Onto Innovation (ONTO) 10-Q 2 Nov 20 2020 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information Document - shares	9 Months Ended
	Sep. 26, 2020	Oct. 14, 2020
Cover [Abstract]
Entity Registrant Name	ONTO INNOVATION INC.
Trading Symbol	ONTO
Entity Central Index Key	0000704532
Current Fiscal Year End Date	--12-28
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Sep. 26, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
Document Quarterly Report	true
Document Transition Report	false
Entity Interactive Data Current	Yes
Amendment Flag	false
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Current Reporting Status	Yes
Entity Shell Company	false
Title of 12(b) Security	Common Stock, $0.001 par value per share
Security Exchange Name	NYSE
Entity Common Stock, Shares Outstanding		48,831,308
Entity File Number	001-39110
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	94-2276314
Entity Address, Address Line One	16 Jonspin Road
Entity Address, City or Town	Wilmington
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	01887
City Area Code	978
Local Phone Number	253-6200

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 30, 2019	Sep. 26, 2020	Sep. 30, 2019
Income Statement [Abstract]
Revenue	$ 126,492	$ 62,935	$ 401,368	$ 185,338
Cost of revenue	57,604	31,424	198,264	89,897
Gross profit	68,888	31,511	203,104	95,441
Operating expenses:
Research and development	19,678	10,455	62,772	31,654
Sales and marketing	11,924	5,090	36,864	15,614
General and administrative	14,358	10,289	50,421	28,696
Amortization	13,646	387	41,081	1,161
Total operating expenses	59,606	26,221	191,138	77,125
Operating income	9,282	5,290	11,966	18,316
Interest income, net	544	1,001	2,440	2,667
Other (expense) income, net	(899)	617	(2,065)	841
Income before provision for income taxes	8,927	6,908	12,341	21,824
Provision for income taxes	836	348	1,230	2,162
Net income	$ 8,091	$ 6,560	$ 11,111	$ 19,662
Earnings per share:
Basic	$ 0.17	$ 0.26	$ 0.23	$ 0.79
Diluted	$ 0.16	$ 0.26	$ 0.22	$ 0.78
Weighted average shares outstanding:
Basic	48,900	25,079	49,231	25,012
Diluted	49,131	25,305	49,551	25,254

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 30, 2019	Sep. 26, 2020	Sep. 30, 2019
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 8,091	$ 6,560	$ 11,111	$ 19,662
Other comprehensive income (loss), net of tax:
Change in net unrealized (losses) gains on available-for-sale marketable securities	(72)		197	209
Change in currency translation adjustments	1,803	(264)	2,067	(466)
Total other comprehensive income (loss), net of tax	1,731	(264)	2,264	(257)
Total comprehensive income	$ 9,822	$ 6,296	$ 13,375	$ 19,405

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Sep. 26, 2020	Dec. 31, 2019
Current Assets:
Cash and cash equivalents	$ 101,606	$ 130,673
Marketable securities	238,797	189,563
Accounts receivable, less allowance of $1,634 and $1,247	131,429	123,656
Inventories, net	184,981	176,134
Prepaid expenses and other current assets	19,908	21,638
Total current assets	676,721	641,664
Property, plant and equipment, net	92,716	98,420
Goodwill	307,626	307,148
Identifiable intangible assets, net	330,923	371,953
Deferred income taxes	1,292	1,456
Other assets	21,437	27,939
Total assets	1,430,715	1,448,580
Current liabilities:
Accounts payable	37,486	27,738
Accrued liabilities	31,063	26,204
Deferred revenue	15,871	12,629
Other current liabilities	12,811	19,172
Total current liabilities	97,231	85,743
Deferred and other tax liabilities	64,278	67,040
Other non-current liabilities	31,523	31,771
Total liabilities	193,032	184,554
Commitments and contingencies
Stockholders’ equity:
Common stock	49	50
Additional paid-in capital	1,229,720	1,269,437
Accumulated other comprehensive income (loss)	1,666	(598)
Retained earnings (accumulated deficit)	6,248	(4,863)
Total stockholders’ equity	1,237,683	1,264,026
Total liabilities and stockholders’ equity	$ 1,430,715	$ 1,448,580

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) (Unaudited) - USD ($) $ in Thousands	Sep. 26, 2020	Dec. 31, 2019
Statement Of Financial Position [Abstract]
Allowances for doubtful accounts	$ 1,634	$ 1,247

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 26, 2020	Sep. 30, 2019
Cash flows from operating activities:
Net income	$ 11,111	$ 19,662
Adjustments to reconcile net income to net cash and cash equivalents provided by operating activities:
Amortization of intangibles	41,081	1,161
Depreciation	9,834	3,399
Foreign currency exchange loss (gain)	2,311	(774)
Share-based compensation	12,983	5,391
Acquired inventory step-up amortization	10,172
Provision for doubtful accounts and inventory valuation	5,437	1,921
Other, net	(1,765)	267
Changes in operating assets and liabilities	(18,305)	(6,127)
Net cash and cash equivalents provided by operating activities	72,859	24,900
Cash flows from investing activities:
Purchases of marketable securities	(250,928)	(52,945)
Proceeds from sales of marketable securities	201,764	62,231
Cash received from convertible note receivable	2,848
Purchases of property, plant and equipment	(3,391)	(4,201)
Net cash and cash equivalents (used in) provided by investing activities	(49,707)	5,085
Cash flows from financing activities:
Purchase of common stock	(52,000)	(744)
Tax payments related to shares withheld for share-based compensation plans	(3,546)	(750)
Payment of contingent consideration for acquired business	(435)	(1,121)
Issuance of shares through share-based compensation plans	2,845	283
Net cash and cash equivalents used in financing activities	(53,136)	(2,332)
Effect of exchange rate changes on cash and cash equivalents	917	(339)
Net (decrease) increase in cash and cash equivalents	(29,067)	27,314
Cash and cash equivalents at beginning of period	130,673	112,388
Cash and cash equivalents at end of period	101,606	139,702
Supplemental disclosure of cash flow information:
Income taxes paid (refunded)	$ 4,562	$ (4,067)

CONDENSED CONSOLIDATED STATEM_4

CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Retained Earnings (Accumulated Deficit) [Member]
Balance at Dec. 31, 2018	$ 361,888	$ 31	$ 369,893	$ (1,263)	$ (6,773)
Balance, Shares at Dec. 31, 2018		24,855
Issuance of shares through share-based compensation plans, net, Shares		83
Repurchase of common stock	(744)		(744)
Repurchase of common stock, Shares		(30)
Net income (loss)	7,576				7,576
Share-based compensation	2,163		2,163
Share-based compensation plan withholdings	(598)		(598)
Share-based compensation plan withholdings, Shares		(22)
Currency translation	(518)			(518)
Unrealized gain (loss) on investments	95			95
Balance at Mar. 31, 2019	369,862	$ 31	370,714	(1,686)	803
Balance, shares at Mar. 31, 2019		24,886
Balance at Dec. 31, 2018	361,888	$ 31	369,893	(1,263)	(6,773)
Balance, Shares at Dec. 31, 2018		24,855
Net income (loss)	19,662
Currency translation	(466)
Balance at Sep. 30, 2019	385,473	$ 31	374,073	(1,520)	12,889
Balance, shares at Sep. 30, 2019		25,025
Balance at Mar. 31, 2019	369,862	$ 31	370,714	(1,686)	803
Balance, Shares at Mar. 31, 2019		24,886
Issuance of shares through share-based compensation plans, net	160		160
Issuance of shares through share-based compensation plans, net, Shares		143
Net income (loss)	5,526				5,526
Share-based compensation	1,673		1,673
Share-based compensation plan withholdings	(151)		(151)
Share-based compensation plan withholdings, Shares		(5)
Currency translation	316			316
Unrealized gain (loss) on investments	114			114
Balance at Jun. 30, 2019	377,500	$ 31	372,396	(1,256)	6,329
Balance, shares at Jun. 30, 2019		25,024
Issuance of shares through share-based compensation plans, net	123		123
Issuance of shares through share-based compensation plans, net, Shares		1
Net income (loss)	6,560				6,560
Share-based compensation	1,555		1,555
Share-based compensation plan withholdings	(1)		(1)
Currency translation	(264)			(264)
Balance at Sep. 30, 2019	385,473	$ 31	374,073	(1,520)	12,889
Balance, shares at Sep. 30, 2019		25,025
Balance at Dec. 31, 2019	1,264,026	$ 50	1,269,437	(598)	(4,863)
Balance, Shares at Dec. 31, 2019		50,184
Issuance of shares through share-based compensation plans, net	164		164
Issuance of shares through share-based compensation plans, net, Shares		240
Repurchase of common stock	(33,614)	$ (1)	(33,613)
Repurchase of common stock, Shares		(1,250)
Net income (loss)	(4,404)				(4,404)
Share-based compensation	3,955		3,955
Share-based compensation plan withholdings	(1,565)		(1,565)
Share-based compensation plan withholdings, Shares		(42)
Currency translation	(2,231)			(2,231)
Unrealized gain (loss) on investments	(526)			(526)
Balance at Mar. 28, 2020	1,225,805	$ 49	1,238,378	(3,355)	(9,267)
Balance, shares at Mar. 28, 2020		49,132
Balance at Dec. 31, 2019	1,264,026	$ 50	1,269,437	(598)	(4,863)
Balance, Shares at Dec. 31, 2019		50,184
Net income (loss)	11,111
Currency translation	2,067
Balance at Sep. 26, 2020	1,237,683	$ 49	1,229,720	1,666	6,248
Balance, shares at Sep. 26, 2020		48,832
Balance at Mar. 28, 2020	1,225,805	$ 49	1,238,378	(3,355)	(9,267)
Balance, Shares at Mar. 28, 2020		49,132
Issuance of shares through share-based compensation plans, net	15		15
Issuance of shares through share-based compensation plans, net, Shares		279
Repurchase of common stock	(18,385)		(18,385)
Repurchase of common stock, Shares		(632)
Net income (loss)	7,424				7,424
Share-based compensation	4,775		4,775
Share-based compensation plan withholdings	(1,715)		(1,715)
Share-based compensation plan withholdings, Shares		(55)
Currency translation	2,495			2,495
Unrealized gain (loss) on investments	795			795
Balance at Jun. 27, 2020	1,221,209	$ 49	1,223,068	(65)	(1,843)
Balance, shares at Jun. 27, 2020		48,724
Issuance of shares through share-based compensation plans, net	2,665		2,665
Issuance of shares through share-based compensation plans, net, Shares		116
Net income (loss)	8,091				8,091
Share-based compensation	4,253		4,253
Share-based compensation plan withholdings	(266)		(266)
Share-based compensation plan withholdings, Shares		(8)
Currency translation	1,803			1,803
Unrealized gain (loss) on investments	(72)			(72)
Balance at Sep. 26, 2020	$ 1,237,683	$ 49	$ 1,229,720	$ 1,666	$ 6,248
Balance, shares at Sep. 26, 2020		48,832

