Onto Innovation (ONTO) 10-Q 28 Oct 16 2016 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 24, 2016	Oct. 21, 2016
Document And Entity Information [Abstract]
Entity Registrant Name	NANOMETRICS INC
Entity Central Index Key	704,532
Document Type	10-Q
Document Period End Date	Sep. 24, 2016
Amendment Flag	false
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q3
Trading Symbol	NANO
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		24,916,470

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 24, 2016	Dec. 26, 2015
Current assets:
Cash and cash equivalents	$ 37,421	$ 38,154
Marketable securities	81,106	44,931
Accounts receivable, net of allowances of $92 and $150, respectively	41,182	37,832
Inventories	39,260	47,749
Inventories-delivered systems	4,416	2,856
Prepaid expenses and other	5,835	6,592
Total current assets	209,220	178,114
Property, plant and equipment, net	44,324	44,493
Goodwill	9,665	9,415
Intangible assets, net	552	1,867
Deferred income tax assets	1,319	1,118
Other assets	526	533
Total assets	265,606	235,540
Current liabilities:
Accounts payable	8,562	11,675
Accrued payroll and related expenses	11,631	10,097
Deferred revenue	16,804	12,790
Other current liabilities	8,630	8,878
Income taxes payable	278	1,771
Total current liabilities	45,905	45,211
Deferred revenue	639	827
Income taxes payable	848	775
Deferred tax liability	709	521
Other long-term liabilities	866	878
Total liabilities	48,967	48,212
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: 24,897,878 and 24,224,286, respectively, issued and outstanding	25	24
Additional paid-in capital	268,553	258,715
Accumulated deficit	(48,828)	(66,209)
Accumulated other comprehensive income	(3,111)	(5,202)
Total stockholders’ equity	216,639	187,328
Total liabilities and stockholders’ equity	$ 265,606	$ 235,540

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 24, 2016	Dec. 26, 2015
Statement Of Financial Position [Abstract]
Allowances for doubtful accounts	$ 92	$ 150
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	24,897,878	24,224,286
Common stock, shares outstanding	24,897,878	24,224,286

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 24, 2016	Sep. 26, 2015	Sep. 24, 2016	Sep. 26, 2015
Net revenues:
Products	$ 49,631,000	$ 36,414,000	$ 136,290,000	$ 113,689,000
Service	9,083,000	9,264,000	25,680,000	30,993,000
Total net revenues	58,714,000	45,678,000	161,970,000	144,682,000
Costs of net revenues:
Cost of products	22,810,000	19,242,000	62,625,000	59,106,000
Cost of service	5,066,000	3,749,000	14,714,000	15,158,000
Amortization of intangible assets	434,000	468,000	1,311,000	1,557,000
Total costs of net revenues	28,310,000	23,459,000	78,650,000	75,821,000
Gross profit	30,404,000	22,219,000	83,320,000	68,861,000
Operating expenses:
Research and development	7,868,000	8,579,000	23,447,000	24,896,000
Selling	7,495,000	6,760,000	22,567,000	20,905,000
General and administrative	5,975,000	5,590,000	17,150,000	16,901,000
Amortization of intangible assets		26,000	24,000	89,000
Restructuring charge			0	56,000
Total operating expenses	21,338,000	20,955,000	63,188,000	62,847,000
Income from operations	9,066,000	1,264,000	20,132,000	6,014,000
Other (income) expense:
Interest income	12,000	7,000	33,000	63,000
Interest expense	(92,000)	(86,000)	(276,000)	(252,000)
Other income, net	229,000	346,000	60,000	740,000
Total other income (expense), net	149,000	267,000	(183,000)	551,000
Income before income taxes	9,215,000	1,531,000	19,949,000	6,565,000
Provision for income taxes	1,332,000	713,000	2,568,000	1,847,000
Net income	$ 7,883,000	$ 818,000	$ 17,381,000	$ 4,718,000
Net income per share:
Basic (in dollars per share)	$ 0.32	$ 0.03	$ 0.71	$ 0.20
Diluted (in dollars per share)	$ 0.31	$ 0.03	$ 0.70	$ 0.19
Weighted average shares used in per share calculation:
Basic (in shares)	24,826	24,145	24,550	24,010
Diluted (in shares)	25,282	24,352	24,979	24,347

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 24, 2016	Sep. 26, 2015	Sep. 24, 2016	Sep. 26, 2015
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 7,883	$ 818	$ 17,381	$ 4,718
Other comprehensive income (loss):
Change in foreign currency translation adjustment	519	(235)	2,018	(1,980)
Net change on unrealized gains on available-for-sale investments	1	17	73	42
Other comprehensive income (loss):	520	(218)	2,091	(1,938)
Comprehensive income	$ 8,403	$ 600	$ 19,472	$ 2,780

Condensed Consolidated Stateme6

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 24, 2016	Sep. 26, 2015
Cash flows from operating activities:
Net income	$ 17,381	$ 4,718
Reconciliation of net income to net cash provided by operating activities:
Depreciation and amortization	6,440	6,826
Stock-based compensation	5,432	4,664
Disposal of fixed assets	162	578
Inventory write-down	1,451	1,971
Deferred income taxes	(14)	173
Changes in fair value of contingent payments to Zygo Corporation	158	137
Changes in assets and liabilities:
Accounts receivable	(986)	(14,873)
Inventories	6,652	(15,893)
Inventories-delivered systems	(1,560)	370
Prepaid expenses and other	889	4,436
Accounts payable, accrued and other liabilities	(4,310)	9,634
Deferred revenue	3,825	(688)
Income taxes payable	(1,419)	295
Net cash provided by operating activities	34,101	2,348
Cash flows from investing activities:
Sales of marketable securities	2,093	2,884
Maturities of marketable securities	25,461	30,279
Purchases of marketable securities	(63,840)	(27,298)
Purchases of property, plant and equipment	(3,349)	(1,365)
Net cash provided by (used in) investing activities	(39,635)	4,500
Cash flows from financing activities:
Payments to Zygo Corporation related to acquisition	(315)	(614)
Proceeds from sale of shares under employee stock option plans and purchase plan	5,984	3,642
Taxes paid on net issuance of stock awards	(1,578)	(1,104)
Repurchases of common stock		(1,721)
Net cash provided by financing activities	4,091	203
Effect of exchange rate changes on cash and cash equivalents	710	(166)
Net increase (decrease) in cash and cash equivalents	(733)	6,885
Cash and cash equivalents, beginning of period	38,154	34,676
Cash and cash equivalents, end of period	37,421	41,561
Supplemental disclosure of non-cash investing activities:
Transfer of inventory to property, plant and equipment, net	1,699	$ 1,068
Transfer of property, plant and equipment to inventory, net	$ 491

Nature of Business and Basis of

Nature of Business and Basis of Presentation	9 Months Ended
	Sep. 24, 2016
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Nature of Business and Basis of Presentation	Note 1. Nature of Business and Basis of Presentation 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 accompanying condensed consolidated financial statements (“financial statements”) have been prepared on a consistent basis with the audited consolidated financial statements as of December 26, 2015, and include all normal recurring adjustments necessary to fairly state the information set forth therein. All significant intercompany accounts and transactions have been eliminated in consolidation. The financial statements have been prepared in accordance with the regulations of the United States Securities and Exchange Commission (“SEC”) for interim periods in accordance with S-X Article 10, and, therefore, omit certain information and footnote disclosure necessary to present the statements in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”). The operating results for interim periods are not necessarily indicative of the operating results that may be expected for the entire year. These financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto for the fiscal year ended December 26, 2015, which were included in the Company’s Annual Report on Form 10-K filed with the SEC on February 24, 2016. Fiscal Period – The Company uses a 52/53 week fiscal year ending on the last Saturday of the calendar year. All references to the quarter refer to Nanometrics’ fiscal quarter. The fiscal quarters reported herein are 13 week periods. Upgrade Revenue and Related Cost - Beginning the first quarter of 2016, revenues associated with upgrade sales are now included under Products Revenues, and the related costs in Cost of Products Revenue. This change was due to the types of upgrades currently being sold, which are primarily system software and hardware performance upgrades to extend the features and functionality of a product. Previously upgrades consisted of a group of parts and/or software that change the existing configuration of a product. For the three months ended September 26, 2015, $0.8 million related to upgrade sales, and $0.1 million of costs, are included in Service Revenues and Costs of Service Revenues, respectively, in the accompanying Condensed Consolidated Statement of Operations. For the nine months ended September 26, 2015, $7.6 million related to upgrade sales, and $2.9 million of costs, are included in Service Revenues and Costs of Service Revenues, respectively, in the accompanying Condensed Consolidated Statement of Operations. Use of Estimates – The preparation of financial statements in conformity with 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. Revenue Recognition – The Company derives revenue from the sale of process control metrology and inspection systems and related upgrades (“product revenue”) as well as spare part sales, billable service and service contracts (together “service revenue”). Upgrades are system software and hardware performance upgrades that extend the features and functionality of a product. As discussed above, commencing in the first quarter of 2016, upgrades are included in product revenue, which consists of sales 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. 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. 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.

