Onto Innovation (ONTO) 10-K 24 Feb 16 2015 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 26, 2015	Feb. 12, 2016	Jun. 27, 2015
Document And Entity Information [Abstract]
Entity Registrant Name	NANOMETRICS INC
Entity Central Index Key	704,532
Document Type	10-K
Document Period End Date	Dec. 26, 2015
Amendment Flag	false
Document Fiscal Year Focus	2,015
Document Fiscal Period Focus	FY
Trading Symbol	NANO
Current Fiscal Year End Date	--12-26
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		24,297,590
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 400.6

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 26, 2015	Dec. 27, 2014
Current assets:
Cash and cash equivalents	$ 38,154	$ 34,676
Marketable securities	44,931	49,286
Accounts receivable, net of allowances of $150 and $253, respectively	37,832	26,121
Inventories	47,749	35,105
Inventories-delivered systems	2,856	1,912
Prepaid expenses and other	6,592	9,289
Deferred income tax assets		1,457
Total current assets	178,114	157,846
Property, plant and equipment, net	44,493	49,633
Goodwill	9,415	10,494
Intangible assets, net	1,867	4,294
Deferred income tax assets	1,118	410
Other assets	533	559
Total assets	235,540	223,236
Current liabilities:
Accounts payable	11,675	10,199
Accrued payroll and related expenses	10,097	8,700
Deferred revenue	12,790	10,021
Other current liabilities	8,878	8,265
Income taxes payable	1,771	1,017
Total current liabilities	45,211	38,202
Deferred revenue	827	2,591
Income taxes payable	775	701
Deferred tax liability	521	926
Other long-term liabilities	878	1,279
Total liabilities	$ 48,212	$ 43,699
Commitments and contingencies (Note 11)
Stockholders’ equity:
Preferred stock, $0.001 par value; 3,000,000 shares authorized; no shares issued or outstanding	$ 0	$ 0
Common stock, $0.001 par value, 47,000,000 shares authorized: 24,224,286 and 23,813,729, respectively, issued and outstanding	24	24
Additional paid-in capital	258,715	251,396
Accumulated deficit	(66,209)	(69,114)
Accumulated other comprehensive income	(5,202)	(2,769)
Total stockholders’ equity	187,328	179,537
Total liabilities and stockholders’ equity	$ 235,540	$ 223,236

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 26, 2015	Dec. 27, 2014
Statement Of Financial Position [Abstract]
Allowances for doubtful accounts	$ 150	$ 253
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized	3,000,000	3,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	47,000,000	47,000,000
Common stock, shares issued	24,224,286	23,813,729
Common stock, shares outstanding	24,224,286	23,813,729

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Net revenues:
Products	$ 146,945	$ 133,589	$ 107,402
Service	40,422	32,854	36,905
Total net revenues	187,367	166,443	144,307
Costs of net revenues:
Cost of products	76,224	68,812	59,509
Cost of service	19,450	19,086	19,489
Amortization of intangible assets	2,026	2,723	2,633
Total costs of net revenues	97,700	90,621	81,631
Gross profit	89,667	75,822	62,676
Operating expenses:
Research and development	32,701	33,776	32,714
Selling	28,055	27,033	27,129
General and administrative	22,444	23,980	22,101
Amortization of intangible assets	114	420	701
Restructuring charge	1,380	2,266	1,740
Total operating expenses	84,694	87,475	84,385
Income (loss) from operations	4,973	(11,653)	(21,709)
Other (income) expense:
Interest income	71	47	62
Interest expense	(289)	(389)	(651)
Other income (expense), net	813	374	(1,267)
Total other income (expense), net	595	32	(1,856)
Income (loss) before income taxes	5,568	(11,621)	(23,565)
Provision for (benefit from) income taxes	2,663	19,497	(9,419)
Net income (loss)	$ 2,905	$ (31,118)	$ (14,146)
Net income (loss) per share:
Basic (in dollars per share)	$ 0.12	$ (1.30)	$ (0.61)
Diluted (in dollars per share)	$ 0.12	$ (1.30)	$ (0.61)
Weighted average shares used in per share calculation:
Basic (in shares)	24,059	23,958	23,290
Diluted (in shares)	24,375	23,958	23,290

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Statement Of Income And Comprehensive Income [Abstract]
Net income (loss)	$ 2,905	$ (31,118)	$ (14,146)
Other comprehensive income (loss):
Change in foreign currency translation adjustment	(2,344)	(3,239)	(818)
Employee benefit plan adjustment	(76)	(106)	151
Net change on unrealized gains (losses) on available-for-sale investments	(13)	(36)	7
Other comprehensive loss	(2,433)	(3,381)	(660)
Comprehensive income (loss)	$ 472	$ (34,499)	$ (14,806)

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Deficit	Accumulated Other Comprehensive Income
Beginning Balance Value at Dec. 29, 2012	$ 215,771	$ 23	$ 238,326	$ (23,850)	$ 1,272
Beginning Balance Shares at Dec. 29, 2012		23,250,429
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(14,146)			(14,146)
Employee benefit plan adjustment	151				151
Foreign currency translation adjustments	(818)				(818)
Unrealized gain (loss) on investments, net of tax	7				7
Issuance of common stock under stock-based compensation plans	3,734	$ 1	3,733
Issuance of common stock under stock-based compensation plans, Shares		619,617
Stock-based compensation expense	7,674		7,674
Repurchases and retirement of common stock	$ (5,000)		(5,000)
Repurchases and retirement of common stock, Shares	(332,771)	(332,771)
Ending Balance Value at Dec. 28, 2013	$ 207,373	$ 24	244,733	(37,996)	612
Ending Balance Shares at Dec. 28, 2013		23,537,275
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(31,118)			(31,118)
Employee benefit plan adjustment	(106)				(106)
Foreign currency translation adjustments	(3,239)				(3,239)
Unrealized gain (loss) on investments, net of tax	(36)				(36)
Issuance of common stock under stock-based compensation plans	5,255		5,255
Issuance of common stock under stock-based compensation plans, Shares		639,087
Stock-based compensation expense	6,752		6,752
Repurchases and retirement of common stock	$ (5,344)		(5,344)
Repurchases and retirement of common stock, Shares	(362,633)	(362,633)
Ending Balance Value at Dec. 27, 2014	$ 179,537	$ 24	251,396	(69,114)	(2,769)
Ending Balance Shares at Dec. 27, 2014	23,813,729	23,813,729
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	$ 2,905			2,905
Employee benefit plan adjustment	(76)				(76)
Foreign currency translation adjustments	(2,344)				(2,344)
Unrealized gain (loss) on investments, net of tax	(13)				(13)
Issuance of common stock under stock-based compensation plans	2,792		2,792
Issuance of common stock under stock-based compensation plans, Shares		521,607
Stock-based compensation expense	6,248		6,248
Repurchases and retirement of common stock	$ (1,721)		(1,721)
Repurchases and retirement of common stock, Shares	(111,050)	(111,050)
Ending Balance Value at Dec. 26, 2015	$ 187,328	$ 24	$ 258,715	$ (66,209)	$ (5,202)
Ending Balance Shares at Dec. 26, 2015	24,224,286	24,224,286

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Cash flows from operating activities:
Net income (loss)	$ 2,905	$ (31,118)	$ (14,146)
Reconciliation of net income (loss) to net cash provided by (used in) operating activities:
Depreciation and amortization	9,075	9,767	8,787
Stock-based compensation	6,248	6,752	7,674
Excess tax benefit from equity awards	0	0	53
Disposal of fixed assets	1,121	249	177
Inventory write-down	2,645	2,897	7,579
Deferred income taxes	345	17,915	(6,889)
Changes in fair value of contingent payments to Zygo Corporation	(56)	201	1,325
Changes in assets and liabilities:
Accounts receivable	(12,610)	3,861	(10,376)
Inventories	(16,431)	(7,173)	(7,024)
Inventories-delivered systems	(943)	4,988	(4,627)
Prepaid expenses and other	3,271	2,303	(1,855)
Accounts payable, accrued and other liabilities	4,167	1,790	4,840
Deferred revenue	1,006	(12,855)	12,717
Income taxes payable	828	(212)	(666)
Net cash provided by (used in) operating activities	1,571	(635)	(2,431)
Cash flows from investing activities:
Sales of marketable securities	3,383	0	0
Maturities of marketable securities	41,863	38,839	47,089
Purchases of marketable securities	(41,449)	(41,100)	(49,182)
Purchases of property, plant and equipment	(1,846)	(5,792)	(5,689)
Net cash provided by (used in) investing activities	1,951	(8,053)	(7,782)
Cash flows from financing activities:
Payments to Zygo Corporation related to acquisition	(851)	(587)	(1,004)
Repayments of debt obligations	0	0	(5,224)
Proceeds from sale of shares under employee stock option plans and purchase plan	3,974	5,958	4,967
Excess tax benefit from equity awards	0	0	(53)
Taxes paid on net issuance of stock awards	(1,182)	(702)	(1,181)
Repurchases of common stock	(1,721)	(5,344)	(5,000)
Net cash provided by (used in) financing activities	220	(675)	(7,495)
Effect of exchange rate changes on cash and cash equivalents	(264)	(726)	(442)
Net increase (decrease) in cash and cash equivalents	3,478	(10,089)	(18,150)
Cash and cash equivalents, beginning of period	34,676	44,765	62,915
Cash and cash equivalents, end of period	38,154	34,676	44,765
Supplemental disclosure of cash flow information:
Cash paid for interest	0	0	232
Cash paid (refund) for income taxes, net	(826)	861	313
Supplemental disclosure of non-cash investing activities:
Transfer of inventory to property, plant and equipment, net	$ 1,469	$ 3,275	$ 3,145

Nature of Business, Basis of Pr

Nature of Business, Basis of Presentation and Significant Accounting Policies	12 Months Ended
	Dec. 26, 2015
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Nature of Business, Basis of Presentation and Significant Accounting Policies	Note 1. Nature of Business, Basis of Presentation and Significant Accounting Policies Description of Business – Nanometrics Incorporated (“Nanometrics” or the “Company”) and its wholly-owned subsidiaries design, manufacture, market, sell and support optical critical dimension ("OCD"), thin film and overlay dimension metrology and inspection systems used primarily in the manufacturing of semiconductors, solar photovoltaics (“solar PV”) and high-brightness LEDs (“HB-LED”), as well as by customers in the silicon wafer and data storage industries. Nanometrics' metrology systems precisely measure a wide range of film types deposited on substrates during manufacturing to control manufacturing processes and increase production yields in the fabrication of integrated circuits. The Company’s OCD technology is a patented critical dimension measurement technology that is used to precisely determine the dimensions on the semiconductor wafer that directly control the resulting performance of the integrated circuit devices. The thin film metrology systems use a broad spectrum of wavelengths, high-sensitivity optics, proprietary software, and patented technology to measure the thickness and uniformity of films deposited on silicon and other substrates as well as their chemical composition. The overlay metrology systems are used to measure the overlay accuracy of successive layers of semiconductor patterns on wafers in the photolithography process. Nanometrics' inspection systems are used to find defects on patterned and unpatterned wafers at nearly every stage of the semiconductor production flow. The corporate headquarters of Nanometrics is located in Milpitas, California. Basis of Presentation – The consolidated financial statements include Nanometrics Incorporated and its wholly-owned subsidiaries. All significant intercompany accounts and transactions have been eliminated in consolidation. Fiscal Year – On October 17, 2014, the Board of Directors of the Company approved a change in the Company's fiscal year from a fiscal year ending on the Saturday closest to December 31 to a 52/53 week fiscal year ending on the last Saturday of the calendar year. All periods presented consisted of a 52-week year. Use of Estimates – The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America ("U.S. GAAP") requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reported period. Actual results could differ materially from those estimates. Estimates are used for, but not limited to, revenue recognition, the provision for doubtful accounts, the provision for excess, obsolete, or slow moving inventories, valuation of intangible and long-lived assets, warranty accruals, income taxes, valuation of stock-based compensation, and contingencies. Foreign Currency Translation – The assets and liabilities of foreign subsidiaries are translated from their respective local functional currencies at exchange rates in effect at the balance sheet date and income and expense accounts are translated at average exchange rates during the reporting period. Resulting translation adjustments are reflected in “Accumulated other comprehensive income,” a component of stockholders’ equity. Foreign currency transaction gains and losses, as well as remeasurement of assets and liabilities denominated in a currency other than the functional currency are reflected in “Other income (expense)” in the consolidated statements of operations in the period incurred, and consists of a $0.5 million gain, a $0.1 million gain and a $0.7 million loss for the years ended December 26, 2015, December 27, 2014, and December 28, 2013, respectively. Revenue Recognition – The Company derives revenue from the sale of process control metrology systems (“product revenue”) as well as spare part sales, billable service, service contracts, and upgrades (together “service revenue”). Upgrades are a group of parts and/or software that change the existing configuration of a product and are included in service revenue. They are distinguished from product revenue, which consists of complete, advanced process control metrology and inspection systems (the “system(s)”). Nanometrics' systems consist of hardware and software components that function together to deliver the essential functionality of the system. Arrangements for sales of systems often include defined customer-specified acceptance criteria. In summary, the Company recognizes revenue when persuasive evidence of an arrangement exists, delivery has occurred or services have been rendered, the seller's price is fixed or determinable, and collectability is reasonably assured. For product sales to existing customers, revenue recognition occurs at the time title and risk of loss transfer to the customer, which usually occurs upon shipment from the Company's manufacturing location, if it can be reliably demonstrated that the product has successfully met the defined customer specified acceptance criteria and all other recognition criteria have been met. For initial sales where the product has not previously met the defined customer specified acceptance criteria, product revenues are recognized upon the earlier of receipt of written customer acceptance or expiration of the contractual acceptance period. In Japan, where contractual terms with the customer specify risk of loss and title transfers upon customer acceptance, revenue is recognized upon receipt of written customer acceptance, provided that all other recognition criteria have been met. The Company warrants its products against defects in manufacturing. Upon recognition of product revenue, a liability is recorded for anticipated warranty costs. On occasion, customers request a warranty period longer than the Company's standard warranty. In those instances where extended warranty services are separately quoted to the customer, the associated revenue is deferred and recognized as service revenue ratably over the term of the contract. The portion of service contracts and extended warranty services agreements that are uncompleted at the end of any reporting period are included in deferred revenue. As part of its customer services, the Company sells software that is considered to be an upgrade to a customer's existing systems. These standalone software upgrades are not essential to the tangible product's functionality and are accounted for under software revenue recognition rules which require vendor specific objective evidence ("VSOE") of fair value to allocate revenue in a multiple element arrangement. Revenue from upgrades is recognized when the upgrades are delivered to the customer, provided that all other recognition criteria have been met. Revenue related to spare parts is recognized upon shipment. Revenue related to billable services is recognized as the services are performed. Service contracts may be purchased by the customer during or after the warranty period and revenue is recognized ratably over the service contract period. Frequently, the Company delivers products and various services in a single transaction. The Company's deliverables consist of tools, installation, upgrades, billable services, spare parts, and service contracts. The Company's typical multi-element arrangements include a sale of one or multiple tools that include installation and standard warranty. Other arrangements consist of a sale of tools bundled with service elements or delivery of different types of services. The Company's tools, upgrades, and spare parts are generally delivered to customers within a period of up to six months from order date. Installation is usually performed soon after delivery of the tool. The portion of revenue associated with installation is deferred based on relative selling price and that revenue is recognized upon completion of the installation. Billable services are billed on a time and materials basis and performed as requested by customers. Under service contract arrangements, services are provided as needed over the fixed arrangement term, which terms can be up to twelve months. The Company does not grant its customers a general right of return or any refund terms and imposes a penalty on orders cancelled prior to the scheduled shipment date. The Company regularly evaluates its revenue arrangements to identify deliverables and to determine whether these deliverables are separable into multiple units of accounting. In accordance with revenue recognition guidance, the Company allocates the arrangement consideration among the deliverables based on relative selling prices. The Company has established VSOE for some of its products and services when a substantial majority of selling prices falls within a narrow range when sold separately. For deliverables with no established VSOE, the Company uses best estimate of selling price to determine standalone selling price for such deliverable. The Company does not use third party evidence to determine standalone selling price since this information is not widely available in the market as the Company's products contain a significant element of proprietary technology and the solutions offered differ substantially from competitors. The Company has established a process for developing estimated selling prices, which incorporates historical selling prices, the effect of market conditions, gross margin objectives, pricing practices, as well as entity-specific factors. The Company monitors and evaluates estimated selling price on a regular basis to ensure that changes in circumstances are accounted for in a timely manner. When certain elements in multiple-element arrangements are not delivered or accepted at the end of a reporting period, the relative selling prices of undelivered elements are deferred until these elements are delivered and/or accepted. If deliverables cannot be accounted for as separate units of accounting, the entire arrangement is accounted for as a single unit of accounting and revenue is deferred until all elements are delivered and all revenue recognition requirements are met. Business Combinations - The Company allocates the purchase price of acquired companies to the tangible and intangible assets acquired and liabilities assumed based upon their estimated fair values at the acquisition date. The purchase price allocation process requires management to make significant estimates and assumptions, especially at the acquisition date with respect to intangible assets and inventory acquired. While best estimates and assumptions as a part of the purchase price allocation process are used to accurately value assets acquired and liabilities assumed at the acquisition date, estimates are inherently uncertain and subject to refinement. As a result, during the measurement period, which may be up to one year from the acquisition date, the Company may record adjustments to the assets acquired and liabilities assumed, with the corresponding offset to goodwill. Upon the conclusion of the measurement period or final determination of the values of assets acquired or liabilities assumed, whichever comes first, any subsequent adjustments are recorded in the consolidated statements of operations. The Company estimates the fair value of inventory acquired by utilizing the net realizable value method which is based on the estimated sales price of the product less appropriate costs to complete and selling costs. Examples of critical estimates in valuing certain intangible assets that were acquired or may be acquired in the future include but are not limited to: · future expected cash flows from sales of products, services and acquired developed technologies and patents; · expected costs to develop the in-process research and development into commercially viable products and estimated cash flows from the projects when completed; · the acquired company's customer relationships, as well as assumptions about the estimated useful lives of the relationships; and · discount rates. Unanticipated events and circumstances may occur that may affect the accuracy or validity of assumptions, estimates or actual results associated with business combinations. Cash, Cash Equivalents and Marketable Securities – The Company considers all highly liquid investments with original maturities of three months or less, when purchased, to be cash equivalents. Marketable securities are classified as “available-for-sale” and are reported at fair value with unrealized gains and losses reported in stockholders' equity as a component of other comprehensive income. The cost of securities sold is based on the specific identification method. The Company classifies its investments as current based on the nature of the investment and their availability for use in current operations. The Company reviews its investment portfolio quarterly to determine if any securities may be other-than-temporarily impaired due to increased credit risk, changes in industry or sector of a certain instrument or ratings downgrades. Fair Value of Financial Instruments – Financial instruments include cash and cash equivalents, accounts receivable and accounts payable. Cash equivalents are stated at fair market value based on quoted market prices. The carrying values of accounts receivable and accounts payable approximate their fair values because of the short-term maturity of these financial instruments. Derivatives – The Company enters into foreign currency forward exchange contracts to protect against currency exchange risks associated with existing assets and liabilities. A foreign currency forward exchange contract acts as a hedge by increasing in value when underlying assets decrease in value or underlying liabilities increase in value due to changes in foreign exchange rates. Conversely, a foreign currency forward exchange contract decreases in value when underlying assets increase in value or underlying liabilities decrease in value due to changes in foreign exchange rates. These forward contracts are not designated as accounting hedges, so the unrealized gains and losses are recognized in other income, net, in advance of the actual foreign currency cash flows with the fair value of these forward contracts being recorded as accrued liabilities or other current assets. The Company does not use forward contracts for trading purposes. Allowance for Doubtful Accounts – The Company maintains allowances for estimated losses resulting from the inability of its customers to make required payments. Credit limits are established through a process of reviewing the financial history and stability of its customers. Where appropriate and available, the Company obtains credit rating reports and financial statements of customers when determining or modifying their credit limits. The Company regularly evaluates the collectability of its trade receivable balances based on a combination of factors such as the length of time the receivables are past due, customary payment practices in the respective geographies and historical collection experience with customers. The Company believes that its allowance for doubtful accounts adequately reflects the risk associated with its receivables. If the financial conditions of a customer were to deteriorate, resulting in their inability to make payments, the Company may need to record additional allowances, which would result in additional general and administrative expenses being recorded for the period in which such determination was made. Inventories – Inventories are stated at the lower of cost, which approximates actual cost on a first-in, first-out basis, or market. The Company is exposed to a number of economic and industry factors that could result in portions of inventory becoming either obsolete or in excess of anticipated usage, or saleable only for amounts that are less than their carrying amounts. These factors include, but are not limited to, technological changes in the market, the Company’s ability to meet changing customer requirements, competitive pressures in products and prices, and the availability of key components from suppliers. The Company has established inventory reserves when conditions exist that suggest that inventory may be in excess of anticipated demand or is obsolete based upon assumptions about future demand for the Company’s products and market conditions. Once a reserve has been established, it is maintained until the part to which it relates is sold or is otherwise disposed of. The Company regularly evaluates its ability to realize the value of inventory based on a combination of factors including the following: historical usage rates, forecasted sales of usage, product end-of-life dates, estimated current and future market values and new product introductions. For demonstration inventory, the Company also considers the age of the inventory and potential cost to refurbish the inventory prior to sale. Demonstration inventory is amortized over its useful life and the amortization expense is included in total inventory write down on the statements of cash flows. When recorded, reserves are intended to reduce the carrying value of the Company’s inventory to its net realizable value. If actual demand for the Company’s products deteriorates, or market conditions are less favorable than those that the Company projects, additional reserves may be required. Inventories – delivered systems – The Company reflects the cost of systems that were invoiced upon shipment but deferred for revenue recognition purposes separate from its inventory held for sale as “Inventories – delivered systems.” Property, Plant and Equipment – Property, plant and equipment are stated at cost. Depreciation and amortization is computed using the straight–line method over the following estimated useful lives of the assets: Building and Improvements 5-40 years Machinery and equipment 3-10 years Furniture and fixtures 3-10 years Software 3-7 years Goodwill and Intangible Assets – Goodwill is initially recorded when the purchase price paid for an acquisition exceeds the estimated fair value of the net identified tangible and intangible assets acquired. Intangible assets with finite lives are amortized over their respective useful lives on a straight-line basis and are also evaluated annually for impairment or whenever events or circumstances occur which indicate that those assets might be impaired. Goodwill and indefinite lived assets are not amortized but tested annually for impairment. The Company’s impairment review process is completed during the fourth quarter of each year or whenever events, or circumstances occur which indicate that an impairment may have occurred. The Company assesses qualitative factors to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying value. If, after assessing the qualitative factors, the Company determines that it is not likely that the fair value of a reporting unit is less than its carrying value, then performing the two-step impairment test is unnecessary. However, if the Company concludes otherwise, then it is required to perform the first step of the two-step goodwill impairment test. The first step requires a comparison of the fair value of Nanometrics’ reporting unit to its net book value. If the fair value of the reporting unit is greater than its carrying value, then no impairment is deemed to have occurred. If the fair value is less, then the second step must be performed to determine the amount, if any, of actual impairment. Amortization of intangible assets with finite lives is computed using the straight-line method over the following estimated useful lives of the assets: Developed technology 5-10 years Customer relationships 2-10 years Brand name 5-10 years Patented technology 7-10 years Trademark 5 years Long-Lived Assets – The Company evaluates its long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. When the sum of the undiscounted future net cash flows expected to result from the use of the asset and its eventual disposition is less than its carrying amount, impairment may exist. To determine the amount of impairment, the Company compares the fair value of the asset to its carrying value. If the carrying value of the asset exceeds its fair value, an impairment loss equal to the difference is recognized. See Note 7, "Goodwill and Intangible Assets" for further details. Income Tax Assets and Liabilities – The Company accounts for income taxes such that deferred tax assets and liabilities must be recognized using enacted tax rates for the effect of temporary differences between the book and tax accounting for assets and liabilities. Also, deferred tax assets are reduced by a valuation allowance to the extent that management cannot conclude that it is more likely than not that a portion of the deferred tax asset will be realized in the future. The Company evaluates the deferred tax assets on a continuous basis throughout the year to determine whether or not a valuation allowance is appropriate. Factors used in this determination include future expected income and the underlying asset or liability which generated the temporary tax difference. The income tax provision is primarily impacted by federal statutory rates, state and foreign income taxes and changes in the valuation allowance. Product Warranties – The Company sells the majority of its products with a twelve months repair or replacement warranty from the date of acceptance, which generally represents the date of shipment. The Company provides an accrual for estimated future warranty costs based upon the historical relationship of warranty costs to the cost of products sold. The estimated future warranty obligations related to product sales are reported in the period in which the related revenue is recognized. The estimated future warranty obligations are affected by the warranty periods, sales volumes, product failure rates, material usage and labor and replacement costs incurred in correcting a product failure. If actual product failure rates, material usage, labor or replacement costs differ from the Company’s estimates, revisions to the estimated warranty obligations would be required. For new product introductions where limited or no historical information exists, the Company may use warranty information from other previous product introductions to guide it in estimating the warranty accrual. The warranty accrual represents the best estimate of the amount necessary to settle future and existing claims on products sold as of the balance sheet date. The Company periodically assesses the adequacy of its recorded warranty reserve and adjusts the amounts in accordance with changes in these factors. Shipping and Handling Costs – Shipping and handling costs are included as a component of cost of net revenues. Advertising Costs – The Company expenses advertising costs as incurred. Advertising costs were $0.3 million in 2015, $0.2 million in 2014, and $0.2 million in 2013. Defined Employee Benefit Plans – The Company maintains a defined benefit pension plan in Taiwan for which current service costs are charged to operations as they accrue based on services rendered by employees during the year. Pension benefit obligations are determined by using management’s actuarial assumptions, including discount rates, assumed asset rates of return, compensation increases and employee turnover rates. Net Income (Loss) Per Share - Basic net income (loss) per share excludes dilution and is computed by dividing net income (loss) by the number of weighted average common shares outstanding for the period. Diluted net income (loss) per share reflects the potential dilution from outstanding dilutive stock options (using the treasury stock method) restricted stock units subject to vesting and shares issuable under the employee stock purchase plan. In applying the treasury stock method, 0.3 million stock option shares for fiscal year 2015 were included because their effects were anti-dilutive. While these stock option shares are currently anti-dilutive, they could be dilutive in the future. During both fiscal 2014 and 2013, the Company incurred a net loss, therefore, diluted net loss per share excludes 0.4 million shares that were anti-dilutive. Certain Significant Risks and Uncertainties – Financial instruments that potentially subject us to a concentration of credit risk consist of cash, cash equivalents, marketable securities, and accounts receivable. The Company's cash and cash equivalents are primarily invested in deposit accounts and money market accounts with large financial institutions. At times, these deposits and securities may exceed federally insured limits; however, the Company has not experienced any losses on such accounts. The Company invests its cash not required for use in operations in high credit quality securities based on the Company's investment policy. The Company's investment policy provides guidelines and limits regarding credit quality, investment concentration, investment type, and maturity that the Company believes will provide liquidity while reducing risk of loss of capital. Investments are of a short-term nature and include investments in commercial paper, corporate debt securities, U.S. Treasury, U.S. Government, and U.S. Agency debt. The Company sells its products primarily to end users in the United States, Asia and Europe and, generally, does not require its customers to provide collateral or other security to support accounts receivable. Management performs ongoing credit evaluations of its customers’ financial condition and maintains an allowance for estimated potential bad debt losses. The Company’s customer base is highly concentrated and historically, a relatively small number of customers have accounted for a significant portion of its revenues. Aggregate revenue from the Company's top five largest customers in 2015, 2014 and 2013 consisted of 69%, 72% and 71%, respectively, of its total net revenues. The Company participates in a dynamic high technology industry and believes that changes in any of the following areas could have a material adverse effect on its future financial position, results of operations or cash flows: advances and trends in new technologies and industry standards; competitive pressures in the form of new products or price reductions on current products; changes in product mix; changes in the overall demand for products offered; changes in third-party manufacturers; changes in key suppliers; changes in certain strategic relationships or customer relationships; litigation or claims against the Company based on intellectual property, patent, product, regulatory or other factors; fluctuations in foreign currency exchange rates; risk associated with changes in domestic and international economic and/or political regulations; availability of necessary components or sub-assemblies; disruption of manufacturing facilities; and its ability to attract and retain employees necessary to support its growth. Certain components and sub-assemblies used in the Company’s products are purchased from a sole supplier or a limited group of suppliers. In particular, the Company currently purchases its spectroscopic ellipsometer and robotics used in its advanced measurement systems from a sole supplier or a limited group of suppliers located in the United States. Any shortage or interruption in the supply of any of the components or sub-assemblies used in its products or its inability to procure these components or sub-assemblies from alternate sources on acceptable terms could have a material adverse effect on its business, financial condition and results of operations.