Basis of Presentation

Basis of Presentation	9 Months Ended
	Sep. 26, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Basis of Presentation	NOTE 1. Basis of Presentation The accompanying interim unaudited Condensed Consolidated Financial Statements have been prepared by Onto Innovation Inc., together with its consolidated subsidiaries, unless otherwise specified or suggested by the context, (the “Company,” or “Onto Innovation”, “we”, “our”, or “us”) and in the opinion of management reflect all adjustments, consisting of normal recurring accruals, necessary for their fair presentation in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”). Preparing financial statements requires management to make estimates and assumptions that affect amounts reported in the financial statements and accompanying notes. Actual amounts could differ materially from reported amounts. The interim results for the three and nine months ended September 26, 2020 are not necessarily indicative of results to be expected for the entire year or any future periods. This interim financial information should be read in conjunction with the financial statements and the notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2019 (“2019 Form 10-K”) filed with the Securities and Exchange Commission (“SEC”) on February 25, 2020. The accompanying Condensed Consolidated Balance Sheet at December 31, 2019 has been derived from the audited consolidated financial statements included in the 2019 Form 10-K. As further discussed in Note 2 of the Notes to the Condensed Consolidated Financial Statements, Rudolph Technologies, Inc. (“Rudolph”) and Nanometrics Incorporated (“Nanometrics”) completed a merger effective October 25, 2019 (the “Merger”). Upon consummation of the Merger, the combined company was renamed Onto Innovation Inc. The Merger was accounted for as a reverse acquisition where Rudolph was the accounting acquirer and Nanometrics was the legal acquirer in accordance with Accounting Standards Codification (“ASC”) Topic 805, “Business Combinations”. Accordingly, Rudolph’s historical results of operations replaced the Nanometrics historical results of operations for all periods prior to the Merger. Specifically, the accompanying Condensed Consolidated Financial Statements for all periods prior to the Merger are those of Rudolph and for the period after the Merger, also include Nanometrics. The Condensed Consolidated Financial Statements reflect the assets and liabilities of Rudolph at historical cost basis and the assets and liabilities of Nanometrics are reflected at fair value under the acquisition method. While Rudolph applied the acquisition method of accounting to Nanometrics, the legal capital in the current and prior periods has been retroactively adjusted to reflect the legal capital of Nanometrics. Accordingly, earnings per share has been retroactively restated for periods prior to the merger date. On February 28, 2020, the Company’s Board of Directors determined it is in the best interests of the Company to change its fiscal year end from December 31 to a 52-53 week fiscal year ending on the Saturday closest to December 31. The change is intended to align the Company’s fiscal periods more closely with industry peers and improve comparability. The Company made the fiscal year change on a prospective basis and has not adjusted operating results for prior periods. The change affects the prior year comparability of the Company’s fiscal quarters in 2020 and results in shifts in the quarterly periods, which has not had, and is not expected to have, a material impact on quarterly financial results. The third fiscal quarter of 2020 began on June 28, 2020 and ended September 26, 2020 and is referred to throughout this Quarterly Report on Form 10-Q as the “three months ended September 26, 2020” or the “third quarter of 2020.” The Company’s current fiscal year will end on December 26, 2020. Reclassifications In conjunction with the Merger, the Company assessed the need to realign its financial statement presentation and certain income statement classifications were adjusted with prior periods reclassified to conform with current period presentation. The changes made were as follows: • Amounts related to sales and marketing are now presented on a separate line on the Condensed Consolidated Statements of Operations and were previously reported under the caption “Selling, general and administrative.” • Amounts related to applications engineering are now presented under the caption, “Sales and marketing” on the Condensed Consolidated Statements of Operations and were previously reported under the caption “Research and development.” 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 as of the date of the financial statements and the reported amounts of revenue and expenses during the reporting period. Significant estimates made by management that are evaluated on an ongoing basis include the allowances for doubtful accounts and convertible notes receivable, excess and obsolete inventory, fair value of assets acquired and liabilities assumed in a business combination, recoverability and useful lives of property, plant and equipment and identifiable intangible assets, recoverabilit y of goodwill, recoverability of deferred tax assets, liabilities for product warranty, contingencies, including litigation reserves, share-based payments and liabilities for tax uncertainties. Actual results could differ from those estimates. These estimates and assumptions are based on historical experience and on various other factors which the Company believes to be reasonable under the circumstances. The Company may engage third-party valuation specialists to assist with estimates related to the valuation of financial instruments, assets and stock awards associated with various contractual arrangements. Such estimates often require the selection of appropriate valuation methodologies and significant judgment. Actual results could differ from these estimates under different assumptions or circumstances and such differences could be material. The Company also assessed the impacts of COVID-19 on the above accounting matters as of September 26, 2020 and through the date of this report. While there was not a material impact as of and for the quarter ended September 26, 2020, future actual magnitude and duration of COVID-19, as well as other associated factors, could result in material negative impacts to its condensed consolidated financial statements in future reporting periods. Recent Accounting Pronouncements Recently Adopted Effective January 1, 2020, the Company adopted Accounting Standards Update (“ASU”) No. 2018-13, “Fair Value Measurement (Topic 820): Disclosure Framework – Changes to the Disclosure Requirements for Fair Value Measurement.” This ASU is part of the Financial Accounting Standard Board’s (“FASB”) larger disclosure framework project intended to improve the effectiveness of financial statement footnote disclosure. ASU No. 2018-13 modifies required fair value disclosures related primarily to Level 3 investments. This ASU is effective for annual periods beginning after December 15, 2019 and interim periods within those annual periods. The adoption of ASU No. 2018-13 did not have a material impact on the Company’s consolidated financial position, results of operations, and cash flows. Effective January 1, 2020, the Company adopted ASU No. 2017-09, “Compensation - Stock Compensation (Topic 718): Scope of Modification Accounting.” This ASU amends the scope of modification accounting for share-based payment arrangements and provides guidance on the types of changes to the terms or conditions of share-based payment awards to which an entity would be required to apply modification accounting under Accounting Standards Codification (“ASC”) 718. The ASU is effective for the fiscal years beginning after December 15, 2019 and for interim periods within those fiscal years. The adoption of ASU No. 2017-09 did not have a material impact on the Company’s consolidated financial position, results of operations, and cash flows. Effective January 1, 2020, the Company adopted ASU No. 2016-13, “Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments,” which represents a credit loss standard that changes the impairment model for most financial assets and certain other financial instruments. Specifically, this guidance requires entities to utilize a new “expected loss” model as it relates to trade receivables, notes and other commitments to extend credit held by a reporting entity Recently Issued In December 2019, the FASB issued ASU No. 2019-12, “Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes.” This standard simplifies the accounting for income taxes by eliminating certain exceptions to the guidance in Topic 740 related to the approach for intraperiod tax allocation, the methodology for calculating income taxes in an interim period and the recognition of deferred tax liabilities for outside basis differences. The new guidance also simplifies aspects of the accounting for franchise Recently issued accounting guidance not discussed above is not applicable or is not expected to have a material impact to the Company’s c onsolidated financial position, results of operations, and cash flows.

Business Combination

Business Combination	9 Months Ended
	Sep. 26, 2020
Business Combinations [Abstract]
Business Combination	NOTE 2. Business Combination Rudolph and Nanometrics completed the Merger effective October 25, 2019. The Company accounted for the Merger as a reverse acquisition, using the acquisition method of accounting in accordance with U.S. GAAP, with Rudolph being treated as the accounting acquiring entity. The acquired assets and liabilities of Nanometrics were recorded at their respective fair values including an amount for goodwill, which represents the purchase price paid in excess of the fair value of the net tangible and intangible assets acquired and liabilities assumed, and is attributable primarily to expected synergies, economies of scale and the assembled workforce of Nanometrics. The following table summarizes the preliminary allocation of the total purchase consideration to the initial estimated fair values of the assets acquired and liabilities assumed as of October 25, 2019, as well as adjustments aggregating $0 and $478 to other non-current liabilities during the three and nine months ended September 26, 2020: Cash and cash equivalents $ 43,882 Marketable securities 94,389 Account receivables 49,917 Inventories 98,478 Prepaid expenses and other current assets 7,734 Property, plant and equipment 77,451 Operating lease right-of-use assets 9,658 Identifiable intangible assets 374,900 Deferred income taxes 1,352 Other assets 850 Total assets acquired 758,611 Accounts payable (23,361 ) Payroll and related expenses (20,290 ) Deferred revenue (5,931 ) Other current liabilities (10,739 ) Income taxes payable (2,699 ) Other non-current liabilities (90,591 ) Net assets acquired 605,000 Goodwill 285,131 Total purchase consideration $ 890,131

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 26, 2020
Fair Value Disclosures [Abstract]
Fair Value Measurements	NOTE 3. Fair Value Measurements Fair Value of Financial Instruments The Company has evaluated the estimated fair value of financial instruments using available market information and valuations as provided by third-party sources. The use of different market assumptions and/or estimation methodologies could have a significant effect on the estimated fair value amounts. The carrying value of cash and cash equivalents, accounts receivable, accounts payable and accrued liabilities approximates fair value because of the short-term maturity of these instruments. Fair Value Hierarchy The Company applies a three-level valuation hierarchy for fair value measurements. This hierarchy prioritizes the inputs into three broad levels. Level 1 inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities. Level 2 inputs are 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 asset or liability. Level 3 inputs are unobservable inputs based on management’s assumptions used to measure assets and liabilities at fair value. A financial asset’s or liability’s fair value measurement classification within the hierarchy is determined based on the lowest level input that is significant to the fair value measurement. The following tables provide the assets and liabilities carried at fair value measured on a recurring basis at September 26, 2020 and December 31, 2019: Fair Value Measurements Using Carrying Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) September 26, 2020 Assets: Available-for-sale debt securities: Municipal notes and bonds $ 111,401 $ — $ 111,401 $ — Asset-backed securities 15,160 — 15,160 — Certificates of deposit 39,685 — 39,685 — Commercial paper 27,489 — 27,489 — Corporate bonds 45,062 — 45,062 — Total assets $ 238,797 $ — $ 238,797 $ — Liabilities: Contingent consideration - acquisitions $ 134 $ — $ — $ 134 Foreign currency forward contracts 239 — 239 — Total liabilities $ 373 $ — $ 239 $ 134 December 31, 2019 Assets: Available-for-sale debt securities: Municipal notes and bonds $ 81,108 $ — $ 81,108 $ — Asset-backed securities 10,779 — 10,779 — Certificates of deposit 30,507 — 30,507 — Commercial paper 30,708 — 30,708 — Corporate bonds 36,461 — 36,461 — Foreign currency forward contracts 120 — 120 — Total assets $ 189,683 $ — $ 189,683 $ — Liabilities: Contingent consideration - acquisitions $ 569 $ — $ — $ 569 Total liabilities $ 569 $ — $ — $ 569 Available-for-sale debt securities classified as Level 2 are valued using observable inputs to quoted market prices, benchmark yields, reported trades, broker/dealer quotes or alternative pricing sources with reasonable levels of price transparency. The foreign currency forward contracts are primarily measured based on the foreign currency spot and forward rates quoted by the banks or foreign currency dealers. Investment prices are obtained from third party pricing providers, which model prices utilizing the above observable inputs, for each asset class. Level 3 liabilities consisted of contingent consideration related to an acquisition for which the Company uses a discounted cash flow model to value these liabilities. The Level 3 assumptions used in the discounted cash flow model for the contingent consideration included projected revenue, timing of cash flows and estimates of discount rates. This table presents a reconciliation of the Contingent consideration - acquisitions liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3) for the nine months ended September 26, 2020: Fair Value Measurements Using Significant Unobservable Inputs (Level 3) Balance at December 31, 2019 $ 569 Additions — Payments (435 ) Transfer into (out of) Level 3 — Balance at September 26, 2020 $ 134 See Note 4 for additional discussion regarding the fair value of the Company’s marketable securities.