Recent Accounting Pronouncement

Recent Accounting Pronouncements	9 Months Ended
	Sep. 24, 2016
Accounting Changes And Error Corrections [Abstract]
Recent Accounting Pronouncements	Note 2. Recent Accounting Pronouncements In August 2016, the Financial Accounting Standards Board (the "FASB") issued an accounting standard which addresses eight specific cash flow classification issues. This update is effective for public companies for fiscal years beginning after December 15, 2017 and interim periods within those fiscal years. Early adoption is permitted, including in an interim period. If early adopted in an interim period, any adjustments should be reflected as of the beginning of the fiscal year that includes that interim period, and all the amendments must be adopted in the same period. The standard is to be applied through a retrospective transition method to each period presented. If it is impracticable to apply retrospectively for some of the issues, the amendments for those issues would be applied prospectively as of the earliest date practicable. The Company is currently evaluating the impact of adopting this update on its consolidated statements of cash flows. In June 2016, the FASB issued an accounting standard which requires measurement and timely recognition of expected credit losses for financial assets. The update is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. Early adoption is permitted as of the fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. The standard is to be applied through a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period in which the guidance is effective. The Company is currently evaluating the effect of this update on its consolidated financial statements. In March 2016, the FASB issued an accounting standards update that simplifies several aspects of the accounting for share-based payment award transactions, including income tax consequences, classification of awards as equity or liability, and classification on the statement of cash flows. The standard is effective for public companies for annual reporting periods beginning after December 16, 2016, and interim periods within those annual periods. Early adoption is permitted. The Company is currently evaluating the timing and effects of the adoption of this standard on its consolidated financial statements. In February 2016, the FASB issued an accounting standards update which requires lessees to record a right-of-use asset and a corresponding lease liability on the balance sheet (with the exception of short-term leases). For lessees, leases will continue to be classified as either operating or financing in the income statement. The standard is effective for public companies for annual reporting periods beginning after December 15, 2018, including interim periods within those fiscal years. This standard is required to be applied with a modified retrospective transition approach. Early adoption is permitted. The Company is currently evaluating the effect of this standard on its Consolidated Financial Statements and related disclosures. 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. This guidance clarifies the principles of revenue recognition to improve operability and understandability of the guidance. 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 revenue standard update, but early adoption will be permitted. The 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 has not yet selected a transition method and is currently evaluating the timing and effects of the adoption of this standard and related updates on its consolidated financial statements and related disclosures.

Fair Value Measurements and Dis

Fair Value Measurements and Disclosures	9 Months Ended
	Sep. 24, 2016
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: September 24, 2016 December 26, 2015 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 $ 840 $ — $ — $ 840 $ 590 $ — $ — $ 590 Commercial paper and corporate debt securities — 4,244 — 4,244 — 4,568 — 4,568 Total cash equivalents $ 840 $ 4,244 $ — $ 5,084 $ 590 $ 4,568 $ — $ 5,158 Marketable securities: U.S. Treasury securities and U.S. Government agency debt securities — 21,256 — 21,256 4,401 20,164 — 24,565 Certificates of deposits — 16,008 — 16,008 — — — — Commercial paper — 23,848 — 23,848 — 1,884 — 1,884 Municipal securities and corporate debt securities — 12,526 — 12,526 — 18,482 — 18,482 Asset-backed Securities — 7,468 — 7,468 — — — — Total marketable securities $ — $ 81,106 $ — $ 81,106 $ 4,401 $ 40,530 $ — $ 44,931 Total (1) $ 840 $ 85,350 $ — $ 86,190 $ 4,991 $ 45,098 $ — $ 50,089 Liabilities: Contingent consideration payable $ — $ — $ 1,333 $ 1,333 $ — $ — $ 1,490 $ 1,490 (1) 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 26, 2015 $ 1,490 Payments made to Zygo Corporation (315 ) Change in fair value included in earnings 158 Fair value at September 24, 2016 $ 1,333 As of September 24, 2016, the Company had liabilities of $1.3 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 $1.3 million of Zygo liabilities at September 24, 2016, $0.8 million was a current liability and $0.5 million was a long-term liability. As of December 26, 2015, the liabilities totaled $1.5 million of which $0.9 million was a current liability and $0.6 million was a long-term liability. The fair values of these liabilities were determined using Level 3 inputs applying 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 settlement of forward foreign currency contracts included in the three months ended September 24, 2016 and September 26, 2015 was a gain of $0.1 million and a loss of $0.3 million, respectively. The loss on settlement of forward foreign currency contracts included in the nine months ended September 24, 2016 and September 26, 2015 was $1.2 million and $0.3 million respectively. These are included in other income (expense), net, in the consolidated statements of operations. The following table summarizes the Company’s outstanding derivative instruments on a gross basis as of September 24, 2016: Notional Principal (in millions) Undesignated Hedges: Forward Foreign Currency Contracts $ 15.9

Cash and Investments

Cash and Investments	9 Months Ended
	Sep. 24, 2016
Investments Debt And Equity Securities [Abstract]
Cash and Investments	Note 4. Cash and Investments The following tables present cash, cash equivalents, and available-for-sale investments as of the following dates (in thousands): September 24, 2016 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Market Value Cash $ 32,337 $ — $ — 32,337 Cash equivalents: Money market funds 840 — — 840 Commercial paper and corporate debt securities 4,245 — (1 ) 4,244 Marketable securities: U.S. Treasury securities 6,935 9 — 6,944 U.S. Government agency securities 14,301 11 — 14,312 Certificate of deposits 15,997 11 — 16,008 Commercial paper 23,845 3 — 23,848 Municipal securities 765 — — 765 Corporate debt securities 11,762 — (1 ) 11,761 Asset-backed securities 7,470 — (2 ) 7,468 Total cash, cash equivalents, and marketable securities $ 118,497 $ 34 $ (4 ) $ 118,527 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: U.S. Treasury securities 4,411 — (10 ) 4,401 U.S. Government agency securities 20,193 1 (29 ) 20,165 Commercial paper 1,884 — — 1,884 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 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 September 24, 2016 and December 26, 2015, were available-for-sale and reported at fair value based on the estimated or quoted market prices as of the balance sheet date. Realized gains and losses on sale of securities are recorded in other income, net, in the Company’s statement of operations. Net realized gains and losses for three and nine months ended September 24, 2016 and September 26, 2015 were not material. 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 three and nine months ended September 24, 2016 and September 26, 2015 were insignificant and no marketable securities had other than temporary impairment. All marketable securities as of September 24, 2016 and December 26, 2015, had maturity dates of less than two years.

Accounts Receivable

Accounts Receivable	9 Months Ended
	Sep. 24, 2016
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. The Company pays administrative fees as well as interest ranging from 0.76% 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 $10.1 million and $4.3 million of receivables during the three months ended September 24, 2016 and September 26, 2015, respectively and $29.6 million and $7.3 million of receivables during the nine months ended September 24, 2016 and September 26, 2015, 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 September 24, 2016 and December 26, 2015.

Financial Statement Components

Financial Statement Components	9 Months Ended
	Sep. 24, 2016
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 September 24, 2016 December 26, 2015 Inventories: Raw materials and sub-assemblies $ 21,953 $ 26,784 Work in process 9,508 12,862 Finished goods 7,799 8,103 Inventories 39,260 47,749 Inventories-delivered systems 4,416 2,856 Total inventories $ 43,676 $ 50,605 Property, plant and equipment, net: (1) Land $ 15,570 $ 15,569 Building and improvements 20,511 20,158 Machinery and equipment 36,109 32,995 Furniture and fixtures 2,357 2,266 Software 9,007 8,245 Capital in progress 2,091 1,328 Total property, plant and equipment, gross 85,645 80,561 Accumulated depreciation and amortization (41,321 ) (36,068 ) Total property, plant and equipment, net $ 44,324 $ 44,493 (1) Other Current Liabilities: Accrued warranty $ 4,185 $ 4,504 Accrued restructuring — 256 Accrued professional services 492 481 Accrued royalties 1,029 437 Fair value of current portion of contingent payments to Zygo Corporation related to acquisition 814 945 Other 2,110 2,255 Total other current liabilities $ 8,630 $ 8,878 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 26, 2015 $ (4,948 ) $ (210 ) $ (44 ) $ (5,202 ) Current period change 2,018 — 73 2,091 Balance as of September 24, 2016 $ (2,930 ) $ (210 ) $ 29 $ (3,111 ) 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	9 Months Ended
	Sep. 24, 2016
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 nine months ended September 24, 2016: (in thousands) Balance as of December 26, 2015 $ 9,415 Foreign currency movements 250 Balance as of September 24, 2016 $ 9,665 Finite-lived intangible assets are recorded at cost, less accumulated amortization. Finite-lived intangible assets as of September 24, 2016 and December 26, 2015 consisted of the following (in thousands): September 24, 2016 Adjusted cost Accumulated amortization Net carrying amount Developed technology $ 16,336 $ (15,867 ) $ 469 Customer relationships 9,387 (9,387 ) — Brand names 1,927 (1,927 ) — Patented technology 2,252 (2,169 ) 83 Trademark 80 (80 ) — Total $ 29,982 $ (29,430 ) $ 552 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 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. The total amortization expense for the three months ended September 24, 2016 and September 26, 2015 was $0.4 million and $0.5 million, respectively. Total amortization expense for the nine months ended September 24, 2016 and September 26, 2015 was $1.3 million and $1.6 million, respectively. There were no impairment charges related to intangible assets recorded during the three and nine months ended September 24, 2016 and September 26, 2015. The estimated future amortization expense of finite intangible assets as of September 24, 2016 is as follows (in thousands): Fiscal Years Amounts 2016 (remaining three months) $ 140 2017 206 2018 140 2019 66 Thereafter — Total future amortization expense $ 552

