgments regarding risks inherent in the development process, including the likelihood of achieving technological success and market acceptance. If an IPR&D project is abandoned, the acquired technology attributable to the project will be expensed in the Consolidated Statement of Operations.

We recorded $18.8 million, $16.7 million and $6.6 million, in amortization expense related to our intangible assets in fiscal 2014, 2013, and 2012, respectively. Of the total amortization expense for fiscal 2014, 2013, and 2012, $16.1 million, $13.8 million, and $6.0 million were charged to cost of revenues, respectively, and $2.7 million, $2.9 million and $0.6 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 27, 2014, 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
2015	$	12,739
2016	8,720
2017	2,551
2018	2,501
2019	2,447
and thereafter	2,831
Total	$	31,789

Commitments and Contingencies

12 Months Ended

Dec. 27, 2014

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

Leases

We lease facilities under non-cancellable operating leases with various expiration dates through 2021. During fiscal 2014, we extended an operating lease term relating to our San Jose, California facility from April 2016 to November 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 2014, 2013, and 2012 was $4.8 million, $4.9 million and $4.7 million, respectively.

We leased certain equipment under capital leases. The cost and accumulated depreciation for assets under capital leases, which were included in property, plant and equipment in the accompanying Consolidated Balance Sheets are as follows (in thousands):



	Fiscal Years Ended
	December 27, 2014		December 28, 2013
Cost	$	—	$	866
Accumulated depreciation	—		637
Net book value	$	—	$	229

The depreciation expense of these leased assets was $0.2 million in fiscal 2014, $0.5 million for fiscal 2013 and $0.2 million for fiscal 2012, respectively. As of December 27, 2014, we did not lease any equipment under capital leases.

Future minimum payments under our non-cancelable operating leases are as follows as of December 27, 2014 (in thousands):



	Operating Leases
Fiscal years:
2015	$	4,157
2016-2017	7,078
2018-2019	6,982
Thereafter	5,936
Total	$	24,153

Other Contractual Obligations

The following table sets forth our commitments to settle other contractual obligations in cash as of December 27, 2014:



	Payments Due In Fiscal Years
	2015		2016-2017		2018-2019		After 2019		Total
	(In thousands)
Purchase obligations	$	10,899	$	502	$	—	$	—	$	11,401

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 27, 2014. 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 $16.3 million as of December 27, 2014. 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 27, 2014, 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 and 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 2014, 2013 or 2012. We do not believe that any loss from environmental remediation liabilities would have an material impact on our financial condition.

While we believe that we are in compliance in all material respects with the environmental laws and regulations that apply to us, in the future, we may receive additional environmental violation notices, and if received, final resolution of the violations identified by these notices could harm our operations, which may adversely impact our operating results and cash flows. New laws and regulations, amended enforcement practices around existing laws and regulations, the discovery of previously unknown contamination at our or others' sites or the imposition of new cleanup requirements could also harm our operations, thereby adversely impacting our operating results and cash flows.

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 probe cards 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 27, 2014.

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 27, 2014, 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.

Customs and Trade Matters

From time to time, we receive communications from certain jurisdictions regarding customs and indirect tax matters such as customs duties and value added taxes. For fiscal 2014, we did not receive any communications from jurisdictions regarding any material customs duties or indirect tax matters.

Intellectual Property Litigation

In the ordinary course of business, the Company has been, currently is, and may in the future be, involved in commercial litigation relating to intellectual property, as well as third party initiated patent office proceedings in the United States and foreign patent offices.

No provision has been made for intellectual property litigation because we believe that it is not probable that a liability had been incurred as of December 27, 2014. We could incur material attorneys' fees in prosecuting and defending actions related to intellectual property.

Other Litigation

In August 2013, a former employee (“Plaintiff”) 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. In February 2014, the Court granted the Company’s motion to strike portions of Plaintiff’s first amended complaint, clarifying the scope of the putative class. A second amended complaint has also been filed. Procedurally, the case is in the early stages of litigation and no defined class has been certified. The parties participated in a mediation during the third quarter of fiscal 2014, which did not result in a settlement. The Company currently believes that any settlement reached would be in an amount that is not material to the Company's financial statements. 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. If the matter is not settled, the Company could incur material attorneys’ fees in defending the lawsuit.

Stockholders' Equity

12 Months Ended

Dec. 27, 2014

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 27, 2014.

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. 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 1.55 shares for every one share issued. Effective January 1, 2015, restricted shares will reduce the shares available for issuance by 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, nonqualified stock options or stock appreciation rights during fiscal 2014 and 2013.

At December 27, 2014, there were 3.3 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 31, 2011	4,619,022		$	13.11
Options granted	70,000		5.34
Options exercised	—		—
Options canceled	(480,175	)	11.94
Outstanding at December 29, 2012	4,208,847		13.11
Options granted	—		—
Options exercised	(20,000	)	5.28
Options canceled	(734,421	)	17.04
Outstanding at December 28, 2013	3,454,426		12.32
Options granted	—		—
Options exercised	—		—
Options canceled	(883,050	)	17.00
Outstanding at December 27, 2014	2,571,376		$	10.72	2.43	$	598,212
Vested and expected to vest at December 27, 2014	2,571,359		$	10.72	2.38	$	598,212
Exercisable at December 27, 2014	2,513,320		$	10.73	2.41	$	598,207

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 31, 2011	1,307,303		$	12.88
Granted	1,630,210		5.50
Vested	(484,540	)	13.99
Canceled	(224,027	)	8.78
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

On May 5, 2014, we issued 350,000 shares of restricted stock units to seven senior executives of our company that will vest based on certain market performance criteria. The performance criteria are based on the Company's Total Shareholder Return (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 compensation cost will be recognized ratably over the requisite service period. For fiscal 2014, we recorded $0.6 million of stock-based compensation expense related to these awards.

The total fair value of restricted stock units vested during fiscal 2014, 2013 and 2012 was $8.2 million, $3.9 million and $2.9 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 2014, 2013, and 2012, employees purchased 586,386 shares, 583,173 shares and 533,077 shares under this program at a weighted average exercise price of $4.80, $4.29 and $4.42, respectively.

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

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 Regulation S-X (SX)
-Number 210
-Section 08
-Paragraph d
-Article 4

Reference 15: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 29, 30, 31
-Article 5

Reference 16: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 4
-Section E

Reference 17: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 08
-Article 4

Reference 18: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 4
-Section C

Reference 19: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Article 3

+ Details

Stock-Based Compensation

12 Months Ended

Dec. 27, 2014

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 27, 2014		December 28, 2013		December 29, 2012
Stock-based compensation expense included in:
Cost of revenues	$	2,433	$	2,436	$	2,588
Research and development	3,529		3,440		4,262
Selling, general and administrative	7,317		6,248		6,199
Total stock-based compensation	13,279		12,124		13,049
Tax effect on stock-based compensation	—		—		—
Total stock-based compensation, net of tax	$	13,279	$	12,124	$	13,049

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 2014, 2013 and 2012:



	Fiscal Years Ended
	December 27, 2014		December 28, 2013		December 29, 2012
Stock Options:
Dividend yield	—	%	—	%	—	%
Expected volatility	—	%	—	%	48.44	%
Risk-free interest rate	—	%	—	%	0.67	%
Expected life (in years)	0		0		4.75

No options were granted in fiscal 2014 and 2013 and hence there are no assumptions in the table above for these years. During fiscal 2012, we granted 70,000 stock options under our approved plans with a weighted average grant-date fair value of $2.17 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 27, 2014, the unamortized stock-based compensation balance related to stock options was $0.1 million after estimated forfeitures, which will be recognized over an estimated period of 0.5 years based on the weighted average days to vest.

Employee Stock Purchase Plan

During fiscal 2014, we issued 586,386 shares under our approved employee stock purchase plans. As of December 27, 2014, 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 27, 2014		December 28, 2013		December 29, 2012
Employee Stock Purchase Plan:
Dividend yield	—	%	—	%	—	%
Expected volatility	41.71	%	39.80	%	46.44	%
Risk-free interest rate	0.09	%	0.13	%	0.11	%
Expected life (in years)	0.7		0.7		0.8

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 2014, 2013 and 2012, we granted 1,900,000 shares, 1,708,000 shares and 1,630,210 shares of restricted stock units with the weighted average grant-date fair values of $6.52, $5.04 and $5.50 per share, respectively. As of December 27, 2014, the unamortized stock-based compensation balance related to restricted stock units was $9.3 million after estimated forfeitures, which will be recognized over an estimated period of 1.2 years based on the weighted average days to vest.

Income Taxes

12 Months Ended

Dec. 27, 2014

Income Tax Disclosure [Abstract]

Income Taxes

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



	Fiscal Years Ended
	December 27, 2014			December 28, 2013			December 29, 2012
United States	$	(23,230	)	$	(60,447	)	$	(64,252	)
Foreign	3,135			2,665			2,286
	$	(20,095	)	$	(57,782	)	$	(61,966	)

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



	Fiscal Years Ended
	December 27, 2014			December 28, 2013			December 29, 2012
Current provision (benefit):
Federal	$	(983	)	$	(770	)	$	(1,929	)
State	(386		)	76			60
Foreign	234			287			(81		)
	(1,135		)	(407		)	(1,950		)
Deferred provision (benefit):
Federal	—			—			(25,520		)
State	—			—			—
Foreign	225			308			1,050
	225			308			(24,470		)
Total benefit from income taxes	$	(910	)	$	(99	)	$	(26,420	)

The following is a reconciliation of the difference between income taxes computed by applying the federal statutory rate of 35% and the benefit from income taxes for fiscal 2014, 2013 and 2012 (in thousands):



	Fiscal Years Ended
	December 27, 2014			December 28, 2013			December 29, 2012
U.S. statutory federal tax rate	$	(7,033	)	$	(20,224	)	$	(21,687	)
State taxes and credits, net of Federal benefit	(186		)	(345		)	(1,991		)
Amortization of stock-based compensation, net of tax benefit	686			923			376
Research and development credits	(1,183		)	(560		)	(674		)
Foreign taxes at rates different than the U.S.	(84		)	162			598
Other permanent differences	(972		)	(378		)	(1,164		)
Change in valuation allowance	7,886			20,505			(1,818		)
Other	(24		)	(182		)	(60		)
Total	$	(910	)	$	(99	)	$	(26,420	)