Marketable Securities

Marketable Securities	9 Months Ended
	Sep. 26, 2020
Marketable Securities [Abstract]
Marketable Securities	NOTE 4. Marketable Securities The Company has evaluated its investment policies and determined that all of its marketable securities, which are comprised of debt securities, are to be classified as available-for-sale. The Company’s available-for-sale debt securities are carried at fair value, with the unrealized gains and losses reported in Stockholders’ equity under the caption “Accumulated other comprehensive loss.” Realized gains and losses on available-for-sale securities are included in “Other (expense) income, net” on the Condensed Consolidated Statements of Operations. The Company records other-than-temporary impairment charges for its available-for-sale debt securities when it intends to sell the securities, it is more-likely-than not that it will be required to sell the securities before a recovery, or when it does not expect to recover the entire amortized cost basis of the securities. The cost of securities sold is based on the specific identification method. The Company has determined that the gross unrealized losses on its marketable securities at September 26, 2020 and December 31, 2019 are temporary in nature. The Company reviews its investment portfolio to identify and evaluate marketable securities that have indications of possible impairment. Factors considered in determining whether a loss is other-than-temporary include the length of time and extent to which fair value has been less than the cost basis, credit quality and the Company’s ability and intent to hold the securities for a period of time sufficient to allow for any anticipated recovery in market value. At September 26, 2020 and December 31, 2019, marketable securities are categorized as follows: Amortized Cost Gross Unrealized Holding Gains Gross Unrealized Holding Losses Fair Value September 26, 2020 Municipal notes and bonds $ 111,137 $ 270 $ 6 $ 111,401 Asset-backed securities 15,109 51 — 15,160 Certificates of deposit 39,649 36 — 39,685 Commercial paper 27,472 18 1 27,489 Corporate bonds 44,963 126 27 45,062 Total marketable securities $ 238,330 $ 501 $ 34 $ 238,797 December 31, 2019 Municipal notes and bonds $ 80,926 $ 188 $ 6 $ 81,108 Asset-backed securities 10,767 12 — 10,779 Certificates of deposit 30,500 7 — 30,507 Commercial paper 30,707 1 — 30,708 Corporate bonds 36,409 52 — 36,461 Total marketable securities $ 189,309 $ 260 $ 6 $ 189,563 The amortized cost and estimated fair value of marketable securities classified by the maturity date listed on the security, regardless of the Condensed Consolidated Balance Sheets classification, is as follows at September 26, 2020 and December 31, 2019: September 26, 2020 December 31, 2019 Amortized Cost Fair Value Amortized Cost Fair Value Due within one year $ 172,828 $ 173,166 $ 152,649 $ 152,852 Due after one through five years 65,502 65,631 36,660 36,711 Due after five through ten years — — — — Due after ten years — — — — Total marketable securities $ 238,330 $ 238,797 $ 189,309 $ 189,563 The following table summarizes the estimated fair value and gross unrealized holding losses of marketable securities, aggregated by investment instrument and period of time in an unrealized loss position, at September 26, 2020 and December 31, 2019: In Unrealized Loss Position For Less Than 12 Months In Unrealized Loss Position For Greater Than 12 Months Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses September 26, 2020 Municipal notes and bonds $ 6,026 $ 6 $ — $ — Commercial paper 4,497 1 — — Corporate bonds 17,858 27 — — Total $ 28,381 $ 34 $ — $ — December 31, 2019 Municipal notes and bonds $ 14,166 $ 6 $ — $ — Total $ 14,166 $ 6 $ — $ — See Note 3 for additional discussion regarding the fair value of the Company’s marketable securities.

Derivative Instruments and Hedg

Derivative Instruments and Hedging Activities	9 Months Ended
	Sep. 26, 2020
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Derivative Instruments and Hedging Activities	NOTE 5. Derivative Instruments and Hedging Activities The Company, when it considers it to be appropriate, enters into forward contracts to hedge the economic exposures arising from foreign currency denominated transactions. At September 26, 2020 and December 31, 2019, these contracts included the future sale of British Pound, European Euro, Israeli Shekel, Japanese Yen, Korean Won, Singapore Dollar, Taiwanese Dollar, and Chinese Yuan Renminbi to purchase U.S. Dollars. Foreign currency forward contracts are not designated as hedges for accounting purposes and therefore, the change in fair value is recorded in “Other (expense) income, net,” in the Condensed Consolidated Statements of Operations. The Company records its forward contracts at fair value in either prepaid expenses and other current assets or other current liabilities in the Condensed Consolidated Balance Sheets. The dollar equivalent of the U.S. dollar forward contracts and related fair values as of September 26, 2020 and December 31, 2019 were as follows: September 26, 2020 December 31, 2019 Notional amount $ 33,590 $ 38,887 Fair value of (liability) asset $ (239 ) $ 120

Purchased Intangible Assets

Purchased Intangible Assets	9 Months Ended
	Sep. 26, 2020
Goodwill And Intangible Assets Disclosure [Abstract]
Purchased Intangible Assets	NOTE 6. Purchased Intangible Assets Goodwill The changes in the carrying amount of goodwill are as follows: Balance at December 31, 2019 $ 307,148 Goodwill adjustments (Note 2) 478 Balance at September 26, 2020 $ 307,626 Purchased intangible assets as of September 26, 2020 and December 31, 2019 are as follows: Gross Carrying Amount Accumulated Amortization Net September 26, 2020 Finite-lived intangibles: Developed technology $ 326,777 $ 100,122 $ 226,655 Customer and distributor relationships 69,261 19,013 50,248 Trademarks and trade names 12,461 5,041 7,420 Total finite-lived intangible assets 408,499 124,176 284,323 In-process research and development 46,600 — 46,600 Total identifiable intangible assets $ 455,099 $ 124,176 $ 330,923 December 31, 2019 Finite-lived intangibles: Developed technology $ 326,726 $ 67,861 $ 258,865 Customer and distributor relationships 69,261 11,078 58,183 Trademarks and trade names 12,461 4,156 8,305 Total finite-lived intangible assets 408,448 83,095 325,353 In-process research and development 46,600 — 46,600 Total identifiable intangible assets $ 455,048 $ 83,095 $ 371,953 Intangible assets amortization expenses for the three and nine months ended September 26, 2020 were $13,646 and $41,081, respectively. For the three and nine month periods ended September 30, 2019, intangible assets amortization expenses were $387 and $1,161, respectively. Assuming no change in the gross carrying value of identifiable intangible assets and estimated lives, estimated amortization expenses for the remainder of fiscal 2020 are $12,663, and for each of the next five fiscal years estimated amortization expenses are $48,014 for 2021, $47,615 for 2022, $47,140 for 2023, $41,455 for 2024, and $24,905 for 2025.

Convertible Notes Receivable

Convertible Notes Receivable	9 Months Ended
	Sep. 26, 2020
Receivables [Abstract]
Convertible Notes Receivable	NOTE 7. Convertible Notes Receivable On May 31, 2018, the Company entered into a convertible note agreement with Simax Precision Technologies Limited (“the borrower”), which allowed the borrower to borrow up to $15,000 from the Company in multiple promissory notes with an interest rate of 4.25% per annum payable on a semi-annual basis. The Company expected to be a supplier of lithography modules to Simax, which is used in the manufacture, sale and service of lithography systems. At December 31, 2019, the Company had $3,000, net of allowance, in outstanding convertible notes receivable with the borrower. The Company and the borrower entered into a settlement agreement to end their relationship as it pertains to this convertible note agreement. The Company agreed to the settlement amount of $2,848, which was paid to the Company in April 2020.

Balance Sheet Details

Balance Sheet Details	9 Months Ended
	Sep. 26, 2020
Balance Sheet Detail [Abstract]
Balance Sheet Details	NOTE 8. Balance Sheet Details Inventories Inventories, net are comprised of the following: September 26, 2020 December 31, 2019 Materials $ 117,680 $ 108,492 Work-in-process 44,968 42,694 Finished goods 22,333 24,948 Total inventories, net $ 184,981 $ 176,134 Property, Plant and Equipment Property, plant and equipment, net is comprised of the following: September 26, 2020 December 31, 2019 Land and building $ 46,941 $ 47,222 Machinery and equipment 57,571 56,504 Furniture and fixtures 4,305 3,968 Computer equipment and software 16,361 15,770 Leasehold improvements 13,463 13,069 138,641 136,533 Accumulated depreciation (45,925 ) (38,113 ) Total property, plant and equipment, net $ 92,716 $ 98,420 Other assets Other assets is comprised of the following: September 26, 2020 December 31, 2019 Convertible notes receivable, net of allowance of $2,000 at December 31, 2019 $ — $ 3,000 Operating lease right-of-use assets 20,076 23,588 Other 1,361 1,351 Total other assets $ 21,437 $ 27,939 Accrued liabilities Accrued liabilities is comprised of the following: September 26, 2020 December 31, 2019 Payroll and related expenses $ 24,501 $ 19,365 Warranty 6,009 6,348 Other 553 491 Total accrued liabilities $ 31,063 $ 26,204 Other current liabilities Other current liabilities is comprised of the following: September 26, 2020 December 31, 2019 Contingent consideration - acquisitions $ 134 $ 569 Income tax payable 639 2,783 Current operating lease obligations 4,129 4,906 Customer deposits 1,215 1,994 Accrued professional fees 926 1,520 Other 5,768 7,400 Total other current liabilities $ 12,811 $ 19,172 Other non-current liabilities Other non-current liabilities is comprised of the following: September 26, 2020 December 31, 2019 Unrecognized tax benefits (including interest) $ 7,063 $ 6,384 Non-current operating lease obligations 17,373 19,970 Deferred revenue 1,764 2,464 Other 5,323 2,953 Total other non-current liabilities $ 31,523 $ 31,771