Warranties

Warranties	9 Months Ended
	Sep. 24, 2016
Product Warranties Disclosures [Abstract]
Warranties	Note 8. Warranties 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. Components of the warranty accrual, which were included in the accompanying condensed consolidated balance sheets with other current liabilities, were as follows (in thousands): Three Months Ended Nine Months Ended September 24, 2016 September 26, 2015 September 24, 2016 September 26, 2015 Balance as of beginning of period $ 4,556 $ 3,792 $ 4,504 $ 2,953 Accruals for warranties issued during period 1,100 2,288 3,529 6,240 Settlements during the period (1,471 ) (1,789 ) (3,848 ) (4,902 ) Balance as of end of period $ 4,185 $ 4,291 $ 4,185 $ 4,291

Restructuring

Restructuring	9 Months Ended
	Sep. 24, 2016
Restructuring And Related Activities [Abstract]
Restructuring	Note. 9. Restructuring There were no restructuring charges recorded during the nine months ended September 24, 2016. The Company recorded a restructuring charge of approximately $0.1 million during the nine months ended September 26, 2015 as a result of its decision to consolidate and reorganize certain of its operations, primarily in the U.K. The Company completed this restructuring plan in March 2015. Other related costs will be recognized as incurred. As of September 24, 2016, 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 26, 2015 $ — $ 249 $ 7 $ 256 Charges — — — — Cash Payments — (249 ) (7 ) (256 ) Balance as of September 24, 2016 $ — $ — $ — $ — Employee severance and benefits Facility termination costs Other Total Balance as of December 27, 2014 $ 383 $ 583 $ 31 $ 997 Charges 45 — 11 56 Cash Payments (428 ) (249 ) (35 ) (712 ) Balance as of September 26, 2015 $ — $ 334 $ 7 $ 341

Line of Credit and Debt Obligat

Line of Credit and Debt Obligations	9 Months Ended
	Sep. 24, 2016
Debt Disclosure [Abstract]
Line of Credit and Debt Obligations	Note 10. Line of Credit and Debt Obligations Line of Credit - The Company’s revolving line of credit facility of up to $12.0 million expired on May 30, 2016 and was not renewed.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 24, 2016
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 the Company’s 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 condensed consolidated balance sheets as of September 24, 2016 and December 26, 2015.

Net Income Per Share

Net Income Per Share	9 Months Ended
	Sep. 24, 2016
Earnings Per Share [Abstract]
Net Income Per Share	Note 12. Net Income Per Share The Company presents both basic and diluted net income per share on the face of its condensed consolidated statements of operations. Basic net income per share excludes the effect of potentially dilutive shares and is computed by dividing net income by the weighted-average number of shares of common stock outstanding for the period. Diluted net income per share is computed using the weighted-average number of shares of common stock outstanding for the period plus the effect of all dilutive securities representing potential shares of common stock outstanding during the period. A reconciliation of the share denominator of the basic and diluted net income per share computations for three and nine months ended September 24, 2016 and September 26, 2015 is as follows (in thousands): Three Month Ended Nine Months Ended September 24, 2016 September 26, 2015 September 24, 2016 September 26, 2015 Weighted average common shares outstanding used in basic net income (loss) per share calculation 24,826 24,145 24,550 24,010 Potential dilutive common stock equivalents, using treasury stock method 456 207 429 337 Weighted average shares used in diluted net income (loss) per share calculation 25,282 24,352 24,979 24,347

Stockholders' Equity and Stock-

Stockholders' Equity and Stock-Based Compensation	9 Months Ended
	Sep. 24, 2016
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stockholders' Equity and Stock-Based Compensation	Note 13. Stockholders’ Equity and Stock-Based Compensation Options and Employee Stock Purchase Plan (“ESPP”) Awards The fair value of each option and ESPP award is estimated on the grant date using the Black-Scholes valuation model and the assumptions noted in the following table. The expected lives of options granted were calculated using the simplified method allowed by the Staff Accounting Bulletin No. 107, Share-Based Payment Three Months Ended Nine Months Ended September 24, 2016 September 26, 2015 September 24, 2016 September 26, 2015 Employee Stock Purchase Plan: Expected life 0.5 years 0.5 years 0.5 years 0.5 years Volatility 38.2% 36.7% 38.7 % 36.9% Risk free interest rate 0.37% 0.13% 0.44 % 0.12% Dividends — — — — No stock options were awarded during the nine months ended September 24, 2016 and September 26, 2015, respectively. A summary of activity of stock options during the nine months ended September 24, 2016 is as follows: Number of Shares Outstanding (Options) Weighted Average Exercise Price Weighted Average Remaining Contractual Term (Years) Aggregate Intrinsic Value (in Options Outstanding at December 26, 2015 1,051,867 $ 14.60 2.46 $ 1,916 Exercised (352,996 ) $ 13.33 Cancelled (166,849 ) $ 15.79 Outstanding at September 24, 2016 532,022 $ 15.06 2.32 $ 3,849 Exercisable at September 24, 2016 480,462 $ 14.91 2.15 $ 3,546 The aggregate intrinsic value in the above table represents the total pretax intrinsic value, based on the Company’s closing stock price of $22.29 as of September 23,2016, the last trading day of the quarter, 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 the three months ended September 24, 2016 and September 26, 2015 was $0.5 million and $0.1 million, respectively, and during the nine months ended September 24, 2016 and September 26, 2015 was $1.9 and $1.4 million, respectively. Restricted Stock Units (“RSUs”) Time-based RSUs are valued using the market value of the Company’s common stock on the date of grant, assuming no expectation of dividends paid. 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 26, 2015 713,243 $ 15.99 Granted 455,907 $ 17.15 Released (286,260 ) $ 16.11 Cancelled (45,852 ) $ 16.00 Outstanding RSUs as of September 24, 2016 837,038 $ 15.58 Market-Based Performance Stock Units (“PSUs”) 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 target stock price performance is achieved, 66.7% of the shares of the Company’s common stock subject to the PSUs will vest, and up to a maximum of 100% of the shares subject to the PSUs will vest if the maximum stock price performance is achieved for each tranche. A summary of activity for PSUs is as follows: Summary of activity for PSUs Number of PSUs Weighted Average Fair Value Outstanding PSUs as of December 26, 2015 60,000 $ 18.35 Granted 67,500 $ 8.52 Released (13,333 ) $ 18.04 Cancelled (6,667 ) $ 18.04 Outstanding PSUs as of September 24, 2016 107,500 $ 12.24 The preceding table reflects the maximum awards that can be achieved upon full vesting. 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: 2016 Award 2015 Award Grant Date Fair Value Per Share $ 8.52 $ 18.35 Weighted-average assumptions/inputs: Expected Dividend — — Range of risk-free interest rates 0.92% 0.25%-1.1% Range of expected volatilities for peer group 22%-93% 23%-65% 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): Three Months Ended Nine Months Ended September 24, 2016 September 26, 2015 September 24, 2016 September 26, 2015 Cost of products $ 116 $ 96 $ 273 $ 229 Cost of service 138 104 355 195 Research and development 387 300 985 796 Selling 537 511 1,492 1,403 General and administrative 822 671 2,327 2,041 Total stock-based compensation expense related to employee stock options and employee stock purchases $ 2,000 $ 1,682 $ 5,432 $ 4,664

Income Taxes

Income Taxes	9 Months Ended
	Sep. 24, 2016
Income Tax Disclosure [Abstract]
Income Taxes	Note 14. Income Taxes The Company accounts for income taxes under the provisions of ASC 740, Accounting for Income Taxes. The Company adjusts its effective tax rate each quarter to be consistent with the estimated annual effective tax rate. The Company also records the tax effect of unusual or infrequently occurring discrete items, including changes in judgment about valuation allowances and effects of changes in tax laws or tax rates, in the interim period in which they occur. The Company's effective tax rate reflects the impact of a portion of its earnings being taxed in foreign jurisdictions as well as a valuation allowance maintained on certain deferred tax assets. The provision for income taxes consists of the following (in thousands): Three Months Ended Nine Months Ended September 24, 2016 September 26, 2015 September 24, 2016 September 26, 2015 Provision for income taxes $ 1,332 $ 713 $ 2,568 $ 1,847 The Company recorded a tax provision of $1.3 million and $0.7 million for the three months ended September 24, 2016 and September 26, 2015, respectively, and $2.6 million and $1.8 million for the nine months ended September 24, 2016 and September 26, 2015, respectively. The increase in the tax provision for 2016 from 2015 was primarily related to an increase in the Company’s earnings for the three and nine months ended September 24, 2016. As of September 24, 2016, the Company continues to maintain a valuation allowance against its U.S. and 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 allowance will be reflected in the tax provision for the period such determination is made. 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 is 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. 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 September 24, 2016 and September 26, 2015. During the next twelve months, the Company anticipates increases in its unrecognized tax benefits of approximately $0.1 million.