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 27, 2014			December 28, 2013
Tax credits	$	28,458		$	26,181
Inventory reserve	16,612			15,280
Other reserves and accruals	7,610			6,620
Non-statutory stock options	18,096			18,765
Depreciation and amortization	14,037			5,297
Net operating loss carryforwards	120,110			132,857
Gross deferred tax assets	204,923			205,000
Valuation allowance	(187,759		)	(180,913		)
Total deferred tax assets	17,164			24,087
Acquired intangibles & fixed assets	(13,867		)	(20,373		)
Unrealized investment gains	(3		)	(7		)
Total deferred tax liabilities	(13,870		)	(20,380		)
Net deferred tax assets	$	3,294		$	3,707

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 2014 and 2013, 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 2014, 2013 and 2012 (in thousands):



Description	Balance at Beginning of Year		Additions		Reduction			Balance at End of Year
Allowance against deferred tax assets
Year ended December 31, 2014	$	180,913	$	6,846	$	—		$	187,759
Year ended December 31, 2013	163,265		17,648		—			180,913
Year ended December 29, 2012	$	168,875	$	19,910	$	(25,520	)	$	163,265

At December 27, 2014, we had Federal research and development tax credit, net operating loss, and foreign tax credit carryforwards of $19.3 million, $293.9 million and $1.9 million, respectively, which will expire at various dates from 2016 through 2034. 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 $26.5 million and $270.8 million, respectively. The California research credit can be carried forward indefinitely while California net operating loss carryforwards will expire at various dates from 2015 through 2034. We had Singapore net operating loss carryforwards of $10.6 million which can be carried forward indefinitely.

We have not provided U.S. Federal and State income taxes, nor foreign withholding taxes, on approximately $5.0 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 $0.3 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 2014, 2013 and 2012, 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 27, 2014			December 28, 2013			December 29, 2012
Unrecognized tax benefit beginning balance	$	16,972		$	17,181		$	17,752
Additions based on tax positions related to the current year	498			307			2,237
Additions based on tax position from prior year	324			—			—
Reductions for tax positions of prior years	(1,109		)	(60		)	9
Reductions to unrecognized tax benefits due to lapse of the applicable statute of limitations	(352		)	(456		)	(2,817		)
Unrecognized tax benefit ending balance	$	16,333		$	16,972		$	17,181

At December 27, 2014, we had gross tax-effected unrecognized tax benefits of $16.3 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 $(0.1) million, $(0.2) million and $0.3 million in fiscal 2014, 2013, and 2012, respectively. As of December 27, 2014 and December 28, 2013, we have accrued total interest charges and penalties of $0.1 million and $0.2 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 27, 2014 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 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 and Japan purposes, we are subject to audit for tax years after 2010.

Employee Benefit Plans	12 Months Ended
Employee Benefit Plans	Dec. 27, 2014
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 2014, 2013 and 2012 aggregated $1.0 million, $1.0 million and $0.8 million, respectively.

Operating Segment and Geographic Information

12 Months Ended

Dec. 27, 2014

Segment Reporting [Abstract]

Operating Segment and Geographic Information

Operating Segments and Geographic Information

We report in one reportable segment consisting of two operating segments relating to our FormFactor and MicroProbe product groups. Both our operating segments are focused on the design, development, manufacture, sale and support of precision, high performance advanced semiconductor probe card products and solutions. The two operating segments have been aggregated into one reportable segment as they share similar economic characteristics in terms of the nature of their products and services, production processes, customers and methods of distributing their products and services. 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 27, 2014		December 28, 2013		December 29, 2012
North America	28.1	%	27.2	%	15.4	%
South Korea	19.6		19.8		32.8
Taiwan	18.4		27.9		20.7
Asia-Pacific (1)	12.9		9.2		12.7
Europe	11.4		8.6		6.5
Japan	9.6		7.3		11.9
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 27, 2014		December 28, 2013		December 29, 2012
SoC	$	142,360	$	115,597	$	46,586
DRAM	110,800		92,603		102,499
Flash	15,370		23,333		29,450
Total revenues	$	268,530	$	231,533	$	178,535

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 27, 2014		December 28, 2013
North America	$	91,862	$	119,706
South Korea	1,578		1,676
Asia-Pacific (1)	935		1,206
Japan	358		517
Singapore	172		262
Europe	13		24
Total	$	94,918	$	123,391


(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 2014, fiscal 2013 and fiscal 2012:



	Fiscal 2014		Fiscal 2013		Fiscal 2012
Intel	19.7	%	17.7	%	* %
SK hynix	16.9		16.5		29.4
Micron	15.0		11.7		13.3
Samsung	*		*		12.4
Total	51.6	%	45.9	%	55.1	%

* Less than 10% of revenues

Quarterly Financial Information Disclosure [Abstract]

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=6534315&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=6534315&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=6534315&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=6534315&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=6534315&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=6534315&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=6534315&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=6534315&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=6534315&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=6534315&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=6534315&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=6534315&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=6534315&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=6534315&loc=d3e8906-108599

+ Details

Selected Quarterly Financial Data (Unaudited)

12 Months Ended

Dec. 27, 2014

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. 27, 2014			Sep. 27, 2014			June. 28, 2014			March 29, 2014			Dec. 28, 2013			Sep. 28, 2013			June. 29, 2013 (1)			March 30, 2013
	(in thousands, except per share data)
Revenues	$	71,285		$	73,934		$	67,352		$	55,959		$	48,546		$	67,634		$	62,733		$	52,620
Cost of revenues	50,337			49,792			47,328			43,634			44,288			55,088			46,328			43,545
Gross profit	20,948			24,142			20,024			12,325			4,258			12,546			16,405			9,075
Operating Expenses:
Research and development	10,706			11,198			11,074			9,747			9,994			10,301			10,915			10,929
Selling, general and administrative	12,631			13,309			13,191			12,254			12,160			12,952			13,487			14,618
Loss on sale of subsidiary	—			—			—			—			—			—			300			—
Restructuring charges, net	584			28			59			1,997			443			143			92			3,980
Impairment of long-lived assets	390			86			—			743			567			15			121			58
Total operating expenses	24,311			24,621			24,324			24,741			23,164			23,411			24,915			29,585
Operating loss	(3,363		)	(479		)	(4,300		)	(12,416		)	(18,906		)	(10,865		)	(8,510		)	(20,510		)
Interest income, net	69			75			79			79			88			95			96			107
Other income (expense), net	155			228			(156		)	(66		)	82			(91		)	209			423
Loss before income taxes	(3,139		)	(176		)	(4,377		)	(12,403		)	(18,736		)	(10,861		)	(8,205		)	(19,980		)
(Benefit from) provision for income taxes	(1,268		)	101			(51		)	308			53			(147		)	202			(207		)
Net loss	$	(1,871	)	$	(277	)	$	(4,326	)	$	(12,711	)	$	(18,789	)	$	(10,714	)	$	(8,407	)	$	(19,773	)
Net loss per share:
Basic and diluted	$	(0.03	)	$	0.00		$	(0.08	)	$	(0.23	)	$	(0.34	)	$	(0.20	)	$	(0.16	)	$	(0.37	)
Weighted average number of shares used in per share calculations:
Basic and diluted	56,472			56,297			55,812			55,050			54,608			54,437			54,105			53,664


(1)	In the second quarter of fiscal 2013, we recorded a $0.3 million loss on the sale of our subsidiary, TMMC. See Note 7, Fair Value, to the Notes to Consolidated Financial Statements for further details relating to the terms of the sale.

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 27, 2014

Accounting Policies [Abstract]

Fiscal Period, Policy

Fiscal Year

Our fiscal year ends on the last Saturday in December. The fiscal years ended on December 27, 2014, December 28, 2013 and December 29, 2012, respectively, consisted of 52 weeks each.

Reclassification, Policy

Reclassifications

Certain reclassifications have been made to the prior year's Consolidated Balance Sheet to conform to the current year presentation.

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

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.


•	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 and Equipment

Property, Plant, and Equipment

Goodwill

Intangible Assets

Impairment of Long-Lived Assets

Long Lived Asset Held for Sale

Long-Lived Assets Held For Sale

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

Comprehensive Loss

Accumulated Other Comprehensive Loss

Derivatives, Methods of Accounting, Derivatives Not Designated or Qualifying as Hedges

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


•	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.


•	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. 27, 2014

Accounting Policies [Abstract]

Schedules of Concentration of Risk, by Risk Factor

The following customers represented greater than 10% of our revenues in fiscal 2014, fiscal 2013 and fiscal 2012:



	Fiscal 2014		Fiscal 2013		Fiscal 2012
Intel	19.7	%	17.7	%	* %
SK hynix	16.9		16.5		29.4
Micron	15.0		11.7		13.3
Samsung	*		*		12.4
Total	51.6	%	45.9	%	55.1	%

* 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 27, 2014			December 28, 2013
Balance at beginning of year	$	691		$	734
Accruals	2,972			1,916
Settlements	(2,071		)	(1,959		)
Balance at end of year	$	1,592		$	691

Schedule of Credit Losses for Financing Receivables, Current

The allowance for doubtful accounts receivable consisted of the following activity for fiscal years 2014, 2013 and 2012 (in thousands):



	Balance at Beginning of Year		Additions		Reductions			Balance at End of Year
Fiscal year ended December 29, 2012	$	238	$	202	$	(151	)	$	289
Fiscal year ended December 28, 2013	289		—		(24		)	265
Fiscal year ended December 27, 2014	$	265	$	5	$	(4	)	$	266

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 27, 2014			December 28, 2013			December 29, 2012
Numerator:
Net loss used in computing basic and diluted net loss per share	$	(19,185	)	$	(57,683	)	$	(35,546	)
Denominator:
Weighted-average shares used in computing basic net loss per share	55,908			54,204			50,551
Add potentially dilutive securities	—			—			—
Weighted-average shares used in computing basic and diluted net loss per share	55,908			54,204			50,551

Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share



	Fiscal Years Ended
	December 27, 2014	December 28, 2013	December 29, 2012
Options to purchase common stock	2,874	3,805	4,430
Restricted stock units	—	373	1,246
Employee stock purchase plan	28	22	39
Total potentially dilutive securities	2,902	4,200	5,715

Schedule of Accumulated Other Comprehensive Income (Loss)