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 26, 2020
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	NOTE 9. Commitments and Contingencies Factoring The Company maintains arrangements under which eligible accounts receivable in Japan are sold without recourse to unrelated third-party financial institutions. The Company sold $7,738 of receivables during the three months ended September 26, 2020. These receivables were not included in the condensed consolidated balance sheets as the criteria for sale treatment had been met. 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 26, 2020. Intellectual Property Indemnification Obligations The Company has entered into agreements with customers that include limited intellectual property indemnification obligations that are customary in the industry. These guarantees generally require the Company to compensate the other party for certain damages and costs incurred as a result of third-party intellectual property claims arising from these transactions. The nature of the intellectual property indemnification obligations prevents the Company from making a reasonable estimate of the maximum potential amount it could be required to pay to its customers. Historically, the Company has not made any indemnification payments under such agreements, and no amount has been accrued in the accompanying consolidated financial statements with respect to these indemnification guarantees. Warranty Reserves The Company generally provides a warranty on its products for a period of 12 to 14 months against defects in material and workmanship. The Company estimates the costs that may be incurred during the warranty period and records a liability in the amount of such costs at the time revenue is recognized. The Company’s estimate is based primarily on historical experience. The Company periodically assesses the adequacy of its recorded warranty liabilities and adjusts the amounts as necessary. Settlements of warranty reserves are generally associated with sales that occurred during the 12 to 14 months prior to the year-end and warranty accruals are related to sales during the same year. Changes in the Company’s warranty reserves are as follows: Nine Months Ended September 26, September 30, 2020 2019 Balance, beginning of the period $ 6,348 $ 2,441 Accruals 5,646 2,078 Usage (5,710 ) (2,477 ) Balance, end of the period $ 6,284 $ 2,042 Warranty reserves are reported in the Condensed Consolidated Balance Sheets under the captions “Accrued liabilities” and “Other non-current liabilities.” Legal Matters From time to time, the Company is subject to legal proceedings and claims in the ordinary course of business. The following reflects an overview of the material developments with regard to the Company’s pending material legal proceedings. Optical Solutions Inc. v. Nanometrics Incorporated (Case No. 18-cv-00417-BLF): On August 2, 2017, Nanometrics was named as defendant in a complaint filed in New Hampshire Superior Court (the “Complaint”). The Complaint, brought by Optical Solutions, Inc. (“OSI”), alleges claims arising from a purported exclusive purchase contract between OSI and Nanometrics pertaining to certain products. On September 18, 2017, Nanometrics removed the action to the United States District Court for the District of New Hampshire (the “District of New Hampshire”). On September 25, 2017, Nanometrics moved to transfer the Complaint to the United States District Court for the Northern District of California (the “Northern District of California”). On December 20, 2017, Nanometrics filed its complaint against OSI in the California Superior Court for the County of Santa Clara alleging claims arising from OSI’s breach of certain purchase orders. Nanometrics’ complaint was later removed by OSI to the Northern District of California. On May 29, 2018, the District of New Hampshire issued an order granting Nanometrics’ motion to transfer the Complaint to the Northern District of California and denying Nanometrics’ motion to dismiss the Complaint without prejudice. On June 14, 2018, the Complaint was consolidated with Nanometrics’ complaint against OSI. On August 9, 2018, OSI filed an Amended Complaint. On September 19, 2018, Nanometrics filed a motion to dismiss OSI’s Amended Complaint for failure to state a claim. Nanometrics’ motion to dismiss was heard on February 28, 2019. On March 5, 2019, the Northern District of California granted Nanometrics’ motion to dismiss with leave to amend. OSI filed a Second Amended Complaint on March 29, 2019. Nanometrics filed a motion to dismiss OSI’s Second Amended Complaint on May 31, 2019. In October 2019, Nanometrics was renamed Onto Innovation Inc. as a result of the Merger. Thereafter, the Company’s second motion to dismiss was heard on November 14, 2019. On November 26, 2019, the Northern District of California granted the Company’s motion to dismiss with leave to amend. OSI filed a Third Amended Complaint on January 21, 2020. On Ma rch 2, 2020, the Company filed a motion to dismiss OSI’s Third Amended Complaint and a hearing on the motion was held on June 11, 2020. On June 23, 2020, the Northern District of California granted the Company’s motion to dismiss with prejudice with regar d to two claims asserted by OSI and dismissed two other claims asserted by OSI with leave to amend. Thereafter, on July 7, 2020, OSI filed a Fourth Amended Complaint. On August 14, 2020, the Company filed a motion to dismiss with regard to one of the two remaining claims. A hearing on this motion has not been set to date. Trial has been set for May 16, 2022. At this time the loss contingency in this matter is remote and the Company does not anticipate the outcome of the matter to have a material impact on its financial position, results of operations, or cash flows. Line of Credit The Company has a credit agreement with a bank that provides for a line of credit which is secured by the marketable securities the Company has with the bank. The Company is permitted to borrow up to 70% of the value of eligible securities held at the time the line of credit is accessed. The available line of credit as of September 26, 2020 was approximately $71.2 million with an available interest rate of 1.8%. The credit agreement is available to the Company until such time that either party terminates the arrangement at their discretion. The Company has not utilized the line of credit to date.

Revenue

Revenue	9 Months Ended
	Sep. 26, 2020
Revenue From Contract With Customer [Abstract]
Revenue	NOTE 10. Revenue The following table represents a disaggregation of revenue by timing of revenue: Three Months Ended Nine Months Ended September 26, September 30, September 26, September 30, 2020 2019 2020 2019 Point-in-time $ 122,015 $ 58,663 $ 387,556 $ 172,562 Over-time 4,477 4,272 13,812 12,776 Total revenue $ 126,492 $ 62,935 $ 401,368 $ 185,338 See Note 16 for additional discussion of the Company’s disaggregated revenue in detail. Contract Liabilities The Company records contract liabilities when the customer has been billed in advance of the Company completing its performance obligations. These amounts are recorded as deferred revenue in the Condensed Consolidated Balance Sheets. Changes in deferred revenue were as follows: Three Months Ended Nine Months Ended September 26, September 30, September 26, September 30, 2020 2019 2020 2019 Balance, beginning of the period $ 17,894 $ 9,349 $ 15,093 $ 8,080 Deferral of revenue 10,137 5,860 33,389 17,492 Recognition of deferred revenue (10,396 ) (7,937 ) (30,847 ) (18,300 ) Balance, end of the period $ 17,635 $ 7,272 $ 17,635 $ 7,272

Share-Based Compensation

Share-Based Compensation	9 Months Ended
	Sep. 26, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Share-Based Compensation	NOTE 11. Share-Based Compensation Restricted Stock Unit Activity A summary of the Company’s restricted stock unit activity with respect to the nine months ended September 26, 2020 is as follows: Number of Shares Weighted Average Grant Date Fair Value Nonvested at December 31, 2019 1,107 $ 28.89 Granted 490 $ 34.66 Vested (470 ) $ 29.37 Forfeited (116 ) $ 29.86 Nonvested at September 26, 2020 1,011 $ 31.28 As of September 26, 2020 and December 31, 2019, there was $23,128 and $22,230 of total unrecognized compensation cost related to restricted stock units granted under the Company’s stock plans, respectively. That cost is expected to be recognized over a weighted average period of 1.9 years

Other (Expense) Income, Net

Other (Expense) Income, Net	9 Months Ended
	Sep. 26, 2020
Other Income Expense [Abstract]
Other (Expense) Income, Net	NOTE 12. Other (Expense) Income, Net Other (expense) income, net, is comprised of the following: Three Months Ended Nine Months Ended September 26, September 30, September 26, September 30, 2020 2019 2020 2019 Foreign currency exchange gains (losses), net $ (1,005 ) $ 552 $ (2,311 ) $ 774 Other 106 65 246 67 Total other (expense) income, net $ (899 ) $ 617 $ (2,065 ) $ 841

Income Taxes

Income Taxes	9 Months Ended
	Sep. 26, 2020
Income Tax Disclosure [Abstract]
Income Taxes	NOTE 13. Income Taxes The following table provides details of income taxes: Three Months Ended Nine Months Ended September 26, September 30, September 26, September 30, 2020 2019 2020 2019 Income before income taxes $ 8,927 $ 6,908 $ 12,341 $ 21,824 Provision for income taxes $ 836 $ 348 $ 1,230 $ 2,162 Effective tax rate 9 % 5 % 10 % 10 % The income tax provision for the nine months ended September 26, 2020 was computed based on the Company’s annual forecast of profit by jurisdiction and forecasted effective tax rate for the year. The changes in the Company’s effective tax rate for the three and nine months ended September 26, 2020 as compared to the three and nine months ended September 30, 2019 are primarily due to (i) changes in forecasted earnings, (ii) computed research and development credits on forecasted earnings levels, (iii) the Foreign Derived Intangible Income (“FDII”) deduction on forecasted earnings levels, and (iv) a one-time provision for additional withholding tax related to a dividend distribution from the Company’s Korea subsidiary offset by a one-time benefit related to the filings of the Company’s 2019 foreign income tax returns. The Company’s recorded effective tax rate is less than the U.S. statutory rate primarily due to projected FDII deductions and federal research and development tax credits. The Company currently has a partial valuation allowance recorded against certain foreign and state net operating loss and credit carryforwards where the realizability of such deferred tax assets is substantially in doubt. Each quarter, the Company assesses the likelihood that it will be able to recover its deferred tax assets. The Company considers available evidence, both positive and negative, including forecasted earnings in assessing its need for a valuation allowance. As a result of the Company’s analysis, it concluded that it is more likely than not that a portion of its deferred tax assets will not be realized. Therefore, the Company continues to provide a valuation allowance against certain deferred tax assets. The Company continues to monitor available evidence and may reverse some or all of the remaining valuation allowance in future periods, if appropriate. The Company has a recorded valuation allowance against certain of its deferred tax assets of $ 14,150 and $ 14,160 as of September 26, 2020 and December 31, 2019 , respectively. On March 27, 2020, the “Coronavirus Aid, Relief and Economic Security Act” (the “CARES Act”) was enacted. The CARES Act includes provisions relating to refundable payroll tax credits, deferment of the employer portion of certain payroll taxes, net operating loss carryback periods, alternative minimum tax credit refunds, modifications to the net interest deduction limitations and technical corrections to tax depreciation methods for qualified improvement property. These changes did not have a material impact on the Company’s consolidated financial position, results of operations, and cash flows.