Segment, Geographic, Product an

Segment, Geographic, Product and Significant Customer Information	9 Months Ended
	Sep. 24, 2016
Segment Reporting [Abstract]
Geographic And Significant Customer Information Text Block	Note 15. Segment, Geographic, Product and Significant Customer Information The Company has one operating segment, which is the sale, design, manufacture, marketing and support of optical critical dimension and thin film systems. The following tables summarize total net revenues and long-lived assets (excluding intangible assets) attributed to significant countries (in thousands): Three Months Ended Nine Months Ended September 24, 2016 September 26, 2015 September 24, 2016 September 26, 2015 Total net revenues (1): China $ 15,710 $ 6,731 $ 35,226 $ 12,357 South Korea 11,765 6,794 24,669 28,807 United States 8,211 7,985 24,306 32,115 Singapore 7,364 2,988 33,883 15,875 Taiwan 6,334 11,331 16,962 35,173 Japan 5,078 7,778 18,645 15,919 Other 4,252 2,071 8,279 4,436 Total net revenues $ 58,714 $ 45,678 $ 161,970 $ 144,682 September 24, 2016 December 26, 2015 Long-lived tangible assets: United States $ 42,603 $ 42,581 International 1,721 1,912 Total long-lived tangible assets $ 44,324 $ 44,493 The following customers accounted for 10% or more of total accounts receivable, net: At September 24, 2016 December 26, 2015 Taiwan Semiconductor Manufacturing Company Limited 20.0 % 25.6 % Micron 15.3 % *** Intel 13.6 % *** United Semiconductor (Xiamen) Co., Ltd. 10.6 % *** Toshiba Corporation *** 27.1 % *** 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 revenues: Three Months Ended Nine Months Ended September 24, 2016 September 26, 2015 September 24, 2016 September 26, 2015 SK Hynix 18.8 % 15.0 % 14.0 % 13.0 % Intel Corporation 18.5 % *** 19.4 % *** Micron 14.6 % 14.0 % 25.2 % 18.0 % Toshiba Corporation *** 13.0 % *** *** Taiwan Semiconductor Manufacturing Company Limited *** 17.0 % *** 19.0 % Samsung Electronics Co. Ltd. *** *** *** 16.0 % *** The customer accounted for less than 10% of total net revenues during the period.

Nature of Business and Basis 22

Nature of Business and Basis of Presentation (Policies)	9 Months Ended
	Sep. 24, 2016
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 accompanying condensed consolidated financial statements (“financial statements”) have been prepared on a consistent basis with the audited consolidated financial statements as of December 26, 2015, and include all normal recurring adjustments necessary to fairly state the information set forth therein. All significant intercompany accounts and transactions have been eliminated in consolidation. The financial statements have been prepared in accordance with the regulations of the United States Securities and Exchange Commission (“SEC”) for interim periods in accordance with S-X Article 10, and, therefore, omit certain information and footnote disclosure necessary to present the statements in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”). The operating results for interim periods are not necessarily indicative of the operating results that may be expected for the entire year. These financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto for the fiscal year ended December 26, 2015, which were included in the Company’s Annual Report on Form 10-K filed with the SEC on February 24, 2016.
Fiscal Period	Fiscal Period – The Company uses a 52/53 week fiscal year ending on the last Saturday of the calendar year. All references to the quarter refer to Nanometrics’ fiscal quarter. The fiscal quarters reported herein are 13 week periods.
Upgrade Revenue and Related Cost	Upgrade Revenue and Related Cost - Beginning the first quarter of 2016, revenues associated with upgrade sales are now included under Products Revenues, and the related costs in Cost of Products Revenue. This change was due to the types of upgrades currently being sold, which are primarily system software and hardware performance upgrades to extend the features and functionality of a product. Previously upgrades consisted of a group of parts and/or software that change the existing configuration of a product. For the three months ended September 26, 2015, $0.8 million related to upgrade sales, and $0.1 million of costs, are included in Service Revenues and Costs of Service Revenues, respectively, in the accompanying Condensed Consolidated Statement of Operations. For the nine months ended September 26, 2015, $7.6 million related to upgrade sales, and $2.9 million of costs, are included in Service Revenues and Costs of Service Revenues, respectively, in the accompanying Condensed Consolidated Statement of Operations.
Use of Estimates	Use of Estimates – The preparation of financial statements in conformity with 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.
Revenue Recognition	Revenue Recognition – The Company derives revenue from the sale of process control metrology and inspection systems and related upgrades (“product revenue”) as well as spare part sales, billable service and service contracts (together “service revenue”). Upgrades are system software and hardware performance upgrades that extend the features and functionality of a product. As discussed above, commencing in the first quarter of 2016, upgrades are included in product revenue, which consists of sales 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. 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. 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.

Fair Value Measurements and D23

Fair Value Measurements and Disclosures (Tables)	9 Months Ended
	Sep. 24, 2016
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: September 24, 2016 December 26, 2015 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 $ 840 $ — $ — $ 840 $ 590 $ — $ — $ 590 Commercial paper and corporate debt securities — 4,244 — 4,244 — 4,568 — 4,568 Total cash equivalents $ 840 $ 4,244 $ — $ 5,084 $ 590 $ 4,568 $ — $ 5,158 Marketable securities: U.S. Treasury securities and U.S. Government agency debt securities — 21,256 — 21,256 4,401 20,164 — 24,565 Certificates of deposits — 16,008 — 16,008 — — — — Commercial paper — 23,848 — 23,848 — 1,884 — 1,884 Municipal securities and corporate debt securities — 12,526 — 12,526 — 18,482 — 18,482 Asset-backed Securities — 7,468 — 7,468 — — — — Total marketable securities $ — $ 81,106 $ — $ 81,106 $ 4,401 $ 40,530 $ — $ 44,931 Total (1) $ 840 $ 85,350 $ — $ 86,190 $ 4,991 $ 45,098 $ — $ 50,089 Liabilities: Contingent consideration payable $ — $ — $ 1,333 $ 1,333 $ — $ — $ 1,490 $ 1,490 (1)
Fair value measurement on recurring basis, unobservable input reconciliation	Changes in Level 3 liabilities (in thousands) Fair value at December 26, 2015 $ 1,490 Payments made to Zygo Corporation (315 ) Change in fair value included in earnings 158 Fair value at September 24, 2016 $ 1,333
Outstanding derivative instruments	The following table summarizes the Company’s outstanding derivative instruments on a gross basis as of September 24, 2016: Notional Principal (in millions) Undesignated Hedges: Forward Foreign Currency Contracts $ 15.9

Cash and Investments (Tables)

Cash and Investments (Tables)	9 Months Ended
	Sep. 24, 2016
Investments Debt And Equity Securities [Abstract]
Cash, Cash Equivalents and Available-for-Sale Investments	The following tables present cash, cash equivalents, and available-for-sale investments as of the following dates (in thousands): September 24, 2016 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Market Value Cash $ 32,337 $ — $ — 32,337 Cash equivalents: Money market funds 840 — — 840 Commercial paper and corporate debt securities 4,245 — (1 ) 4,244 Marketable securities: U.S. Treasury securities 6,935 9 — 6,944 U.S. Government agency securities 14,301 11 — 14,312 Certificate of deposits 15,997 11 — 16,008 Commercial paper 23,845 3 — 23,848 Municipal securities 765 — — 765 Corporate debt securities 11,762 — (1 ) 11,761 Asset-backed securities 7,470 — (2 ) 7,468 Total cash, cash equivalents, and marketable securities $ 118,497 $ 34 $ (4 ) $ 118,527 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: U.S. Treasury securities 4,411 — (10 ) 4,401 U.S. Government agency securities 20,193 1 (29 ) 20,165 Commercial paper 1,884 — — 1,884 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