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



	December 27, 2014			December 28, 2013
Unrealized loss on marketable securities, net of tax of $428 in fiscal 2014 and fiscal 2013, respectively	$	(419	)	$	(409	)
Cumulative translation adjustments	(1,342		)	160
Accumulated other comprehensive loss	$	(1,761	)	$	(249	)

Balance Sheet Components (Tables)

12 Months Ended

Dec. 27, 2014

Balance Sheet Components [Abstract]

Schedule of Available-for-sale Securities Reconciliation

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

Marketable securities at December 28, 2013 consisted of the following (in thousands):



	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
U.S. Treasuries	$	48,991	$	33	$	(10	)	$	49,014
Commercial paper	11,623		—		—			11,623
Agency securities (Federal)	31,261		1		(4		)	31,258
	$	91,875	$	34	$	(14	)	$	91,895

Investments Classified by Contractual Maturity Date

The contractual maturities of marketable securities as of December 27, 2014 and December 28, 2013 were as follows (in thousands):



	December 27, 2014				December 28, 2013
	Amortized Cost		Fair Value		Amortized Cost		Fair Value
Due in one year or less	$	38,499	$	38,509	$	59,888	$	59,894
Due after one year to five years	11,389		11,388		31,987		32,001
	$	49,888	$	49,897	$	91,875	$	91,895

Schedule of Asset Retirement Obligations



	Fiscal Years Ended
	December 27, 2014			December 28, 2013
Asset retirement obligation beginning balance	$	988		$	1,292
Liabilities settled	—			(169		)
Currency translation	(85		)	(135		)
Asset retirement obligation ending balance	$	903		$	988

Schedule of Inventory, Current

Net inventories consisted of the following (in thousands):



	Fiscal Years Ended
	December 27, 2014		December 28, 2013
Raw materials	$	10,646	$	7,411
Work-in-progress	12,813		10,531
Finished goods	2,089		2,765
	$	25,548	$	20,707

Property, plant and equipment Including Construction-in-progress

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



	Fiscal Years Ended
	December 27, 2014			December 28, 2013
Building	$	—		$	790
Machinery and equipment	145,995			143,463
Computer equipment and software	28,953			34,547
Capital leases	—			866
Furniture and fixtures	5,402			5,495
Leasehold improvements	66,821			67,384
Sub-total	247,171			252,545
Less: Accumulated depreciation and amortization	(224,135		)	(221,346		)
Net long-lived assets	23,036			31,199
Construction-in-progress	2,462			3,991
Total	$	25,498		$	35,190

Schedule of Accrued Liabilities

Accrued liabilities consisted of the following (in thousands):



	Fiscal Years Ended
	December 27, 2014		December 28, 2013
Accrued compensation and benefits	$	12,431	$	7,975
Accrued indirect and other taxes	2,223		1,400
Accrued commissions	460		448
Accrued warranty	1,592		691
Deferred rent	216		154
Accrued restructuring	584		138
Other accrued expenses	3,711		3,179
	$	21,217	$	13,985

Restructuring Charges (Tables)

12 Months Ended

Dec. 27, 2014

Restructuring Charges [Abstract]

Schedule of Restructuring Reserve by Type of Cost

The following table summarizes the activities related to the restructuring actions from fiscal 2012 to 2014 (in thousands):



	Employee Severance and Benefits			Property and Equipment Impairment			Contract Termination and Other Costs			Total
Accrual at December 31, 2011	$	200		$	—		$	—		$	200
Restructuring charges	2,261			462			194			2,917
Adjustments to restructuring charges	—			—			31			31
Cash payments	(1,913		)	—			(157		)	(2,070		)
Non-cash settlements	—			(462		)	—			(462		)
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

Derivative Financial Instruments (Tables)

12 Months Ended

Dec. 27, 2014

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Schedule of Foreign Exchange Contracts, Statement of Financial Position

The following tables provide information about our foreign currency forward contracts outstanding as of December 27, 2014 and December 28, 2013 (in thousands):



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



December 28, 2013		Contract Position	Contract Amount (Local Currency)		Contract Amount (U.S. Dollar)
			(In thousands)
Japanese Yen		Sell	439,328		$	4,174
Taiwan Dollar		Buy	(13,772	)	(462		)
Korean Won		Buy	(1,034,319	)	(983		)
	Total USD notional amount of outstanding foreign exchange contracts				$	2,729

Schedule of Other Derivatives Not Designated as Hedging Instruments, Statements of Financial Performance and Financial Position, Location



		Fiscal Years Ended
Derivatives Not Designated as Hedging Instruments	Location of Gain (Loss) Recognized on Derivatives	December 27, 2014		December 28, 2013
Foreign exchange forward contracts	Other Income, net	$	1,768	$	(5	)

Impairment of Long-lived Assets (Tables)

12 Months Ended

Dec. 27, 2014

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 2014, 2013 and 2012 (in thousands):



	Fiscal Years Ended
	December 27, 2014		December 28, 2013		December 29, 2012
Impairment of long-lived assets:
Assets held for sale	$	191	$	—	$	168
Assets to be disposed of other than by sale	1,028		761		253
Total	$	1,219	$	761	$	421

Fair Value (Tables)

12 Months Ended

Dec. 27, 2014

Fair Value Disclosures [Abstract]

Fair Value Measured on Recurring Basis

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

Fair values measured on a recurring basis as of December 28, 2013 (in thousands):



	Level 1		Level 2		Total
Assets:
Cash equivalents
Money market funds	$	27,943	$	—	$	27,943
Marketable securities
Commercial paper	—		11,623		11,623
U.S. Treasuries	—		49,014		49,014
Agency securities (Federal)	—		31,258		31,258
Total	$	27,943	$	91,895	$	119,838

Goodwill and Intangible Assets (Tables)

12 Months Ended

Dec. 27, 2014

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of Finite-Lived Intangible Assets

The changes in intangible assets for fiscal 2014 and the net book value of intangible assets at December 27, 2014 and December 28, 2013 were as follows (in thousands):



	Intangible Assets, Gross Amount						Accumulated Amortization						Intangible Assets, Net				Weight Average Useful Life
Other Intangible Assets (1)	December 28, 2013		Additions/Disposals		December 27, 2014		December 28, 2013		Expense, net		December 27, 2014		December 28, 2013		December 27, 2014		December 27, 2014
Existing developed technologies	$	51,248	$	—	$	51,248	$	18,955	$	16,090	$	35,045	$	32,293	$	16,203	1.8
Trade name	4,388		—		4,388		530		440		970		3,858		3,418		7.8
Customer relationships	17,000		—		17,000		2,581		2,251		4,832		14,419		12,168		5.8
Total finite-lived intangible assets	72,636		—		72,636		22,066		18,781		40,847		50,570		31,789
In-process research and development	6,900		—		6,900		—		—		—		6,900		6,900
Total intangible assets	$	79,536	$	—	$	79,536	$	22,066	$	18,781	$	40,847	$	57,470	$	38,689

(1) Excludes fully amortized intangible assets

Schedule of Finite-Lived Intangible Assets, Future Amortization Expense



Fiscal Year	Amount
2015	$	12,739
2016	8,720
2017	2,551
2018	2,501
2019	2,447
and thereafter	2,831
Total	$	31,789

Commitments and Contingencies (Tables)

12 Months Ended

Dec. 27, 2014

Commitments and Contingencies Disclosure [Abstract]

Schedule of Capital Leased Assets

The cost and accumulated depreciation for assets under capital leases, which were included in property, plant and equipment in the accompanying Consolidated Balance Sheets are as follows (in thousands):



	Fiscal Years Ended
	December 27, 2014		December 28, 2013
Cost	$	—	$	866
Accumulated depreciation	—		637
Net book value	$	—	$	229

Schedule Of Capital and Operating Leases

Future minimum payments under our non-cancelable operating leases are as follows as of December 27, 2014 (in thousands):



	Operating Leases
Fiscal years:
2015	$	4,157
2016-2017	7,078
2018-2019	6,982
Thereafter	5,936
Total	$	24,153

Contractual Obligation, Fiscal Year Maturity Schedule

The following table sets forth our commitments to settle other contractual obligations in cash as of December 27, 2014:



	Payments Due In Fiscal Years
	2015		2016-2017		2018-2019		After 2019		Total
	(In thousands)
Purchase obligations	$	10,899	$	502	$	—	$	—	$	11,401

Stockholders' Equity (Tables)

12 Months Ended

Dec. 27, 2014

Stockholders' Equity Note [Abstract]

Schedule of Share-based Compensation, Stock Options, 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 31, 2011	4,619,022		$	13.11
Options granted	70,000		5.34
Options exercised	—		—
Options canceled	(480,175	)	11.94
Outstanding at December 29, 2012	4,208,847		13.11
Options granted	—		—
Options exercised	(20,000	)	5.28
Options canceled	(734,421	)	17.04
Outstanding at December 28, 2013	3,454,426		12.32
Options granted	—		—
Options exercised	—		—
Options canceled	(883,050	)	17.00
Outstanding at December 27, 2014	2,571,376		$	10.72	2.43	$	598,212
Vested and expected to vest at December 27, 2014	2,571,359		$	10.72	2.38	$	598,212
Exercisable at December 27, 2014	2,513,320		$	10.73	2.41	$	598,207

Schedule of Share-based Compensation, Restricted Stock Units Award Activity

Restricted stock unit activity is set forth below:



	Number of Shares		Weighted Average Grant Date Fair Value
Restricted stock units at December 31, 2011	1,307,303		$	12.88
Granted	1,630,210		5.50
Vested	(484,540	)	13.99
Canceled	(224,027	)	8.78
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

Stock-Based Compensation (Tables)

12 Months Ended

Dec. 27, 2014

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 27, 2014		December 28, 2013		December 29, 2012
Stock-based compensation expense included in:
Cost of revenues	$	2,433	$	2,436	$	2,588
Research and development	3,529		3,440		4,262
Selling, general and administrative	7,317		6,248		6,199
Total stock-based compensation	13,279		12,124		13,049
Tax effect on stock-based compensation	—		—		—
Total stock-based compensation, net of tax	$	13,279	$	12,124	$	13,049

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions

The following weighted-average assumptions were used in the estimated grant-date fair value calculations for stock options granted in fiscal 2014, 2013 and 2012:



	Fiscal Years Ended
	December 27, 2014		December 28, 2013		December 29, 2012
Stock Options:
Dividend yield	—	%	—	%	—	%
Expected volatility	—	%	—	%	48.44	%
Risk-free interest rate	—	%	—	%	0.67	%
Expected life (in years)	0		0		4.75