Earnings Per Share

Earnings Per Share	9 Months Ended
	Sep. 26, 2020
Earnings Per Share [Abstract]
Earnings Per Share	NOTE 14. Earnings Per Share Basic earnings per share is calculated using the weighted average number of shares of common stock outstanding during the period. Diluted earnings per share is computed in the same manner and also gives effect to all dilutive common stock equivalent shares outstanding during the period. Potential common shares that would have the effect of increasing diluted earnings per share are considered to be anti-dilutive. In accordance with U.S. GAAP, these shares were not included in calculating diluted earnings per share. The following table sets forth the weighted average number of restricted stock units that have been excluded from the calculation of diluted earnings per share as their effect would have been anti-dilutive: Three Months Ended Nine Months Ended September 26, September 30, September 26, September 30, 2020 2019 2020 2019 Restricted stock units 4 56 23 92 Total 4 56 23 92 The Company’s basic and diluted earnings per share amounts are as follows: Three Months Ended Nine Months Ended September 26, September 30, September 26, September 30, 2020 2019 2020 2019 Numerator: Net income $ 8,091 $ 6,560 $ 11,111 $ 19,662 Denominator: Basic earnings per share - weighted average shares outstanding 48,900 25,079 49,231 25,012 Effect of potential dilutive securities: Employee stock options, employee stock purchase grants and restricted stock units - dilutive shares 231 226 320 242 Diluted earnings per share - weighted average shares outstanding 49,131 25,305 49,551 25,254 Earnings per share: Basic $ 0.17 $ 0.26 $ 0.23 $ 0.79 Diluted $ 0.16 $ 0.26 $ 0.22 $ 0.78

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Loss)	9 Months Ended
	Sep. 26, 2020
Accumulated Other Comprehensive Income Loss Net Of Tax [Abstract]
Accumulated Other Comprehensive Income (Loss)	NOTE 15. Accumulated Other Comprehensive Income (Loss) The components of accumulated other comprehensive income (loss), net of tax at September 26, 2020, as well as the activity for the nine months ended September 26, 2020, were as follows: Accumulated Foreign Currency Translation Adjustment Accumulated Net Unrealized Gain (Loss) on Available-For-Sale Marketable Securities Accumulated Other Comprehensive Income (Loss) Balance at December 31, 2019 $ (564 ) $ (34 ) $ (598 ) Net current period other comprehensive gain 2,067 197 2,264 Reclassifications — — — Balance at September 26, 2020 $ 1,503 $ 163 $ 1,666

Segment Reporting and Geographi

Segment Reporting and Geographic Information	9 Months Ended
	Sep. 26, 2020
Segment Reporting [Abstract]
Segment Reporting and Geographic Information	NOTE 16. Segment Reporting and Geographic Information The Company and its subsidiaries currently operate in a single operating segment: the design, development, manufacture and support of high-performance process control defect inspection and metrology, advanced packaging lithography and process control software systems used by microelectronics device manufacturers. Therefore, the Company has one reportable segment. The Company’s chief operating decision maker is the Chief Executive Officer (the “CEO”). The CEO allocates resources and assesses performance of the business and other activities at the reportable segment level. The following table lists the different sources of revenue: Three Months Ended Nine Months Ended September 26, September 30, September 26, September 30, 2020 2019 2020 2019 Systems and software $ 97,774 77 % $ 52,786 84 % $ 321,062 80 % $ 154,207 83 % Parts 18,815 15 % 7,142 11 % 48,719 12 % 22,292 12 % Services 9,903 8 % 3,007 5 % 31,587 8 % 8,839 5 % Total revenue $ 126,492 100 % $ 62,935 100 % $ 401,368 100 % $ 185,338 100 % The Company’s significant operations outside the United States include sales, service and application offices in Asia and Europe. For geographical revenue reporting, revenue is attributed to the geographic location to which the product is shipped. Revenue by geographic region is as follows: Three Months Ended Nine Months Ended September 26, September 30, September 26, September 30, 2020 2019 2020 2019 Revenue from third parties: United States $ 16,036 $ 8,816 $ 58,062 $ 26,879 Taiwan 30,028 14,304 97,206 32,446 Japan 13,698 8,962 42,632 16,330 China 31,911 14,666 90,295 54,887 South Korea 13,250 8,481 56,971 30,027 Singapore 5,690 2,396 14,619 6,007 Other Asia 3,706 1,386 4,252 3,425 Germany 3,760 735 12,352 3,260 Other Europe 8,413 3,189 24,979 12,077 Total revenue $ 126,492 $ 62,935 $ 401,368 $ 185,338 The following customers accounted for more than 10% of total revenue for the indicated periods: Nine Months Ended September 26, September 30, 2020 2019 Customer A 16.2 % 7.8 % Customer B 14.4 % 6.1 % Customer C 7.4 % 17.6 %

Share Repurchase Authorization

Share Repurchase Authorization	9 Months Ended
	Sep. 26, 2020
Share Repurchase Program [Abstract]
Share Repurchase Authorization	NOTE 17. Share Repurchase Authorization Following the Merger, the Company assumed the share repurchase authorization previously approved by the former Nanometrics Board of Directors. This share repurchase authorization allows for the Company to purchase up to $80,000 worth of shares of its common stock. Under the terms of this share repurchase authorization, shares may be repurchased through open market or privately negotiated transactions. Share repurchases during the nine months ended September 26, 2020 were made under this repurchase authorization and at September 26, 2020, there was $28,000 available for future share repurchases. During the nine months ended September 30, 2019, share repurchases were made under a legacy Rudolph share repurchase authorization which was terminated on October 25, 2019 due to closing of the Merger. See Note 2 for additional information regarding the Merger. The following table summarizes the Company’s share repurchases for the periods indicated: Three Months Ended Nine Months Ended September 26, September 30, September 26, September 30, 2020 2019 2020 2019 Shares of common stock repurchased — — 1,882 30 Cost of shares repurchased $ — $ — $ 52,000 $ 744 Average price paid per share $ — $ — $ 27.62 $ 24.68

Basis of Presentation (Policies

Basis of Presentation (Policies)	9 Months Ended
	Sep. 26, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Reclassifications	Reclassifications In conjunction with the Merger, the Company assessed the need to realign its financial statement presentation and certain income statement classifications were adjusted with prior periods reclassified to conform with current period presentation. The changes made were as follows: • Amounts related to sales and marketing are now presented on a separate line on the Condensed Consolidated Statements of Operations and were previously reported under the caption “Selling, general and administrative.” • Amounts related to applications engineering are now presented under the caption, “Sales and marketing” on the Condensed Consolidated Statements of Operations and were previously reported under the caption “Research and development.”
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 as of the date of the financial statements and the reported amounts of revenue and expenses during the reporting period. Significant estimates made by management that are evaluated on an ongoing basis include the allowances for doubtful accounts and convertible notes receivable, excess and obsolete inventory, fair value of assets acquired and liabilities assumed in a business combination, recoverability and useful lives of property, plant and equipment and identifiable intangible assets, recoverabilit y of goodwill, recoverability of deferred tax assets, liabilities for product warranty, contingencies, including litigation reserves, share-based payments and liabilities for tax uncertainties. Actual results could differ from those estimates. These estimates and assumptions are based on historical experience and on various other factors which the Company believes to be reasonable under the circumstances. The Company may engage third-party valuation specialists to assist with estimates related to the valuation of financial instruments, assets and stock awards associated with various contractual arrangements. Such estimates often require the selection of appropriate valuation methodologies and significant judgment. Actual results could differ from these estimates under different assumptions or circumstances and such differences could be material. The Company also assessed the impacts of COVID-19 on the above accounting matters as of September 26, 2020 and through the date of this report. While there was not a material impact as of and for the quarter ended September 26, 2020, future actual magnitude and duration of COVID-19, as well as other associated factors, could result in material negative impacts to its condensed consolidated financial statements in future reporting periods.
Recent Accounting Pronouncements	Recent Accounting Pronouncements Recently Adopted Effective January 1, 2020, the Company adopted Accounting Standards Update (“ASU”) No. 2018-13, “Fair Value Measurement (Topic 820): Disclosure Framework – Changes to the Disclosure Requirements for Fair Value Measurement.” This ASU is part of the Financial Accounting Standard Board’s (“FASB”) larger disclosure framework project intended to improve the effectiveness of financial statement footnote disclosure. ASU No. 2018-13 modifies required fair value disclosures related primarily to Level 3 investments. This ASU is effective for annual periods beginning after December 15, 2019 and interim periods within those annual periods. The adoption of ASU No. 2018-13 did not have a material impact on the Company’s consolidated financial position, results of operations, and cash flows. Effective January 1, 2020, the Company adopted ASU No. 2017-09, “Compensation - Stock Compensation (Topic 718): Scope of Modification Accounting.” This ASU amends the scope of modification accounting for share-based payment arrangements and provides guidance on the types of changes to the terms or conditions of share-based payment awards to which an entity would be required to apply modification accounting under Accounting Standards Codification (“ASC”) 718. The ASU is effective for the fiscal years beginning after December 15, 2019 and for interim periods within those fiscal years. The adoption of ASU No. 2017-09 did not have a material impact on the Company’s consolidated financial position, results of operations, and cash flows. Effective January 1, 2020, the Company adopted ASU No. 2016-13, “Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments,” which represents a credit loss standard that changes the impairment model for most financial assets and certain other financial instruments. Specifically, this guidance requires entities to utilize a new “expected loss” model as it relates to trade receivables, notes and other commitments to extend credit held by a reporting entity Recently Issued In December 2019, the FASB issued ASU No. 2019-12, “Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes.” This standard simplifies the accounting for income taxes by eliminating certain exceptions to the guidance in Topic 740 related to the approach for intraperiod tax allocation, the methodology for calculating income taxes in an interim period and the recognition of deferred tax liabilities for outside basis differences. The new guidance also simplifies aspects of the accounting for franchise Recently issued accounting guidance not discussed above is not applicable or is not expected to have a material impact to the Company’s c onsolidated financial position, results of operations, and cash flows.