Recent Accounting Pronouncement

Recent Accounting Pronouncements	12 Months Ended
	Dec. 26, 2015
Accounting Changes And Error Corrections [Abstract]
Recent Accounting Pronouncements	Note 2. Recent Accounting Pronouncements Recently Issued Accounting Pronouncements In November 2015, the Financial Accounting Standards Board (“FASB”) issued an accounting standards update that amends existing guidance to require that deferred income tax liabilities and assets be classified as noncurrent in a classified balance sheet, and eliminates the prior guidance which required an entity to separate deferred tax liabilities and assets into a current amount and a noncurrent amount in a classified balance sheet. As permitted, the Company early-adopted this standard in fiscal year 2015 on a prospective basis. No prior periods were retrospectively adjusted. In July 2015, the FASB issued an accounting standards update which simplifies the measurement of inventory by requiring inventory to be measured at the lower of cost and net realizable value. The new standard applies only to inventories for which cost is determined by methods other than last-in-first-out and the retail inventory method. It is effective for public companies for annual reporting periods beginning after December 15, 2016, and interim periods within those fiscal years. Early adoption is permitted. The Company is currently evaluating the impact of this standard to determine if this guidance will have a material impact on its consolidated financial statements. In January 2015, the FASB issued an accounting standard update which simplifies income statement classification by removing the concept of extraordinary items from U.S. GAAP. As a result, items that are both unusual and infrequent will no longer be separately reported net of tax after continuing operations. The new standard is effective for the fiscal years, and interim periods within those fiscal years, beginning after December 15, 2015. Early adoption is permitted. The Company does not expect any impact on the adoption of this standard on its consolidated financial statements. In August 2014, the FASB issued an accounting standard update related to the disclosures around going concern. The new standard provides guidance around management’s responsibility to evaluate whether there are conditions or events that raise substantial doubt about the entity’s ability to continue as a going concern within one year after the date that the financial statements are issued. The new standard is effective for the annual periods and interim periods within those annual periods beginning after December 15, 2016. Early application is permitted. The Company does not expect any impact on the adoption of this standard on its consolidated financial statements. In May 2014, the FASB issued an accounting standards update which requires an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to customers. The standard will replace most existing revenue recognition guidance in U.S. GAAP when it becomes effective. In July 2015, the FASB deferred for one year the effective date of the new revenue standard, but early adoption will be permitted. The new standard will be effective for the Company on January 1, 2018. The standard permits the use of either the retrospective or cumulative effect transition method. The Company is evaluating the effect that the standard will have on its consolidated financial statements and related disclosures. The Company has not yet selected a transition method nor has it determined the effect of the standard on its ongoing financial reporting. In July 2013, the FASB issued an accounting standards update which provides that a liability related to an unrecognized tax benefit would be offset against a deferred tax asset for a net operating loss carryforward, a similar tax loss or a tax credit carryforward if such settlement is required or expected in the event the uncertain tax position is disallowed. In situations in which a net operating loss carryforward, a similar tax loss or a tax credit carryforward is not available at the reporting date under the tax law of the jurisdiction or the tax law of the jurisdiction does not require, and the entity does not intend to use, the deferred tax asset for such purpose, the unrecognized tax benefit will be presented in the financial statements as a liability and will not be combined with deferred tax assets. The amendments should be applied prospectively to all unrecognized tax benefits that exist at the effective date. Retrospective application is permitted. The new standard is effective for fiscal years and interim periods beginning after December 15, 2013. The Company adopted this standard during the three months ended March 29, 2014, resulting in a one-time tax benefit of $0.3 million, a reduction in deferred tax assets of $0.3 million, and a reduction in long-term income taxes payable of $0.6 million.

Fair Value Measurements and Dis

Fair Value Measurements and Disclosures	12 Months Ended
	Dec. 26, 2015
Fair Value Disclosures [Abstract]
Fair Value Measurements and Disclosures	Note 3. Fair Value Measurements and Disclosures The Company determines the fair values of its financial instruments based on the fair value hierarchy established in FASB Accounting Standards Codification ("ASC") 820, Fair Value Measurement Level 1 — Quoted prices in active markets for identical assets or liabilities. Level 2 — Inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices for similar assets and liabilities in active markets or inputs that are observable for the asset or liability, either directly or indirectly through market corroboration, for substantially the full term of the financial instrument. Level 3 — Unobservable inputs that are supported by little or no market activity and are significant to the fair value of the assets or liabilities. Such unobservable inputs include an estimated discount rate used in the Company's discounted present value analysis of future cash flows, which reflects the Company's estimate of debt with similar terms in the current credit markets. As there is currently minimal activity in such markets, the actual rate could be materially different. Fair value is defined as the price that would be received upon the sale of an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. The standard assumes that the transaction to sell the asset or transfer the liability occurs in the principal or most advantageous market for the asset or liability and establishes that the fair value of an asset or liability shall be determined based on the assumptions that market participants would use in pricing the asset or liability. The following tables present the Company’s assets and liabilities measured at estimated fair value on a recurring basis, excluding accrued interest components, categorized in accordance with the fair value hierarchy (in thousands), as of the following dates: December 26, 2015 December 27, 2014 Fair Value Measurements Using Input Types Fair Value Measurements Using Input Types Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total Assets: Cash equivalents: Money market funds $ 590 $ — $ — $ 590 $ 610 $ — $ — $ 610 Commercial paper and corporate debt securities — 4,568 — 4,568 — — — — Total cash equivalents $ 590 $ 4,568 $ — $ 5,158 $ 610 $ — $ — $ 610 Marketable securities: U.S. Treasury, U.S. Government and U.S. Government agency debt securities 4,401 20,164 — 24,565 2,497 20,537 — 23,034 Commercial paper, municipal securities and corporate debt securities — 20,366 — 20,366 — 26,252 — 26,252 Total marketable securities $ 4,401 $ 40,530 $ — $ 44,931 $ 2,497 $ 46,789 $ — $ 49,286 Total (1) $ 4,991 $ 45,098 $ — $ 50,089 $ 3,107 $ 46,789 $ — $ 49,896 Liabilities: Contingent consideration payable $ — $ — $ 1,490 $ 1,490 $ — $ — $ 2,397 $ 2,397 (1) Excludes $33.0 million and $34.1 million held in operating accounts as of December 26, 2015 and December 27, 2014, respectively. The fair values of the marketable securities that are classified as Level 1 in the table above were derived from quoted market prices for identical assets or liabilities in active markets that the Company has the ability to access. The fair value of marketable securities that are classified as Level 2 in the table above were derived from non-binding market consensus prices that were corroborated by observable market data, quoted market prices for similar instruments, or pricing models, such as discounted cash flow techniques with all significant inputs derived from or corroborated by observable market data. There were no transfers of instruments between Level 1, Level 2 and Level 3 during the financial periods presented. Changes in Level 3 liabilities (in thousands) Fair value at December 28, 2013 $ 2,783 Payments made to Zygo Corporation (587 ) Change in fair value included in earnings 201 Fair value at December 27, 2014 2,397 Payments made to Zygo Corporation (851 ) Change in fair value included in earnings (56 ) Fair value at December 26, 2015 $ 1,490 As of December 26, 2015, the Company had liabilities of $1.5 million resulting from the acquisition of certain assets from Zygo Corporation, a wholly-owned subsidiary of AMETEK, Inc. (“Zygo”), which are measured at fair value on a recurring basis, and changes in fair value recorded in other income (expense), net. Of the $1.5 million of Zygo liabilities at December 26, 2015, $0.9 million was a current liability and $0.6 million was a long-term liability. As of December 27, 2014, the Company had liabilities of $2.4 million resulting from the acquisition of certain assets from Zygo which are measured at fair value on a recurring basis. Of the $2.4 million of Zygo liability at December 27, 2014, $1.4 million was a current liability and $1.0 million was a long-term liability. The fair values of these liabilities were determined using Level 3 inputs using a discounted cash flow model incorporating assumptions that market participants would use in their estimates of fair value. Some of these assumptions included estimates for discount rate, and timing and the amount of cash flows. Derivatives The Company uses foreign currency forward contracts to mitigate variability in gains and losses generated from the re-measurement of certain monetary assets and liabilities denominated in foreign currencies. These derivatives are carried at fair value with changes recorded in other income (expense), net in the consolidated statements of operations. Changes in the fair value of these derivatives are largely offset by re-measurement of the underlying assets and liabilities. The derivatives have maturities of approximately 30 days. The loss on settlement of forward foreign currency contracts included in the fiscal year ended December 26, 2015, was $0.3 million, and is included in other income (expense), net, in the consolidated statements of operations. There were no forward foreign currency contracts entered into in fiscal 2014. The following table summarizes the Company’s outstanding derivative instruments on a gross basis as of December 26, 2015: Notional Principal (in millions) Undesignated Hedges: Forward Foreign Currency Contracts $ 30.5

Cash and Investments

Cash and Investments	12 Months Ended
	Dec. 26, 2015
Investments Debt And Equity Securities [Abstract]
Cash and Investments	Note 4. Cash and Investments The following table presents cash, cash equivalents, and available-for-sale investments as of the following dates (in thousands): December 26, 2015 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Market Value Cash $ 32,996 $ — $ — $ 32,996 Cash equivalents: Money market funds 590 — — 590 Commercial paper and corporate debt securities 4,568 — — 4,568 Marketable securities: Commercial paper 1,884 — — 1,884 U.S. Treasury securities 4,411 — (10 ) 4,401 U.S. Government agency securities 20,193 1 (29 ) 20,165 Municipal securities 3,747 1 (3 ) 3,745 Corporate debt securities 14,759 — (23 ) 14,736 Total cash, cash equivalents, and marketable securities $ 83,148 $ 2 $ (65 ) $ 83,085 December 27, 2014 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Market Value Cash $ 34,066 $ — $ — $ 34,066 Cash equivalents: Money market funds 610 — — 610 Marketable securities: Commercial paper and corporate debt securities 805 — — 805 U.S. Treasury securities 2,498 — (1 ) 2,497 U.S. Government agency securities 20,556 1 (19 ) 20,538 Municipal securities 3,755 1 (7 ) 3,749 Corporate debt securities 21,722 1 (26 ) 21,697 Total cash, cash equivalents, and marketable securities $ 84,012 $ 3 $ (53 ) $ 83,962 Available-for-sale marketable securities, readily convertible to cash, with maturity dates of 90 days or less are classified as cash equivalents, while those with maturity dates greater than 90 days are classified as marketable securities within short-term assets. All marketable securities as of December 26, 2015 and December 27, 2014, were available-for-sale and reported at fair value based on the estimated or quoted market prices as of the balance sheet date. Gross realized gain and losses on sale of securities are recorded in other income, net, in our statement of operations. Net realized gain and losses for fiscal 2015, 2014, and 2013 was $0.2 million, $0.2 million and $0.2 million, respectively. Unrealized gains or losses, net of tax effect, are recorded in accumulated other comprehensive income (loss) within stockholders' equity. Both the gross unrealized gains and gross unrealized losses for the fiscal years ended December 26, 2015, and December 27, 2014 were insignificant and no marketable securities had other than temporary impairment. All marketable securities as of December 26, 2015 and December 27, 2014, had maturity dates of less than two years and were not invested in foreign entities.

Accounts Receivable

Accounts Receivable	12 Months Ended
	Dec. 26, 2015
Receivables [Abstract]
Accounts Receivable	Note 5. Accounts Receivable The Company maintains arrangements under which eligible accounts receivable in Japan are sold without recourse to unrelated third-party financial institutions. These receivables were not included in the consolidated balance sheets as the criteria for sale treatment had been met. After a transfer of financial assets, an entity stops recognizing the financial assets when control has been surrendered. The agreement met the criteria of a true sale of these assets since the acquiring party retained the title to these receivables and had assumed the risk that the receivables will be collectible. The Company pays administrative fees as well as interest ranging from 1.15% to 1.68% based on the anticipated length of time between the date the sale is consummated and the expected collection date of the receivables sold. The Company sold $15.7 million and $7.7 million of receivables during fiscal years ended December 26, 2015 and December 27, 2014, respectively. There were no material gains or losses on the sale of such receivables. There were no amounts due from such third party financial institutions at December 26, 2015, and December 27, 2014.