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 27, 2014		December 28, 2013		December 29, 2012
Employee Stock Purchase Plan:
Dividend yield	—	%	—	%	—	%
Expected volatility	41.71	%	39.80	%	46.44	%
Risk-free interest rate	0.09	%	0.13	%	0.11	%
Expected life (in years)	0.7		0.7		0.8

Income Taxes (Tables)

12 Months Ended

Dec. 27, 2014

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 27, 2014			December 28, 2013			December 29, 2012
United States	$	(23,230	)	$	(60,447	)	$	(64,252	)
Foreign	3,135			2,665			2,286
	$	(20,095	)	$	(57,782	)	$	(61,966	)

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 27, 2014			December 28, 2013			December 29, 2012
Current provision (benefit):
Federal	$	(983	)	$	(770	)	$	(1,929	)
State	(386		)	76			60
Foreign	234			287			(81		)
	(1,135		)	(407		)	(1,950		)
Deferred provision (benefit):
Federal	—			—			(25,520		)
State	—			—			—
Foreign	225			308			1,050
	225			308			(24,470		)
Total benefit from income taxes	$	(910	)	$	(99	)	$	(26,420	)

Schedule of Effective Income Tax Rate Reconciliation



	Fiscal Years Ended
	December 27, 2014			December 28, 2013			December 29, 2012
U.S. statutory federal tax rate	$	(7,033	)	$	(20,224	)	$	(21,687	)
State taxes and credits, net of Federal benefit	(186		)	(345		)	(1,991		)
Amortization of stock-based compensation, net of tax benefit	686			923			376
Research and development credits	(1,183		)	(560		)	(674		)
Foreign taxes at rates different than the U.S.	(84		)	162			598
Other permanent differences	(972		)	(378		)	(1,164		)
Change in valuation allowance	7,886			20,505			(1,818		)
Other	(24		)	(182		)	(60		)
Total	$	(910	)	$	(99	)	$	(26,420	)

Schedule of Deferred Tax Assets and Liabilities

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



	Fiscal Years Ended
	December 27, 2014			December 28, 2013
Tax credits	$	28,458		$	26,181
Inventory reserve	16,612			15,280
Other reserves and accruals	7,610			6,620
Non-statutory stock options	18,096			18,765
Depreciation and amortization	14,037			5,297
Net operating loss carryforwards	120,110			132,857
Gross deferred tax assets	204,923			205,000
Valuation allowance	(187,759		)	(180,913		)
Total deferred tax assets	17,164			24,087
Acquired intangibles & fixed assets	(13,867		)	(20,373		)
Unrealized investment gains	(3		)	(7		)
Total deferred tax liabilities	(13,870		)	(20,380		)
Net deferred tax assets	$	3,294		$	3,707

Summary of Valuation Allowance

The valuation allowance against deferred tax assets consisted of the following activity for the fiscal years 2014, 2013 and 2012 (in thousands):



Description	Balance at Beginning of Year		Additions		Reduction			Balance at End of Year
Allowance against deferred tax assets
Year ended December 31, 2014	$	180,913	$	6,846	$	—		$	187,759
Year ended December 31, 2013	163,265		17,648		—			180,913
Year ended December 29, 2012	$	168,875	$	19,910	$	(25,520	)	$	163,265

Schedule of Unrecognized Tax Benefits Roll Forward

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



	Fiscal Years Ended
	December 27, 2014			December 28, 2013			December 29, 2012
Unrecognized tax benefit beginning balance	$	16,972		$	17,181		$	17,752
Additions based on tax positions related to the current year	498			307			2,237
Additions based on tax position from prior year	324			—			—
Reductions for tax positions of prior years	(1,109		)	(60		)	9
Reductions to unrecognized tax benefits due to lapse of the applicable statute of limitations	(352		)	(456		)	(2,817		)
Unrecognized tax benefit ending balance	$	16,333		$	16,972		$	17,181

Operating Segment and Geographic Information (Tables)

12 Months Ended

Dec. 27, 2014

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 27, 2014		December 28, 2013		December 29, 2012
North America	28.1	%	27.2	%	15.4	%
South Korea	19.6		19.8		32.8
Taiwan	18.4		27.9		20.7
Asia-Pacific (1)	12.9		9.2		12.7
Europe	11.4		8.6		6.5
Japan	9.6		7.3		11.9
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 27, 2014		December 28, 2013		December 29, 2012
SoC	$	142,360	$	115,597	$	46,586
DRAM	110,800		92,603		102,499
Flash	15,370		23,333		29,450
Total revenues	$	268,530	$	231,533	$	178,535

Schedule of Long-Lived Assets, by Geographical Location



	December 27, 2014		December 28, 2013
North America	$	91,862	$	119,706
South Korea	1,578		1,676
Asia-Pacific (1)	935		1,206
Japan	358		517
Singapore	172		262
Europe	13		24
Total	$	94,918	$	123,391


(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 2014, fiscal 2013 and fiscal 2012:



	Fiscal 2014		Fiscal 2013		Fiscal 2012
Intel	19.7	%	17.7	%	* %
SK hynix	16.9		16.5		29.4
Micron	15.0		11.7		13.3
Samsung	*		*		12.4
Total	51.6	%	45.9	%	55.1	%

* Less than 10% of revenues

Selected Quarterly Financial Data (Unaudited) (Tables)

12 Months Ended

Dec. 27, 2014

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. 27, 2014			Sep. 27, 2014			June. 28, 2014			March 29, 2014			Dec. 28, 2013			Sep. 28, 2013			June. 29, 2013 (1)			March 30, 2013
	(in thousands, except per share data)
Revenues	$	71,285		$	73,934		$	67,352		$	55,959		$	48,546		$	67,634		$	62,733		$	52,620
Cost of revenues	50,337			49,792			47,328			43,634			44,288			55,088			46,328			43,545
Gross profit	20,948			24,142			20,024			12,325			4,258			12,546			16,405			9,075
Operating Expenses:
Research and development	10,706			11,198			11,074			9,747			9,994			10,301			10,915			10,929
Selling, general and administrative	12,631			13,309			13,191			12,254			12,160			12,952			13,487			14,618
Loss on sale of subsidiary	—			—			—			—			—			—			300			—
Restructuring charges, net	584			28			59			1,997			443			143			92			3,980
Impairment of long-lived assets	390			86			—			743			567			15			121			58
Total operating expenses	24,311			24,621			24,324			24,741			23,164			23,411			24,915			29,585
Operating loss	(3,363		)	(479		)	(4,300		)	(12,416		)	(18,906		)	(10,865		)	(8,510		)	(20,510		)
Interest income, net	69			75			79			79			88			95			96			107
Other income (expense), net	155			228			(156		)	(66		)	82			(91		)	209			423
Loss before income taxes	(3,139		)	(176		)	(4,377		)	(12,403		)	(18,736		)	(10,861		)	(8,205		)	(19,980		)
(Benefit from) provision for income taxes	(1,268		)	101			(51		)	308			53			(147		)	202			(207		)
Net loss	$	(1,871	)	$	(277	)	$	(4,326	)	$	(12,711	)	$	(18,789	)	$	(10,714	)	$	(8,407	)	$	(19,773	)
Net loss per share:
Basic and diluted	$	(0.03	)	$	0.00		$	(0.08	)	$	(0.23	)	$	(0.34	)	$	(0.20	)	$	(0.16	)	$	(0.37	)
Weighted average number of shares used in per share calculations:
Basic and diluted	56,472			56,297			55,812			55,050			54,608			54,437			54,105			53,664


(1)	In the second quarter of fiscal 2013, we recorded a $0.3 million loss on the sale of our subsidiary, TMMC. See Note 7, Fair Value, to the Notes to Consolidated Financial Statements for further details relating to the terms of the sale.

Formation and Business of the Company - Fiscal Year (Details)	12 Months Ended
	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
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. 27, 2014	Dec. 28, 2013
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. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Accounting Policies [Abstract]
Aggregate inventory write downs.	$ 7,127	$ 10,461	$ 7,232

Summary of Significant Accounting Policies - Property, Plant and Equipment (Details)	12 Months Ended
	Dec. 27, 2014
Machinery and Equipment
Finite-Lived Intangible Assets [Line Items]
Property, Plant and Equipment, Useful Life	5 years
Machinery and Equipment \| Minimum
Finite-Lived Intangible Assets [Line Items]
Property, Plant and Equipment, Useful Life	1 year
Computer Equipment and Software \| Minimum
Finite-Lived Intangible Assets [Line Items]
Property, Plant and Equipment, Useful Life	1 year
Computer Equipment and Software \| Maximum
Finite-Lived Intangible Assets [Line Items]
Property, Plant and Equipment, Useful Life	5 years
Furniture and Fixtures \| Minimum
Finite-Lived Intangible Assets [Line Items]
Property, Plant and Equipment, Useful Life	1 year
Furniture and Fixtures \| Maximum
Finite-Lived Intangible Assets [Line Items]
Property, Plant and Equipment, Useful Life	5 years

Summary of Significant Accounting Policies - Intangibles (Details)	12 Months Ended
	Dec. 27, 2014
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	12 Months Ended
	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Concentration Risk [Line Items]
Percentage of concentration of risk	100.00%	100.00%	100.00%
Customer Concentration Risk \| Sales Revenue, Goods, Net
Concentration Risk [Line Items]
Percentage of concentration of risk	51.60%	45.90%	55.10%
Customer Concentration Risk \| Accounts Receivable
Concentration Risk [Line Items]
Number of major customers.	2	3
Customer Concentration Risk \| Intel \| Sales Revenue, Goods, Net
Concentration Risk [Line Items]
Percentage of concentration of risk	19.70%	17.70%
Customer Concentration Risk \| SK Hynix \| Sales Revenue, Goods, Net
Concentration Risk [Line Items]
Percentage of concentration of risk	16.90%	16.50%	29.40%
Customer Concentration Risk \| Micron Technology \| Sales Revenue, Goods, Net
Concentration Risk [Line Items]
Percentage of concentration of risk	15.00%	11.70%	13.30%
Customer Concentration Risk \| Samsung \| Sales Revenue, Goods, Net
Concentration Risk [Line Items]
Percentage of concentration of risk			12.40%
Customer Concentration Risk \| Major Customer 1 \| Accounts Receivable
Concentration Risk [Line Items]
Percentage of concentration of risk	26.00%	21.00%
Customer Concentration Risk \| Major Customer 2 \| Accounts Receivable
Concentration Risk [Line Items]
Percentage of concentration of risk	18.00%	15.00%
Customer Concentration Risk \| Major Customer 3 \| Accounts Receivable
Concentration Risk [Line Items]
Percentage of concentration of risk		11.00%