Business Combination (Tables)

Business Combination (Tables)	9 Months Ended
	Sep. 26, 2020
Business Combinations [Abstract]
Summary of Preliminary Allocation of the Total Purchase Consideration to Initial Estimated Fair Values of the Assets Acquired and Liabilities Assumed	The following table summarizes the preliminary allocation of the total purchase consideration to the initial estimated fair values of the assets acquired and liabilities assumed as of October 25, 2019, as well as adjustments aggregating $0 and $478 to other non-current liabilities during the three and nine months ended September 26, 2020: Cash and cash equivalents $ 43,882 Marketable securities 94,389 Account receivables 49,917 Inventories 98,478 Prepaid expenses and other current assets 7,734 Property, plant and equipment 77,451 Operating lease right-of-use assets 9,658 Identifiable intangible assets 374,900 Deferred income taxes 1,352 Other assets 850 Total assets acquired 758,611 Accounts payable (23,361 ) Payroll and related expenses (20,290 ) Deferred revenue (5,931 ) Other current liabilities (10,739 ) Income taxes payable (2,699 ) Other non-current liabilities (90,591 ) Net assets acquired 605,000 Goodwill 285,131 Total purchase consideration $ 890,131

Fair Value Measurements - (Tabl

Fair Value Measurements - (Tables)	9 Months Ended
	Sep. 26, 2020
Fair Value Disclosures [Abstract]
Schedule of Assets and Liabilities Carried at Fair Value Measured on a Recurring Basis	The following tables provide the assets and liabilities carried at fair value measured on a recurring basis at September 26, 2020 and December 31, 2019: Fair Value Measurements Using Carrying Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) September 26, 2020 Assets: Available-for-sale debt securities: Municipal notes and bonds $ 111,401 $ — $ 111,401 $ — Asset-backed securities 15,160 — 15,160 — Certificates of deposit 39,685 — 39,685 — Commercial paper 27,489 — 27,489 — Corporate bonds 45,062 — 45,062 — Total assets $ 238,797 $ — $ 238,797 $ — Liabilities: Contingent consideration - acquisitions $ 134 $ — $ — $ 134 Foreign currency forward contracts 239 — 239 — Total liabilities $ 373 $ — $ 239 $ 134 December 31, 2019 Assets: Available-for-sale debt securities: Municipal notes and bonds $ 81,108 $ — $ 81,108 $ — Asset-backed securities 10,779 — 10,779 — Certificates of deposit 30,507 — 30,507 — Commercial paper 30,708 — 30,708 — Corporate bonds 36,461 — 36,461 — Foreign currency forward contracts 120 — 120 — Total assets $ 189,683 $ — $ 189,683 $ — Liabilities: Contingent consideration - acquisitions $ 569 $ — $ — $ 569 Total liabilities $ 569 $ — $ — $ 569
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation	This table presents a reconciliation of the Contingent consideration - acquisitions liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3) for the nine months ended September 26, 2020: Fair Value Measurements Using Significant Unobservable Inputs (Level 3) Balance at December 31, 2019 $ 569 Additions — Payments (435 ) Transfer into (out of) Level 3 — Balance at September 26, 2020 $ 134

Marketable Securities - (Tables

Marketable Securities - (Tables)	9 Months Ended
	Sep. 26, 2020
Marketable Securities [Abstract]
Schedule of Marketable Securities by Category	At September 26, 2020 and December 31, 2019, marketable securities are categorized as follows: Amortized Cost Gross Unrealized Holding Gains Gross Unrealized Holding Losses Fair Value September 26, 2020 Municipal notes and bonds $ 111,137 $ 270 $ 6 $ 111,401 Asset-backed securities 15,109 51 — 15,160 Certificates of deposit 39,649 36 — 39,685 Commercial paper 27,472 18 1 27,489 Corporate bonds 44,963 126 27 45,062 Total marketable securities $ 238,330 $ 501 $ 34 $ 238,797 December 31, 2019 Municipal notes and bonds $ 80,926 $ 188 $ 6 $ 81,108 Asset-backed securities 10,767 12 — 10,779 Certificates of deposit 30,500 7 — 30,507 Commercial paper 30,707 1 — 30,708 Corporate bonds 36,409 52 — 36,461 Total marketable securities $ 189,309 $ 260 $ 6 $ 189,563
Schedule of Amortized Cost and Estimated Fair Value of Marketable Securities Classified by Maturity Date	The amortized cost and estimated fair value of marketable securities classified by the maturity date listed on the security, regardless of the Condensed Consolidated Balance Sheets classification, is as follows at September 26, 2020 and December 31, 2019: September 26, 2020 December 31, 2019 Amortized Cost Fair Value Amortized Cost Fair Value Due within one year $ 172,828 $ 173,166 $ 152,649 $ 152,852 Due after one through five years 65,502 65,631 36,660 36,711 Due after five through ten years — — — — Due after ten years — — — — Total marketable securities $ 238,330 $ 238,797 $ 189,309 $ 189,563
Summary of Estimated Fair Value and Gross Unrealized Holding Losses of Marketable Securities in Unrealized Loss Position	The following table summarizes the estimated fair value and gross unrealized holding losses of marketable securities, aggregated by investment instrument and period of time in an unrealized loss position, at September 26, 2020 and December 31, 2019: In Unrealized Loss Position For Less Than 12 Months In Unrealized Loss Position For Greater Than 12 Months Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses September 26, 2020 Municipal notes and bonds $ 6,026 $ 6 $ — $ — Commercial paper 4,497 1 — — Corporate bonds 17,858 27 — — Total $ 28,381 $ 34 $ — $ — December 31, 2019 Municipal notes and bonds $ 14,166 $ 6 $ — $ — Total $ 14,166 $ 6 $ — $ —

Derivative Instruments and He_2

Derivative Instruments and Hedging Activities (Tables)	9 Months Ended
	Sep. 26, 2020
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Forward Contracts and Related Fair Values	The dollar equivalent of the U.S. dollar forward contracts and related fair values as of September 26, 2020 and December 31, 2019 were as follows: September 26, 2020 December 31, 2019 Notional amount $ 33,590 $ 38,887 Fair value of (liability) asset $ (239 ) $ 120

Purchased Intangible Assets - (

Purchased Intangible Assets - (Tables)	9 Months Ended
	Sep. 26, 2020
Goodwill And Intangible Assets Disclosure [Abstract]
Changes in the Carrying Amount of Goodwill	The changes in the carrying amount of goodwill are as follows: Balance at December 31, 2019 $ 307,148 Goodwill adjustments (Note 2) 478 Balance at September 26, 2020 $ 307,626
Schedule of Purchased Intangible Assets	Purchased intangible assets as of September 26, 2020 and December 31, 2019 are as follows: Gross Carrying Amount Accumulated Amortization Net September 26, 2020 Finite-lived intangibles: Developed technology $ 326,777 $ 100,122 $ 226,655 Customer and distributor relationships 69,261 19,013 50,248 Trademarks and trade names 12,461 5,041 7,420 Total finite-lived intangible assets 408,499 124,176 284,323 In-process research and development 46,600 — 46,600 Total identifiable intangible assets $ 455,099 $ 124,176 $ 330,923 December 31, 2019 Finite-lived intangibles: Developed technology $ 326,726 $ 67,861 $ 258,865 Customer and distributor relationships 69,261 11,078 58,183 Trademarks and trade names 12,461 4,156 8,305 Total finite-lived intangible assets 408,448 83,095 325,353 In-process research and development 46,600 — 46,600 Total identifiable intangible assets $ 455,048 $ 83,095 $ 371,953

Balance Sheet Details (Tables)

Balance Sheet Details (Tables)	9 Months Ended
	Sep. 26, 2020
Balance Sheet Detail [Abstract]
Schedule of Inventories	Inventories, net are comprised of the following: September 26, 2020 December 31, 2019 Materials $ 117,680 $ 108,492 Work-in-process 44,968 42,694 Finished goods 22,333 24,948 Total inventories, net $ 184,981 $ 176,134
Schedule of Property, Plant and Equipment, Net	Property, plant and equipment, net is comprised of the following: September 26, 2020 December 31, 2019 Land and building $ 46,941 $ 47,222 Machinery and equipment 57,571 56,504 Furniture and fixtures 4,305 3,968 Computer equipment and software 16,361 15,770 Leasehold improvements 13,463 13,069 138,641 136,533 Accumulated depreciation (45,925 ) (38,113 ) Total property, plant and equipment, net $ 92,716 $ 98,420
Schedule of Other Assets	Other assets is comprised of the following: September 26, 2020 December 31, 2019 Convertible notes receivable, net of allowance of $2,000 at December 31, 2019 $ — $ 3,000 Operating lease right-of-use assets 20,076 23,588 Other 1,361 1,351 Total other assets $ 21,437 $ 27,939
Schedule of Accrued Liabilities	Accrued liabilities is comprised of the following: September 26, 2020 December 31, 2019 Payroll and related expenses $ 24,501 $ 19,365 Warranty 6,009 6,348 Other 553 491 Total accrued liabilities $ 31,063 $ 26,204
Schedule of Other Current Liabilities	Other current liabilities is comprised of the following: September 26, 2020 December 31, 2019 Contingent consideration - acquisitions $ 134 $ 569 Income tax payable 639 2,783 Current operating lease obligations 4,129 4,906 Customer deposits 1,215 1,994 Accrued professional fees 926 1,520 Other 5,768 7,400 Total other current liabilities $ 12,811 $ 19,172
Schedule of Other Non-Current Liabilities	Other non-current liabilities is comprised of the following: September 26, 2020 December 31, 2019 Unrecognized tax benefits (including interest) $ 7,063 $ 6,384 Non-current operating lease obligations 17,373 19,970 Deferred revenue 1,764 2,464 Other 5,323 2,953 Total other non-current liabilities $ 31,523 $ 31,771

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 26, 2020
Commitments And Contingencies Disclosure [Abstract]
Schedule of Changes in Warranty Reserves	Changes in the Company’s warranty reserves are as follows: Nine Months Ended September 26, September 30, 2020 2019 Balance, beginning of the period $ 6,348 $ 2,441 Accruals 5,646 2,078 Usage (5,710 ) (2,477 ) Balance, end of the period $ 6,284 $ 2,042

Revenue (Tables)

Revenue (Tables)	9 Months Ended
	Sep. 26, 2020
Revenue From Contract With Customer [Abstract]
Schedule of Disaggregation of Revenue	The following table represents a disaggregation of revenue by timing of revenue: Three Months Ended Nine Months Ended September 26, September 30, September 26, September 30, 2020 2019 2020 2019 Point-in-time $ 122,015 $ 58,663 $ 387,556 $ 172,562 Over-time 4,477 4,272 13,812 12,776 Total revenue $ 126,492 $ 62,935 $ 401,368 $ 185,338
Schedule of Changes in Deferred Revenue	Changes in deferred revenue were as follows: Three Months Ended Nine Months Ended September 26, September 30, September 26, September 30, 2020 2019 2020 2019 Balance, beginning of the period $ 17,894 $ 9,349 $ 15,093 $ 8,080 Deferral of revenue 10,137 5,860 33,389 17,492 Recognition of deferred revenue (10,396 ) (7,937 ) (30,847 ) (18,300 ) Balance, end of the period $ 17,635 $ 7,272 $ 17,635 $ 7,272