Financial Statement Components

Financial Statement Components	12 Months Ended
	Dec. 26, 2015
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Financial Statement Components	Note 6. Financial Statement Components The following tables provide details of selected financial statement components as of the following dates (in thousands): At December 26, 2015 December 27, 2014 Inventories: Raw materials and sub-assemblies $ 26,784 $ 19,463 Work in process 12,862 7,723 Finished goods 8,103 7,919 Inventories 47,749 35,105 Inventories-delivered systems 2,856 1,912 Total inventories $ 50,605 $ 37,017 Property, plant and equipment, net: (1) Land $ 15,569 $ 15,572 Building and improvements 20,158 19,641 Machinery and equipment 32,995 29,456 Furniture and fixtures 2,266 2,225 Software 8,245 7,942 Capital in progress 1,328 3,512 Total property, plant and equipment, gross 80,561 78,348 Accumulated depreciation and amortization (36,068 ) (28,715 ) Total property, plant and equipment, net $ 44,493 $ 49,633 (1) Total depreciation and amortization expense for the years ended December 26, 2015, December 27, 2014 and December 28, 2013 was $6.9 million, $6.6 million, and $5.4 million, respectively. Other Current Liabilities: Accrued warranty $ 4,504 $ 2,953 Accrued restructuring 256 997 Accrued professional services 481 778 Fair value of current portion of contingent payments to Zygo Corporation related to acquisition 945 1,385 Other 2,692 2,152 Total other current liabilities $ 8,878 $ 8,265 Components of Accumulated Other Comprehensive Income (Loss) Years Ended Foreign Currency Translations Defined Benefit Pension Plans Unrealized Income (Loss) on Investment Accumulated Other Comprehensive Income Balance as of December 28, 2013 $ 635 $ (28 ) $ 5 $ 612 Current period change (3,239 ) (106 ) (36 ) (3,381 ) Balance as of December 27, 2014 (2,604 ) (134 ) (31 ) (2,769 ) Current period change (2,344 ) (76 ) (13 ) (2,433 ) Balance as of December 26, 2015 $ (4,948 ) $ (210 ) $ (44 ) $ (5,202 ) The items above, except for unrealized income (loss) on investment, did not impact the Company’s income tax provision. The amounts reclassified from each component of accumulated other comprehensive income into income statement line items were insignificant.

Goodwill and Intangible Assets

Goodwill and Intangible Assets	12 Months Ended
	Dec. 26, 2015
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	Note 7. Goodwill and Intangible Assets The following table summarizes the activity in the Company’s goodwill during the years ended December 26, 2015 and December 27, 2014, respectively (in thousands): Balance as of December 29, 2013 $ 11,743 Foreign currency movements (1,249 ) Balance as of December 28, 2014 10,494 Foreign currency movements (1,079 ) Balance as of December 26, 2015 $ 9,415 There were no business acquisitions made by the Company during fiscal years 2015, 2014 and 2013. Goodwill Impairment and Long-lived Asset Impairment The Company’s impairment review process is completed during the fourth quarter of each year, or whenever events or circumstances occur that indicate that an impairment may have occurred. The goodwill impairment assessment involves three tests, Step 0, Step 1 and Step 2. The Company performs a Step 0 test, which involves an initial qualitative assessment to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying value. If, after assessing the qualitative factors, the Company determines that it is more likely than not that the fair value of a reporting unit is less than its carrying value, then performing the two-step impairment test is necessary. Otherwise, no further testing is necessary. The Company completed its annual goodwill impairment assessment during the fourth quarter of 2015 by first performing a Step 0 qualitative assessment. As part of this assessment, the Company considered the trading value of the Company's stock, the industry trends, and the Company's sales forecast and products plans. The Company concluded that it was more likely than not that the fair value was more than the carrying values of the Company's reporting unit and therefore did not proceed to the Step 1 goodwill impairment test. The process of evaluating the potential impairment of long-lived assets is highly subjective and requires significant judgment. In estimating the fair value of these assets, the Company made estimates and judgments about future revenues and cash flows. The Company’s forecasts were based on assumptions that are consistent with the plans and estimates the Company is using to manage its business. Changes in these estimates could change the Company’s conclusion regarding impairment of the long-lived assets and potentially result in future impairment charges for all or a portion of their balance at December 26, 2015. The Company did not record any impairment charges related to goodwill in fiscal year 2015. The Company assesses if there have been triggers that may require it to evaluate the reasonableness of the remaining estimated useful lives of its intangible assets. No such triggers were identified during fiscal year 2015. Finite-lived intangible assets are recorded at cost, less accumulated amortization. Finite-lived intangible assets as of December 26, 2015 and December 27, 2014 consisted of the following (in thousands): December 26, 2015 Adjusted cost Accumulated amortization Net carrying amount Developed technology $ 16,098 $ (14,387 ) $ 1,711 Customer relationships 9,364 (9,364 ) — Brand names 1,927 (1,903 ) 24 Patented technology 2,252 (2,120 ) 132 Trademark 80 (80 ) — Total $ 29,721 $ (27,854 ) $ 1,867 December 27, 2014 Adjusted cost Accumulated amortization Net carrying amount Developed technology $ 16,950 $ (12,991 ) $ 3,959 Customer relationships 9,461 (9,449 ) 12 Brand names 1,927 (1,802 ) 125 Patented technology 2,252 (2,054 ) 198 Trademark 80 (80 ) — Total $ 30,670 $ (26,376 ) $ 4,294 The amortization of finite-lived intangibles is computed using the straight-line method. Estimated lives of finite-lived intangibles range from two to ten years. Total amortization expense for the fiscal years ended December 26, 2015, December 27, 2014 and December 28, 2013, was $2.1 million, $3.1 million and $3.3 million, respectively. There were no impairment charges related to intangible assets recorded during the year ended December 26, 2015. The estimated future amortization expense of finite intangible assets as of December 26, 2015, is as follows (in thousands): Fiscal Years Amounts 2016 $ 1,455 2017 206 2018 140 2019 66 Thereafter — Total future amortization expense $ 1,867

Warranties

Warranties	12 Months Ended
	Dec. 26, 2015
Product Warranties Disclosures [Abstract]
Warranties	Note 8. Warranties Product Warranty – The Company sells the majority of its products with a 12 months repair or replacement warranty from the date of acceptance or shipment date. The Company provides an accrual for estimated future warranty costs based upon the historical relationship of warranty costs to the cost of products sold. The estimated future warranty obligations related to product sales are recorded in the period in which the related revenue is recognized. The estimated future warranty obligations are affected by the warranty periods, sales volumes, product failure rates, material usage, and labor and replacement costs incurred in correcting a product failure. If actual product failure rates, material usage, labor or replacement costs were to differ from the Company’s estimates, revisions to the estimated warranty obligations would be required. For new product introductions where limited or no historical information exists, the Company may use warranty information from other previous product introductions to guide it in estimating its warranty accrual. The warranty accrual represents the best estimate of the amount necessary to settle future and existing claims on products sold as of the balance sheet date. The Company periodically assesses the adequacy of its reported warranty reserve and adjusts such amounts in accordance with changes in these factors. Components of the warranty accrual, which were included in the accompanying consolidated balance sheets with other current liabilities, were as follows (in thousands): Years Ended December 26, 2015 December 27, 2014 Balance as of beginning of period $ 2,953 $ 3,426 Accruals for warranties issued during period 8,332 5,987 Settlements during the period (6,781 ) (6,460 ) Balance as of end of period $ 4,504 $ 2,953

Restructuring

Restructuring	12 Months Ended
	Dec. 26, 2015
Restructuring And Related Activities [Abstract]
Restructuring	Note. 9. Restructuring The Company recorded a restructuring charge of approximately $1.4 million in 2015 as a result of its decision to maximize operating effectiveness. This amount includes charges primarily related to employee severance and related costs. As of December 26, 2015, the Company had completed and settled in full all cash payments related to these charges. The Company recorded a restructuring charge of approximately $2.3 million in 2014 as a result of its decision to consolidate and reorganize certain of its operations, primarily in the U.K. This amount included charges primarily related to employee severance, other expenses (primarily vendor contract termination costs) and early termination costs of a facility lease due to expire in 2017 in the amounts of $0.3 million and $0.8 million, respectively. The Company completed this restructuring plan by March 2015 and does not expect any remaining charges. Other related costs will be recognized as incurred. As of December 26, 2015 and December 27, 2014, respectively, the components of the Company’s restructuring reserves were included in other current liabilities and were as follows (in thousands): Employee severance and benefits Facility termination costs Other Total Balance as of December 27, 2014 $ 383 $ 583 $ 31 $ 997 Charges 1,369 — 11 1,380 Cash Payments (1,752 ) (334 ) (35 ) (2,121 ) Balance as of December 26, 2015 $ — $ 249 $ 7 $ 256 Employee severance and benefits Facility termination costs Other Total Balance as of December 28, 2013 $ — $ — $ — $ — Charges 1,163 784 319 2,266 Cash Payments (780 ) (201 ) (288 ) (1,269 ) Balance as of December 27, 2014 $ 383 $ 583 $ 31 $ 997

Line of Credit and Debt Obligat

Line of Credit and Debt Obligations	12 Months Ended
	Dec. 26, 2015
Debt Disclosure [Abstract]
Line of Credit and Debt Obligations	Note 10. Line of Credit and Debt Obligations Line of Credit – On May 30, 2014, the Company amended its revolving line of credit facility to (i) extend the maturity date of such facility by two years to May 30, 2016, and (ii) to increase the minimum amount available to borrow to $12.0 million. The instrument governing the line of credit facility includes certain financial covenants regarding tangible net worth. The revolving line of credit agreement includes a provision for the issuance of commercial or standby letters of credit by the bank on behalf of the Company. The value of all letters of credit outstanding reduces the total line of credit available. The revolving line of credit is collateralized by a blanket lien on all of the Company’s domestic assets excluding intellectual property and real estate. The minimum borrowing interest rate is 3.00% per annum. Borrowing is limited to the lesser of (a) $12.0 million plus the borrowing base, or (b) $20.0 million. The total borrowing base available as of December 26, 2015 was $16.7 million. As of December 26, 2015, the Company was not in breach of any restrictive covenants in connection with this line of credit. There were no outstanding amounts drawn on this facility as of December 26, 2015. Although management has no current plans to request advances under this credit facility, the Company may use the proceeds of any future borrowing for general corporate purposes, future acquisitions or expansion of the Company’s business.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 26, 2015
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	Note 11. Commitments and Contingencies Intellectual Property Indemnification Obligations – The Company will, from time to time, in the normal course of business, agree to indemnify certain customers, vendors or others against third party claims that Nanometrics’ products, when used for their intended purpose(s), or the Company’s intellectual property, infringe the intellectual property rights of such third parties or other claims made against parties with whom it enters into contractual relationships. It is not possible to determine the maximum potential amount of liability under these indemnification obligations due to the limited history of prior indemnification claims and the unique facts and circumstances that are likely to be involved in each particular claim. Historically, the Company has not made payments under these obligations and believes that the estimated fair value of these agreements is immaterial. Accordingly, no liabilities have been recorded for these obligations in the accompanying consolidated balance sheets as of December 26, 2015 and December 27, 2014. The Company maintains certain open inventory purchase agreements with its suppliers to ensure a smooth and continuous supply availability for key components. The Company’s liability under these purchase commitments is generally restricted to a forecasted time-horizon as mutually agreed upon between the parties. This forecasted time-horizon can vary among different suppliers. The Company estimates its open inventory purchase commitment as of December 26, 2015 was approximately $24.9 million. Actual expenditures will vary based upon the volume of the transactions and length of contractual service provided. In addition, the amounts paid under these arrangements may be less in the event that the arrangements are renegotiated or cancelled. The Company leases facilities and certain equipment under non-cancelable operating leases. Rent expense, which is recorded on a straight-line basis over the term of the respective lease, for 2015, 2014 and 2013, was approximately $1.7 million, $2.0 million and $2.2 million, respectively. Future minimum lease payments under its operating leases are as follows (in thousands): Operating Leases 2016 $ 1,372 2017 733 2018 407 2019 311 Thereafter — Total $ 2,823 On June 17, 2009, the Company announced a strategic business partnership with Zygo Corporation whereby it has purchased inventory and certain other assets from Zygo Corporation, and the two companies entered into a supply agreement. The Company will make payments to Zygo Corporation (with an estimated present value of $1.5 million and an estimated future value of $1.8 million as of December 26, 2015) over a period of time as acquired inventory is sold and other aspects of the supply agreement are executed.

Net Income (Loss) Per Share

Net Income (Loss) Per Share	12 Months Ended
	Dec. 26, 2015
Earnings Per Share [Abstract]
Net Income (Loss) Per Share	Note 12. Net Income (Loss) Per Share The Company presents both basic and diluted net income (loss) per share on the face of its consolidated statements of operations. Basic net income (loss) per share excludes the effect of potentially dilutive shares and is computed by dividing net income (loss) by the weighted-average number of shares of common stock outstanding for the period. Diluted net income (loss) per share is computed using the weighted-average number of shares of common stock outstanding for the period plus the effect to all potentially dilutive common shares outstanding during the period, including contingently issuable shares and certain stock options, calculated using the treasury stock method. A reconciliation of the share denominator of the basic and diluted net income (loss) per share computations is as follows (in thousands): Years Ended December 26, 2015 December 27, 2014 December 28, 2013 Weighted average common shares outstanding used in basic net income (loss) per share calculation 24,059 23,958 23,290 Potential dilutive common stock equivalents, using treasury stock method 316 — — Weighted average shares used in diluted net income (loss) per share calculation 24,375 23,958 23,290 For the year ended December 26, 2015, December 27, 2014, and December 28, 2013, the Company had securities outstanding which could potentially dilute basic earnings per share in the future. For the year ended December 26, 2015, weighted average common share equivalents consisting of stock options and restricted stock units included in the calculation of diluted net income per share were 0.3 million shares. For the years ended December 27, 2014 and December 28, 2013 potential dilutive common stock equivalents of 0.4 million shares and 0.4 million shares, respectively, were anti-dilutive and therefore were excluded from the calculation due to the net loss positions.

Stockholders' Equity and Stock-

Stockholders' Equity and Stock-Based Compensation	12 Months Ended
	Dec. 26, 2015
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stockholders' Equity and Stock-Based Compensation	Note 13. Stockholders' Equity and Stock-Based Compensation Stockholders' Equity Preferred and Common Stock The authorized capital stock of Nanometrics consists of 47,000,000 shares of common stock, par value $0.001 per share, and 3,000,000 shares of preferred stock, par value $0.001 per share. Stock Repurchase On May 29, 2012, the Company's Board of Directors approved a program to repurchase up to $20.0 million of its common stock, referred to as the 2012 program. Stock repurchases under this program may be made through open market and privately negotiated transactions, at times and in such amounts as management deems appropriate. The timing and actual number of shares repurchased is dependent on a variety of factors including price, corporate and regulatory requirements and other market conditions. Shares repurchased and retired for the indicated periods of the applicable repurchase programs with the associated cost of repurchase and amount available for repurchase at the end of the respective periods are as follows (in thousands, except number of shares and weighted average price per share): Fiscal Year 2015 Fiscal Year 2014 Fiscal Year 2013 Number of shares of common stock repurchased 111,050 362,633 332,771 Weighted average price per share $ 15.49 $ 14.74 $ 15.03 Total cost of repurchase $ 1,721 $ 5,344 $ 5,000 Amount available for repurchase at end of period $ 4,397 $ 6,118 $ 11,462 $4.4 million remained available for the future repurchase of our common stock under the 2012 program. Stock Option Plans The Nanometrics option plans are as follows: Plan Name Participants Shares Authorized 2005 Equity Incentive Plan Employees, consultants and directors 7,292,594 2002 Non-statutory Stock Option Plan Employees and consultants 1,200,000 2000 Employee Stock Option Plan Employees and consultants 2,450,000 2000 Director Stock Option Plan Non-employee directors 250,000 Accent Optical Technologies, Inc. Stock Incentive Plan Employees and consultants 205,003 Employee Stock Purchase Plan Under the 2003 Employee Stock Purchase Plan (“ESPP”), eligible employees are allowed to have salary withholdings of up to 10% of their base compensation to purchase shares of common stock at a price equal to 85% of the lower of the market value of the stock at the beginning or end of each six-month offering period, subject to an annual statutory limitation. At the end of the fiscal year ended December 26, 2015, the Company had 0.3 million shares remaining for issuance under the ESPP. Shares purchased under the ESPP were 125,504 shares, 122,112 shares and 126,068 shares in 2015, 2014 and 2013 at a weighted average price of $13.98, $13.76 and $12.36, respectively. Stock-based Compensation The Company measures and recognizes compensation expense for all share-based payment awards made to employees and directors including employee stock options, restricted stock units and employee stock purchases related to the Employee Stock Purchase Plan (collectively “Employee Stock Purchases”) based on estimated fair values. The fair value of share-based payment awards is estimated on the date of grant using an option-pricing model. The value of the portion of the award that is ultimately expected to vest is recognized as expense over the requisite service periods in the Company's consolidated statement of operations. Stock-based compensation expense recognized during the period is based on the value of the portion of share-based payment awards that is ultimately expected to vest during the period. As stock-based compensation expense recognized in the consolidated statement of operations for the years ended December 26, 2015, December 27, 2014 and December 28, 2013 is based on awards expected to vest, it has been reduced for estimated forfeitures. ASC 740 requires forfeitures to be estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates. The Company's estimated forfeiture rates are based on historical forfeiture experience, which the Company believes is the best available information to estimate the future forfeiture rate. Tax benefits resulting from tax deductions in excess of the compensation cost recognized for those options are required to be separately classified in the consolidated statements of cash flows. The Company recognized zero, zero and $0.1 million of excess tax benefit in fiscal years 2015, 2014 and 2013, respectively. Valuation and Expense Information The fair value of stock-based awards to employees is calculated using the Black-Scholes option pricing model, which requires subjective assumptions, including future stock price volatility and expected time to exercise. The expected life of options granted were calculated using the simplified method allowed by the SAB 107. The risk-free rates were based on the U.S Treasury rates in effect during the corresponding period of grant. The expected volatility were based on the historical volatility of the Company's stock price. These factors could change in the future, which would affect the stock-based compensation expense in future periods. The weighted-average fair value of stock-based compensation to employees is based on the single option valuation approach. Forfeitures are estimated and it is assumed no dividends will be declared. The estimated fair value of stock-based compensation awards to employees is amortized over the vesting period of the options. The weighted-average fair value calculations are based on the following average assumptions: Fiscal Year 2015 Fiscal Year 2014 Fiscal Year 2013 Stock Options: Expected life — 4.6 years 4.5 years Volatility — 54.9 % 69.9 % Risk free interest rate — 1.54 % 1.05 % Dividends — — — Employee Stock Purchase Plan: Expected life 0.5 years 0.5 years 0.5 years Volatility 36.9 % 31.2 % 26.8 % Risk free interest rate 0.12 % 0.54 % 0.11 % Dividends — — — Stock Options and Restricted Stock Units (“RSUs”) On May 24, 2013, the Company approved further amendments to the 2005 Equity Incentive Plan including: increasing the number of shares of common stock authorized by 2.6 million shares, changing the multiplier ratio from 2:1 to 1.7:1 against the plan for each award, other than a stock option or stock appreciation right, and providing the maximum term of stock options to be seven years. All other terms remained the same. Stock Options The weighted average fair value per share of the stock options awarded in fiscal years 2014 and 2013 was $8.13 and $8.58, respectively. No stock options were granted in 2015. A summary of activity of stock options in 2015 is as follows: Number of Shares Outstanding (Options) Weighted Average Exercise Price Weighted Average Remaining Contractual Term (Years) Aggregate Intrinsic Value (in Thousands) Options Outstanding at December 27, 2014 1,382,993 $ 13.92 3.41 $ 4,108 Exercised (229,510 ) $ 9.65 Granted — $ — - $ — Cancelled (94,012 ) $ 16.67 Outstanding at December 26, 2015 1,059,471 $ 14.61 2.47 $ 1,920 Exercisable at December 26, 2015 926,415 $ 14.36 2.15 $ 1,879 The aggregate intrinsic value in the above table represents the total pretax intrinsic value, based on the Company’s closing stock price of $15.79 as of December 26, 2015, which would have been received by the option holders had all option holders exercised their options as of that date. The total intrinsic value of options exercised during 2015, 2014 and 2013 was $1.6 million, $3.0 million and $2.9 million, respectively. The fair value of options vested during 2015, 2014 and 2013 was $1.5 million, $3.2 million and $3.7 million, respectively. The following table summarizes ranges of outstanding and exercisable options as of December 26, 2015. Options Outstanding Options Exercisable Exercise Prices Number Outstanding Weighted Average Remaining Contractual Life (Years) Weighted Average Exercise Price Number Exercisable Weighted Average Exercise Price $2.38-$10.46 134,762 0.90 $ 7.84 134,762 $ 7.8400 $10.83-$11.17 14,156 1.30 $ 10.93 14,156 $ 1.9279 $11.37-$11.37 114,166 1.89 $ 11.37 114,166 $ 11.3700 $12.98-$14.8 111,259 2.62 $ 13.67 94,579 $ 13.6200 $14.88-$15.65 111,967 3.84 $ 15.44 78,894 $ 15.4300 $15.74-$15.98 161,850 1.81 $ 15.91 143,100 $ 15.9200 $16.00-$16.50 41,804 4.76 $ 16.43 23,190 $ 16.4200 $16.70-$16.7 186,434 1.86 $ 16.70 186,434 $ 16.7000 $16.89-$18.51 123,773 4.22 $ 17.82 80,931 $ 17.8300 $18.79-$19.84 59,300 2.98 $ 19.12 56,203 $ 19.1300 $2.38-$19.84 1,059,471 2.47 $ 14.61 926,415 $ 14.3600 As of December 26, 2015, the total unrecognized compensation costs related to unvested stock options was $0.6 million and is expected to be recognized as an expense over a weighted average remaining amortization period of 1.58 years. Restricted Stock Units (“RSUs”) Each RSU counts against the Company’s “2005 Equity Incentive Plan” at a ratio of one and seven tenths shares for each unit granted but represents an amount equal to the fair value of one share of the Company’s common stock. The Company granted 506,459 and 473,600 RSUs during the years ended December 26, 2015 and December 27, 2014, respectively, to key employees with vesting periods up to three years. A summary of activity for RSUs is as follows: Summary of activity for RSUs Number of RSUs Weighted Average Fair Value Outstanding RSUs as of December 27, 2014 563,337 $ 17.90 Granted 506,459 $ 15.62 Released (237,520 ) $ 16.59 Cancelled (119,033 ) $ 16.59 Outstanding RSUs as of December 26, 2015 713,243 $ 15.99 As of December 26, 2015, the total unrecognized compensation costs related to RSU's was $6.9 million and is expected to be recognized as an expense over a weighted average remaining amortization period of 1.95 years. Market-Based Performance Stock Units (“PSUs”) In March 2015, in addition to granting RSUs that vest on the passage of time only, the Company granted PSUs to an executive. The PSUs will vest in three equal tranches over one, two and three years based on the relative performance of the Company’s stock during those periods, compared to a peer group over the same period. If a target stock price performance is achieved, 40,000 shares of the Company’s common stock will vest, and up to a maximum of 60,000 shares will vest if the maximum stock price performance is achieved for each tranche. Valuation of PSUs On the date of grant, the Company estimated the fair value of PSUs using a Monte Carlo simulation model. The assumptions for the valuation of PSUs are summarized as follows: 2015 Award Number of PSUs granted and outstanding as of December 26, 2015 40,000 Grant Date Fair Value Per Share $ 18.35 Weighted-average assumptions/inputs: Expected Divident — Range of risk-free interest rates 0.25%-1.1% Range of expected volatilities for peer group 23%-65% The number of RSUs granted during fiscal year 2015 was 506,459, which counted as 860,980 shares against the 2005 Equity Incentive Plan. The number of RSUs cancelled during fiscal year 2015 was 119,033, which counted as 202,356 shares against the 2005 Equity Incentive Plan. Each RSU represents an amount equal to the fair value of one share of the Company's common stock. A summary of activity under the Company’s stock option plans including options and RSUs during fiscal year 2015, 2014 and 2013 and shares available for grant as of the respective period end dates, is as follows: Fiscal Year 2015 Fiscal Year 2014 Fiscal Year 2013 Shares available for grant at beginning of fiscal year 2,464,082 2,937,001 1,093,565 Increase in authorized shares — — 2,600,000 Options - granted — (74,300 ) (430,800 ) Options - cancelled 94,012 191,061 150,459 Options - expired plan shares (1,800 ) (17,491 ) (53,607 ) RSUs – granted (860,980 ) (805,120 ) (664,902 ) RSUs – cancelled 202,356 167,404 133,418 RSUs - shares issued to satisfy tax withholding obligations 120,919 65,527 108,868 PSUs – granted (68,000 ) — — Shares available for grant at end of fiscal year 1,950,589 2,464,082 2,937,001 Stock-based Compensation Expense Stock-based compensation expense for all share-based payment awards made to the Company’s employees and directors pursuant to the employee stock option and employee stock purchase plans by function were as follows (in thousands): Fiscal Year 2015 Fiscal Year 2014 Fiscal Year 2013 Cost of products $ 274 $ 268 $ 207 Cost of service 309 287 278 Research and development 1,036 1,245 1,478 Selling 1,881 1,642 1,894 General and administrative 2,748 3,243 2,919 Restructuring — 67 898 Total stock-based compensation expense related to employee stock options and employee stock purchases $ 6,248 $ 6,752 $ 7,674