Summary of Significant Accounting Policies - Warrany Obligations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 27, 2014	Dec. 28, 2013
Movement in Standard Product Warranty Accrual [Roll Forward]
Warranty Accrual beginning balance	$ 691	$ 734
Accruals	2,972	1,916
Settlements	(2,071)	(1,959)
Warranty Accrual ending balance	$ 1,592	$ 691

Summary of Significant Accounting Policies - Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Allowance for Doubtful Accounts Receivable [Roll Forward]
Balance at Beginning of Year	$ 265	$ 289	$ 238
Reductions	(4)	(24)	(151)
Balance at End of Year	266	265	289
Uncollectable Accounts
Allowance for Doubtful Accounts Receivable [Roll Forward]
Additions	$ 5	$ 0	$ 202

Summary of Significant Accounting Policies - Restructuring Charges (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 2,668
2012 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Restructuring charges		$ 4,658
2011 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Restructuring charges			$ 2,917

Summary of Significant Accounting Policies - Net Loss per Share (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 27, 2014	Sep. 27, 2014	Jun. 28, 2014	Mar. 29, 2014	Dec. 28, 2013	Sep. 28, 2013	Jun. 29, 2013	Mar. 30, 2013	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Accounting Policies [Abstract]
Net loss	$ (1,871)	$ (277)	$ (4,326)	$ (12,711)	$ (18,789)	$ (10,714)	$ (8,407)	$ (19,773)	$ (19,185)	$ (57,683)	$ (35,546)
Weighted-average shares used in computing basic net loss per share									55,908	54,204	50,551
Add potentially dilutive securities (Shares)									0	0	0
Weighted-average shares used in computing diluted net loss per share	56,472	56,297	55,812	55,050	54,608	54,437	54,105	53,664	55,908	54,204	50,551

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

Summary of Significant Accounting Policies - Net Loss Per Share Weighted-Average Dilutive Securities (Details) - shares shares in Thousands	12 Months Ended
	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	2,902	4,200	5,715
Stock Options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	2,874	3,805	4,430
Restricted Stock Units (RSUs)
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0	373	1,246
Employee stock purchase plan
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	28	22	39

Summary of Significant Accounting Policies - Comprehensive Loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 27, 2014	Dec. 28, 2013
Accounting Policies [Abstract]
Unrealized loss on marketable securities, net of tax of $428 in fiscal 2014 and fiscal 2013, respectively	$ (419)	$ (409)
Unrealized loss on marketable securities, tax	428	428
Cumulative translation adjustments	(1,342)	160
Accumulated other comprehensive loss	$ (1,761)	$ (249)

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.

Balance Sheet Components - Marketable Securities (Details) - USD ($)	12 Months Ended
	Dec. 27, 2014	Dec. 28, 2013
Available-for-sale Securities [Abstract]
Amortized Cost	$ 49,888,000	$ 91,875,000
Available-for-sale Securities, Gross Unrealized Gains	13,000	34,000
Available-for-sale Securities, Gross Unrealized Losses	(4,000)	(14,000)
Available-for-sale Securities Fair Value	$ 49,897,000	91,895,000
Maximum Remaining Maturity of Foreign Currency Derivatives	3 years
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		0
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Fiscal Year Maturity [Abstract]
Due in one year or less - Amortized Cost	$ 38,499,000	59,888,000
Due in one year to five years - Amortized Cost	11,389,000	31,987,000
Amortized Cost	49,888,000	91,875,000
Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Due in one year or less - Fair Value	38,509,000	59,894,000
Due in one year to five years - Fair Value	11,388,000	32,001,000
Available-for-sale Securities Fair Value	49,897,000	91,895,000
US Treasury Securities
Available-for-sale Securities [Abstract]
Amortized Cost	42,386,000	48,991,000
Available-for-sale Securities, Gross Unrealized Gains	13,000	33,000
Available-for-sale Securities, Gross Unrealized Losses	(4,000)	(10,000)
Available-for-sale Securities Fair Value	42,395,000	49,014,000
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Fiscal Year Maturity [Abstract]
Amortized Cost	42,386,000	48,991,000
Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Available-for-sale Securities Fair Value	42,395,000	49,014,000
Commercial Paper
Available-for-sale Securities [Abstract]
Amortized Cost		11,623,000
Available-for-sale Securities, Gross Unrealized Gains		0
Available-for-sale Securities, Gross Unrealized Losses		0
Available-for-sale Securities Fair Value		11,623,000
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Fiscal Year Maturity [Abstract]
Amortized Cost		11,623,000
Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Available-for-sale Securities Fair Value		11,623,000
Agency securities (Federal)
Available-for-sale Securities [Abstract]
Amortized Cost	7,502,000	31,261,000
Available-for-sale Securities, Gross Unrealized Gains	0	1,000
Available-for-sale Securities, Gross Unrealized Losses	0	(4,000)
Available-for-sale Securities Fair Value	7,502,000	31,258,000
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Fiscal Year Maturity [Abstract]
Amortized Cost	7,502,000	31,261,000
Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Available-for-sale Securities Fair Value	$ 7,502,000	$ 31,258,000

Balance Sheet Components - Asset Retirement Obligation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 27, 2014	Dec. 28, 2013
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Asset retirement obligation beginning balance	$ 988	$ 1,292
Liabilities settled	0	(169)
Currency translation	(85)	(135)
Asset retirement obligation ending balance	$ 903	$ 988

Balance Sheet Components - Inventory (Details) - USD ($) $ in Thousands	Dec. 27, 2014	Dec. 28, 2013
Balance Sheet Components [Abstract]
Raw materials	$ 10,646	$ 7,411
Work-in-progress	12,813	10,531
Finished goods	2,089	2,765
Inventory, Net	$ 25,548	$ 20,707

Balance Sheet Components - Property Plant and Equipment (Details) - USD ($)
$ in Thousands

3 Months Ended

12 Months Ended

Dec. 27, 2014

Sep. 27, 2014

Jun. 28, 2014

Mar. 29, 2014

Dec. 28, 2013

Sep. 28, 2013

Jun. 29, 2013

^[1]

Mar. 30, 2013

Dec. 27, 2014

Dec. 28, 2013

Dec. 29, 2012

Property Plant And Equipment Gross, Excludes Construction in Progress Gross

$ 247,171

$ 252,545

$ 247,171

$ 252,545

Less: Accumulated depreciation, amortization and enterprise-wide impairment

(224,135)

(221,346)

(224,135)

(221,346)

Property Plant And Equipment Net, Excludes Construction in Progress

23,036

31,199

23,036

31,199

Construction-in-progress

2,462

3,991

2,462

3,991

Property, Plant and Equipment, Net

25,498

35,190

25,498

35,190

Impaired Assets to be Disposed of by Method Other than Sale, Carrying Value of Asset

6,600

Depreciation, Depletion and Amortization

390

$ 86

$ 0

$ 743

567

$ 15

$ 121

$ 58

1,219

761

$ 421

11,700

12,200

$ 10,300

Building

Property Plant And Equipment Gross, Excludes Construction in Progress Gross

790

Machinery and Equipment

Property Plant And Equipment Gross, Excludes Construction in Progress Gross

145,995

143,463

145,995

143,463

Computer Equipment and Software

Property Plant And Equipment Gross, Excludes Construction in Progress Gross

28,953

34,547

28,953

34,547

Capital Leases

Property Plant And Equipment Gross, Excludes Construction in Progress Gross

866

Furniture and Fixtures

Property Plant And Equipment Gross, Excludes Construction in Progress Gross

5,402

5,495

5,402

5,495

Leasehold Improvements

Property Plant And Equipment Gross, Excludes Construction in Progress Gross

$ 66,821

$ 67,384

$ 66,821

$ 67,384

[1]	In the second quarter of fiscal 2013, we recorded a $0.3 million loss on the sale of our subsidiary, TMMC. See Note 7, Fair Value, to the Notes to Consolidated Financial Statements for further details relating to the terms of the sale.

Balance Sheet Components - Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 27, 2014	Dec. 28, 2013
Accrued Liabilities, Current [Abstract]
Accrued compensation and benefits	$ 12,431	$ 7,975
Accrued indirect and other taxes	2,223	1,400
Accrued commissions	460	448
Accrued warranty	1,592	691
Deferred rent	216	154
Accrued restructuring	584	138
Other accrued expense	3,711	3,179
Total	$ 21,217	$ 13,985

Restructuring Charges - Restructuring Charges (Texutal) (Details)
$ in Thousands

3 Months Ended

9 Months Ended

12 Months Ended

Jan. 27, 2014

Employee

Dec. 27, 2014

USD ($)

Sep. 27, 2014

USD ($)

Jun. 28, 2014

USD ($)

Mar. 29, 2014

USD ($)

Dec. 28, 2013

USD ($)

Employee

Sep. 28, 2013

USD ($)

Jun. 29, 2013

USD ($)

^[1]

Mar. 30, 2013

USD ($)

Employee

Sep. 29, 2012

USD ($)

Employee

Jun. 30, 2012

USD ($)

Employee

Dec. 27, 2014

USD ($)

Employee

Dec. 27, 2014

USD ($)

Dec. 28, 2013

USD ($)

Dec. 29, 2012

USD ($)

2014 Global Reorganization Restructuring And Cost Reduction Plan

$ 584

$ 28

$ 59

$ 1,997

$ 443

$ 143

$ 92

$ 3,980

$ 2,668

$ 4,658

$ 2,917

Restructuring and Related Cost, Expected Number of Positions Eliminated | Employee

Restructuring and Related Cost, Number of Positions Eliminated

Q1 2013 Restructuring Activities

2,000

Restructuring and Related Cost, Expected Number of Positions Eliminated | Employee

Restructuring and Related Cost, Number of Positions Eliminated

Q4 2013 Restructuring Activities

$ 4,000

Restructuring and Related Cost, Expected Number of Positions Eliminated | Employee

Restructuring and Related Cost, Number of Positions Eliminated

Q3 2012 Restructuring Activities

Restructuring and Related Cost, Expected Number of Positions Eliminated | Employee

Q4 2012 Restructuring Activities

Restructuring and Related Cost, Expected Number of Positions Eliminated | Employee

Employee Severance and Benefits | 2014 Global Reorganization Restructuring And Cost Reduction Plan

Employee Severance and Benefits | Q1 2013 Restructuring Activities

1,400

$ 700

Employee Severance and Benefits | Q2 2012 Restructuring Activities

1,300

Restructuring and Related Cost, Expected Number of Positions Eliminated | Employee

Employee Severance and Benefits | Q3 2012 Restructuring Activities

$ 100

Employee Severance and Benefits | Q4 2012 Restructuring Activities

$ 1,800

Property and Equipment Impairment | 2014 Global Reorganization Restructuring And Cost Reduction Plan

$ 400

Restructuring Costs and Asset Impairment Charges

$ 600

Property and Equipment Impairment | Q1 2013 Restructuring Activities

Restructuring Costs and Asset Impairment Charges

$ 2,700

Property and Equipment Impairment | Q3 2012 Restructuring Activities

Contract Termination and Other Costs | Q3 2012 Restructuring Activities

400

$ 200

[1]	In the second quarter of fiscal 2013, we recorded a $0.3 million loss on the sale of our subsidiary, TMMC. See Note 7, Fair Value, to the Notes to Consolidated Financial Statements for further details relating to the terms of the sale.