Share-Based Compensation - (Tab

Share-Based Compensation - (Tables)	9 Months Ended
	Sep. 26, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Restricted Stock Unit Activity	A summary of the Company’s restricted stock unit activity with respect to the nine months ended September 26, 2020 is as follows: Number of Shares Weighted Average Grant Date Fair Value Nonvested at December 31, 2019 1,107 $ 28.89 Granted 490 $ 34.66 Vested (470 ) $ 29.37 Forfeited (116 ) $ 29.86 Nonvested at September 26, 2020 1,011 $ 31.28

Other (Expense) Income, Net (Ta

Other (Expense) Income, Net (Tables)	9 Months Ended
	Sep. 26, 2020
Other Income Expense [Abstract]
Schedule of Other (Expense) Income, Net	Other (expense) income, net, is comprised of the following: Three Months Ended Nine Months Ended September 26, September 30, September 26, September 30, 2020 2019 2020 2019 Foreign currency exchange gains (losses), net $ (1,005 ) $ 552 $ (2,311 ) $ 774 Other 106 65 246 67 Total other (expense) income, net $ (899 ) $ 617 $ (2,065 ) $ 841

Income Taxes - (Tables)

Income Taxes - (Tables)	9 Months Ended
	Sep. 26, 2020
Income Tax Disclosure [Abstract]
Details of Income Tax	The following table provides details of income taxes: Three Months Ended Nine Months Ended September 26, September 30, September 26, September 30, 2020 2019 2020 2019 Income before income taxes $ 8,927 $ 6,908 $ 12,341 $ 21,824 Provision for income taxes $ 836 $ 348 $ 1,230 $ 2,162 Effective tax rate 9 % 5 % 10 % 10 %

Earnings Per Share - (Tables)

Earnings Per Share - (Tables)	9 Months Ended
	Sep. 26, 2020
Earnings Per Share [Abstract]
Schedule of Weighted Average Number of Restricted Stock Units Excluded from Calculation of Diluted Earnings Per Share	The following table sets forth the weighted average number of restricted stock units that have been excluded from the calculation of diluted earnings per share as their effect would have been anti-dilutive: Three Months Ended Nine Months Ended September 26, September 30, September 26, September 30, 2020 2019 2020 2019 Restricted stock units 4 56 23 92 Total 4 56 23 92
Schedule of Basic and Diluted Earnings Per Share	The Company’s basic and diluted earnings per share amounts are as follows: Three Months Ended Nine Months Ended September 26, September 30, September 26, September 30, 2020 2019 2020 2019 Numerator: Net income $ 8,091 $ 6,560 $ 11,111 $ 19,662 Denominator: Basic earnings per share - weighted average shares outstanding 48,900 25,079 49,231 25,012 Effect of potential dilutive securities: Employee stock options, employee stock purchase grants and restricted stock units - dilutive shares 231 226 320 242 Diluted earnings per share - weighted average shares outstanding 49,131 25,305 49,551 25,254 Earnings per share: Basic $ 0.17 $ 0.26 $ 0.23 $ 0.79 Diluted $ 0.16 $ 0.26 $ 0.22 $ 0.78

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Income (Loss) (Tables)	9 Months Ended
	Sep. 26, 2020
Accumulated Other Comprehensive Income Loss Net Of Tax [Abstract]
Components of Accumulated Other Comprehensive Income (Loss), Net of Tax	The components of accumulated other comprehensive income (loss), net of tax at September 26, 2020, as well as the activity for the nine months ended September 26, 2020, were as follows: Accumulated Foreign Currency Translation Adjustment Accumulated Net Unrealized Gain (Loss) on Available-For-Sale Marketable Securities Accumulated Other Comprehensive Income (Loss) Balance at December 31, 2019 $ (564 ) $ (34 ) $ (598 ) Net current period other comprehensive gain 2,067 197 2,264 Reclassifications — — — Balance at September 26, 2020 $ 1,503 $ 163 $ 1,666

Segment Reporting and Geograp_2

Segment Reporting and Geographic Information - (Tables)	9 Months Ended
	Sep. 26, 2020
Segment Reporting [Abstract]
Schedule of Revenue from External Customers by Products and Services	The following table lists the different sources of revenue: Three Months Ended Nine Months Ended September 26, September 30, September 26, September 30, 2020 2019 2020 2019 Systems and software $ 97,774 77 % $ 52,786 84 % $ 321,062 80 % $ 154,207 83 % Parts 18,815 15 % 7,142 11 % 48,719 12 % 22,292 12 % Services 9,903 8 % 3,007 5 % 31,587 8 % 8,839 5 % Total revenue $ 126,492 100 % $ 62,935 100 % $ 401,368 100 % $ 185,338 100 %
Schedule of Revenue from External Customers Attributed to Foreign Countries by Geographic Area	For geographical revenue reporting, revenue is attributed to the geographic location to which the product is shipped. Revenue by geographic region is as follows: Three Months Ended Nine Months Ended September 26, September 30, September 26, September 30, 2020 2019 2020 2019 Revenue from third parties: United States $ 16,036 $ 8,816 $ 58,062 $ 26,879 Taiwan 30,028 14,304 97,206 32,446 Japan 13,698 8,962 42,632 16,330 China 31,911 14,666 90,295 54,887 South Korea 13,250 8,481 56,971 30,027 Singapore 5,690 2,396 14,619 6,007 Other Asia 3,706 1,386 4,252 3,425 Germany 3,760 735 12,352 3,260 Other Europe 8,413 3,189 24,979 12,077 Total revenue $ 126,492 $ 62,935 $ 401,368 $ 185,338
Schedule of Revenue by Major Customer by Reporting Segments	The following customers accounted for more than 10% of total revenue for the indicated periods: Nine Months Ended September 26, September 30, 2020 2019 Customer A 16.2 % 7.8 % Customer B 14.4 % 6.1 % Customer C 7.4 % 17.6 %

Share Repurchase Authorization

Share Repurchase Authorization (Tables)	9 Months Ended
	Sep. 26, 2020
Share Repurchase Program [Abstract]
Summary of Stock Repurchases	The following table summarizes the Company’s share repurchases for the periods indicated: Three Months Ended Nine Months Ended September 26, September 30, September 26, September 30, 2020 2019 2020 2019 Shares of common stock repurchased — — 1,882 30 Cost of shares repurchased $ — $ — $ 52,000 $ 744 Average price paid per share $ — $ — $ 27.62 $ 24.68

Business Combination - Textual

Business Combination - Textual (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 26, 2020	Sep. 26, 2020
Business Acquisition [Line Items]
Aggregate adjustments to estimated fair values of assets acquired and liabilities		$ 478
Other Non-current Liabilities [Member] | Rudolph and Nanometrics [Member]
Business Acquisition [Line Items]
Aggregate adjustments to estimated fair values of assets acquired and liabilities	$ 0	$ 478

Business Combination - Summary

Business Combination - Summary of Preliminary Allocation of the Total Purchase Consideration to Initial Estimated Fair Values of the Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	Sep. 26, 2020	Dec. 31, 2019	Oct. 25, 2019
Business Acquisition [Line Items]
Goodwill	$ 307,626	$ 307,148
Rudolph Technologies, Inc. [Member]
Business Acquisition [Line Items]
Cash and cash equivalents			$ 43,882
Marketable securities			94,389
Account receivables			49,917
Inventories			98,478
Prepaid expenses and other current assets			7,734
Property, plant and equipment			77,451
Operating lease right-of-use assets			9,658
Identifiable intangible assets			374,900
Deferred income taxes			1,352
Other assets			850
Total assets acquired			758,611
Accounts payable			(23,361)
Payroll and related expenses			(20,290)
Deferred revenue			(5,931)
Other current liabilities			(10,739)
Income taxes payable			(2,699)
Other non-current liabilities			(90,591)
Net assets acquired			605,000
Goodwill			285,131
Total purchase consideration			$ 890,131

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Assets and Liabilities Carried at Fair Value Measured on a Recurring Basis (Details) - USD ($) $ in Thousands	Sep. 26, 2020	Dec. 31, 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale debt securities	$ 238,797	$ 189,563
Carrying Value [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Foreign currency forward contracts		120
Total assets	238,797	189,683
Contingent consideration - acquisitions	134	569
Foreign currency forward contracts	239
Total liabilities	373	569
Carrying Value [Member] | Fair Value, Measurements, Recurring [Member] | Municipal notes and bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale debt securities	111,401	81,108
Carrying Value [Member] | Fair Value, Measurements, Recurring [Member] | Asset-backed securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale debt securities	15,160	10,779
Carrying Value [Member] | Fair Value, Measurements, Recurring [Member] | Certificates of deposits [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale debt securities	39,685	30,507
Carrying Value [Member] | Fair Value, Measurements, Recurring [Member] | Commercial paper [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale debt securities	27,489	30,708
Carrying Value [Member] | Fair Value, Measurements, Recurring [Member] | Corporate bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale debt securities	45,062	36,461
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Foreign currency forward contracts		0
Total assets	0	0
Contingent consideration - acquisitions	0	0
Foreign currency forward contracts	0
Total liabilities	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Measurements, Recurring [Member] | Municipal notes and bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale debt securities	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Measurements, Recurring [Member] | Asset-backed securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale debt securities	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Measurements, Recurring [Member] | Certificates of deposits [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale debt securities	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Measurements, Recurring [Member] | Commercial paper [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale debt securities	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Measurements, Recurring [Member] | Corporate bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale debt securities	0	0
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Foreign currency forward contracts		120
Total assets	238,797	189,683
Contingent consideration - acquisitions	0	0
Foreign currency forward contracts	239
Total liabilities	239	0
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring [Member] | Municipal notes and bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale debt securities	111,401	81,108
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring [Member] | Asset-backed securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale debt securities	15,160	10,779
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring [Member] | Certificates of deposits [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale debt securities	39,685	30,507
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring [Member] | Commercial paper [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale debt securities	27,489	30,708
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring [Member] | Corporate bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale debt securities	45,062	36,461
Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Foreign currency forward contracts		0
Total assets	0	0
Contingent consideration - acquisitions	134	569
Foreign currency forward contracts	0
Total liabilities	134	569
Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements, Recurring [Member] | Municipal notes and bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale debt securities	0	0
Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements, Recurring [Member] | Asset-backed securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale debt securities	0	0
Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements, Recurring [Member] | Certificates of deposits [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale debt securities	0	0
Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements, Recurring [Member] | Commercial paper [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale debt securities	0	0
Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements, Recurring [Member] | Corporate bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale debt securities	$ 0	$ 0

Fair Value Measurements - Fair

Fair Value Measurements - Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation (Details) - Fair Value, Measurements, Recurring [Member] - Significant Unobservable Inputs (Level 3) [Member] $ in Thousands	9 Months Ended
	Sep. 26, 2020USD ($)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Balance at December 31, 2019	$ 569
Additions	0
Payments	(435)
Transfer into (out of) Level 3	0
Balance at September 26, 2020	$ 134