Defined Benefit Pension Plan

Defined Benefit Pension Plan	12 Months Ended
	Dec. 26, 2015
Compensation And Retirement Disclosure [Abstract]
Defined Benefit Pension Plan	Note 14. Defined Benefit Pension Plan Nanometrics sponsors a statutory government mandated defined benefit pension plan (the “Benefit Plan”) in Taiwan for its local employees. The fair value of plan assets was $0.2 million for each of the fiscal years ended 2015, 2014 and 2013, respectively; and the net funding deficiency of the Benefit Plan was $0.3 million, $0.3 million, and $0.2 million for the fiscal years ended December 26, 2015, December 27, 2014, and December 28, 2013, respectively. Based on the nature and limited extent of the pension plan, we determined this pension plan was not material for separate disclosure.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 26, 2015
Income Tax Disclosure [Abstract]
Income Taxes	Note 15. Income Taxes Income Tax Assets and Liabilities - The Company accounts for income taxes whereby deferred tax assets and liabilities are recognized using enacted tax rates for the effect of temporary differences between the book and tax accounting for assets and liabilities. Also, deferred tax assets are reduced by a valuation allowance to the extent that management cannot conclude that it is more likely than not that a portion of the deferred tax asset will be realized in the future. The Company evaluates the deferred tax assets on a continuous basis throughout the year to determine whether or not a valuation allowance is appropriate. Factors used in this determination include future expected income and the underlying asset or liability which generated the temporary tax difference. The income tax provision is primarily impacted by federal statutory rates, state and foreign income taxes, and changes in the valuation allowance. Income (loss) before provision for income taxes consists of the following (in thousands): Years Ended December 26, 2015 December 27, 2014 December 28, 2013 Domestic $ 178 $ (15,691 ) $ (26,447 ) Foreign 5,390 4,070 2,882 Income (loss) before income taxes $ 5,568 $ (11,621 ) $ (23,565 ) The provision (benefit) for income taxes consists of the following (in thousands): Years Ended December 26, 2015 December 27, 2014 December 28, 2013 Current: Federal $ 148 $ 358 $ 119 State 3 (151 ) 5 Foreign 2,266 1,327 933 2,417 1,534 1,057 Deferred: Federal 190 17,368 (10,686 ) State 3 550 (325 ) Foreign 53 45 535 246 17,963 (10,476 ) Provision (benefit) for income taxes $ 2,663 $ 19,497 $ (9,419 ) Significant components of the Company's deferred tax assets and liabilities are as follows (in thousands): At December 26, 2015 December 27, 2014 Deferred tax assets: Reserves and accruals $ 13,712 $ 10,744 Deferred revenue 1,154 1,370 Shared based compensation 3,856 4,030 Tax credit carry-forwards 8,658 8,122 Net operating losses 13,218 14,695 Depreciation & amortization 366 2,750 Other 94 372 Total deferred tax assets 41,058 42,083 Less: Valuation allowance (36,786 ) (35,835 ) Total deferred tax assets net of valuation allowance 4,272 6,248 Deferred tax liabilities: Depreciation & amortization (2,537 ) (4,020 ) Other (1,137 ) (1,485 ) Total deferred tax liabilities (3,674 ) (5,505 ) Net deferred tax assets $ 598 $ 743 As of December 26, 2015, the Company had net operating loss carryforwards of $9.9 million for federal, $39.5 million in California and $38.5 million in foreign countries, which begin to expire in 2015. A total of $1.4 million of the federal net operating loss, $3.0 million of the California net operating loss carryforward and $1.6 million of the foreign net operating loss carryforwards are related to excess tax benefits as a result of stock option exercises, and therefore will be recorded in additional paid-in capital in the period that they become realized. During the year ended December 26, 2015, the Company did not realize any excess tax benefits as a result of stock option exercises, therefore, there were no amounts recorded to additional paid-in capital. As of December 26, 2015, the Company had available carryforward Federal and California R&D tax credits of $7.5 million and $6.9 million, respectively. Federal R&D tax credit carryforwards begin to expire in 2024. State R&D tax credits carryforward indefinitely. A total of $0.2 million of the state R&D tax credits are related to excess tax benefits as a result of stock option exercises, and therefore will be recorded to additional paid-in-capital in the period that they become realized. During the years ended December 26, 2015 and December 27, 2014, the valuation allowances increased by $1.6 million and $23.9 million, respectively. The valuation allowance increase in 2014 was primarily related to a full valuation allowance recorded against the Company's U.S. deferred tax assets. The realization of deferred tax assets is primarily dependent on the Company generating sufficient U.S. and foreign taxable income in future fiscal years. The Company regularly assesses the need for a valuation allowance against its deferred tax assets. In making that assessment, the Company considers both positive and negative evidence related to the likelihood of realization of the deferred tax assets to determine, based on the weight of available evidence, whether it is more-likely-than-not that some or all of the deferred tax assets will not be realized. In evaluating the need for a valuation allowance, the Company considers its cumulative loss in the U.S. as a significant piece of negative evidence. During the year ended December 27, 2014, the Company recorded a $21.1 million valuation allowance against its U.S. deferred tax assets as it determined, within the period, it would not meet the more likely than not threshold. The Company continues to maintain valuation allowances against certain foreign deferred tax assets as a result of uncertainties regarding the realization of the asset due to cumulative losses and uncertainty of future taxable income. The Company will continue to assess the realizability of the deferred tax assets in each of the applicable jurisdictions and maintain the valuation allowances until sufficient positive evidence exists to support a reversal. In the event the Company determines that the deferred tax assets are realizable, an adjustment to the valuation allowances will be reflected in the tax provision for the period such determination is made. Changes in tax laws and tax rates could affect the Company's recorded deferred tax assets and liabilities in the future. The Company's tax liabilities involve dealing with uncertainties in the application of complex tax laws and regulations in a multitude of jurisdictions across its global operations. Management will account for any such changes or factors in the period in which such law changes are enacted. Differences between income taxes computed by applying the statutory federal income tax rate to income (loss) before income taxes and the provision (benefit) for income taxes consist of the following (in thousands): Years Ended December 26, 2015 December 27, 2014 December 28, 2013 Income taxes computed at U.S. statutory rate $ 1,949 $ (4,067 ) $ (8,247 ) State income taxes 28 (109 ) 147 Foreign tax rate differential 342 777 479 Change in valuation allowance 1,648 23,894 — Non-deductible Equity Compensation 311 242 210 Tax credits (1,834 ) (2,187 ) (2,103 ) Liabilities for uncertain tax positions 74 118 111 Other, net 145 829 (16 ) Provision (benefit) for income taxes $ 2,663 $ 19,497 $ (9,419 ) Certain amounts of the income tax rate reconciliation for the years ended December 27, 2014 and December 28, 2013, were reclassified to other components within the reconciliation to be consistent with classification used for the year ended December 26, 2015. There was no impact to the total provision (benefit) for income taxes based on these reclassifications. As of December 26, 2015, approximately $6.5 million of undistributed earnings from non-U.S. operations held by the Company's foreign subsidiaries are designated as indefinitely reinvested outside the U.S. Accordingly, no additional U.S. income taxes or additional foreign withholding taxes have been provided thereon. The amount of unrecognized deferred tax liability related to these earnings would be immaterial. The Company recognizes tax liabilities for uncertain tax positions and adjust these liabilities when its judgment changes as a result of the evaluation of new information not previously available. Due to the complexity of some of these uncertainties, the ultimate resolution may result in a payment that is materially different from the Company's current estimate of the tax liabilities. These differences will be reflected as increases or decreases to income tax expense in the period in which they are determined. The accounting for uncertainty in income taxes recognized in an enterprise's financial statements prescribes a recognition threshold and measurement attribute for the financial statement recognition and measurement of a tax position taken or expected to be taken on a tax return, and the derecognition of tax benefits, classification on the balance sheet, interest and penalties, accounting in interim periods, disclosure, and transition. A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows (in thousands): Rollforward Table (at Gross): As of December 26, 2015 December 27, 2014 December 28, 2013 Unrecognized tax benefits - beginning of the period $ 6,442 $ 4,436 $ 3,464 Gross increases-tax positions in prior period 127 655 305 Gross decreases-tax positions in prior period (306 ) (123 ) — Gross increases-current-period tax positions 698 1,541 688 Lapse of statute of limitations — (67 ) (21 ) Unrecognized tax benefits - end of the period $ 6,961 $ 6,442 $ 4,436 The unrecognized tax benefit at December 26, 2015 was $7.0 million, of which $0.8 million would impact the effective tax rate if recognized. The Company accrues interest and penalties related to unrecognized tax benefits in its provision for income taxes. The total amount of penalties and interest were not material as of December 26, 2015, December 27, 2014 and December 28, 2013. The Company does not expect a material change in its unrecognized tax benefits within the next 12 months. The Company is subject to taxation in the U.S. and various states including California, and foreign jurisdictions including Korea, Japan, Taiwan, and China. Due to tax attribute carry-forwards, the Company is subject to examination for tax years 2003 forward for U.S. tax purposes. The Company was also subject to examination in various states for tax years 2002 forward. The Company is subject to examination for tax years 2007 forward for various foreign jurisdictions.

Segment, Geographic, Product an

Segment, Geographic, Product and Significant Customer Information	12 Months Ended
	Dec. 26, 2015
Segment Reporting [Abstract]
Geographic And Significant Customer Information Text Block	Note 16. Segment, Geographic, Product and Significant Customer Information The Company has one operating segment, which is the sale, design, manufacture, marketing and support of thin film and optical critical dimension systems. The Chief Executive Officer has been identified as the Chief Operating Decision Maker (“CODM”) because he has the final authority over resource allocation decisions and performance assessment. The CODM does not receive discrete financial information about individual components of the Company's business. For the years ended December 26, 2015, December 27, 2014, and December 28, 2013, the Company recorded revenue from customers primarily in the United States, Asia and Europe. The following tables summarize total net revenues and long-lived assets (excluding intangible assets) attributed to significant countries (in thousands): Years Ended December 26, 2015 December 27, 2014 December 28, 2013 Total net revenues (1): United States $ 36,720 $ 36,123 $ 47,019 China 17,373 28,702 13,063 Japan 31,140 15,185 11,629 South Korea 30,572 41,381 34,873 Taiwan 46,715 19,790 9,645 Other 24,847 25,262 28,078 Total net revenues $ 187,367 $ 166,443 $ 144,307 (1) December 26, 2015 December 27, 2014 Long-lived tangible assets: United States $ 42,581 $ 47,729 Japan 59 71 South Korea 697 284 Taiwan 1,056 1,473 All Other 100 76 Total long-lived tangible assets $ 44,493 $ 49,633 The Company’s product lines differ primarily based on the environment in which the systems will be used. Automated systems are used primarily in high-volume production environments. Materials characterization products are primarily used to measure the composition, band gap, structure, and other physical and electrical properties of semiconducting materials for discrete electronic industry, high brightness LED and solar/photovoltaic structures in both development and high volume environments. Integrated systems are installed inside wafer processing equipment to provide near real-time measurements for improving process control and increasing throughput. Revenues by product type were as follows (in thousands): Years Ended December 26, 2015 December 27, 2014 December 28, 2013 Automated Systems $ 102,386 $ 108,768 $ 82,924 Integrated Systems 31,579 15,334 11,412 Materials Characterization Systems 12,980 9,487 13,066 Total product revenues $ 146,945 $ 133,589 $ 107,402 The following customers accounted for 10% or more of total accounts receivable, net: Years Ended December 26, 2015 December 27, 2014 December 28, 2013 Toshiba Corporation 27.1 % *** *** Taiwan Semiconductor Manufacturing Company Limited 25.6 % 20.2 % 12.1 % SK Hynix *** *** 21.8 % Samsung Electronics Co. Ltd. *** 10.0 % 27.4 % Micron *** 23.7 % *** Intel Corporation *** *** 14.4 % GlobalFoundries *** 10.2 % *** *** The customer accounted for less than 10% of total accounts receivable, net, as of that period end. The following customers accounted for 10% or more of total net revenue: Years Ended December 26, 2015 December 27, 2014 December 28, 2013 Taiwan Semiconductor Manufacturing Company Limited 19.4 % *** *** Micron 15.8 % 10.4 % *** Samsung Electronics Co. Ltd. 13.2 % 26.9 % 14.4 % SK Hynix 10.7 % 12.2 % 18.4 % Toshiba Corporation 10.2 % *** *** Intel Corporation *** 12.6 % 30.0 % *** The customer accounted for less than 10% of total net revenue during the period.

Schedule II - VALUATION AND QUA

Schedule II - VALUATION AND QUALIFYING ACCOUNTS	12 Months Ended
	Dec. 26, 2015
Valuation And Qualifying Accounts [Abstract]
Schedule II - VALUATION AND QUALIFYING ACCOUNTS	NANOMETRICS INCORPORATED VALUATION AND QUALIFYING ACCOUNTS Our allowance for doubtful accounts receivable consists of the following (in thousands): Year Ended Balance at beginning of period Charged to costs and expenses Deductions – write-offs of accounts Balance at end of period December 26, 2015 $ 253 $ (113 ) $ 10 $ 150 December 27, 2014 $ 293 $ (40 ) $ — $ 253 December 28, 2013 $ 82 $ 255 $ (44 ) $ 293 Our valuation allowance for deferred tax assets consists of the following (in thousands): Year Ended Balance at beginning of period Charged to costs and expenses Deductions – write-offs of accounts Balance at end of period December 26, 2015 $ 35,835 $ 951 $ — $ 36,786 December 27, 2014 $ 11,665 $ 24,170 $ — $ 35,835 December 28, 2013 $ 10,229 $ 1,436 $ — $ 11,665