Restructuring Charges - Restructuring Actions (Details) - USD ($)
$ in Thousands

3 Months Ended

12 Months Ended

Dec. 27, 2014

Sep. 27, 2014

Jun. 28, 2014

Mar. 29, 2014

Dec. 28, 2013

Sep. 28, 2013

Jun. 29, 2013

^[1]

Mar. 30, 2013

Dec. 27, 2014

Dec. 28, 2013

Dec. 29, 2012

$ 584

$ 28

$ 59

$ 1,997

$ 443

$ 143

$ 92

$ 3,980

$ 2,668

$ 4,658

$ 2,917

(390)

$ (86)

$ 0

(743)

(567)

$ (15)

$ (121)

(58)

(1,219)

(761)

(421)

2010 Restructuring Plan

200

2011 Restructuring Plan

616

2,917

(2,070)

(462)

616

2012 Restructuring Plan

138

4,841

(2,743)

(183)

(2,369)

(24)

138

2013 Restructuring Plan

2,668

(600)

(1,620)

(2)

Employee Severance and Benefits | 2010 Restructuring Plan

584

Employee Severance and Benefits | 2011 Restructuring Plan

200

548

2,261

(1,913)

Employee Severance and Benefits | 2012 Restructuring Plan

548

138

2,083

(178)

(2,320)

Employee Severance and Benefits | 2013 Restructuring Plan

138

2,068

(1,620)

(2)

Property and Equipment Impairment | 2010 Restructuring Plan

584

Property and Equipment Impairment | 2011 Restructuring Plan

462

(462)

Property and Equipment Impairment | 2012 Restructuring Plan

2,743

(2,743)

(5)

(32)

Property and Equipment Impairment | 2013 Restructuring Plan

600

(600)

Contract Termination and Other Costs | 2010 Restructuring Plan

Contract Termination and Other Costs | 2011 Restructuring Plan

$ 68

194

(157)

Contract Termination and Other Costs | 2012 Restructuring Plan

$ 68

$ 0

(17)

(66)

Contract Termination and Other Costs | 2013 Restructuring Plan

$ 0

Assets to be disposed of other than by sale

$ 0

[1]	In the second quarter of fiscal 2013, we recorded a $0.3 million loss on the sale of our subsidiary, TMMC. See Note 7, Fair Value, to the Notes to Consolidated Financial Statements for further details relating to the terms of the sale.

Derivative Financial Instruments (Details) - Not Designated as Hedging Instrument - Foreign Exchange Forward ₩ in Thousands, ¥ in Thousands, $ in Thousands, $ in Thousands	12 Months Ended
	Dec. 27, 2014 USD ($)	Dec. 28, 2013 USD ($)	Dec. 27, 2014 KRW (₩)	Dec. 27, 2014 TWD ($)	Dec. 27, 2014 JPY (¥)	Dec. 28, 2013 KRW (₩)	Dec. 28, 2013 TWD ($)	Dec. 28, 2013 JPY (¥)
Derivatives, Fair Value [Line Items]
Notional amount of foreign currency derivatives	$ 13,651	$ 2,729
Other Income, net
Derivatives, Fair Value [Line Items]
Gain (Loss) Recognized in Income, Net	1,768	(5)
Japan, Yen
Derivatives, Fair Value [Line Items]
Notional amount of foreign currency derivatives	16,241	4,174			¥ 1,955,798			¥ 439,328
Taiwan Dollar
Derivatives, Fair Value [Line Items]
Notional amount of foreign currency derivatives	977	462		$ 30,886			$ 13,772
Korean Won
Derivatives, Fair Value [Line Items]
Notional amount of foreign currency derivatives	$ 1,613	$ 983	₩ 1,763,054			₩ 1,034,319

Impairment of Long-lived Assets - Asset Impairment (Details) - USD ($)
$ in Thousands

3 Months Ended

12 Months Ended

Dec. 27, 2014

Sep. 27, 2014

Jun. 28, 2014

Mar. 29, 2014

Dec. 28, 2013

Sep. 28, 2013

Jun. 29, 2013

^[1]

Mar. 30, 2013

Dec. 27, 2014

Dec. 28, 2013

Dec. 29, 2012

Asset Impairment Charges [Abstract]

Assets held for sale

$ 191

$ 0

$ 168

1,028

761

253

Total

$ 390

$ 86

$ 0

$ 743

$ 567

$ 15

$ 121

$ 58

$ 1,219

$ 761

$ 421

[1]	In the second quarter of fiscal 2013, we recorded a $0.3 million loss on the sale of our subsidiary, TMMC. See Note 7, Fair Value, to the Notes to Consolidated Financial Statements for further details relating to the terms of the sale.

Impairment of Long-lived Assets - Assets Held for Sale (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Long Lived Assets Held-for-sale [Line Items]
Impairment of long-lived assets	$ 1,219	$ 761	$ 421
Gain (Loss) on Disposition of Property Plant Equipment	10	(365)	(41)
Impairment of Long-Lived Assets Held-for-use	1,028	761	$ 253
Assets previously held for sale
Long Lived Assets Held-for-sale [Line Items]
Impairment of Long-Lived Assets Held-for-use		$ 200
Building
Long Lived Assets Held-for-sale [Line Items]
Impairment of long-lived assets	600
Gain (Loss) on Disposition of Property Plant Equipment	200
Machinery and Equipment
Long Lived Assets Held-for-sale [Line Items]
Impairment of long-lived assets	500
Gain (Loss) on Disposition of Property Plant Equipment	$ 100

Impairment of Long-lived Assets - Assets to be disposed of other than sale (Details) - USD ($)
$ in Thousands

3 Months Ended

12 Months Ended

Dec. 27, 2014

Sep. 27, 2014

Jun. 28, 2014

Mar. 29, 2014

Dec. 28, 2013

Sep. 28, 2013

Jun. 29, 2013

^[1]

Mar. 30, 2013

Dec. 27, 2014

Dec. 28, 2013

Dec. 29, 2012

Impaired Assets to be Disposed of by Method Other than Sale [Line Items]

Impairment of Long-Lived Assets to be Disposed of

$ 390

$ 86

$ 0

$ 743

$ 567

$ 15

$ 121

$ 58

$ 1,219

$ 761

$ 421

$ 1,219

761

$ 421

On going construction in progress project termination

Impaired Assets to be Disposed of by Method Other than Sale [Line Items]

Impairment of Long-Lived Assets to be Disposed of

$ 200

[1]	In the second quarter of fiscal 2013, we recorded a $0.3 million loss on the sale of our subsidiary, TMMC. See Note 7, Fair Value, to the Notes to Consolidated Financial Statements for further details relating to the terms of the sale.

Fair Value - Asset Measured at Fair Value (Details) - USD ($) $ / shares in Units, $ in Thousands	Dec. 27, 2014	Dec. 28, 2013
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable securities	$ 49,897	$ 91,895
Total	115,200	119,838
Money Market Funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents	65,303	27,943
Commercial Paper
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents		11,623
US Treasury Securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable securities	42,395	49,014
Agency securities (Federal)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable securities	7,502	31,258
Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total	$ 65,303	27,943
Level 1 \| Money Market Funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Net asset value (per share)	$ 1
Cash equivalents	$ 65,303	27,943
Level 1 \| Commercial Paper
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents		0
Level 1 \| US Treasury Securities
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	49,897	91,895
Level 2 \| Money Market Funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents	0	0
Level 2 \| Commercial Paper
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents		11,623
Level 2 \| US Treasury Securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable securities	42,395	49,014
Level 2 \| Agency securities (Federal)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable securities	$ 7,502	$ 31,258

Fair Value - Assets Measured at Fair Value on a Nonrecurring Basis (Details) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 28, 2013 USD ($)	Sep. 28, 2013 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Proceeds from Divestiture of Businesses	$ 1.0
Fair Value Assumptions, Expected Term		7 years
Receivable with Imputed Interest, Effective Yield (Interest Rate)	5.00%
Notes Receivable, Fair Value Disclosure	$ 0.5	$ 0.5
Cash
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Proceeds from Divestiture of Businesses	0.2
Notes Receivable
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Proceeds from Divestiture of Businesses	$ 0.8

Goodwill and Intangible Assets - Goodwill (Details) - USD ($)	Dec. 27, 2014	Dec. 28, 2013
Goodwill [Line Items]
Goodwill	$ 30,731,000	$ 30,731,000
FormFactor
Goodwill [Line Items]
Amount of fair value in excess of carrying amount	$ 32
Percentage of fair value in excess of carrying amount	16.00%
MicroProbe
Goodwill [Line Items]
Amount of fair value in excess of carrying amount	$ 41
Percentage of fair value in excess of carrying amount	39.00%