Financial Statement Components

Financial Statement Components (Tables)	9 Months Ended
	Sep. 24, 2016
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 September 24, 2016 December 26, 2015 Inventories: Raw materials and sub-assemblies $ 21,953 $ 26,784 Work in process 9,508 12,862 Finished goods 7,799 8,103 Inventories 39,260 47,749 Inventories-delivered systems 4,416 2,856 Total inventories $ 43,676 $ 50,605 Property, plant and equipment, net: (1) Land $ 15,570 $ 15,569 Building and improvements 20,511 20,158 Machinery and equipment 36,109 32,995 Furniture and fixtures 2,357 2,266 Software 9,007 8,245 Capital in progress 2,091 1,328 Total property, plant and equipment, gross 85,645 80,561 Accumulated depreciation and amortization (41,321 ) (36,068 ) Total property, plant and equipment, net $ 44,324 $ 44,493 (1) Other Current Liabilities: Accrued warranty $ 4,185 $ 4,504 Accrued restructuring — 256 Accrued professional services 492 481 Accrued royalties 1,029 437 Fair value of current portion of contingent payments to Zygo Corporation related to acquisition 814 945 Other 2,110 2,255 Total other current liabilities $ 8,630 $ 8,878
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 26, 2015 $ (4,948 ) $ (210 ) $ (44 ) $ (5,202 ) Current period change 2,018 — 73 2,091 Balance as of September 24, 2016 $ (2,930 ) $ (210 ) $ 29 $ (3,111 )

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	9 Months Ended
	Sep. 24, 2016
Goodwill And Intangible Assets Disclosure [Abstract]
Schedule of goodwill	The following table summarizes the activity in the Company’s goodwill during the nine months ended September 24, 2016: (in thousands) Balance as of December 26, 2015 $ 9,415 Foreign currency movements 250 Balance as of September 24, 2016 $ 9,665
Summary of finite-lived intangible assets	Finite-lived intangible assets are recorded at cost, less accumulated amortization. Finite-lived intangible assets as of September 24, 2016 and December 26, 2015 consisted of the following (in thousands): September 24, 2016 Adjusted cost Accumulated amortization Net carrying amount Developed technology $ 16,336 $ (15,867 ) $ 469 Customer relationships 9,387 (9,387 ) — Brand names 1,927 (1,927 ) — Patented technology 2,252 (2,169 ) 83 Trademark 80 (80 ) — Total $ 29,982 $ (29,430 ) $ 552 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
Estimated future amortization expense	The estimated future amortization expense of finite intangible assets as of September 24, 2016 is as follows (in thousands): Fiscal Years Amounts 2016 (remaining three months) $ 140 2017 206 2018 140 2019 66 Thereafter — Total future amortization expense $ 552

Warranties (Tables)

Warranties (Tables)	9 Months Ended
	Sep. 24, 2016
Product Warranties Disclosures [Abstract]
Components of the warranty accrual	Components of the warranty accrual, which were included in the accompanying condensed consolidated balance sheets with other current liabilities, were as follows (in thousands): Three Months Ended Nine Months Ended September 24, 2016 September 26, 2015 September 24, 2016 September 26, 2015 Balance as of beginning of period $ 4,556 $ 3,792 $ 4,504 $ 2,953 Accruals for warranties issued during period 1,100 2,288 3,529 6,240 Settlements during the period (1,471 ) (1,789 ) (3,848 ) (4,902 ) Balance as of end of period $ 4,185 $ 4,291 $ 4,185 $ 4,291

Restructuring (Tables)

Restructuring (Tables)	9 Months Ended
	Sep. 24, 2016
Restructuring And Related Activities [Abstract]
Components of the restructuring reserve	As of September 24, 2016, 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 26, 2015 $ — $ 249 $ 7 $ 256 Charges — — — — Cash Payments — (249 ) (7 ) (256 ) Balance as of September 24, 2016 $ — $ — $ — $ — Employee severance and benefits Facility termination costs Other Total Balance as of December 27, 2014 $ 383 $ 583 $ 31 $ 997 Charges 45 — 11 56 Cash Payments (428 ) (249 ) (35 ) (712 ) Balance as of September 26, 2015 $ — $ 334 $ 7 $ 341

Net Income Per Share (Tables)

Net Income Per Share (Tables)	9 Months Ended
	Sep. 24, 2016
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 per share computations for three and nine months ended September 24, 2016 and September 26, 2015 is as follows (in thousands): Three Month Ended Nine Months Ended September 24, 2016 September 26, 2015 September 24, 2016 September 26, 2015 Weighted average common shares outstanding used in basic net income (loss) per share calculation 24,826 24,145 24,550 24,010 Potential dilutive common stock equivalents, using treasury stock method 456 207 429 337 Weighted average shares used in diluted net income (loss) per share calculation 25,282 24,352 24,979 24,347

Stockholders' Equity and Stoc30

Stockholders' Equity and Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 24, 2016
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Employee stock purchase plan assumptions	Three Months Ended Nine Months Ended September 24, 2016 September 26, 2015 September 24, 2016 September 26, 2015 Employee Stock Purchase Plan: Expected life 0.5 years 0.5 years 0.5 years 0.5 years Volatility 38.2% 36.7% 38.7 % 36.9% Risk free interest rate 0.37% 0.13% 0.44 % 0.12% Dividends — — — —
Stock option plans activity	A summary of activity of stock options during the nine months ended September 24, 2016 is as follows: Number of Shares Outstanding (Options) Weighted Average Exercise Price Weighted Average Remaining Contractual Term (Years) Aggregate Intrinsic Value (in Options Outstanding at December 26, 2015 1,051,867 $ 14.60 2.46 $ 1,916 Exercised (352,996 ) $ 13.33 Cancelled (166,849 ) $ 15.79 Outstanding at September 24, 2016 532,022 $ 15.06 2.32 $ 3,849 Exercisable at September 24, 2016 480,462 $ 14.91 2.15 $ 3,546
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 26, 2015 713,243 $ 15.99 Granted 455,907 $ 17.15 Released (286,260 ) $ 16.11 Cancelled (45,852 ) $ 16.00 Outstanding RSUs as of September 24, 2016 837,038 $ 15.58
Summary of activity for PSUs	A summary of activity for PSUs is as follows: Summary of activity for PSUs Number of PSUs Weighted Average Fair Value Outstanding PSUs as of December 26, 2015 60,000 $ 18.35 Granted 67,500 $ 8.52 Released (13,333 ) $ 18.04 Cancelled (6,667 ) $ 18.04 Outstanding PSUs as of September 24, 2016 107,500 $ 12.24
PSUs valuation assumptions	The assumptions for the valuation of PSUs are summarized as follows: 2016 Award 2015 Award Grant Date Fair Value Per Share $ 8.52 $ 18.35 Weighted-average assumptions/inputs: Expected Dividend — — Range of risk-free interest rates 0.92% 0.25%-1.1% Range of expected volatilities for peer group 22%-93% 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): Three Months Ended Nine Months Ended September 24, 2016 September 26, 2015 September 24, 2016 September 26, 2015 Cost of products $ 116 $ 96 $ 273 $ 229 Cost of service 138 104 355 195 Research and development 387 300 985 796 Selling 537 511 1,492 1,403 General and administrative 822 671 2,327 2,041 Total stock-based compensation expense related to employee stock options and employee stock purchases $ 2,000 $ 1,682 $ 5,432 $ 4,664

Income Taxes (Tables)

Income Taxes (Tables)	9 Months Ended
	Sep. 24, 2016
Income Tax Disclosure [Abstract]
Provision for income taxes	The provision for income taxes consists of the following (in thousands): Three Months Ended Nine Months Ended September 24, 2016 September 26, 2015 September 24, 2016 September 26, 2015 Provision for income taxes $ 1,332 $ 713 $ 2,568 $ 1,847

Segment, Geographic, Product 32

Segment, Geographic, Product and Significant Customer Information (Tables)	9 Months Ended
	Sep. 24, 2016
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) Three Months Ended Nine Months Ended September 24, 2016 September 26, 2015 September 24, 2016 September 26, 2015 Total net revenues (1): China $ 15,710 $ 6,731 $ 35,226 $ 12,357 South Korea 11,765 6,794 24,669 28,807 United States 8,211 7,985 24,306 32,115 Singapore 7,364 2,988 33,883 15,875 Taiwan 6,334 11,331 16,962 35,173 Japan 5,078 7,778 18,645 15,919 Other 4,252 2,071 8,279 4,436 Total net revenues $ 58,714 $ 45,678 $ 161,970 $ 144,682
Long-lived tangible assets	September 24, 2016 December 26, 2015 Long-lived tangible assets: United States $ 42,603 $ 42,581 International 1,721 1,912 Total long-lived tangible assets $ 44,324 $ 44,493
Customers accounted for 10% or more of total accounts receivable	The following customers accounted for 10% or more of total accounts receivable, net: At September 24, 2016 December 26, 2015 Taiwan Semiconductor Manufacturing Company Limited 20.0 % 25.6 % Micron 15.3 % *** Intel 13.6 % *** United Semiconductor (Xiamen) Co., Ltd. 10.6 % *** Toshiba Corporation *** 27.1 % *** 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 revenues: Three Months Ended Nine Months Ended September 24, 2016 September 26, 2015 September 24, 2016 September 26, 2015 SK Hynix 18.8 % 15.0 % 14.0 % 13.0 % Intel Corporation 18.5 % *** 19.4 % *** Micron 14.6 % 14.0 % 25.2 % 18.0 % Toshiba Corporation *** 13.0 % *** *** Taiwan Semiconductor Manufacturing Company Limited *** 17.0 % *** 19.0 % Samsung Electronics Co. Ltd. *** *** *** 16.0 % *** The customer accounted for less than 10% of total net revenues during the period.