Nature of Business, Basis of 25

Nature of Business, Basis of Presentation and Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 26, 2015
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Description of Business	Description of Business – Nanometrics Incorporated (“Nanometrics” or the “Company”) and its wholly-owned subsidiaries design, manufacture, market, sell and support optical critical dimension ("OCD"), thin film and overlay dimension metrology and inspection systems used primarily in the manufacturing of semiconductors, solar photovoltaics (“solar PV”) and high-brightness LEDs (“HB-LED”), as well as by customers in the silicon wafer and data storage industries. Nanometrics' metrology systems precisely measure a wide range of film types deposited on substrates during manufacturing to control manufacturing processes and increase production yields in the fabrication of integrated circuits. The Company’s OCD technology is a patented critical dimension measurement technology that is used to precisely determine the dimensions on the semiconductor wafer that directly control the resulting performance of the integrated circuit devices. The thin film metrology systems use a broad spectrum of wavelengths, high-sensitivity optics, proprietary software, and patented technology to measure the thickness and uniformity of films deposited on silicon and other substrates as well as their chemical composition. The overlay metrology systems are used to measure the overlay accuracy of successive layers of semiconductor patterns on wafers in the photolithography process. Nanometrics' inspection systems are used to find defects on patterned and unpatterned wafers at nearly every stage of the semiconductor production flow. The corporate headquarters of Nanometrics is located in Milpitas, California.
Basis of Presentation	Basis of Presentation – The consolidated financial statements include Nanometrics Incorporated and its wholly-owned subsidiaries. All significant intercompany accounts and transactions have been eliminated in consolidation.
Fiscal Year	Fiscal Year – On October 17, 2014, the Board of Directors of the Company approved a change in the Company's fiscal year from a fiscal year ending on the Saturday closest to December 31 to a 52/53 week fiscal year ending on the last Saturday of the calendar year. All periods presented consisted of a 52-week year.
Use of Estimates	Use of Estimates – The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America ("U.S. GAAP") requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reported period. Actual results could differ materially from those estimates. Estimates are used for, but not limited to, revenue recognition, the provision for doubtful accounts, the provision for excess, obsolete, or slow moving inventories, valuation of intangible and long-lived assets, warranty accruals, income taxes, valuation of stock-based compensation, and contingencies.
Foreign Currency Translation	Foreign Currency Translation – The assets and liabilities of foreign subsidiaries are translated from their respective local functional currencies at exchange rates in effect at the balance sheet date and income and expense accounts are translated at average exchange rates during the reporting period. Resulting translation adjustments are reflected in “Accumulated other comprehensive income,” a component of stockholders’ equity. Foreign currency transaction gains and losses, as well as remeasurement of assets and liabilities denominated in a currency other than the functional currency are reflected in “Other income (expense)” in the consolidated statements of operations in the period incurred, and consists of a $ 0.5 million gain, a $0.1 million gain and a $0.7 million loss for the years ended December 26, 2015, December 27, 2014, and December 28, 2013, respectively.
Revenue Recognition	Revenue Recognition – The Company derives revenue from the sale of process control metrology systems (“product revenue”) as well as spare part sales, billable service, service contracts, and upgrades (together “service revenue”). Upgrades are a group of parts and/or software that change the existing configuration of a product and are included in service revenue. They are distinguished from product revenue, which consists of complete, advanced process control metrology and inspection systems (the “system(s)”). Nanometrics' systems consist of hardware and software components that function together to deliver the essential functionality of the system. Arrangements for sales of systems often include defined customer-specified acceptance criteria. In summary, the Company recognizes revenue when persuasive evidence of an arrangement exists, delivery has occurred or services have been rendered, the seller's price is fixed or determinable, and collectability is reasonably assured. For product sales to existing customers, revenue recognition occurs at the time title and risk of loss transfer to the customer, which usually occurs upon shipment from the Company's manufacturing location, if it can be reliably demonstrated that the product has successfully met the defined customer specified acceptance criteria and all other recognition criteria have been met. For initial sales where the product has not previously met the defined customer specified acceptance criteria, product revenues are recognized upon the earlier of receipt of written customer acceptance or expiration of the contractual acceptance period. In Japan, where contractual terms with the customer specify risk of loss and title transfers upon customer acceptance, revenue is recognized upon receipt of written customer acceptance, provided that all other recognition criteria have been met. The Company warrants its products against defects in manufacturing. Upon recognition of product revenue, a liability is recorded for anticipated warranty costs. On occasion, customers request a warranty period longer than the Company's standard warranty. In those instances where extended warranty services are separately quoted to the customer, the associated revenue is deferred and recognized as service revenue ratably over the term of the contract. The portion of service contracts and extended warranty services agreements that are uncompleted at the end of any reporting period are included in deferred revenue. As part of its customer services, the Company sells software that is considered to be an upgrade to a customer's existing systems. These standalone software upgrades are not essential to the tangible product's functionality and are accounted for under software revenue recognition rules which require vendor specific objective evidence ("VSOE") of fair value to allocate revenue in a multiple element arrangement. Revenue from upgrades is recognized when the upgrades are delivered to the customer, provided that all other recognition criteria have been met. Revenue related to spare parts is recognized upon shipment. Revenue related to billable services is recognized as the services are performed. Service contracts may be purchased by the customer during or after the warranty period and revenue is recognized ratably over the service contract period. Frequently, the Company delivers products and various services in a single transaction. The Company's deliverables consist of tools, installation, upgrades, billable services, spare parts, and service contracts. The Company's typical multi-element arrangements include a sale of one or multiple tools that include installation and standard warranty. Other arrangements consist of a sale of tools bundled with service elements or delivery of different types of services. The Company's tools, upgrades, and spare parts are generally delivered to customers within a period of up to six months from order date. Installation is usually performed soon after delivery of the tool. The portion of revenue associated with installation is deferred based on relative selling price and that revenue is recognized upon completion of the installation. Billable services are billed on a time and materials basis and performed as requested by customers. Under service contract arrangements, services are provided as needed over the fixed arrangement term, which terms can be up to twelve months. The Company does not grant its customers a general right of return or any refund terms and imposes a penalty on orders cancelled prior to the scheduled shipment date. The Company regularly evaluates its revenue arrangements to identify deliverables and to determine whether these deliverables are separable into multiple units of accounting. In accordance with revenue recognition guidance, the Company allocates the arrangement consideration among the deliverables based on relative selling prices. The Company has established VSOE for some of its products and services when a substantial majority of selling prices falls within a narrow range when sold separately. For deliverables with no established VSOE, the Company uses best estimate of selling price to determine standalone selling price for such deliverable. The Company does not use third party evidence to determine standalone selling price since this information is not widely available in the market as the Company's products contain a significant element of proprietary technology and the solutions offered differ substantially from competitors. The Company has established a process for developing estimated selling prices, which incorporates historical selling prices, the effect of market conditions, gross margin objectives, pricing practices, as well as entity-specific factors. The Company monitors and evaluates estimated selling price on a regular basis to ensure that changes in circumstances are accounted for in a timely manner. When certain elements in multiple-element arrangements are not delivered or accepted at the end of a reporting period, the relative selling prices of undelivered elements are deferred until these elements are delivered and/or accepted. If deliverables cannot be accounted for as separate units of accounting, the entire arrangement is accounted for as a single unit of accounting and revenue is deferred until all elements are delivered and all revenue recognition requirements are met.
Business Combinations	Business Combinations - The Company allocates the purchase price of acquired companies to the tangible and intangible assets acquired and liabilities assumed based upon their estimated fair values at the acquisition date. The purchase price allocation process requires management to make significant estimates and assumptions, especially at the acquisition date with respect to intangible assets and inventory acquired. While best estimates and assumptions as a part of the purchase price allocation process are used to accurately value assets acquired and liabilities assumed at the acquisition date, estimates are inherently uncertain and subject to refinement. As a result, during the measurement period, which may be up to one year from the acquisition date, the Company may record adjustments to the assets acquired and liabilities assumed, with the corresponding offset to goodwill. Upon the conclusion of the measurement period or final determination of the values of assets acquired or liabilities assumed, whichever comes first, any subsequent adjustments are recorded in the consolidated statements of operations. The Company estimates the fair value of inventory acquired by utilizing the net realizable value method which is based on the estimated sales price of the product less appropriate costs to complete and selling costs. Examples of critical estimates in valuing certain intangible assets that were acquired or may be acquired in the future include but are not limited to: · future expected cash flows from sales of products, services and acquired developed technologies and patents; · expected costs to develop the in-process research and development into commercially viable products and estimated cash flows from the projects when completed; · the acquired company's customer relationships, as well as assumptions about the estimated useful lives of the relationships; and · discount rates. Unanticipated events and circumstances may occur that may affect the accuracy or validity of assumptions, estimates or actual results associated with business combinations.
Cash and Cash Equivalents	Cash, Cash Equivalents and Marketable Securities – The Company considers all highly liquid investments with original maturities of three months or less, when purchased, to be cash equivalents.
Marketable Securities	Marketable securities are classified as “available-for-sale” and are reported at fair value with unrealized gains and losses reported in stockholders' equity as a component of other comprehensive income. The cost of securities sold is based on the specific identification method. The Company classifies its investments as current based on the nature of the investment and their availability for use in current operations. The Company reviews its investment portfolio quarterly to determine if any securities may be other-than-temporarily impaired due to increased credit risk, changes in industry or sector of a certain instrument or ratings downgrades.
Fair Value of Financial Instruments	Fair Value of Financial Instruments – Financial instruments include cash and cash equivalents, accounts receivable and accounts payable. Cash equivalents are stated at fair market value based on quoted market prices. The carrying values of accounts receivable and accounts payable approximate their fair values because of the short-term maturity of these financial instruments.
Derivatives	Derivatives – The Company enters into foreign currency forward exchange contracts to protect against currency exchange risks associated with existing assets and liabilities. A foreign currency forward exchange contract acts as a hedge by increasing in value when underlying assets decrease in value or underlying liabilities increase in value due to changes in foreign exchange rates. Conversely, a foreign currency forward exchange contract decreases in value when underlying assets increase in value or underlying liabilities decrease in value due to changes in foreign exchange rates. These forward contracts are not designated as accounting hedges, so the unrealized gains and losses are recognized in other income, net, in advance of the actual foreign currency cash flows with the fair value of these forward contracts being recorded as accrued liabilities or other current assets. The Company does not use forward contracts for trading purposes.
Allowance for Doubtful Accounts	Allowance for Doubtful Accounts – The Company maintains allowances for estimated losses resulting from the inability of its customers to make required payments. Credit limits are established through a process of reviewing the financial history and stability of its customers. Where appropriate and available, the Company obtains credit rating reports and financial statements of customers when determining or modifying their credit limits. The Company regularly evaluates the collectability of its trade receivable balances based on a combination of factors such as the length of time the receivables are past due, customary payment practices in the respective geographies and historical collection experience with customers. The Company believes that its allowance for doubtful accounts adequately reflects the risk associated with its receivables. If the financial conditions of a customer were to deteriorate, resulting in their inability to make payments, the Company may need to record additional allowances, which would result in additional general and administrative expenses being recorded for the period in which such determination was made.
Inventories	Inventories – Inventories are stated at the lower of cost, which approximates actual cost on a first-in, first-out basis, or market. The Company is exposed to a number of economic and industry factors that could result in portions of inventory becoming either obsolete or in excess of anticipated usage, or saleable only for amounts that are less than their carrying amounts. These factors include, but are not limited to, technological changes in the market, the Company’s ability to meet changing customer requirements, competitive pressures in products and prices, and the availability of key components from suppliers. The Company has established inventory reserves when conditions exist that suggest that inventory may be in excess of anticipated demand or is obsolete based upon assumptions about future demand for the Company’s products and market conditions. Once a reserve has been established, it is maintained until the part to which it relates is sold or is otherwise disposed of. The Company regularly evaluates its ability to realize the value of inventory based on a combination of factors including the following: historical usage rates, forecasted sales of usage, product end-of-life dates, estimated current and future market values and new product introductions. For demonstration inventory, the Company also considers the age of the inventory and potential cost to refurbish the inventory prior to sale. Demonstration inventory is amortized over its useful life and the amortization expense is included in total inventory write down on the statements of cash flows. When recorded, reserves are intended to reduce the carrying value of the Company’s inventory to its net realizable value. If actual demand for the Company’s products deteriorates, or market conditions are less favorable than those that the Company projects, additional reserves may be required. Inventories – delivered systems – The Company reflects the cost of systems that were invoiced upon shipment but deferred for revenue recognition purposes separate from its inventory held for sale as “Inventories – delivered systems.”
Property, Plant and Equipment	Property, Plant and Equipment – Property, plant and equipment are stated at cost. Depreciation and amortization is computed using the straight–line method over the following estimated useful lives of the assets: Building and Improvements 5-40 years Machinery and equipment 3-10 years Furniture and fixtures 3-10 years Software 3-7 years
Goodwill and Intangible Assets	Goodwill and Intangible Assets – Goodwill is initially recorded when the purchase price paid for an acquisition exceeds the estimated fair value of the net identified tangible and intangible assets acquired. Intangible assets with finite lives are amortized over their respective useful lives on a straight-line basis and are also evaluated annually for impairment or whenever events or circumstances occur which indicate that those assets might be impaired. Goodwill and indefinite lived assets are not amortized but tested annually for impairment. The Company’s impairment review process is completed during the fourth quarter of each year or whenever events, or circumstances occur which indicate that an impairment may have occurred. The Company assesses qualitative factors to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying value. If, after assessing the qualitative factors, the Company determines that it is not likely that the fair value of a reporting unit is less than its carrying value, then performing the two-step impairment test is unnecessary. However, if the Company concludes otherwise, then it is required to perform the first step of the two-step goodwill impairment test. The first step requires a comparison of the fair value of Nanometrics’ reporting unit to its net book value. If the fair value of the reporting unit is greater than its carrying value, then no impairment is deemed to have occurred. If the fair value is less, then the second step must be performed to determine the amount, if any, of actual impairment. Amortization of intangible assets with finite lives is computed using the straight-line method over the following estimated useful lives of the assets: Developed technology 5-10 years Customer relationships 2-10 years Brand name 5-10 years Patented technology 7-10 years Trademark 5 years
Long-Lived Assets	Long-Lived Assets – The Company evaluates its long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. When the sum of the undiscounted future net cash flows expected to result from the use of the asset and its eventual disposition is less than its carrying amount, impairment may exist. To determine the amount of impairment, the Company compares the fair value of the asset to its carrying value. If the carrying value of the asset exceeds its fair value, an impairment loss equal to the difference is recognized. See Note 7, "Goodwill and Intangible Assets" for further details.
Income Tax Assets and Liabilities	Income Tax Assets and Liabilities – The Company accounts for income taxes such that deferred tax assets and liabilities must be recognized using enacted tax rates for the effect of temporary differences between the book and tax accounting for assets and liabilities. Also, deferred tax assets are reduced by a valuation allowance to the extent that management cannot conclude that it is more likely than not that a portion of the deferred tax asset will be realized in the future. The Company evaluates the deferred tax assets on a continuous basis throughout the year to determine whether or not a valuation allowance is appropriate. Factors used in this determination include future expected income and the underlying asset or liability which generated the temporary tax difference. The income tax provision is primarily impacted by federal statutory rates, state and foreign income taxes and changes in the valuation allowance.
Product Warranties	Product Warranties – The Company sells the majority of its products with a twelve months repair or replacement warranty from the date of acceptance, which generally represents the date of shipment. The Company provides an accrual for estimated future warranty costs based upon the historical relationship of warranty costs to the cost of products sold. The estimated future warranty obligations related to product sales are reported in the period in which the related revenue is recognized. The estimated future warranty obligations are affected by the warranty periods, sales volumes, product failure rates, material usage and labor and replacement costs incurred in correcting a product failure. If actual product failure rates, material usage, labor or replacement costs differ from the Company’s estimates, revisions to the estimated warranty obligations would be required. For new product introductions where limited or no historical information exists, the Company may use warranty information from other previous product introductions to guide it in estimating the warranty accrual. The warranty accrual represents the best estimate of the amount necessary to settle future and existing claims on products sold as of the balance sheet date. The Company periodically assesses the adequacy of its recorded warranty reserve and adjusts the amounts in accordance with changes in these factors.
Shipping and Handling Costs	Shipping and Handling Costs – Shipping and handling costs are included as a component of cost of net revenues.
Advertising Costs	Advertising Costs – The Company expenses advertising costs as incurred. Advertising costs were $ 0.3 million in 2015, $0.2 million in 2014, and $0.2 million in 2013.
Defined Employee Benefit Plans	Defined Employee Benefit Plans – The Company maintains a defined benefit pension plan in Taiwan for which current service costs are charged to operations as they accrue based on services rendered by employees during the year. Pension benefit obligations are determined by using management’s actuarial assumptions, including discount rates, assumed asset rates of return, compensation increases and employee turnover rates.
Net Income (Loss) Per Share	Net Income (Loss) Per Share - Basic net income (loss) per share excludes dilution and is computed by dividing net income (loss) by the number of weighted average common shares outstanding for the period. Diluted net income (loss) per share reflects the potential dilution from outstanding dilutive stock options (using the treasury stock method) restricted stock units subject to vesting and shares issuable under the employee stock purchase plan. In applying the treasury stock method, 0.3 million stock option shares for fiscal year 2015 were included because their effects were anti-dilutive. While these stock option shares are currently anti-dilutive, they could be dilutive in the future. During both fiscal 2014 and 2013, the Company incurred a net loss, therefore, diluted net loss per share excludes 0.4 million shares that were anti-dilutive.
Certain Significant Risks and Uncertainties	Certain Significant Risks and Uncertainties – Financial instruments that potentially subject us to a concentration of credit risk consist of cash, cash equivalents, marketable securities, and accounts receivable. The Company's cash and cash equivalents are primarily invested in deposit accounts and money market accounts with large financial institutions. At times, these deposits and securities may exceed federally insured limits; however, the Company has not experienced any losses on such accounts. The Company invests its cash not required for use in operations in high credit quality securities based on the Company's investment policy. The Company's investment policy provides guidelines and limits regarding credit quality, investment concentration, investment type, and maturity that the Company believes will provide liquidity while reducing risk of loss of capital. Investments are of a short-term nature and include investments in commercial paper, corporate debt securities, U.S. Treasury, U.S. Government, and U.S. Agency debt. The Company sells its products primarily to end users in the United States, Asia and Europe and, generally, does not require its customers to provide collateral or other security to support accounts receivable. Management performs ongoing credit evaluations of its customers’ financial condition and maintains an allowance for estimated potential bad debt losses. The Company’s customer base is highly concentrated and historically, a relatively small number of customers have accounted for a significant portion of its revenues. Aggregate revenue from the Company's top five largest customers in 2015, 2014 and 2013 consisted of 69%, 72% and 71%, respectively, of its total net revenues. The Company participates in a dynamic high technology industry and believes that changes in any of the following areas could have a material adverse effect on its future financial position, results of operations or cash flows: advances and trends in new technologies and industry standards; competitive pressures in the form of new products or price reductions on current products; changes in product mix; changes in the overall demand for products offered; changes in third-party manufacturers; changes in key suppliers; changes in certain strategic relationships or customer relationships; litigation or claims against the Company based on intellectual property, patent, product, regulatory or other factors; fluctuations in foreign currency exchange rates; risk associated with changes in domestic and international economic and/or political regulations; availability of necessary components or sub-assemblies; disruption of manufacturing facilities; and its ability to attract and retain employees necessary to support its growth. Certain components and sub-assemblies used in the Company’s products are purchased from a sole supplier or a limited group of suppliers. In particular, the Company currently purchases its spectroscopic ellipsometer and robotics used in its advanced measurement systems from a sole supplier or a limited group of suppliers located in the United States. Any shortage or interruption in the supply of any of the components or sub-assemblies used in its products or its inability to procure these components or sub-assemblies from alternate sources on acceptable terms could have a material adverse effect on its business, financial condition and results of operations.

Nature of Business, Basis of 26

Nature of Business, Basis of Presentation and Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 26, 2015
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Estimated useful lives of property, plant and equipment	Depreciation and amortization is computed using the straight–line method over the following estimated useful lives of the assets: Building and Improvements 5-40 years Machinery and equipment 3-10 years Furniture and fixtures 3-10 years Software 3-7 years
Estimated Useful Lives of Intangible Assets	Amortization of intangible assets with finite lives is computed using the straight-line method over the following estimated useful lives of the assets: Developed technology 5-10 years Customer relationships 2-10 years Brand name 5-10 years Patented technology 7-10 years Trademark 5 years

Fair Value Measurements and D27

Fair Value Measurements and Disclosures (Tables)	12 Months Ended
	Dec. 26, 2015
Fair Value Disclosures [Abstract]
Assets and liabilities measurements at estimated fair value on recurring basis excluding accrued interest components	The following tables present the Company’s assets and liabilities measured at estimated fair value on a recurring basis, excluding accrued interest components, categorized in accordance with the fair value hierarchy (in thousands), as of the following dates: December 26, 2015 December 27, 2014 Fair Value Measurements Using Input Types Fair Value Measurements Using Input Types Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total Assets: Cash equivalents: Money market funds $ 590 $ — $ — $ 590 $ 610 $ — $ — $ 610 Commercial paper and corporate debt securities — 4,568 — 4,568 — — — — Total cash equivalents $ 590 $ 4,568 $ — $ 5,158 $ 610 $ — $ — $ 610 Marketable securities: U.S. Treasury, U.S. Government and U.S. Government agency debt securities 4,401 20,164 — 24,565 2,497 20,537 — 23,034 Commercial paper, municipal securities and corporate debt securities — 20,366 — 20,366 — 26,252 — 26,252 Total marketable securities $ 4,401 $ 40,530 $ — $ 44,931 $ 2,497 $ 46,789 $ — $ 49,286 Total (1) $ 4,991 $ 45,098 $ — $ 50,089 $ 3,107 $ 46,789 $ — $ 49,896 Liabilities: Contingent consideration payable $ — $ — $ 1,490 $ 1,490 $ — $ — $ 2,397 $ 2,397 (1) Excludes $33.0 million and $34.1 million held in operating accounts as of December 26, 2015 and December 27, 2014, respectively.
Fair value measurement on recurring basis, unobservable input reconciliation	Changes in Level 3 liabilities (in thousands) Fair value at December 28, 2013 $ 2,783 Payments made to Zygo Corporation (587 ) Change in fair value included in earnings 201 Fair value at December 27, 2014 2,397 Payments made to Zygo Corporation (851 ) Change in fair value included in earnings (56 ) Fair value at December 26, 2015 $ 1,490
Outstanding derivative instruments	The following table summarizes the Company’s outstanding derivative instruments on a gross basis as of December 26, 2015: Notional Principal (in millions) Undesignated Hedges: Forward Foreign Currency Contracts $ 30.5

Cash and Investments (Tables)

Cash and Investments (Tables)	12 Months Ended
	Dec. 26, 2015
Investments Debt And Equity Securities [Abstract]
Cash, Cash Equivalents and Available-for-Sale Investments	The following table presents cash, cash equivalents, and available-for-sale investments as of the following dates (in thousands): December 26, 2015 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Market Value Cash $ 32,996 $ — $ — $ 32,996 Cash equivalents: Money market funds 590 — — 590 Commercial paper and corporate debt securities 4,568 — — 4,568 Marketable securities: Commercial paper 1,884 — — 1,884 U.S. Treasury securities 4,411 — (10 ) 4,401 U.S. Government agency securities 20,193 1 (29 ) 20,165 Municipal securities 3,747 1 (3 ) 3,745 Corporate debt securities 14,759 — (23 ) 14,736 Total cash, cash equivalents, and marketable securities $ 83,148 $ 2 $ (65 ) $ 83,085 December 27, 2014 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Market Value Cash $ 34,066 $ — $ — $ 34,066 Cash equivalents: Money market funds 610 — — 610 Marketable securities: Commercial paper and corporate debt securities 805 — — 805 U.S. Treasury securities 2,498 — (1 ) 2,497 U.S. Government agency securities 20,556 1 (19 ) 20,538 Municipal securities 3,755 1 (7 ) 3,749 Corporate debt securities 21,722 1 (26 ) 21,697 Total cash, cash equivalents, and marketable securities $ 84,012 $ 3 $ (53 ) $ 83,962