Goodwill and Intangible Assets - Finite-Lived (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Finite-lived Intangible Assets [Roll Forward]
Intangible Assets, Gross Amount	$ 72,636
Additions/Disposals	0
Intangible Assets, Gross Amount	72,636	$ 72,636
Accumulated Amortization	22,066
Expense, net	18,781	16,700	$ 6,600
Accumulated Amortization	40,847	22,066
Intangible Assets, Net	31,789	50,570
Intangible Assets Net Excluding Goodwill [Roll Forward]
Intangible Assets Net Excluding Goodwill Gross	79,536
Intangible Assets Net Excluding Goodwill Acquired During Period	0
Intangible Assets Net Excluding Goodwill Gross	79,536	79,536
Intangible Assets, Net (Excluding Goodwill)	38,689	57,470
Existing developed technologies
Finite-lived Intangible Assets [Roll Forward]
Intangible Assets, Gross Amount	51,248
Additions/Disposals	0
Intangible Assets, Gross Amount	51,248	51,248
Accumulated Amortization	18,955
Expense, net	16,090
Accumulated Amortization	35,045	18,955
Intangible Assets, Net	$ 16,203	32,293
Weight Average Useful Life	1 year 9 months 6 days
Trade name
Finite-lived Intangible Assets [Roll Forward]
Intangible Assets, Gross Amount	$ 4,388
Additions/Disposals	0
Intangible Assets, Gross Amount	4,388	4,388
Accumulated Amortization	530
Expense, net	440
Accumulated Amortization	970	530
Intangible Assets, Net	$ 3,418	3,858
Weight Average Useful Life	7 years 9 months 6 days
Customer relationships
Finite-lived Intangible Assets [Roll Forward]
Intangible Assets, Gross Amount	$ 17,000
Additions/Disposals	0
Intangible Assets, Gross Amount	17,000	17,000
Accumulated Amortization	2,581
Expense, net	2,251
Accumulated Amortization	4,832	2,581
Intangible Assets, Net	$ 12,168	14,419
Weight Average Useful Life	5 years 9 months 6 days
In-process research and development
Finite-Lived Intangible Assets [Line Items]
Indefinite-lived Intangible Assets Acquired		14,200
Finite-lived Intangible Assets [Roll Forward]
Intangible Assets, Gross Amount	$ 6,900
Intangible Assets, Gross Amount		6,900
Indefinite-lived Intangible Assets [Roll Forward]
Indefinite-lived Intangible Assets, Additions/Disposals During Period	0
Indefinite-lived Intangible Assets	$ 6,900	$ 6,900

Goodwill and Intangible Assets - Amortization (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Property, Plant and Equipment [Line Items]
Amortization of Intangible Assets	$ 18,781	$ 16,700	$ 6,600
Finite-Lived Intangible Assets, Net, Amortization Expense, Rolling Maturity [Abstract]
2015	12,739
2016	8,720
2017	2,551
2018	2,501
2019	2,447
and thereafter	2,831
Total	31,789
Intellectual Property \| Cost of Sales
Property, Plant and Equipment [Line Items]
Amortization of Intangible Assets	16,100	13,800	6,000
Intellectual Property \| Selling, General and Administrative Expenses
Property, Plant and Equipment [Line Items]
Amortization of Intangible Assets	$ 2,700	$ 2,900	$ 600

Commitments and Contingencies - (Textual) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012	Dec. 31, 2011
Commitments and Contingencies Disclosure [Abstract]
Rent Expense	$ 4,800	$ 4,900	$ 4,700
Unrecognized Tax Benefits	$ 16,333	$ 16,972	$ 17,181	$ 17,752

Commitments and Contingencies - Capital Lease (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Commitments and Contingencies Disclosure [Abstract]
Cost	$ 0	$ 866
Accumulated depreciation	0	637
Net book value	0	229
Capital Leases, Income Statement, Amortization Expense	$ 200	$ 500	$ 200

Commitments and Contingencies - Operating Lease (Details) $ in Thousands	Dec. 27, 2014 USD ($)
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2015	$ 4,157
2016-2017	7,078
2018-2019	6,982
Thereafter	5,936
Total	$ 24,153

Commitments and Contingencies - Other Contractual Obligations (Details) $ in Thousands	Dec. 27, 2014 USD ($)
Commitments and Contingencies Disclosure [Abstract]
2015	$ 10,899
2016-2017	502
2018-2019	0
After 2019	0
Total	$ 11,401

Stockholders' Equity - Preferred Stock (Details) - $ / shares	Dec. 27, 2014	Dec. 28, 2013
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 - Equity Incentive Plans (Details) - Equity Incentive Plan - USD ($)	12 Months Ended
	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012	Jan. 01, 2015	Apr. 18, 2012
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Number of Shares Outstanding	3,454,426	4,208,847	4,619,022
Stock options granted (Shares)	0
Options exercised (Shares)	0	(20,000)	0
Options canceled (Shares)	(883,050)	(734,421)	(480,175)
Number of Shares Outstanding	2,571,376	3,454,426	4,208,847
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Weighted Average Exercise Price Outstanding (Per Share)	$ 12.32	$ 13.11	$ 13.11
Weighted Average Exercise Price, Options granted (Per Share)	0.00	0.00	5.34
Weighted Average Exercise Price, Options exercised (Per Share)	0.00	5.28	0.00
Weighted Average Exercise Price, Options canceled (Per Share)	17.00	17.04	11.94
Weighted Average Exercise Price Outstandin (Per Share)	$ 10.72	$ 12.32	$ 13.11
Weighted Average Remaining Contractual Life in Years	2 years 5 months 5 days
Aggregate Intrinsic Value	$ 598,212
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)	2,571,359
Weighted Average Exercise Price, Vested and expected to vest at December 27, 2014 (Per Share)	$ 10.72
Weighted Average Remaining Contractual Term	2 years 4 months 16 days
Aggregate Intrinsic Value	$ 598,212
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Exercisable at December 27, 2014 (Shares)	2,513,320
Weighted average exercise price, exercisable (Per Share)	$ 10.73
Weighted Average Remaining Contractual Term	2 years 4 months 28 days
Aggregate Intrinsic Value	$ 598,207
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares Per Conversion of Restricted Stock					1.55
Stock Options Granted, Award Vesting Period	4 years
Stock Options Granted, Expiration Period	10 years
Shares Available for Grant (Shares)	3,300,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Stock options granted (Shares)		0	70,000
Stock Options \| Subsequent Event
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares Per Conversion of Restricted Stock				1.70
Stock Appreciation Rights (SARs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock Options Granted, Award Vesting Period	4 years

Stockholders' Equity - Restricted Stock Units (Details) - Restricted Stock Units (RSUs) $ / shares in Units, $ in Millions		12 Months Ended
	May 05, 2014 executive shares	Dec. 27, 2014 USD ($) $ / shares shares	Dec. 28, 2013 USD ($) $ / shares shares	Dec. 29, 2012 USD ($) $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Stock Issued During Period, Shares, New Issues	350,000
Stock Issued During Period, Shares, New Issues, Number of Recipients \| executive	7
Allocated Share-based Compensation Expense \| $		$ 0.6
Fair value of restricted stock units vested during the period \| $		$ 8.2	$ 3.9	$ 2.9
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)		2,929,639	2,228,946	1,307,303
Granted (Shares)		1,900,000	1,708,000	1,630,210
Vested (Shares)		(1,282,442)	(760,590)	(484,540)
Canceled (Shares)		(297,151)	(246,717)	(224,027)
Restricted stock units (Shares)		3,250,046	2,929,639	2,228,946
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		$ 5.88	$ 7.66	$ 12.88
Granted (Per Share) \| $ / shares		6.52	5.04	5.50
Vested (Per Share) \| $ / shares		6.30	8.44	13.99
Canceled (Per Share) \| $ / shares		6.17	8.18	8.78
Restricted stock units (Per Share) \| $ / shares		$ 6.07	$ 5.88	$ 7.66

Stockholders' Equity - Employee Stock Purchase Plan (Details)	12 Months Ended
	Dec. 27, 2014 purchase_period $ / shares shares	Dec. 28, 2013 $ / shares shares	Dec. 29, 2012 $ / 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 (Shares) \| shares	586,386	583,173	533,077
Weighted average exercise price, exercisable (Per Share) \| $ / shares	$ 4.80	$ 4.29	$ 4.42

Stock-Based Compensation - Included in Consolidated Statement of Operations (Details) - Employee Stock - USD ($) $ in Thousands	12 Months Ended
	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 13,279	$ 12,124	$ 13,049
Tax effect on stock based compensation	0	0	0
Total stock based compensation, net of tax	13,279	12,124	13,049
Cost of Sales
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	2,433	2,436	2,588
Research and Development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	3,529	3,440	4,262
Selling, General and Administrative Expenses
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 7,317	$ 6,248	$ 6,199

Stock-Based Compensation - Valuation Assumptions (Details)	12 Months Ended
	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend yield	0.00%	0.00%	0.00%
Expected volatility	0.00%	0.00%	48.44%
Risk free interest rate	0.00%	0.00%	0.67%
Expected life (in years)	0 years	0 years	4 years 9 months
Employee Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend yield	0.00%	0.00%	0.00%
Expected volatility	41.71%	39.80%	46.44%
Risk free interest rate	0.09%	0.13%	0.11%
Expected life (in years)	8 months	8 months	9 months

Stock-Based Compensation - (Textuals) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Compensation Cost Not Yet Recognized, Stock Options	$ 0.1
Weighted Average Life, Total Compensation Cost Not Yet Recognized, Employee Stock Purchase Plan	6 months 6 days
Employee Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Issuance of common stock under the Employee Stock Purchase Plan (Shares)	586,386	583,173	533,077
Total Compensation Cost Not Yet Recognized, Other than Options	$ 0.1
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted Average Life, Total Compensation Cost Not Yet Recognized, Employee Stock Purchase Plan	1 year 2 months 6 days
Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock Options Granted	0
Equity Incentive Plan \| Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock Options Granted, Award Vesting Period	4 years
Stock Options Granted		0	70,000
Weighted Average Grant Date Fair Value, Per Share, Stock Options			$ 2.17
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	$ 9.3
Restricted Stock Units, Granted	1,900,000	1,708,000	1,630,210
Weighted Average Grant Date Fair Value Per Share, RSU's	$ 6.52	$ 5.04	$ 5.50
Minimum \| Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock Options Granted, Award Vesting Period	3 years
Stock Options Granted Award Vesting Period, Additional Years	5 years
Maximum \| Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock Options Granted, Award Vesting Period	4 years
Stock Options Granted Award Vesting Period, Additional Years	10 years