Nature of Business and Basis 33

Nature of Business and Basis of Presentation - Textual (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 24, 2016	Sep. 26, 2015	Sep. 24, 2016	Sep. 26, 2015
Accounting Policies [Line Items]
Fiscal year/fiscal quarter duration			91 days	91 days
Products	$ 49,631	$ 36,414	$ 136,290	$ 113,689
Cost of products	$ 22,810	19,242	$ 62,625	59,106
Maximum period of delivery to customers			6 months
Maximum period services are provided over the fixed arrangement term			12 months
Reclassification [Member]
Accounting Policies [Line Items]
Products		800		7,600
Cost of products		$ 100		$ 2,900
Minimum [Member]
Accounting Policies [Line Items]
Fiscal year/fiscal quarter duration			364 days
Maximum [Member]
Accounting Policies [Line Items]
Fiscal year/fiscal quarter duration			371 days

Fair Value Measurements and D34

Fair Value Measurements and Disclosures - Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Sep. 24, 2016	Dec. 26, 2015
Assets:
Total marketable securities	$ 81,106	$ 44,931
Fair Value, Measurements, Recurring [Member]
Assets:
Total cash equivalents	5,084	5,158
Total marketable securities	81,106	44,931
Total	86,190	50,089
Liabilities:
Contingent consideration payable	1,333	1,490
Money market funds [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Total cash equivalents	840	590
Commercial paper and corporate debt securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Total cash equivalents	4,244	4,568
U.S. Treasury securities and U.S. Government agency debt securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Total marketable securities	21,256	24,565
Certificates of deposits [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Total marketable securities	16,008	0
Commercial paper [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Total marketable securities	23,848	1,884
Municipal securities and corporate debt securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Total marketable securities	12,526	18,482
Asset-backed Securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Total marketable securities	7,468	0
Cash [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Total cash equivalents	32,300	33,000
Level 1 [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Total cash equivalents	840	590
Total marketable securities	0	4,401
Total	840	4,991
Liabilities:
Contingent consideration payable	0	0
Level 1 [Member] | Money market funds [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Total cash equivalents	840	590
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 securities and U.S. Government agency debt securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Total marketable securities	0	4,401
Level 1 [Member] | Certificates of deposits [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Total marketable securities	0	0
Level 1 [Member] | Commercial paper [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Total marketable securities	0	0
Level 1 [Member] | Municipal securities and corporate debt securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Total marketable securities	0	0
Level 1 [Member] | Asset-backed 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	4,244	4,568
Total marketable securities	81,106	40,530
Total	85,350	45,098
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	4,244	4,568
Level 2 [Member] | U.S. Treasury securities and U.S. Government agency debt securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Total marketable securities	21,256	20,164
Level 2 [Member] | Certificates of deposits [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Total marketable securities	16,008	0
Level 2 [Member] | Commercial paper [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Total marketable securities	23,848	1,884
Level 2 [Member] | Municipal securities and corporate debt securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Total marketable securities	12,526	18,482
Level 2 [Member] | Asset-backed Securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Total marketable securities	7,468	0
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	1,333	1,490
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 securities and U.S. Government agency debt securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Total marketable securities	0	0
Level 3 [Member] | Certificates of deposits [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Total marketable securities	0	0
Level 3 [Member] | Commercial paper [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Total marketable securities	0	0
Level 3 [Member] | Municipal securities and corporate debt securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Total marketable securities	0	0
Level 3 [Member] | Asset-backed Securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Total marketable securities	$ 0	$ 0

Fair Value Measurements and D35

Fair Value Measurements and Disclosures - Unobservable Input Reconciliation (Details) - Level 3 [Member] $ in Thousands	9 Months Ended
	Sep. 24, 2016USD ($)
Fair value measurement on recurring basis, unobservable input reconciliation [Roll Forward]
Fair value, beginning balance	$ 1,490
Change in fair value included in earnings	158
Fair Value, ending balance	1,333
Zygo Corporation [Member]
Fair value measurement on recurring basis, unobservable input reconciliation [Roll Forward]
Payments made to Zygo Corporation	$ (315)

Fair Value Measurements and D36

Fair Value Measurements and Disclosures - Textual (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 24, 2016	Sep. 26, 2015	Sep. 24, 2016	Sep. 26, 2015	Dec. 26, 2015
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	$ 0.1	$ (0.3)	$ (1.2)	$ (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	1.3		1.3		$ 1.5
Current liability at fair value	0.8		0.8		0.9
Long-term liability at fair value	$ 0.5		$ 0.5		$ 0.6

Fair Value Measurements and D37

Fair Value Measurements and Disclosures - Outstanding Derivative Instruments (Details)	Sep. 24, 2016USD ($)
Not Designated as Hedging Instrument [Member] | Forward Foreign Currency Contracts [Member]
Derivatives Fair Value [Line Items]
Notional Principal	$ 15,900,000

Cash and Investments (Details)

Cash and Investments (Details) - USD ($) $ in Thousands	Sep. 24, 2016	Dec. 26, 2015
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	$ 118,497	$ 83,148
Gross Unrealized Gains	34	2
Gross Unrealized Losses	(4)	(65)
Estimated Fair Market Value	118,527	83,085
U.S. Government agency securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	14,301	20,193
Gross Unrealized Gains	11	1
Gross Unrealized Losses	0	(29)
Estimated Fair Market Value	14,312	20,165
Commercial paper [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	23,845	1,884
Gross Unrealized Gains	3	0
Gross Unrealized Losses	0	0
Estimated Fair Market Value	23,848	1,884
Asset-backed securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	7,470
Gross Unrealized Gains	0
Gross Unrealized Losses	(2)
Estimated Fair Market Value	7,468
Corporate debt securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	11,762	14,759
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(1)	(23)
Estimated Fair Market Value	11,761	14,736
Cash [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	32,337	32,996
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Market Value	32,337	32,996
Money market funds [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	840	590
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Market Value	840	590
U.S. Treasury securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	6,935	4,411
Gross Unrealized Gains	9	0
Gross Unrealized Losses	0	(10)
Estimated Fair Market Value	6,944	4,401
Commercial paper and corporate debt securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	4,245
Gross Unrealized Gains	0
Gross Unrealized Losses	(1)
Estimated Fair Market Value	4,244
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
Certificates of deposits [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	15,997
Gross Unrealized Gains	11
Gross Unrealized Losses	0
Estimated Fair Market Value	16,008
Municipal securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	765	3,747
Gross Unrealized Gains	0	1
Gross Unrealized Losses	0	(3)
Estimated Fair Market Value	$ 765	$ 3,745

Cash and Investments - Addition

Cash and Investments - Additional Information (Details)	9 Months Ended	12 Months Ended
	Sep. 24, 2016	Dec. 26, 2015
Investments Debt And Equity Securities [Abstract]
Investment maturity period, less than	2 years	2 years

Accounts Receivable - Textual (

Accounts Receivable - Textual (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 24, 2016	Sep. 26, 2015	Sep. 24, 2016	Sep. 26, 2015	Dec. 26, 2015
Accounts Receivable (Additional Textual) [Abstract]
Sold receivables amount	$ 10,100,000	$ 4,300,000	$ 29,600,000	$ 7,300,000
Gains or losses on sale of accounts receivables			0
Due from unrelated third parties	$ 0		$ 0		$ 0
Minimum [Member]
Accounts Receivable (Textual) [Abstract]
Administrative fees as well as interest percent			0.76%
Maximum [Member]
Accounts Receivable (Textual) [Abstract]
Administrative fees as well as interest percent			1.68%