Financial Statement Components

Financial Statement Components (Tables)	12 Months Ended
	Dec. 26, 2015
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Selected financial statement components	The following tables provide details of selected financial statement components as of the following dates (in thousands): At December 26, 2015 December 27, 2014 Inventories: Raw materials and sub-assemblies $ 26,784 $ 19,463 Work in process 12,862 7,723 Finished goods 8,103 7,919 Inventories 47,749 35,105 Inventories-delivered systems 2,856 1,912 Total inventories $ 50,605 $ 37,017 Property, plant and equipment, net: (1) Land $ 15,569 $ 15,572 Building and improvements 20,158 19,641 Machinery and equipment 32,995 29,456 Furniture and fixtures 2,266 2,225 Software 8,245 7,942 Capital in progress 1,328 3,512 Total property, plant and equipment, gross 80,561 78,348 Accumulated depreciation and amortization (36,068 ) (28,715 ) Total property, plant and equipment, net $ 44,493 $ 49,633 (1) Total depreciation and amortization expense for the years ended December 26, 2015, December 27, 2014 and December 28, 2013 was $6.9 million, $6.6 million, and $5.4 million, respectively. Other Current Liabilities: Accrued warranty $ 4,504 $ 2,953 Accrued restructuring 256 997 Accrued professional services 481 778 Fair value of current portion of contingent payments to Zygo Corporation related to acquisition 945 1,385 Other 2,692 2,152 Total other current liabilities $ 8,878 $ 8,265
Components of accumulated other comprehensive income (loss)	Components of Accumulated Other Comprehensive Income (Loss) Years Ended Foreign Currency Translations Defined Benefit Pension Plans Unrealized Income (Loss) on Investment Accumulated Other Comprehensive Income Balance as of December 28, 2013 $ 635 $ (28 ) $ 5 $ 612 Current period change (3,239 ) (106 ) (36 ) (3,381 ) Balance as of December 27, 2014 (2,604 ) (134 ) (31 ) (2,769 ) Current period change (2,344 ) (76 ) (13 ) (2,433 ) Balance as of December 26, 2015 $ (4,948 ) $ (210 ) $ (44 ) $ (5,202 )

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	12 Months Ended
	Dec. 26, 2015
Goodwill And Intangible Assets Disclosure [Abstract]
Schedule of goodwill	The following table summarizes the activity in the Company’s goodwill during the years ended December 26, 2015 and December 27, 2014, respectively (in thousands): Balance as of December 29, 2013 $ 11,743 Foreign currency movements (1,249 ) Balance as of December 28, 2014 10,494 Foreign currency movements (1,079 ) Balance as of December 26, 2015 $ 9,415
Summary of finite-lived intangible assets	Finite-lived intangible assets are recorded at cost, less accumulated amortization. Finite-lived intangible assets as of December 26, 2015 and December 27, 2014 consisted of the following (in thousands): December 26, 2015 Adjusted cost Accumulated amortization Net carrying amount Developed technology $ 16,098 $ (14,387 ) $ 1,711 Customer relationships 9,364 (9,364 ) — Brand names 1,927 (1,903 ) 24 Patented technology 2,252 (2,120 ) 132 Trademark 80 (80 ) — Total $ 29,721 $ (27,854 ) $ 1,867 December 27, 2014 Adjusted cost Accumulated amortization Net carrying amount Developed technology $ 16,950 $ (12,991 ) $ 3,959 Customer relationships 9,461 (9,449 ) 12 Brand names 1,927 (1,802 ) 125 Patented technology 2,252 (2,054 ) 198 Trademark 80 (80 ) — Total $ 30,670 $ (26,376 ) $ 4,294
Estimated future amortization expense	The estimated future amortization expense of finite intangible assets as of December 26, 2015, is as follows (in thousands): Fiscal Years Amounts 2016 $ 1,455 2017 206 2018 140 2019 66 Thereafter — Total future amortization expense $ 1,867

Warranties (Tables)

Warranties (Tables)	12 Months Ended
	Dec. 26, 2015
Product Warranties Disclosures [Abstract]
Components of the warranty accrual	Components of the warranty accrual, which were included in the accompanying consolidated balance sheets with other current liabilities, were as follows (in thousands): Years Ended December 26, 2015 December 27, 2014 Balance as of beginning of period $ 2,953 $ 3,426 Accruals for warranties issued during period 8,332 5,987 Settlements during the period (6,781 ) (6,460 ) Balance as of end of period $ 4,504 $ 2,953

Restructuring (Tables)

Restructuring (Tables)	12 Months Ended
	Dec. 26, 2015
Restructuring And Related Activities [Abstract]
Components of the restructuring reserve	As of December 26, 2015 and December 27, 2014, respectively, the components of the Company’s restructuring reserves were included in other current liabilities and were as follows (in thousands): Employee severance and benefits Facility termination costs Other Total Balance as of December 27, 2014 $ 383 $ 583 $ 31 $ 997 Charges 1,369 — 11 1,380 Cash Payments (1,752 ) (334 ) (35 ) (2,121 ) Balance as of December 26, 2015 $ — $ 249 $ 7 $ 256 Employee severance and benefits Facility termination costs Other Total Balance as of December 28, 2013 $ — $ — $ — $ — Charges 1,163 784 319 2,266 Cash Payments (780 ) (201 ) (288 ) (1,269 ) Balance as of December 27, 2014 $ 383 $ 583 $ 31 $ 997

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 26, 2015
Commitments And Contingencies Disclosure [Abstract]
Future minimum lease payments under operating leases	Future minimum lease payments under its operating leases are as follows (in thousands): Operating Leases 2016 $ 1,372 2017 733 2018 407 2019 311 Thereafter — Total $ 2,823

Net Income (Loss) Per Share (Ta

Net Income (Loss) Per Share (Tables)	12 Months Ended
	Dec. 26, 2015
Earnings Per Share [Abstract]
Reconciliation of the basic and diluted net income per share computations	A reconciliation of the share denominator of the basic and diluted net income (loss) per share computations is as follows (in thousands): Years Ended December 26, 2015 December 27, 2014 December 28, 2013 Weighted average common shares outstanding used in basic net income (loss) per share calculation 24,059 23,958 23,290 Potential dilutive common stock equivalents, using treasury stock method 316 — — Weighted average shares used in diluted net income (loss) per share calculation 24,375 23,958 23,290

Stockholders' Equity and Stoc35

Stockholders' Equity and Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 26, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share repurchases	Shares repurchased and retired for the indicated periods of the applicable repurchase programs with the associated cost of repurchase and amount available for repurchase at the end of the respective periods are as follows (in thousands, except number of shares and weighted average price per share): Fiscal Year 2015 Fiscal Year 2014 Fiscal Year 2013 Number of shares of common stock repurchased 111,050 362,633 332,771 Weighted average price per share $ 15.49 $ 14.74 $ 15.03 Total cost of repurchase $ 1,721 $ 5,344 $ 5,000 Amount available for repurchase at end of period $ 4,397 $ 6,118 $ 11,462
Option plans	The Nanometrics option plans are as follows: Plan Name Participants Shares Authorized 2005 Equity Incentive Plan Employees, consultants and directors 7,292,594 2002 Non-statutory Stock Option Plan Employees and consultants 1,200,000 2000 Employee Stock Option Plan Employees and consultants 2,450,000 2000 Director Stock Option Plan Non-employee directors 250,000 Accent Optical Technologies, Inc. Stock Incentive Plan Employees and consultants 205,003
Stock options and employee stock purchase plan assumptions	The weighted-average fair value calculations are based on the following average assumptions: Fiscal Year 2015 Fiscal Year 2014 Fiscal Year 2013 Stock Options: Expected life — 4.6 years 4.5 years Volatility — 54.9 % 69.9 % Risk free interest rate — 1.54 % 1.05 % Dividends — — — Employee Stock Purchase Plan: Expected life 0.5 years 0.5 years 0.5 years Volatility 36.9 % 31.2 % 26.8 % Risk free interest rate 0.12 % 0.54 % 0.11 % Dividends — — —
Stock option plans activity	A summary of activity of stock options in 2015 is as follows: Number of Shares Outstanding (Options) Weighted Average Exercise Price Weighted Average Remaining Contractual Term (Years) Aggregate Intrinsic Value (in Thousands) Options Outstanding at December 27, 2014 1,382,993 $ 13.92 3.41 $ 4,108 Exercised (229,510 ) $ 9.65 Granted — $ — - $ — Cancelled (94,012 ) $ 16.67 Outstanding at December 26, 2015 1,059,471 $ 14.61 2.47 $ 1,920 Exercisable at December 26, 2015 926,415 $ 14.36 2.15 $ 1,879
Ranges of outstanding and exercisable options	The following table summarizes ranges of outstanding and exercisable options as of December 26, 2015. Options Outstanding Options Exercisable Exercise Prices Number Outstanding Weighted Average Remaining Contractual Life (Years) Weighted Average Exercise Price Number Exercisable Weighted Average Exercise Price $2.38-$10.46 134,762 0.90 $ 7.84 134,762 $ 7.8400 $10.83-$11.17 14,156 1.30 $ 10.93 14,156 $ 1.9279 $11.37-$11.37 114,166 1.89 $ 11.37 114,166 $ 11.3700 $12.98-$14.8 111,259 2.62 $ 13.67 94,579 $ 13.6200 $14.88-$15.65 111,967 3.84 $ 15.44 78,894 $ 15.4300 $15.74-$15.98 161,850 1.81 $ 15.91 143,100 $ 15.9200 $16.00-$16.50 41,804 4.76 $ 16.43 23,190 $ 16.4200 $16.70-$16.7 186,434 1.86 $ 16.70 186,434 $ 16.7000 $16.89-$18.51 123,773 4.22 $ 17.82 80,931 $ 17.8300 $18.79-$19.84 59,300 2.98 $ 19.12 56,203 $ 19.1300 $2.38-$19.84 1,059,471 2.47 $ 14.61 926,415 $ 14.3600
Summary of activity for RSUs	A summary of activity for RSUs is as follows: Summary of activity for RSUs Number of RSUs Weighted Average Fair Value Outstanding RSUs as of December 27, 2014 563,337 $ 17.90 Granted 506,459 $ 15.62 Released (237,520 ) $ 16.59 Cancelled (119,033 ) $ 16.59 Outstanding RSUs as of December 26, 2015 713,243 $ 15.99
PSUs valuation assumptions	The assumptions for the valuation of PSUs are summarized as follows: 2015 Award Number of PSUs granted and outstanding as of December 26, 2015 40,000 Grant Date Fair Value Per Share $ 18.35 Weighted-average assumptions/inputs: Expected Divident — Range of risk-free interest rates 0.25%-1.1% Range of expected volatilities for peer group 23%-65%
Stock-based compensation expense for all share-based payment awards	Stock-based compensation expense for all share-based payment awards made to the Company’s employees and directors pursuant to the employee stock option and employee stock purchase plans by function were as follows (in thousands): Fiscal Year 2015 Fiscal Year 2014 Fiscal Year 2013 Cost of products $ 274 $ 268 $ 207 Cost of service 309 287 278 Research and development 1,036 1,245 1,478 Selling 1,881 1,642 1,894 General and administrative 2,748 3,243 2,919 Restructuring — 67 898 Total stock-based compensation expense related to employee stock options and employee stock purchases $ 6,248 $ 6,752 $ 7,674
Stock Options and Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option plans activity including options and RSUs	A summary of activity under the Company’s stock option plans including options and RSUs during fiscal year 2015, 2014 and 2013 and shares available for grant as of the respective period end dates, is as follows: Fiscal Year 2015 Fiscal Year 2014 Fiscal Year 2013 Shares available for grant at beginning of fiscal year 2,464,082 2,937,001 1,093,565 Increase in authorized shares — — 2,600,000 Options - granted — (74,300 ) (430,800 ) Options - cancelled 94,012 191,061 150,459 Options - expired plan shares (1,800 ) (17,491 ) (53,607 ) RSUs – granted (860,980 ) (805,120 ) (664,902 ) RSUs – cancelled 202,356 167,404 133,418 RSUs - shares issued to satisfy tax withholding obligations 120,919 65,527 108,868 PSUs – granted (68,000 ) — — Shares available for grant at end of fiscal year 1,950,589 2,464,082 2,937,001

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 26, 2015
Income Tax Disclosure [Abstract]
Income (loss) before provision for income taxes	Income (loss) before provision for income taxes consists of the following (in thousands): Years Ended December 26, 2015 December 27, 2014 December 28, 2013 Domestic $ 178 $ (15,691 ) $ (26,447 ) Foreign 5,390 4,070 2,882 Income (loss) before income taxes $ 5,568 $ (11,621 ) $ (23,565 )
Provision (benefit) for income taxes	The provision (benefit) for income taxes consists of the following (in thousands): Years Ended December 26, 2015 December 27, 2014 December 28, 2013 Current: Federal $ 148 $ 358 $ 119 State 3 (151 ) 5 Foreign 2,266 1,327 933 2,417 1,534 1,057 Deferred: Federal 190 17,368 (10,686 ) State 3 550 (325 ) Foreign 53 45 535 246 17,963 (10,476 ) Provision (benefit) for income taxes $ 2,663 $ 19,497 $ (9,419 )
Components of deferred tax assets and liabilities	Significant components of the Company's deferred tax assets and liabilities are as follows (in thousands): At December 26, 2015 December 27, 2014 Deferred tax assets: Reserves and accruals $ 13,712 $ 10,744 Deferred revenue 1,154 1,370 Shared based compensation 3,856 4,030 Tax credit carry-forwards 8,658 8,122 Net operating losses 13,218 14,695 Depreciation & amortization 366 2,750 Other 94 372 Total deferred tax assets 41,058 42,083 Less: Valuation allowance (36,786 ) (35,835 ) Total deferred tax assets net of valuation allowance 4,272 6,248 Deferred tax liabilities: Depreciation & amortization (2,537 ) (4,020 ) Other (1,137 ) (1,485 ) Total deferred tax liabilities (3,674 ) (5,505 ) Net deferred tax assets $ 598 $ 743
Income Tax Rate Reconciliation	Differences between income taxes computed by applying the statutory federal income tax rate to income (loss) before income taxes and the provision (benefit) for income taxes consist of the following (in thousands): Years Ended December 26, 2015 December 27, 2014 December 28, 2013 Income taxes computed at U.S. statutory rate $ 1,949 $ (4,067 ) $ (8,247 ) State income taxes 28 (109 ) 147 Foreign tax rate differential 342 777 479 Change in valuation allowance 1,648 23,894 — Non-deductible Equity Compensation 311 242 210 Tax credits (1,834 ) (2,187 ) (2,103 ) Liabilities for uncertain tax positions 74 118 111 Other, net 145 829 (16 ) Provision (benefit) for income taxes $ 2,663 $ 19,497 $ (9,419 )
Reconciliation of unrecognized tax benefits	A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows (in thousands): Rollforward Table (at Gross): As of December 26, 2015 December 27, 2014 December 28, 2013 Unrecognized tax benefits - beginning of the period $ 6,442 $ 4,436 $ 3,464 Gross increases-tax positions in prior period 127 655 305 Gross decreases-tax positions in prior period (306 ) (123 ) — Gross increases-current-period tax positions 698 1,541 688 Lapse of statute of limitations — (67 ) (21 ) Unrecognized tax benefits - end of the period $ 6,961 $ 6,442 $ 4,436

Segment, Geographic, Product 37

Segment, Geographic, Product and Significant Customer Information (Tables)	12 Months Ended
	Dec. 26, 2015
Segment Reporting [Abstract]
Total net revenue	The following tables summarize total net revenues and long-lived assets (excluding intangible assets) attributed to significant countries (in thousands): Years Ended December 26, 2015 December 27, 2014 December 28, 2013 Total net revenues (1): United States $ 36,720 $ 36,123 $ 47,019 China 17,373 28,702 13,063 Japan 31,140 15,185 11,629 South Korea 30,572 41,381 34,873 Taiwan 46,715 19,790 9,645 Other 24,847 25,262 28,078 Total net revenues $ 187,367 $ 166,443 $ 144,307 (1)
Long-lived tangible assets	December 26, 2015 December 27, 2014 Long-lived tangible assets: United States $ 42,581 $ 47,729 Japan 59 71 South Korea 697 284 Taiwan 1,056 1,473 All Other 100 76 Total long-lived tangible assets $ 44,493 $ 49,633
Revenues by product type	The Company’s product lines differ primarily based on the environment in which the systems will be used. Automated systems are used primarily in high-volume production environments. Materials characterization products are primarily used to measure the composition, band gap, structure, and other physical and electrical properties of semiconducting materials for discrete electronic industry, high brightness LED and solar/photovoltaic structures in both development and high volume environments. Integrated systems are installed inside wafer processing equipment to provide near real-time measurements for improving process control and increasing throughput. Revenues by product type were as follows (in thousands): Years Ended December 26, 2015 December 27, 2014 December 28, 2013 Automated Systems $ 102,386 $ 108,768 $ 82,924 Integrated Systems 31,579 15,334 11,412 Materials Characterization Systems 12,980 9,487 13,066 Total product revenues $ 146,945 $ 133,589 $ 107,402 Revenues by product type were as follows (in thousands):
Customers accounted for 10% or more of total accounts receivable	The following customers accounted for 10% or more of total accounts receivable, net: Years Ended December 26, 2015 December 27, 2014 December 28, 2013 Toshiba Corporation 27.1 % *** *** Taiwan Semiconductor Manufacturing Company Limited 25.6 % 20.2 % 12.1 % SK Hynix *** *** 21.8 % Samsung Electronics Co. Ltd. *** 10.0 % 27.4 % Micron *** 23.7 % *** Intel Corporation *** *** 14.4 % GlobalFoundries *** 10.2 % *** *** The customer accounted for less than 10% of total accounts receivable, net, as of that period end.
Customers accounted for 10% or more of total revenue	The following customers accounted for 10% or more of total net revenue: Years Ended December 26, 2015 December 27, 2014 December 28, 2013 Taiwan Semiconductor Manufacturing Company Limited 19.4 % *** *** Micron 15.8 % 10.4 % *** Samsung Electronics Co. Ltd. 13.2 % 26.9 % 14.4 % SK Hynix 10.7 % 12.2 % 18.4 % Toshiba Corporation 10.2 % *** *** Intel Corporation *** 12.6 % 30.0 % *** The customer accounted for less than 10% of total net revenue during the period.