Income Taxes - Components (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 27, 2014	Sep. 27, 2014	Jun. 28, 2014	Mar. 29, 2014	Dec. 28, 2013	Sep. 28, 2013	Jun. 29, 2013	Mar. 30, 2013	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest [Abstract]
United States									$ (23,230)	$ (60,447)	$ (64,252)
Foreign									3,135	2,665	2,286
Loss before income taxes	$ (3,139)	$ (176)	$ (4,377)	$ (12,403)	$ (18,736)	$ (10,861)	$ (8,205)	$ (19,980)	$ (20,095)	$ (57,782)	$ (61,966)

Income Taxes - Provision for Income Taxes (Details) - USD ($)
$ in Thousands

3 Months Ended

12 Months Ended

Dec. 27, 2014

Sep. 27, 2014

Jun. 28, 2014

Mar. 29, 2014

Dec. 28, 2013

Sep. 28, 2013

Jun. 29, 2013

^[1]

Mar. 30, 2013

Dec. 27, 2014

Dec. 28, 2013

Dec. 29, 2012

Current provision (benefit): [Abstract]

Federal

$ (983)

$ (770)

$ (1,929)

State

(386)

Foreign

234

287

(81)

Total

(1,135)

(407)

(1,950)

Deferred provision (benefit)

Federal

(25,520)

State

Foreign

225

308

1,050

Deferred income tax provision (benefit)

225

308

(24,470)

Income Tax Expense (Benefit)

$ (1,268)

$ 101

$ (51)

$ 308

$ 53

$ (147)

$ 202

$ (207)

$ (910)

$ (99)

$ (26,420)

[1]	In the second quarter of fiscal 2013, we recorded a $0.3 million loss on the sale of our subsidiary, TMMC. See Note 7, Fair Value, to the Notes to Consolidated Financial Statements for further details relating to the terms of the sale.

Income Taxes - Federal Statutory Rate (Details) - USD ($)
$ in Thousands

3 Months Ended

12 Months Ended

Dec. 27, 2014

Sep. 27, 2014

Jun. 28, 2014

Mar. 29, 2014

Dec. 28, 2013

Sep. 28, 2013

Jun. 29, 2013

^[1]

Mar. 30, 2013

Dec. 27, 2014

Dec. 28, 2013

Dec. 29, 2012

Income Tax Disclosure [Abstract]

Federal statutory rate.

35.00%

Income Tax Reconciliation, Other Reconciling Items [Abstract]

U.S. statutory Federal tax rate

$ (7,033)

$ (20,224)

$ (21,687)

State taxes and credits, net of Fereral benefit

(186)

(345)

(1,991)

Amortization of stock-based compensation, net of tax benefit

686

923

376

Research and development credits

(1,183)

(560)

(674)

Foreign taxes at rates different that the U.S.

(84)

162

598

Other permanent differences

(972)

(378)

(1,164)

Change in valuation allowance

7,886

20,505

(1,818)

Other

(24)

(182)

(60)

Income Tax Expense (Benefit)

$ (1,268)

$ 101

$ (51)

$ 308

$ 53

$ (147)

$ 202

$ (207)

$ (910)

$ (99)

$ (26,420)

[1]	In the second quarter of fiscal 2013, we recorded a $0.3 million loss on the sale of our subsidiary, TMMC. See Note 7, Fair Value, to the Notes to Consolidated Financial Statements for further details relating to the terms of the sale.

Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012	Dec. 31, 2011
Deferred Tax Assets, Net, Classification [Abstract]
Tax credits	$ 28,458	$ 26,181
Inventory reserve	16,612	15,280
Other reserves and accruals	7,610	6,620
Non-statutory stock options	18,096	18,765
Depreciation and amortization	14,037	5,297
Net operating loss carryforwards	120,110	132,857
Gross deferred tax assets	204,923	205,000
Valuation allowance	(187,759)	(180,913)	$ (163,265)	$ (168,875)
Total deferred tax assets	17,164	24,087
Deferred Tax Liabilities, Net, Classification [Abstract]
Acquired intangibles & fixed assets	(13,867)	(20,373)
Unrealized investment gains	(3)	(7)
Total deferred tax liabilities	(13,870)	(20,380)
Net deferred tax assets	$ 3,294	$ 3,707

Income Taxes - Valuation Allowance Against Deferred Tax Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Deferred Tax Assets Valuation Allowance [Roll Forward]
Balance at Beginning of Year	$ 180,913	$ 163,265	$ 168,875
Additions	6,846	17,648	19,910
Reduction	0	0	(25,520)
Balance at End of Year	187,759	$ 180,913	$ 163,265
Federal
Deferred Tax Assets Valuation Allowance [Roll Forward]
Federal research and development tax credit, carryforwards.	19,300
Federal foreign tax credit carryforwards.	293,900
Federal foreign tax credit carryforwards.	1,900
Alternative minimum tax credits.	2,400
Livermore, California
Deferred Tax Assets Valuation Allowance [Roll Forward]
Federal foreign tax credit carryforwards.	270,800
California research credit carryforwards.	26,500
Singapore
Deferred Tax Assets Valuation Allowance [Roll Forward]
Singapore net operating loss carryforwards.	$ 10,600

Income Taxes - Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Income Tax Disclosure [Abstract]
Repatriation of earnings of foreign subsidiaries.	$ 5,000
Deferred Tax Liability Not Recognized, Amount of Unrecognized Deferred Tax Liability, Undistributed Earnings of Foreign Subsidiaries	300
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefit beginning balance	16,972	$ 17,181	$ 17,752
Additions based on tax positions related to the current year	498	307	2,237
Additions based on tax position from prior year	324	0	0
Reductions for tax positions of prior years	(1,109)	(60)	9
Reductions to unrecognized tax benefits due to lapse of the applicable statute of limitations	(352)	(456)	(2,817)
Unrecognized tax benefit ending balance	16,333	16,972	17,181
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 and penalties.	(100)	(200)	$ (300)
Amount of accrued interest charges and penalties.	$ 100	$ 200

Employee Benefit Plans (Details) - USD ($) $ in Millions	12 Months Ended
Employee Benefit Plans (Details) - USD ($) $ in Millions	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
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	$ 1.0	$ 1.0	$ 0.8
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

12 Months Ended

Dec. 27, 2014

Dec. 28, 2013

Dec. 29, 2012

Number of Reportable Segments

Number of Operating Segments

100.00%

North America

28.10%

27.20%

15.40%

South Korea

19.60%

19.80%

32.80%

Taiwan

18.40%

27.90%

20.70%

Asia-Pacific

^[1]

12.90%

9.20%

12.70%

Europe

11.40%

8.60%

6.50%

Japan

9.60%

7.30%

11.90%

[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. 27, 2014

Sep. 27, 2014

Jun. 28, 2014

Mar. 29, 2014

Dec. 28, 2013

Sep. 28, 2013

Jun. 29, 2013

^[1]

Mar. 30, 2013

Dec. 27, 2014

Dec. 28, 2013

Dec. 29, 2012

$ 71,285

$ 73,934

$ 67,352

$ 55,959

$ 48,546

$ 67,634

$ 62,733

$ 52,620

$ 268,530

$ 231,533

$ 178,535

SoC

142,360

115,597

46,586

DRAM

110,800

92,603

102,499

Flash

$ 15,370

$ 23,333

$ 29,450

[1]	In the second quarter of fiscal 2013, we recorded a $0.3 million loss on the sale of our subsidiary, TMMC. See Note 7, Fair Value, to the Notes to Consolidated Financial Statements for further details relating to the terms of the sale.

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

Dec. 27, 2014

Dec. 28, 2013

$ 94,918

$ 123,391

North America

91,862

119,706

South Korea

1,578

1,676

Asia-Pacific

^[1]

935

1,206

Japan

358

517

Singapore

172

262

Europe

$ 13

$ 24

[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)	12 Months Ended
	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Revenue, Major Customer [Line Items]
Percentage of concentration of risk	100.00%	100.00%	100.00%
Customer Concentration Risk \| Sales Revenue, Goods, Net
Revenue, Major Customer [Line Items]
Percentage of concentration of risk	51.60%	45.90%	55.10%
Customer Concentration Risk \| Sales Revenue, Goods, Net \| Intel
Revenue, Major Customer [Line Items]
Percentage of concentration of risk	19.70%	17.70%
Customer Concentration Risk \| Sales Revenue, Goods, Net \| SK Hynix
Revenue, Major Customer [Line Items]
Percentage of concentration of risk	16.90%	16.50%	29.40%
Customer Concentration Risk \| Sales Revenue, Goods, Net \| Micron
Revenue, Major Customer [Line Items]
Percentage of concentration of risk	15.00%	11.70%	13.30%
Customer Concentration Risk \| Sales Revenue, Goods, Net \| Samsung
Revenue, Major Customer [Line Items]
Percentage of concentration of risk			12.40%

Selected Quarterly Financial Data (Unaudited) (Details) - USD ($)
$ / shares in Units, shares in Thousands, $ in Thousands

3 Months Ended

12 Months Ended

Dec. 27, 2014

Sep. 27, 2014

Jun. 28, 2014

Mar. 29, 2014

Dec. 28, 2013

Sep. 28, 2013

Jun. 29, 2013

Mar. 30, 2013

Dec. 27, 2014

Dec. 28, 2013

Dec. 29, 2012

Quarterly Financial Data [Abstract]

Selling, general and administrative

$ 71,285

$ 73,934

$ 67,352

$ 55,959

$ 48,546

$ 67,634

$ 62,733

^[1]

$ 52,620

$ 268,530

$ 231,533

$ 178,535

Cost of revenues

50,337

49,792

47,328

43,634

44,288

55,088

46,328

^[1]

43,545

191,091

189,249

153,204

Gross profit

20,948

24,142

20,024

12,325

4,258

12,546

16,405

9,075

77,439

42,284

25,331

Research and development

10,706

11,198

11,074

9,747

9,994

10,301

10,915

^[1]

10,929

42,725

42,139

40,130

12,631

13,309

13,191

12,254

12,160

12,952

13,487

^[1]

14,618

51,385

53,217

49,231

Loss on sale of subsidiary

300

584

1,997

443

143

^[1]

3,980

2,668

4,658

2,917