Financial Statement Component41

Financial Statement Components - Selected Financial Statement Components (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 24, 2016	Sep. 26, 2015	Sep. 24, 2016	Sep. 26, 2015	Jun. 25, 2016	Dec. 26, 2015	Jun. 27, 2015	Dec. 27, 2014
Inventories:
Raw materials and sub-assemblies	$ 21,953		$ 21,953			$ 26,784
Work in process	9,508		9,508			12,862
Finished goods	7,799		7,799			8,103
Inventories	39,260		39,260			47,749
Inventories-delivered systems	4,416		4,416			2,856
Total inventories	43,676		43,676			50,605
Property, plant and equipment, net:
Total property, plant and equipment, gross	85,645		85,645			80,561
Accumulated depreciation and amortization	(41,321)		(41,321)			(36,068)
Total property, plant and equipment, net	44,324		44,324			44,493
Depreciation and amortization expense	1,700	$ 1,800	5,100	$ 5,200
Accrued warranty	4,185	4,291	4,185	4,291	$ 4,556	4,504	$ 3,792	$ 2,953
Accrued restructuring	0	$ 341	0	$ 341		256		$ 997
Accrued professional services	492		492			481
Accrued royalties	1,029		1,029			437
Fair value of current portion of contingent payments to Zygo Corporation related to acquisition	814		814			945
Other	2,110		2,110			2,255
Total other current liabilities	8,630		8,630			8,878
Land [Member]
Property, plant and equipment, net:
Total property, plant and equipment, gross	15,570		15,570			15,569
Building and improvements [Member]
Property, plant and equipment, net:
Total property, plant and equipment, gross	20,511		20,511			20,158
Machinery and equipment [Member]
Property, plant and equipment, net:
Total property, plant and equipment, gross	36,109		36,109			32,995
Furniture and fixtures [Member]
Property, plant and equipment, net:
Total property, plant and equipment, gross	2,357		2,357			2,266
Software [Member]
Property, plant and equipment, net:
Total property, plant and equipment, gross	9,007		9,007			8,245
Capital in progress [Member]
Property, plant and equipment, net:
Total property, plant and equipment, gross	$ 2,091		$ 2,091			$ 1,328

Financial Statement Component42

Financial Statement Components - Components of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 24, 2016	Sep. 26, 2015	Sep. 24, 2016	Sep. 26, 2015
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning of period			$ (5,202)
Current period change	$ 520	$ (218)	2,091	$ (1,938)
End of period	(3,111)		(3,111)
Foreign Currency Translations [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning of period			(4,948)
Current period change			2,018
End of period	(2,930)		(2,930)
Defined Benefit Pension Plans [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning of period			(210)
End of period	(210)		(210)
Unrealized Income (Loss) on Investment [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning of period			(44)
Current period change			73
End of period	$ 29		$ 29

Goodwill and Intangible Asset43

Goodwill and Intangible Assets - Goodwill (Details) $ in Thousands	9 Months Ended
	Sep. 24, 2016USD ($)
Goodwill [Roll Forward]
Beginning balance	$ 9,415
Foreign currency movements	250
Ending balance	$ 9,665

Goodwill and Intangible Asset44

Goodwill and Intangible Assets - Intangible Assets (Details) - USD ($) $ in Thousands	Sep. 24, 2016	Dec. 26, 2015
Summary of Finite-lived intangible assets
Adjusted cost	$ 29,982	$ 29,721
Accumulated amortization	(29,430)	(27,854)
Finite lived intangible assets, Net carrying amount	552	1,867
Developed technology [Member]
Summary of Finite-lived intangible assets
Adjusted cost	16,336	16,098
Accumulated amortization	(15,867)	(14,387)
Finite lived intangible assets, Net carrying amount	469	1,711
Customer relationships [Member]
Summary of Finite-lived intangible assets
Adjusted cost	9,387	9,364
Accumulated amortization	(9,387)	(9,364)
Finite lived intangible assets, Net carrying amount	0	0
Brand names [Member]
Summary of Finite-lived intangible assets
Adjusted cost	1,927	1,927
Accumulated amortization	(1,927)	(1,903)
Finite lived intangible assets, Net carrying amount	0	24
Patented technology [Member]
Summary of Finite-lived intangible assets
Adjusted cost	2,252	2,252
Accumulated amortization	(2,169)	(2,120)
Finite lived intangible assets, Net carrying amount	83	132
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 Asset45

Goodwill and Intangible Assets - Textual (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 24, 2016	Sep. 26, 2015	Sep. 24, 2016	Sep. 26, 2015
Finite-Lived Intangible Assets [Line Items]
Total amortization expense	$ 400,000	$ 500,000	$ 1,300,000	$ 1,600,000
Impairment charges	$ 0	$ 0	$ 0	$ 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 Asset46

Goodwill and Intangible Assets - Future Amortization (Details) - USD ($) $ in Thousands	Sep. 24, 2016	Dec. 26, 2015
Estimated future amortization expense
2016 (remaining three months)	$ 140
2,017	206
2,018	140
2,019	66
Thereafter	0
Finite lived intangible assets, Net carrying amount	$ 552	$ 1,867

Warranties - Textual (Details)

Warranties - Textual (Details)	9 Months Ended
	Sep. 24, 2016
Product Warranties Disclosures [Abstract]
Product warranty period	12 months

Warranties (Details)

Warranties (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 24, 2016	Sep. 26, 2015	Sep. 24, 2016	Sep. 26, 2015
Components of the warranty accrual [Roll Forward]
Balance as of beginning of period	$ 4,556	$ 3,792	$ 4,504	$ 2,953
Accruals for warranties issued during period	1,100	2,288	3,529	6,240
Settlements during the period	(1,471)	(1,789)	(3,848)	(4,902)
Balance as of end of period	$ 4,185	$ 4,291	$ 4,185	$ 4,291

Restructuring - Textual (Detail

Restructuring - Textual (Details) - USD ($)	9 Months Ended
	Sep. 24, 2016	Sep. 26, 2015
Restructuring And Related Activities [Abstract]
Restructuring charge	$ 0	$ 56,000

Restructuring (Details)

Restructuring (Details) - USD ($)	9 Months Ended
	Sep. 24, 2016	Sep. 26, 2015
Restructuring Reserve [Roll Forward]
Beginning Balance	$ 256,000	$ 997,000
Charges	0	56,000
Cash Payments	(256,000)	(712,000)
Ending Balance	0	341,000
Employee severance and benefits [Member]
Restructuring Reserve [Roll Forward]
Beginning Balance	0	383,000
Charges	0	45,000
Cash Payments	0	(428,000)
Ending Balance	0	0
Facility termination costs [Member]
Restructuring Reserve [Roll Forward]
Beginning Balance	249,000	583,000
Charges	0	0
Cash Payments	(249,000)	(249,000)
Ending Balance	0	334,000
Other [Member]
Restructuring Reserve [Roll Forward]
Beginning Balance	7,000	31,000
Charges	0	11,000
Cash Payments	(7,000)	(35,000)
Ending Balance	$ 0	$ 7,000

Line of Credit and Debt Oblig51

Line of Credit and Debt Obligations - Textual (Details) - Revolving line of credit facility [Member] - USD ($)	9 Months Ended
	Sep. 24, 2016	May 30, 2016
Debt Instrument [Line Items]
Expiration date	May 30, 2016
Maximum amount of credit facility		$ 12,000,000

Commitments and Contingencies -

Commitments and Contingencies - Textual (Details) - USD ($)	Sep. 24, 2016	Dec. 26, 2015
Commitments And Contingencies Disclosure [Abstract]
Liabilities recorded for obligations	$ 0	$ 0

Net Income Per Share (Details)

Net Income Per Share (Details) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 24, 2016	Sep. 26, 2015	Sep. 24, 2016	Sep. 26, 2015
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	24,826	24,145	24,550	24,010
Potential dilutive common stock equivalents, using treasury stock method	456	207	429	337
Weighted average shares used in diluted net income (loss) per share calculation	25,282	24,352	24,979	24,347

Stockholders' Equity and Stoc54

Stockholders' Equity and Stock-Based Compensation - Employee Stock Purchase Plan Assumptions (Details) - Employee Stock Purchase Plan [Member]	3 Months Ended		9 Months Ended
	Sep. 24, 2016	Sep. 26, 2015	Sep. 24, 2016	Sep. 26, 2015
Assumption of stock option's fair value
Expected life	6 months	6 months	6 months	6 months
Volatility	38.20%	36.70%	38.70%	36.90%
Risk free interest rate	0.37%	0.13%	0.44%	0.12%
Dividends	0.00%	0.00%	0.00%	0.00%

Stockholders' Equity and Stoc55

Stockholders' Equity and Stock-Based Compensation - Textual (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 24, 2016	Sep. 26, 2015	Sep. 24, 2016	Sep. 26, 2015	Sep. 23, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares Outstanding (Options), Granted (in shares)			0	0
Closing stock price (in dollars per share)					$ 22.29
Intrinsic value of options exercised	$ 0.5	$ 0.1	$ 1.9	$ 1.4
Performance-Based Restricted Stock Units (PSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percent of granted shares that will vest if target stock price performance is achieved			66.70%
Maximum percent of granted shares that will vest if maximum stock price performance is achieved			100.00%
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