Nature of Business, Basis of 38

Nature of Business, Basis of Presentation and Significant Accounting Policies - Textual (Details) shares in Millions, $ in Millions	12 Months Ended
	Dec. 26, 2015USD ($)Customershares	Dec. 27, 2014USD ($)Customershares	Dec. 28, 2013USD ($)Customershares
Accounting Policies [Line Items]
Fiscal year duration	364 days	364 days	364 days
Foreign currency transaction gains (losses) | $	$ 0.5	$ 0.1	$ (0.7)
Maximum period of delivery to customers	6 months
Maximum period services are provided over the fixed arrangement term	12 months
Maximum measurement period	1 year
Product warranty period	12 months
Advertising costs | $	$ 0.3	$ 0.2	$ 0.2
Anti-dilutive common stock equivalents excluded from calculation | shares		0.4	0.4
Number of Major Customer | Customer	5	5	5
Sales Revenue, Goods, Net [Member] | Customer Concentration Risk [Member]
Accounting Policies [Line Items]
Concentration of risk percentage	69.00%	72.00%	71.00%
Stock Options [Member]
Accounting Policies [Line Items]
Anti-dilutive common stock equivalents excluded from calculation | shares	0.3
Minimum [Member]
Accounting Policies [Line Items]
Fiscal year duration	364 days
Maximum [Member]
Accounting Policies [Line Items]
Fiscal year duration	371 days

Nature of Business, Basis of 39

Nature of Business, Basis of Presentation and Significant Accounting Policies - Estimated Useful Lives of Property, Plant and Equipment (Details)	12 Months Ended
	Dec. 26, 2015
Building and Improvements [Member] | Minimum [Member]
Accounting Policies [Line Items]
Estimated useful lives of depreciable assets	5 years
Building and Improvements [Member] | Maximum [Member]
Accounting Policies [Line Items]
Estimated useful lives of depreciable assets	40 years
Machinery and equipment [Member] | Minimum [Member]
Accounting Policies [Line Items]
Estimated useful lives of depreciable assets	3 years
Machinery and equipment [Member] | Maximum [Member]
Accounting Policies [Line Items]
Estimated useful lives of depreciable assets	10 years
Furniture and fixtures [Member] | Minimum [Member]
Accounting Policies [Line Items]
Estimated useful lives of depreciable assets	3 years
Furniture and fixtures [Member] | Maximum [Member]
Accounting Policies [Line Items]
Estimated useful lives of depreciable assets	10 years
Software [Member] | Minimum [Member]
Accounting Policies [Line Items]
Estimated useful lives of depreciable assets	3 years
Software [Member] | Maximum [Member]
Accounting Policies [Line Items]
Estimated useful lives of depreciable assets	7 years

Nature of Business, Basis of 40

Nature of Business, Basis of Presentation and Significant Accounting Policies - Estimated Useful Lives of Intangible Assets (Details)	12 Months Ended
	Dec. 26, 2015
Minimum [Member]
Accounting Policies [Line Items]
Finite-lived intangibles estimated lives	2 years
Maximum [Member]
Accounting Policies [Line Items]
Finite-lived intangibles estimated lives	10 years
Developed technology [Member] | Minimum [Member]
Accounting Policies [Line Items]
Finite-lived intangibles estimated lives	5 years
Developed technology [Member] | Maximum [Member]
Accounting Policies [Line Items]
Finite-lived intangibles estimated lives	10 years
Customer relationships [Member] | Minimum [Member]
Accounting Policies [Line Items]
Finite-lived intangibles estimated lives	2 years
Customer relationships [Member] | Maximum [Member]
Accounting Policies [Line Items]
Finite-lived intangibles estimated lives	10 years
Brand name [Member] | Minimum [Member]
Accounting Policies [Line Items]
Finite-lived intangibles estimated lives	5 years
Brand name [Member] | Maximum [Member]
Accounting Policies [Line Items]
Finite-lived intangibles estimated lives	10 years
Patented technology [Member] | Minimum [Member]
Accounting Policies [Line Items]
Finite-lived intangibles estimated lives	7 years
Patented technology [Member] | Maximum [Member]
Accounting Policies [Line Items]
Finite-lived intangibles estimated lives	10 years
Trademark [Member]
Accounting Policies [Line Items]
Finite-lived intangibles estimated lives	5 years

Recent Accounting Pronounceme41

Recent Accounting Pronouncements (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 29, 2014	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Error Corrections And Prior Period Adjustments Restatement [Line Items]
Income tax expense (benefit)		$ 2,663	$ 19,497	$ (9,419)
Increase (decrease) in long-term income taxes payable		$ 828	$ (212)	$ (666)
Adjustments for New Accounting Pronouncement [Member] | Restatement Adjustment [Member]
Error Corrections And Prior Period Adjustments Restatement [Line Items]
Income tax expense (benefit)	$ (300)
Increase (decrease) in deferred tax assets	(300)
Increase (decrease) in long-term income taxes payable	$ (600)

Fair Value Measurements and D42

Fair Value Measurements and Disclosures - Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 26, 2015	Dec. 27, 2014
Assets:
Total marketable securities	$ 44,931	$ 49,286
Fair Value, Measurements, Recurring [Member]
Assets:
Total cash equivalents	5,158	610
Total marketable securities	44,931	49,286
Total	50,089	49,896
Liabilities:
Contingent consideration payable	1,490	2,397
Money market funds [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Total cash equivalents	590	610
Commercial paper and corporate debt securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Total cash equivalents	4,568	0
U.S. Treasury, U.S. Government and U.S. Government agency debt securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Total marketable securities	24,565	23,034
Commercial paper, municipal securities and corporate debt securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Total marketable securities	20,366	26,252
Cash [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Total cash equivalents	33,000	34,100
Level 1 [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Total cash equivalents	590	610
Total marketable securities	4,401	2,497
Total	4,991	3,107
Liabilities:
Contingent consideration payable	0	0
Level 1 [Member] | Money market funds [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Total cash equivalents	590	610
Level 1 [Member] | Commercial paper and corporate debt securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Total cash equivalents	0	0
Level 1 [Member] | U.S. Treasury, U.S. Government and U.S. Government agency debt securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Total marketable securities	4,401	2,497
Level 1 [Member] | Commercial paper, municipal securities and corporate debt securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Total marketable securities	0	0
Level 2 [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Total cash equivalents	4,568	0
Total marketable securities	40,530	46,789
Total	45,098	46,789
Liabilities:
Contingent consideration payable	0	0
Level 2 [Member] | Money market funds [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Total cash equivalents	0	0
Level 2 [Member] | Commercial paper and corporate debt securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Total cash equivalents	4,568	0
Level 2 [Member] | U.S. Treasury, U.S. Government and U.S. Government agency debt securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Total marketable securities	20,164	20,537
Level 2 [Member] | Commercial paper, municipal securities and corporate debt securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Total marketable securities	20,366	26,252
Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Total cash equivalents	0	0
Total marketable securities	0	0
Total	0	0
Liabilities:
Contingent consideration payable	1,490	2,397
Level 3 [Member] | Money market funds [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Total cash equivalents	0	0
Level 3 [Member] | Commercial paper and corporate debt securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Total cash equivalents	0	0
Level 3 [Member] | U.S. Treasury, U.S. Government and U.S. Government agency debt securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Total marketable securities	0	0
Level 3 [Member] | Commercial paper, municipal securities and corporate debt securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Total marketable securities	$ 0	$ 0

Fair Value Measurements and D43

Fair Value Measurements and Disclosures - Unobservable Input Reconciliation (Details) - Level 3 [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014
Fair value measurement on recurring basis, unobservable input reconciliation [Roll Forward]
Fair value, beginning balance	$ 2,397	$ 2,783
Change in fair value included in earnings	(56)	201
Fair Value, ending balance	1,490	2,397
Zygo Corporation [Member]
Fair value measurement on recurring basis, unobservable input reconciliation [Roll Forward]
Payments made to Zygo Corporation	$ (851)	$ (587)

Fair Value Measurements and D44

Fair Value Measurements and Disclosures - Textual (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014
Forward Foreign Currency Contracts [Member]
Fair Value Measurements and Disclosures (Textual) [Abstract]
Derivative term	30 days
Forward Foreign Currency Contracts [Member] | Other Income (Expense), Net [Member]
Fair Value Measurements and Disclosures (Textual) [Abstract]
Gain (loss) on settlement of derivatives	$ (0.3)
Fair Value, Measurements, Recurring [Member] | Zygo Corporation [Member]
Fair Value Measurements and Disclosures (Textual) [Abstract]
Liabilities resulting from the acquisition of certain assets from acquisitions, measured at fair value	1.5	$ 2.4
Current liability at fair value	0.9	1.4
Long-term liability at fair value	$ 0.6	$ 1

Fair Value Measurements and D45

Fair Value Measurements and Disclosures - Outstanding Derivative Instruments (Details)	Dec. 26, 2015USD ($)
Not Designated as Hedging Instrument [Member] | Forward Foreign Currency Contracts [Member]
Derivatives Fair Value [Line Items]
Notional Principal	$ 30,500,000

Cash and Investments (Details)

Cash and Investments (Details) - USD ($) $ in Thousands	Dec. 26, 2015	Dec. 27, 2014
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	$ 83,148	$ 84,012
Gross Unrealized Gains	2	3
Gross Unrealized Losses	(65)	(53)
Estimated Fair Market Value	83,085	83,962
Commercial paper [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	1,884
Gross Unrealized Gains	0
Gross Unrealized Losses	0
Estimated Fair Market Value	1,884
U.S. Government agency securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	20,193	20,556
Gross Unrealized Gains	1	1
Gross Unrealized Losses	(29)	(19)
Estimated Fair Market Value	20,165	20,538
Corporate debt securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	14,759	21,722
Gross Unrealized Gains	0	1
Gross Unrealized Losses	(23)	(26)
Estimated Fair Market Value	14,736	21,697
Cash [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	32,996	34,066
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Market Value	32,996	34,066
Money market funds [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	590	610
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Market Value	590	610
U.S. Treasury securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	4,411	2,498
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(10)	(1)
Estimated Fair Market Value	4,401	2,497
Commercial paper and corporate debt securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	4,568
Gross Unrealized Gains	0
Gross Unrealized Losses	0
Estimated Fair Market Value	4,568
Commercial paper and corporate debt securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost		805
Gross Unrealized Gains		0
Gross Unrealized Losses		0
Estimated Fair Market Value		805
Municipal securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	3,747	3,755
Gross Unrealized Gains	1	1
Gross Unrealized Losses	(3)	(7)
Estimated Fair Market Value	$ 3,745	$ 3,749

Cash and Investments - Addition

Cash and Investments - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Investments Debt And Equity Securities [Abstract]
Net realized gain and losses	$ 0.2	$ 0.2	$ 0.2
Investment maturity period, less than	2 years	2 years

Accounts Receivable - Textual (

Accounts Receivable - Textual (Details) - USD ($)	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014
Accounts Receivable (Additional Textual) [Abstract]
Sold receivables amount	$ 15,700,000	$ 7,700,000
Gains or losses on sale of accounts receivables	0	0
Due from unrelated third parties	$ 0	$ 0
Minimum [Member]
Accounts Receivable (Textual) [Abstract]
Administrative fees as well as interest percent	1.15%
Maximum [Member]
Accounts Receivable (Textual) [Abstract]
Administrative fees as well as interest percent	1.68%

Financial Statement Component49

Financial Statement Components - Selected Financial Statement Components (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Inventories:
Raw materials and sub-assemblies	$ 26,784	$ 19,463
Work in process	12,862	7,723
Finished goods	8,103	7,919
Inventories	47,749	35,105
Inventories-delivered systems	2,856	1,912
Total inventories	50,605	37,017
Property, plant and equipment, net:
Total property, plant and equipment, gross	80,561	78,348
Accumulated depreciation and amortization	(36,068)	(28,715)
Total property, plant and equipment, net	44,493	49,633
Depreciation and amortization expense	6,900	6,600	$ 5,400
Accrued warranty	4,504	2,953
Accrued restructuring	256	997
Accrued professional services	481	778
Fair value of current portion of contingent payments to Zygo Corporation related to acquisition	945	1,385
Other	2,692	2,152
Total other current liabilities	8,878	8,265
Land [Member]
Property, plant and equipment, net:
Total property, plant and equipment, gross	15,569	15,572
Building and improvements [Member]
Property, plant and equipment, net:
Total property, plant and equipment, gross	20,158	19,641
Machinery and equipment [Member]
Property, plant and equipment, net:
Total property, plant and equipment, gross	32,995	29,456
Furniture and fixtures [Member]
Property, plant and equipment, net:
Total property, plant and equipment, gross	2,266	2,225
Software [Member]
Property, plant and equipment, net:
Total property, plant and equipment, gross	8,245	7,942
Capital in progress [Member]
Property, plant and equipment, net:
Total property, plant and equipment, gross	$ 1,328	$ 3,512

Financial Statement Component50

Financial Statement Components - Components of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning of period	$ (2,769)	$ 612
Current period change	(2,433)	(3,381)	$ (660)
End of period	(5,202)	(2,769)	612
Foreign Currency Translations [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning of period	(2,604)	635
Current period change	(2,344)	(3,239)
End of period	(4,948)	(2,604)	635
Defined Benefit Pension Plans [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning of period	(134)	(28)
Current period change	(76)	(106)
End of period	(210)	(134)	(28)
Unrealized Income (Loss) on Investment [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning of period	(31)	5
Current period change	(13)	(36)
End of period	$ (44)	$ (31)	$ 5

Goodwill and Intangible Asset51

Goodwill and Intangible Assets - Goodwill (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014
Goodwill [Roll Forward]
Beginning balance	$ 10,494	$ 11,743
Foreign currency movements	(1,079)	(1,249)
Ending balance	$ 9,415	$ 10,494

Goodwill and Intangible Asset52

Goodwill and Intangible Assets - Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 26, 2015	Dec. 27, 2014
Summary of Finite-lived intangible assets
Adjusted cost	$ 29,721	$ 30,670
Accumulated amortization	(27,854)	(26,376)
Finite lived intangible assets, Net carrying amount	1,867	4,294
Developed technology [Member]
Summary of Finite-lived intangible assets
Adjusted cost	16,098	16,950
Accumulated amortization	(14,387)	(12,991)
Finite lived intangible assets, Net carrying amount	1,711	3,959
Customer relationships [Member]
Summary of Finite-lived intangible assets
Adjusted cost	9,364	9,461
Accumulated amortization	(9,364)	(9,449)
Finite lived intangible assets, Net carrying amount	0	12
Brand names [Member]
Summary of Finite-lived intangible assets
Adjusted cost	1,927	1,927
Accumulated amortization	(1,903)	(1,802)
Finite lived intangible assets, Net carrying amount	24	125
Patented technology [Member]
Summary of Finite-lived intangible assets
Adjusted cost	2,252	2,252
Accumulated amortization	(2,120)	(2,054)
Finite lived intangible assets, Net carrying amount	132	198
Trademark [Member]
Summary of Finite-lived intangible assets
Adjusted cost	80	80
Accumulated amortization	(80)	(80)
Finite lived intangible assets, Net carrying amount	$ 0	$ 0

Goodwill and Intangible Asset53

Goodwill and Intangible Assets - Textual (Details) - USD ($)	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Finite-Lived Intangible Assets [Line Items]
Total amortization expense	$ 2,100,000	$ 3,100,000	$ 3,300,000
Impairment charges	$ 0
Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangibles estimated lives	2 years
Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangibles estimated lives	10 years

Goodwill and Intangible Asset54

Goodwill and Intangible Assets - Future Amortization (Details) - USD ($) $ in Thousands	Dec. 26, 2015	Dec. 27, 2014
Estimated future amortization expense
2,016	$ 1,455
2,017	206
2,018	140
2,019	66
Thereafter	0
Finite lived intangible assets, Net carrying amount	$ 1,867	$ 4,294

Warranties - Textual (Details)

Warranties - Textual (Details)	12 Months Ended
	Dec. 26, 2015
Product Warranties Disclosures [Abstract]
Product warranty period	12 months

Warranties (Details)

Warranties (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014
Components of the warranty accrual [Roll Forward]
Balance as of beginning of period	$ 2,953	$ 3,426
Accruals for warranties issued during period	8,332	5,987
Settlements during the period	(6,781)	(6,460)
Balance as of end of period	$ 4,504	$ 2,953

Restructuring - Textual (Detail

Restructuring - Textual (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Restructuring Cost And Reserve [Line Items]
Restructuring charge	$ 1,380	$ 2,266	$ 1,740
Employee severance and benefits [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring charge	1,369	1,163
Other [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring charge	11	319
Facility termination costs [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring charge	$ 0	$ 784

Restructuring (Details)

Restructuring (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Restructuring Reserve [Roll Forward]
Beginning Balance	$ 997	$ 0
Charges	1,380	2,266	$ 1,740
Cash Payments	(2,121)	(1,269)
Ending Balance	256	997	0
Employee severance and benefits [Member]
Restructuring Reserve [Roll Forward]
Beginning Balance	383	0
Charges	1,369	1,163
Cash Payments	(1,752)	(780)
Ending Balance	0	383	0
Facility termination costs [Member]
Restructuring Reserve [Roll Forward]
Beginning Balance	583	0
Charges	0	784
Cash Payments	(334)	(201)
Ending Balance	249	583	0
Other [Member]
Restructuring Reserve [Roll Forward]
Beginning Balance	31	0
Charges	11	319
Cash Payments	(35)	(288)
Ending Balance	$ 7	$ 31	$ 0

Line of Credit and Debt Oblig59

Line of Credit and Debt Obligations - Textual (Details) - Revolving line of credit facility [Member] - USD ($)	May. 30, 2014	Dec. 26, 2015
Debt Instrument [Line Items]
Extension of maturity period on amendment of existing credit facility	2 years
Maturity date	May 30, 2016
Amount available to borrow	$ 12,000,000
Line of Credit [Member]
Debt Instrument [Line Items]
Borrowing interest rate, minimum	3.00%
Borrowing, minimum of lesser amount, before addition of borrowing base	$ 12,000,000
Borrowing, maximum of lesser amount	$ 20,000,000
Total borrowing available		$ 16,700,000
Amount outstanding		$ 0

Commitments and Contingencies -

Commitments and Contingencies - Textual (Details) - USD ($)	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Long Term Purchase Commitment [Line Items]
Liabilities recorded for obligations	$ 0	$ 0
Rent expense	1,700,000	2,000,000	$ 2,200,000
Fair Value, Measurements, Recurring [Member] | Zygo Corporation [Member]
Long Term Purchase Commitment [Line Items]
Liabilities resulting from the acquisition of certain assets from acquisitions, measured at fair value	1,500,000	$ 2,400,000
Inventories [Member]
Long Term Purchase Commitment [Line Items]
Purchase commitment	24,900,000
Inventories [Member] | Zygo Corporation [Member]
Long Term Purchase Commitment [Line Items]
Purchase commitment, estimated future amount	$ 1,800,000

Commitments and Contingencies61

Commitments and Contingencies - Future minimum lease payments (Details) $ in Thousands	Dec. 26, 2015USD ($)
Future minimum lease payments under operating leases
2,016	$ 1,372
2,017	733
2,018	407
2,019	311
Thereafter	0
Total	$ 2,823

Net Income (Loss) Per Share (De

Net Income (Loss) Per Share (Details) - shares shares in Thousands	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Reconciliation of the basic and diluted net income per share computations
Weighted average common shares outstanding used in basic net income (loss) per share calculation	24,059	23,958	23,290
Potential dilutive common stock equivalents, using treasury stock method	316	0	0
Weighted average shares used in diluted net income (loss) per share calculation	24,375	23,958	23,290
Net Income Per Share (Textual) [Abstract]
Weighted average common share equivalents consisting of stock options included in the calculation of diluted net income per share	316	0	0
Anti-dilutive common stock equivalents excluded from calculation		400	400

Stockholders' Equity and Stoc63

Stockholders' Equity and Stock-Based Compensation - Textual (Details)	May. 24, 2013shares	Mar. 31, 2015shares	Dec. 26, 2015USD ($)$ / sharesshares	Dec. 27, 2014USD ($)$ / sharesshares	Dec. 28, 2013USD ($)$ / sharesshares	May. 29, 2012USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock authorized			47,000,000	47,000,000
Common stock, par value per share (in dollars per share) | $ / shares			$ 0.001	$ 0.001
Shares of preferred stock authorized			3,000,000	3,000,000
Preferred stock, par value per share (in dollars per share) | $ / shares			$ 0.001	$ 0.001
Amount available for repurchase at end of period | $			$ 4,397,000	$ 6,118,000	$ 11,462,000
Excess tax benefit | $			$ 0	$ 0	$ 100,000
Option term	7 years
Weighted average fair value per share of stock options (in dollars per share) | $ / shares				$ 8.13	$ 8.58
Number of Shares Outstanding (Options), Granted (in shares)			0	74,300	430,800
Closing stock price (in dollars per share) | $ / shares			$ 15.79
Intrinsic value of options exercised | $			$ 1,600,000	$ 3,000,000	$ 2,900,000
Fair value of options vested | $			1,500,000	$ 3,200,000	$ 3,700,000
Unrecognized compensation costs | $			$ 600,000
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum percentage of salary withholdings			10.00%
Purchase price of common stock, percent			85.00%
Shares remaining for issuance under the ESPP			300,000
Shares purchased under the ESPP			125,504	122,112	126,068
Weighted average price of shares issued (in dollars per share) | $ / shares			$ 13.98	$ 13.76	$ 12.36
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average remaining amortization period for unrecognized compensation costs			1 year 11 months 12 days
Unrecognized compensation costs | $			$ 6,900,000
Shares per unit granted			1.7
RSUs granted (in shares)			506,459
RSUs cancelled (in shares)			119,033
Restricted Stock Units (RSUs) [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Period of vesting			1 year
Restricted Stock Units (RSUs) [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Period of vesting			3 years
Restricted Stock Units (RSUs) [Member] | Key Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
RSUs granted (in shares)			506,459	473,600
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average remaining amortization period for unrecognized compensation costs			1 year 6 months 29 days
Performance-Based Restricted Stock Units (PSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares that will vest if target stock price performance is achieved		40,000
Number of shares that will vest if maximum stock price performance is achieved		60,000
RSUs granted (in shares)			68,000	0
Performance-Based Restricted Stock Units (PSUs) [Member] | Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Period of vesting		1 year
Performance-Based Restricted Stock Units (PSUs) [Member] | Tranche Two [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Period of vesting		2 years
Performance-Based Restricted Stock Units (PSUs) [Member] | Tranche Three [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Period of vesting		3 years
2012 Share Repurchase Program [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Amount available for repurchase at end of period | $			$ 4,397,000
May 29, 2012 Program [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum amount of common stock approved to repurchase, Value | $						$ 20,000,000
2005 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Ratio of restricted stock units against available for grant pool	1.7
Number of shares of common stock authorized	2,600,000		7,292,594
RSUs granted (in shares)			860,980
RSUs cancelled (in shares)			202,356

Stockholders' Equity and Stoc64

Stockholders' Equity and Stock-Based Compensation - Share Repurchases (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of shares of common stock repurchased	111,050	362,633	332,771
Weighted average price (in dollars per share)	$ 15.49	$ 14.74	$ 15.03
Total cost of repurchase	$ 1,721	$ 5,344	$ 5,000
Amount available for repurchase at end of period	$ 4,397	$ 6,118	$ 11,462

Stockholders' Equity and Stoc65

Stockholders' Equity and Stock-Based Compensation - Option Plans (Details) - shares	Dec. 26, 2015	May. 24, 2013
2005 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares Authorized	7,292,594	2,600,000
2002 Non-statutory Stock Option Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares Authorized	1,200,000
2000 Employee Stock Option Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares Authorized	2,450,000
2000 Director Stock Option Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares Authorized	250,000
Accent Optical Technologies, Inc. Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares Authorized	205,003

Stockholders' Equity and Stoc66

Stockholders' Equity and Stock-Based Compensation - Stock Options and Employee Stock Purchase Plan Assumptions (Details)	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Stock Options [Member]
Assumption of stock option's fair value
Expected life		4 years 7 months 6 days	4 years 6 months
Volatility		54.90%	69.90%
Risk free interest rate		1.54%	1.05%
Dividends		0.00%	0.00%
Employee Stock Purchase Plan [Member]
Assumption of stock option's fair value
Expected life	6 months	6 months	6 months
Volatility	36.90%	31.20%	26.80%
Risk free interest rate	0.12%	0.54%	0.11%
Dividends	0.00%	0.00%	0.00%

Stockholders' Equity and Stoc67

Stockholders' Equity and Stock-Based Compensation - Summary of Activity of Stock Options (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Activity of stock option plans [Roll Forward]
Number of Shares Outstanding (Options), Beginning Balance (in shares)	1,382,993
Number of Shares Outstanding (Options), Exercised (in shares)	(229,510)
Number of Shares Outstanding (Options), Granted (in shares)	0	74,300	430,800
Number of Shares Outstanding (Options), Cancelled (in shares)	(94,012)	(191,061)	(150,459)
Number of Shares Outstanding (Options), Ending Balance (in shares)	1,059,471	1,382,993
Number of Shares Outstanding (Options), Exercisable (in shares)	926,415
Weighted average exercise price for stock option plans [Roll Forward]
Weighted Average Exercise Price, Beginning Balance (in dollars per share)	$ 13.92
Weighted Average Exercise Price, Exercised (in dollars per share)	9.65
Weighted Average Exercise Price, Cancelled (in dollars per share)	16.67
Weighted Average Exercise Price, Ending Balance (in dollars per share)	14.61	$ 13.92
Weighted Average Exercise Price, Exercisable (in dollars per share)	$ 14.36
Weighed Average Remaining Contractual Term, Outstanding	2 years 5 months 19 days	3 years 4 months 28 days
Weighed Average Remaining Contractual Term, Exercisable	2 years 1 month 24 days
Aggregate Intrinsic Value, Outstanding	$ 4,108
Aggregate Intrinsic Value, Outstanding	1,920	$ 4,108
Aggregate Intrinsic Value, Exercisable	$ 1,879

Stockholders' Equity and Stoc68

Stockholders' Equity and Stock-Based Compensation - Ranges of Outstanding and Exercisable Options (Details) - $ / shares	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Number Outstanding (in shares)	1,059,471	1,382,993
Options Outstanding, Weighted Average Remaining Contractual Life (Years)	2 years 5 months 19 days	3 years 4 months 28 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 14.61	$ 13.92
Options Exercisable, Number Exercisable (in shares)	926,415
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 14.36
$2.38-$10.46 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price, Lower Range Limit	2.38
Exercise Price, Upper Range Limit	$ 10.46
Options Outstanding, Number Outstanding (in shares)	134,762
Options Outstanding, Weighted Average Remaining Contractual Life (Years)	10 months 24 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 7.84
Options Exercisable, Number Exercisable (in shares)	134,762
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 7.8400
$10.83-$11.17 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price, Lower Range Limit	10.83
Exercise Price, Upper Range Limit	$ 11.17
Options Outstanding, Number Outstanding (in shares)	14,156
Options Outstanding, Weighted Average Remaining Contractual Life (Years)	1 year 3 months 18 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 10.93
Options Exercisable, Number Exercisable (in shares)	14,156
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 1.9279
$11.37-$11.37 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price, Lower Range Limit	11.37
Exercise Price, Upper Range Limit	$ 11.37
Options Outstanding, Number Outstanding (in shares)	114,166
Options Outstanding, Weighted Average Remaining Contractual Life (Years)	1 year 10 months 21 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 11.37
Options Exercisable, Number Exercisable (in shares)	114,166
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 11.3700
$12.98-$14.8 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price, Lower Range Limit	12.98
Exercise Price, Upper Range Limit	$ 14.8
Options Outstanding, Number Outstanding (in shares)	111,259
Options Outstanding, Weighted Average Remaining Contractual Life (Years)	2 years 7 months 13 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 13.67
Options Exercisable, Number Exercisable (in shares)	94,579
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 13.6200
$14.88-$15.65 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price, Lower Range Limit	14.88
Exercise Price, Upper Range Limit	$ 15.65
Options Outstanding, Number Outstanding (in shares)	111,967
Options Outstanding, Weighted Average Remaining Contractual Life (Years)	3 years 10 months 2 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 15.44
Options Exercisable, Number Exercisable (in shares)	78,894
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 15.4300
$15.74-$15.98 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price, Lower Range Limit	15.74
Exercise Price, Upper Range Limit	$ 15.98
Options Outstanding, Number Outstanding (in shares)	161,850
Options Outstanding, Weighted Average Remaining Contractual Life (Years)	1 year 9 months 22 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 15.91
Options Exercisable, Number Exercisable (in shares)	143,100
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 15.9200
$16.00-$16.50 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price, Lower Range Limit	16
Exercise Price, Upper Range Limit	$ 16.50
Options Outstanding, Number Outstanding (in shares)	41,804
Options Outstanding, Weighted Average Remaining Contractual Life (Years)	4 years 9 months 4 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 16.43
Options Exercisable, Number Exercisable (in shares)	23,190
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 16.4200
$16.70-$16.7 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price, Lower Range Limit	16.70
Exercise Price, Upper Range Limit	$ 16.7
Options Outstanding, Number Outstanding (in shares)	186,434
Options Outstanding, Weighted Average Remaining Contractual Life (Years)	1 year 10 months 10 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 16.70
Options Exercisable, Number Exercisable (in shares)	186,434
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 16.7000
$16.89-$18.51 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price, Lower Range Limit	16.89
Exercise Price, Upper Range Limit	$ 18.51
Options Outstanding, Number Outstanding (in shares)	123,773
Options Outstanding, Weighted Average Remaining Contractual Life (Years)	4 years 2 months 19 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 17.82
Options Exercisable, Number Exercisable (in shares)	80,931
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 17.8300
$18.79-$19.84 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price, Lower Range Limit	18.79
Exercise Price, Upper Range Limit	$ 19.84
Options Outstanding, Number Outstanding (in shares)	59,300
Options Outstanding, Weighted Average Remaining Contractual Life (Years)	2 years 11 months 23 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 19.12
Options Exercisable, Number Exercisable (in shares)	56,203
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 19.1300
$2.38-$19.84 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price, Lower Range Limit	2.38
Exercise Price, Upper Range Limit	$ 19.84
Options Outstanding, Number Outstanding (in shares)	1,059,471
Options Outstanding, Weighted Average Remaining Contractual Life (Years)	2 years 5 months 19 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 14.61
Options Exercisable, Number Exercisable (in shares)	926,415
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 14.3600

Stockholders' Equity and Stoc69

Stockholders' Equity and Stock-Based Compensation - RSU Activity (Details) - Restricted Stock Units (RSUs) [Member]	12 Months Ended
	Dec. 26, 2015$ / sharesshares
Activity for RSUs [Roll Forward]
Number of RSU Beginning balance (in shares) | shares	563,337
Number of RSU, Granted (in shares) | shares	506,459
Number of RSU, Released (in shares) | shares	(237,520)
Number of RSU, Cancelled (in shares) | shares	(119,033)
Number of RSU, Ending balance (in shares) | shares	713,243
Weighted Average Fair Value for RSUs [Roll Forward]
Weighted Average Fair Value, Beginning balance (in dollars per share) | $ / shares	$ 17.90
Weighted Average Fair Value, Granted (in dollars per share) | $ / shares	15.62
Weighted Average Fair Value, Released (in dollars per share) | $ / shares	16.59
Weighted Average Fair Value, Cancelled (in dollars per share) | $ / shares	16.59
Weighted Average Fair Value, Ending balance (in dollars per share) | $ / shares	$ 15.99

Stockholders' Equity and Stoc70

Stockholders' Equity and Stock-Based Compensation - PSU Valuation Assumptions (Details) - Performance-Based Restricted Stock Units (PSUs) [Member]	12 Months Ended
	Dec. 26, 2015$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of PSUs granted and outstanding (in shares) | shares | shares	40,000
Grant Date Fair Value Per Share (in dollars per share) | $ / shares	$ 18.35
Range of risk-free interest rates, minimum	0.25%
Range of risk-free interest rates, maximum	1.10%
Range of expected volatilities for peer group, minimum	23.00%
Range of expected volatilities for peer group, maximum	65.00%

Stockholders' Equity and Stoc71

Stockholders' Equity and Stock-Based Compensation - Stock Option Plans Activity Including Options and RSUs (Details) - shares	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Activity of stock option plans including options and RSUs [Roll Forward]
Options granted (in shares)	0	(74,300)	(430,800)
Options cancelled (in shares)	94,012	191,061	150,459
Options - expired plan shares (in shares)	(1,800)	(17,491)	(53,607)
Stock Options and Restricted Stock Units [Member]
Activity of stock option plans including options and RSUs [Roll Forward]
Number of Shares Outstanding (Options), Beginning Balance (in shares)	2,464,082	2,937,001	1,093,565
Increase in authorized shares (in shares)	0	0	2,600,000
Number of Shares Outstanding (Options), Ending Balance (in shares)	1,950,589	2,464,082	2,937,001
Restricted Stock Units - Equivalent Shares [Member]
Activity of stock option plans including options and RSUs [Roll Forward]
Granted (in shares)	(860,980)	(805,120)	(664,902)
RSUs cancelled (in shares)	202,356	167,404	133,418
RSUs - shares issued to satisfy tax withholding obligations (in shares)	120,919	65,527	108,868
Performance-Based Restricted Stock Units (PSUs) [Member]
Activity of stock option plans including options and RSUs [Roll Forward]
Granted (in shares)	(68,000)	0

Stockholders' Equity and Stoc72

Stockholders' Equity and Stock-Based Compensation - Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense related to employee stock options and employee stock purchases	$ 6,248	$ 6,752	$ 7,674
Cost of products [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense related to employee stock options and employee stock purchases	274	268	207
Cost of service [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense related to employee stock options and employee stock purchases	309	287	278
Research and development [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense related to employee stock options and employee stock purchases	1,036	1,245	1,478
Selling [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense related to employee stock options and employee stock purchases	1,881	1,642	1,894
General and administrative [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense related to employee stock options and employee stock purchases	$ 2,748	3,243	2,919
Restructuring [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense related to employee stock options and employee stock purchases		$ 67	$ 898

Defined Benefit Pension Plan (D

Defined Benefit Pension Plan (Details) - Pension Plans, Defined Benefit [Member] - USD ($) $ in Millions	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 0.2	$ 0.2	$ 0.2
Net funding deficiency of the Benefit Plan	$ 0.3	$ 0.3	$ 0.2

Income Taxes - Income (Loss) Be

Income Taxes - Income (Loss) Before Provision for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Income Tax Disclosure [Abstract]
Domestic	$ 178	$ (15,691)	$ (26,447)
Foreign	5,390	4,070	2,882
Income (loss) before income taxes	$ 5,568	$ (11,621)	$ (23,565)

Income Taxes - Provision (Benef

Income Taxes - Provision (Benefit) for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Current:
Federal	$ 148	$ 358	$ 119
State	3	(151)	5
Foreign	2,266	1,327	933
Total current	2,417	1,534	1,057
Deferred:
Federal	190	17,368	(10,686)
State	3	550	(325)
Foreign	53	45	535
Total deferred	246	17,963	(10,476)
Provision (benefit) for income taxes	$ 2,663	$ 19,497	$ (9,419)

Income Taxes - Income Taxes - C

Income Taxes - Income Taxes - Components of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 26, 2015	Dec. 27, 2014
Deferred tax assets:
Reserves and accruals	$ 13,712	$ 10,744
Deferred revenue	1,154	1,370
Shared based compensation	3,856	4,030
Tax credit carry-forwards	8,658	8,122
Net operating losses	13,218	14,695
Depreciation & amortization	366	2,750
Other	94	372
Total deferred tax assets	41,058	42,083
Less: Valuation allowance	(36,786)	(35,835)
Total deferred tax assets net of valuation allowance	4,272	6,248
Deferred tax liabilities:
Depreciation & amortization	(2,537)	(4,020)
Other	(1,137)	(1,485)
Total deferred tax liabilities	(3,674)	(5,505)
Net deferred tax assets	$ 598	$ 743

Income Taxes - Textual (Details

Income Taxes - Textual (Details) - USD ($)	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Income Taxes (Textual) [Abstract]
Excess benefits due to stock option exercise	$ 0
Change in amount of operating loss carryforwards valuation allowance	1,600,000	$ 23,900,000
Increase in valuation allowance for deferred tax assets		21,100,000
Undistributed earnings from non-U.S. operations	6,500,000
Maximum amount company recognize from unrecognized tax benefit	6,961,000	$ 6,442,000	$ 4,436,000	$ 3,464,000
Unrecognized tax benefits that would impact effective tax rate if recognized	800,000
Federal [Member]
Income Taxes (Textual) [Abstract]
Operating loss carryforwards	9,900,000
State research and experimental tax credit carryforward	7,500,000
Federal [Member] | Excess Tax Benefit Related to Exercise of Stock Option [Member]
Income Taxes (Textual) [Abstract]
Operating loss carryforwards	1,400,000
California [Member]
Income Taxes (Textual) [Abstract]
Operating loss carryforwards	39,500,000
State research and experimental tax credit carryforward	6,900,000
California [Member] | Excess Tax Benefit Related to Exercise of Stock Option [Member]
Income Taxes (Textual) [Abstract]
Operating loss carryforwards	3,000,000
State research and experimental tax credit carryforward	200,000
Foreign Tax Authority [Member]
Income Taxes (Textual) [Abstract]
Operating loss carryforwards	38,500,000
Foreign Tax Authority [Member] | Excess Tax Benefit Related to Exercise of Stock Option [Member]
Income Taxes (Textual) [Abstract]
Operating loss carryforwards	$ 1,600,000

Income Taxes - Income Tax Rate

Income Taxes - Income Tax Rate Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Income Tax Expense Benefit Continuing Operations Income Tax Reconciliation [Abstract]
Income taxes computed at U.S. statutory rate	$ 1,949	$ (4,067)	$ (8,247)
State income taxes	28	(109)	147
Foreign tax rate differential	342	777	479
Change in valuation allowance	1,648	23,894	0
Non-deductible Equity Compensation	311	242	210
Tax credits	(1,834)	(2,187)	(2,103)
Liabilities for uncertain tax positions	74	118	111
Other, net	145	829	(16)
Provision (benefit) for income taxes	$ 2,663	$ 19,497	$ (9,419)

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Reconciliation Of Unrecognized Tax Benefits Excluding Amounts Pertaining To Examined Tax Returns Roll Forward
Unrecognized tax benefits - beginning of the period	$ 6,442	$ 4,436	$ 3,464
Gross increases-tax positions in prior period	127	655	305
Gross decreases-tax positions in prior period	(306)	(123)	0
Gross increases-current-period tax positions	698	1,541	688
Lapse of statute of limitations	0	(67)	(21)
Unrecognized tax benefits - end of the period	$ 6,961	$ 6,442	$ 4,436

Segment, Geographic, Product 80

Segment, Geographic, Product and Significant Customer Information - Net Revenue (Details) $ in Thousands	12 Months Ended
	Dec. 26, 2015USD ($)segment	Dec. 27, 2014USD ($)	Dec. 28, 2013USD ($)
Revenues from External Customers and Long-Lived Assets [Line Items]
Number of operating segments | segment	1
Net revenues:
Total net revenues	$ 187,367	$ 166,443	$ 144,307
United States [Member]
Net revenues:
Total net revenues	36,720	36,123	47,019
China [Member]
Net revenues:
Total net revenues	17,373	28,702	13,063
Japan [Member]
Net revenues:
Total net revenues	31,140	15,185	11,629
South Korea [Member]
Net revenues:
Total net revenues	30,572	41,381	34,873
Taiwan [Member]
Net revenues:
Total net revenues	46,715	19,790	9,645
Other [Member]
Net revenues:
Total net revenues	$ 24,847	$ 25,262	$ 28,078

Segment, Geographic, Product 81

Segment, Geographic, Product and Significant Customer Information - Long-lived Tangible Assets (Details) - USD ($) $ in Thousands	Dec. 26, 2015	Dec. 27, 2014
Long-lived tangible assets:
Total long-lived tangible assets	$ 44,493	$ 49,633
United States [Member]
Long-lived tangible assets:
Total long-lived tangible assets	42,581	47,729
Japan [Member]
Long-lived tangible assets:
Total long-lived tangible assets	59	71
South Korea [Member]
Long-lived tangible assets:
Total long-lived tangible assets	697	284
Taiwan [Member]
Long-lived tangible assets:
Total long-lived tangible assets	1,056	1,473
All other [Member]
Long-lived tangible assets:
Total long-lived tangible assets	$ 100	$ 76

Segment, Geographic, Product 82

Segment, Geographic, Product and Significant Customer Information - Product Revenues (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Segment Reporting Information [Line Items]
Products	$ 146,945	$ 133,589	$ 107,402
Automated Systems [Member]
Segment Reporting Information [Line Items]
Products	102,386	108,768	82,924
Integrated Systems [Member]
Segment Reporting Information [Line Items]
Products	31,579	15,334	11,412
Materials Characterization Systems [Member]
Segment Reporting Information [Line Items]
Products	$ 12,980	$ 9,487	$ 13,066

Segment, Geographic, Product 83

Segment, Geographic, Product and Significant Customer Information - Customers More Than 10% of Accounts Receivable (Details) - Accounts Receivable [Member]	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Toshiba Corporation [Member]
Customers accounted for 10% or more of total accounts receivable
Customers accounted for 10% or more of total accounts receivable	27.10%
Taiwan Semiconductor Manufacturing Company Limited [Member]
Customers accounted for 10% or more of total accounts receivable
Customers accounted for 10% or more of total accounts receivable	25.60%	20.20%	12.10%
SK Hynix [Member]
Customers accounted for 10% or more of total accounts receivable
Customers accounted for 10% or more of total accounts receivable			21.80%
Samsung Electronics Co. Ltd. [Member]
Customers accounted for 10% or more of total accounts receivable
Customers accounted for 10% or more of total accounts receivable		10.00%	27.40%
Micron [Member]
Customers accounted for 10% or more of total accounts receivable
Customers accounted for 10% or more of total accounts receivable		23.70%
Intel Corporation [Member]
Customers accounted for 10% or more of total accounts receivable
Customers accounted for 10% or more of total accounts receivable			14.40%
GlobalFoundries [Member]
Customers accounted for 10% or more of total accounts receivable
Customers accounted for 10% or more of total accounts receivable		10.20%

Segment, Geographic, Product 84

Segment, Geographic, Product and Significant Customer Information - Customers More Than 10% of Revenues (Details) - Sales Revenue, Net [Member]	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Taiwan Semiconductor Manufacturing Company Limited [Member]
Net revenues:
Customers accounted for 10% or more of total revenue	19.40%
Micron [Member]
Net revenues:
Customers accounted for 10% or more of total revenue	15.80%	10.40%
Samsung Electronics Co. Ltd. [Member]
Net revenues:
Customers accounted for 10% or more of total revenue	13.20%	26.90%	14.40%
SK Hynix [Member]
Net revenues:
Customers accounted for 10% or more of total revenue	10.70%	12.20%	18.40%
Toshiba Corporation [Member]
Net revenues:
Customers accounted for 10% or more of total revenue	10.20%
Intel Corporation [Member]
Net revenues:
Customers accounted for 10% or more of total revenue		12.60%	30.00%

Schedule II - VALUATION AND Q85

Schedule II - VALUATION AND QUALIFYING ACCOUNTS (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Allowance for Doubtful Accounts [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	$ 253	$ 293	$ 82
Charged to costs and expenses	(113)	(40)	255
Deductions – write-offs of accounts	10	0	(44)
Balance at end of period	150	253	293
Valuation Allowance for Deferred Tax Assets [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	35,835	11,665	10,229
Charged to costs and expenses	951	24,170	1,436
Deductions – write-offs of accounts	0	0	0
Balance at end of period	$ 36,786	$ 35,835	$ 11,665