Stockholders' Equity and Stoc56

Stockholders' Equity and Stock-Based Compensation - Summary of Activity of Stock Options (Details) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 24, 2016	Dec. 26, 2015
Activity of stock option plans [Roll Forward]
Number of Shares Outstanding (Options), Beginning Balance (in shares)	1,051,867
Number of Shares Outstanding (Options), Exercised (in shares)	(352,996)
Number of Shares Outstanding (Options), Cancelled (in shares)	(166,849)
Number of Shares Outstanding (Options), Ending Balance (in shares)	532,022	1,051,867
Number of Shares Outstanding (Options), Exercisable (in shares)	480,462
Weighted average exercise price for stock option plans [Roll Forward]
Weighted Average Exercise Price, Beginning Balance (in dollars per share)	$ 14.60
Weighted Average Exercise Price, Exercised (in dollars per share)	13.33
Weighted Average Exercise Price, Cancelled (in dollars per share)	15.79
Weighted Average Exercise Price, Ending Balance (in dollars per share)	15.06	$ 14.60
Weighted Average Exercise Price, Exercisable (in dollars per share)	$ 14.91
Weighed Average Remaining Contractual Term, Outstanding	2 years 3 months 26 days	2 years 5 months 16 days
Weighed Average Remaining Contractual Term, Exercisable	2 years 1 month 24 days
Aggregate Intrinsic Value, Outstanding	$ 3,849	$ 1,916
Aggregate Intrinsic Value, Exercisable	$ 3,546

Stockholders' Equity and Stoc57

Stockholders' Equity and Stock-Based Compensation - Restricted Stock Unit Activity (Details) - Restricted Stock Units (RSUs) [Member]	9 Months Ended
	Sep. 24, 2016$ / sharesshares
Activity for RSUs [Roll Forward]
Number of units Beginning balance (in shares) | shares	713,243
Number of units, Granted (in shares) | shares	455,907
Number of units, Released (in shares) | shares	(286,260)
Number of units, Cancelled (in shares) | shares	(45,852)
Number of units, Ending balance (in shares) | shares	837,038
Weighted Average Fair Value for RSUs [Roll Forward]
Weighted Average Fair Value, Beginning balance (in dollars per share) | $ / shares	$ 15.99
Weighted Average Fair Value, Granted (in dollars per share) | $ / shares	17.15
Weighted Average Fair Value, Released (in dollars per share) | $ / shares	16.11
Weighted Average Fair Value, Cancelled (in dollars per share) | $ / shares	16
Weighted Average Fair Value, Ending balance (in dollars per share) | $ / shares	$ 15.58

Stockholders' Equity and Stoc58

Stockholders' Equity and Stock-Based Compensation - Performance Stock Units Activity (Details) - Performance-Based Restricted Stock Units (PSUs) [Member] - $ / shares	9 Months Ended
	Sep. 24, 2016	Sep. 26, 2015
Activity for PSUs [Roll Forward]
Number of units Beginning balance (in shares)	60,000
Number of units, Granted (in shares)	67,500
Number of units, Released (in shares)	(13,333)
Number of units, Cancelled (in shares)	(6,667)
Number of units, Ending balance (in shares)	107,500
Weighted Average Fair Value for PSUs [Roll Forward]
Weighted Average Fair Value, Beginning balance (in dollars per share)	$ 18.35
Weighted Average Fair Value, Granted (in dollars per share)	8.52	$ 18.35
Weighted Average Fair Value, Released (in dollars per share)	18.04
Weighted Average Fair Value, Cancelled (in dollars per share)	18.04
Weighted Average Fair Value, Ending balance (in dollars per share)	$ 12.24

Stockholders' Equity and Stoc59

Stockholders' Equity and Stock-Based Compensation - Performance Stock Units Valuation Assumptions (Details) - Performance-Based Restricted Stock Units (PSUs) [Member] - $ / shares	9 Months Ended
	Sep. 24, 2016	Sep. 26, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant Date Fair Value Per Share (in dollars per share)	$ 8.52	$ 18.35
Dividends	0.00%	0.00%
Risk free interest rate	0.92%
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	22.00%	23.00%
Range of expected volatilities for peer group, maximum	93.00%	65.00%

Stockholders' Equity and Stoc60

Stockholders' Equity and Stock-Based Compensation - Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 24, 2016	Sep. 26, 2015	Sep. 24, 2016	Sep. 26, 2015
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	$ 2,000	$ 1,682	$ 5,432	$ 4,664
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	116	96	273	229
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	138	104	355	195
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	387	300	985	796
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	537	511	1,492	1,403
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	$ 822	$ 671	$ 2,327	$ 2,041

Income Taxes - Provision for In

Income Taxes - Provision for Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 24, 2016	Sep. 26, 2015	Sep. 24, 2016	Sep. 26, 2015
Income Tax Disclosure [Abstract]
Provision for income taxes	$ 1,332	$ 713	$ 2,568	$ 1,847

Income Taxes - Textual (Details

Income Taxes - Textual (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 24, 2016	Sep. 26, 2015	Sep. 24, 2016	Sep. 26, 2015
Income Taxes (Textual) [Abstract]
Provision for income taxes	$ 1,332	$ 713	$ 2,568	$ 1,847
Anticipated increase in unrecognized tax benefits during next twelve months	$ 100		$ 100

Segment, Geographic, Product 63

Segment, Geographic, Product and Significant Customer Information - Revenue Net (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 24, 2016USD ($)	Sep. 26, 2015USD ($)	Sep. 24, 2016USD ($)segment	Sep. 26, 2015USD ($)
Revenues From External Customers And Long Lived Assets [Line Items]
Number of operating segments | segment			1
Net revenues:
Total net revenues	$ 58,714	$ 45,678	$ 161,970	$ 144,682
China [Member]
Net revenues:
Total net revenues	15,710	6,731	35,226	12,357
South Korea [Member]
Net revenues:
Total net revenues	11,765	6,794	24,669	28,807
United States [Member]
Net revenues:
Total net revenues	8,211	7,985	24,306	32,115
Singapore [Member]
Net revenues:
Total net revenues	7,364	2,988	33,883	15,875
Taiwan [Member]
Net revenues:
Total net revenues	6,334	11,331	16,962	35,173
Japan [Member]
Net revenues:
Total net revenues	5,078	7,778	18,645	15,919
Other [Member]
Net revenues:
Total net revenues	$ 4,252	$ 2,071	$ 8,279	$ 4,436

Segment, Geographic, Product 64

Segment, Geographic, Product and Significant Customer Information - Long-lived Tangible Assets (Details) - USD ($) $ in Thousands	Sep. 24, 2016	Dec. 26, 2015
Long-lived tangible assets:
Total long-lived tangible assets	$ 44,324	$ 44,493
United States [Member]
Long-lived tangible assets:
Total long-lived tangible assets	42,603	42,581
International [Member]
Long-lived tangible assets:
Total long-lived tangible assets	$ 1,721	$ 1,912

Segment, Geographic, Product 65

Segment, Geographic, Product and Significant Customer Information - Customers More Than 10% of Accounts Receivable (Details) - Accounts Receivable [Member] - Customer Concentration Risk	9 Months Ended	12 Months Ended
	Sep. 24, 2016	Dec. 26, 2015
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	20.00%	25.60%
Micron [Member]
Customers accounted for 10% or more of total accounts receivable
Customers accounted for 10% or more of total accounts receivable	15.30%
Intel [Member]
Customers accounted for 10% or more of total accounts receivable
Customers accounted for 10% or more of total accounts receivable	13.60%
United Semiconductor (Xiamen) Co., Ltd. [Member]
Customers accounted for 10% or more of total accounts receivable
Customers accounted for 10% or more of total accounts receivable	10.60%
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%

Segment, Geographic, Product 66

Segment, Geographic, Product and Significant Customer Information - Customers More Than 10% of Revenues (Details) - Sales Revenue, Net [Member] - Customer Concentration Risk	3 Months Ended		9 Months Ended
	Sep. 24, 2016	Sep. 26, 2015	Sep. 24, 2016	Sep. 26, 2015
SK Hynix [Member]
Net revenues:
Customers accounted for 10% or more of total revenue	18.80%	15.00%	14.00%	13.00%
Intel Corporation [Member]
Net revenues:
Customers accounted for 10% or more of total revenue	18.50%		19.40%
Micron [Member]
Net revenues:
Customers accounted for 10% or more of total revenue	14.60%	14.00%	25.20%	18.00%
Toshiba Corporation [Member]
Net revenues:
Customers accounted for 10% or more of total revenue		13.00%
Taiwan Semiconductor Manufacturing Company Limited [Member]
Net revenues:
Customers accounted for 10% or more of total revenue		17.00%		19.00%
Samsung Electronics Co. Ltd. [Member]
Net revenues:
Customers accounted for 10% or more of total revenue				16.00%