Marketable Securities - Schedul

Marketable Securities - Schedule of Marketable Securities by Category (Details) - USD ($) $ in Thousands	Sep. 26, 2020	Dec. 31, 2019
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 238,330	$ 189,309
Gross Unrealized Holding Gains	501	260
Gross Unrealized Holding Losses	34	6
Fair Value	238,797	189,563
Municipal notes and bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	111,137	80,926
Gross Unrealized Holding Gains	270	188
Gross Unrealized Holding Losses	6	6
Fair Value	111,401	81,108
Asset-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	15,109	10,767
Gross Unrealized Holding Gains	51	12
Fair Value	15,160	10,779
Certificates of deposits [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	39,649	30,500
Gross Unrealized Holding Gains	36	7
Fair Value	39,685	30,507
Commercial paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	27,472	30,707
Gross Unrealized Holding Gains	18	1
Gross Unrealized Holding Losses	1
Fair Value	27,489	30,708
Corporate bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	44,963	36,409
Gross Unrealized Holding Gains	126	52
Gross Unrealized Holding Losses	27
Fair Value	$ 45,062	$ 36,461

Marketable Securities - Sched_2

Marketable Securities - Schedule of Amortized Cost and Estimated Fair Value of Marketable Securities Classified by Maturity Date (Details) - USD ($) $ in Thousands	Sep. 26, 2020	Dec. 31, 2019
Available For Sale Securities Debt Maturities Fair Value [Abstract]
Amortized Cost, Due within one year	$ 172,828	$ 152,649
Amortized Cost, Due after one through five years	65,502	36,660
Amortized Cost, Due after five through ten years	0	0
Amortized Cost, Due after ten years	0	0
Amortized Cost	238,330	189,309
Fair Value, Due within one year	173,166	152,852
Fair Value, Due after one through five years	65,631	36,711
Fair Value, Due after five through ten years	0	0
Fair Value, Due after ten years	0	0
Fair Value, Total marketable securities	$ 238,797	$ 189,563

Marketable Securities - Summary

Marketable Securities - Summary of Estimated Fair Value and Gross Unrealized Holding Losses of Marketable Securities in Unrealized Loss Position (Details) - USD ($) $ in Thousands	Sep. 26, 2020	Dec. 31, 2019
Schedule of Available-for-sale Securities [Line Items]
In Unrealized Loss Position For Less Than 12 Months, Fair Value	$ 28,381	$ 14,166
In Unrealized Loss Position For Less Than 12 Months, Gross Unrealized Losses	34	6
In Unrealized Loss Position For Greater Than 12 Months, Fair Value	0	0
In Unrealized Loss Position For Greater Than 12 Months, Gross Unrealized Losses	0	0
Municipal notes and bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
In Unrealized Loss Position For Less Than 12 Months, Fair Value	6,026	14,166
In Unrealized Loss Position For Less Than 12 Months, Gross Unrealized Losses	6	6
In Unrealized Loss Position For Greater Than 12 Months, Fair Value	0	0
In Unrealized Loss Position For Greater Than 12 Months, Gross Unrealized Losses	0	$ 0
Commercial paper [Member]
Schedule of Available-for-sale Securities [Line Items]
In Unrealized Loss Position For Less Than 12 Months, Fair Value	4,497
In Unrealized Loss Position For Less Than 12 Months, Gross Unrealized Losses	1
In Unrealized Loss Position For Greater Than 12 Months, Fair Value	0
In Unrealized Loss Position For Greater Than 12 Months, Gross Unrealized Losses	0
Corporate bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
In Unrealized Loss Position For Less Than 12 Months, Fair Value	17,858
In Unrealized Loss Position For Less Than 12 Months, Gross Unrealized Losses	27
In Unrealized Loss Position For Greater Than 12 Months, Fair Value	0
In Unrealized Loss Position For Greater Than 12 Months, Gross Unrealized Losses	$ 0

Derivative Instruments and He_3

Derivative Instruments and Hedging Activities - Forward Contracts and Related Fair Values (Details) - USD ($) $ in Thousands	Sep. 26, 2020	Dec. 31, 2019
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Notional amount	$ 33,590	$ 38,887
Fair value of (liability) asset	$ (239)	$ 120

Purchased Intangible Assets - C

Purchased Intangible Assets - Changes in the Carrying Amount of Goodwill (Details) $ in Thousands	9 Months Ended
	Sep. 26, 2020USD ($)
Goodwill Roll Forward
Balance at December 31, 2019	$ 307,148
Goodwill adjustments (Note 2)	478
Balance at September 26, 2020	$ 307,626

Purchased Intangible Assets - S

Purchased Intangible Assets - Schedule of Purchased Intangible Assets (Details) - USD ($) $ in Thousands	Sep. 26, 2020	Dec. 31, 2019
Finite Lived Intangible Assets [Line Items]
Finite-lived intangibles, Gross Carrying Amount	$ 408,499	$ 408,448
Finite-lived intangibles, Accumulated Amortization	124,176	83,095
Finite-lived intangibles, Net	284,323	325,353
Identifiable intangibles assets, Gross Carrying Amount	455,099	455,048
Identifiable intangibles assets, Accumulated Amortization	124,176	83,095
Identifiable intangibles assets, Net	330,923	371,953
Developed technology [Member]
Finite Lived Intangible Assets [Line Items]
Finite-lived intangibles, Gross Carrying Amount	326,777	326,726
Finite-lived intangibles, Accumulated Amortization	100,122	67,861
Finite-lived intangibles, Net	226,655	258,865
Customer and distributor relationships [Member]
Finite Lived Intangible Assets [Line Items]
Finite-lived intangibles, Gross Carrying Amount	69,261	69,261
Finite-lived intangibles, Accumulated Amortization	19,013	11,078
Finite-lived intangibles, Net	50,248	58,183
Trademarks and trade names [Member]
Finite Lived Intangible Assets [Line Items]
Finite-lived intangibles, Gross Carrying Amount	12,461	12,461
Finite-lived intangibles, Accumulated Amortization	5,041	4,156
Finite-lived intangibles, Net	7,420	8,305
In-process research and development [Member]
Finite Lived Intangible Assets [Line Items]
Identifiable intangibles assets, Gross Carrying Amount	46,600	46,600
Identifiable intangibles assets, Net	$ 46,600	$ 46,600

Purchased Intangible Assets - T

Purchased Intangible Assets - Textual (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 30, 2019	Sep. 26, 2020	Sep. 30, 2019
Goodwill And Intangible Assets Disclosure [Abstract]
Amortization of intangibles	$ 13,646	$ 387	$ 41,081	$ 1,161
Estimated amortization expense, Remainder of 2020	12,663		12,663
Estimated amortization expense, 2021	48,014		48,014
Estimated amortization expense, 2022	47,615		47,615
Estimated amortization expense, 2023	47,140		47,140
Estimated amortization expense, 2024	41,455		41,455
Estimated amortization expense, 2025	$ 24,905		$ 24,905

Convertible Notes Receivable -

Convertible Notes Receivable - Textual (Details) - USD ($)	9 Months Ended
	Sep. 26, 2020	Dec. 31, 2019	May 31, 2018
Loans And Leases Receivable Disclosure [Line Items]
Convertible notes receivable	$ 0	$ 3,000,000
Convertible Loan Agreement [Member] | Simax Precision Technologies Limited [Member]
Loans And Leases Receivable Disclosure [Line Items]
Funds available in multiple promissory notes			$ 15,000,000
Convertible notes rate of interest			4.25%
Settlement Agreement [Member] | Simax Precision Technologies Limited [Member]
Loans And Leases Receivable Disclosure [Line Items]
Settlement of convertible notes receivable	$ 2,848,000

Balance Sheet Details - Schedul

Balance Sheet Details - Schedule of Inventories (Details) - USD ($) $ in Thousands	Sep. 26, 2020	Dec. 31, 2019
Inventory Details [Abstract]
Materials	$ 117,680	$ 108,492
Work-in-process	44,968	42,694
Finished goods	22,333	24,948
Total inventories, net	$ 184,981	$ 176,134

Balance Sheet Details - Sched_2

Balance Sheet Details - Schedule of Property, Plant and Equipment, Net (Details) - USD ($) $ in Thousands	Sep. 26, 2020	Dec. 31, 2019
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 138,641	$ 136,533
Accumulated depreciation	(45,925)	(38,113)
Total property, plant and equipment, net	92,716	98,420
Land and building [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	46,941	47,222
Machinery and equipment [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	57,571	56,504
Furniture and fixtures [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	4,305	3,968
Computer equipment and software [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	16,361	15,770
Leasehold improvements [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 13,463	$ 13,069

Balance Sheet Details - Sched_3

Balance Sheet Details - Schedule of Other Assets (Details) - USD ($) $ in Thousands	Sep. 26, 2020	Dec. 31, 2019
Other Assets [Abstract]
Convertible notes receivable	$ 0	$ 3,000
Operating lease right-of-use assets	20,076	23,588
Other	1,361	1,351
Total other assets	$ 21,437	$ 27,939

Balance Sheet Details - Sched_4

Balance Sheet Details - Schedule of Other Assets (Parenthetical) (Details) $ in Thousands	Dec. 31, 2019USD ($)
Other Assets [Abstract]
Allowance for convertible notes receivable	$ 2,000

Balance Sheet Details - Sched_5

Balance Sheet Details - Schedule of Accrued Liabilities (Details) - USD ($) $ in Thousands	Sep. 26, 2020	Dec. 31, 2019
Accrued Liabilities Current [Abstract]
Payroll and related expenses	$ 24,501	$ 19,365
Warranty	6,009	6,348
Other	553	491
Total accrued liabilities	$ 31,063	$ 26,204

Balance Sheet Details - Sched_6

Balance Sheet Details - Schedule of Other Current Liabilities (Details) - USD ($) $ in Thousands	Sep. 26, 2020	Dec. 31, 2019
Other Liabilities Current [Abstract]
Contingent consideration - acquisitions	$ 134	$ 569
Income tax payable	639	2,783
Current operating lease obligations	4,129	4,906
Customer deposits	1,215	1,994
Accrued professional fees	926	1,520
Other	5,768	7,400
Total other current liabilities	$ 12,811	$ 19,172

Balance Sheet Details - Sched_7

Balance Sheet Details - Schedule of Other Non-Current Liabilities (Details) - USD ($) $ in Thousands	Sep. 26, 2020	Dec. 31, 2019
Other Liabilities Noncurrent [Abstract]
Unrecognized tax benefits (including interest)	$ 7,063	$ 6,384
Non-current operating lease obligations	17,373	19,970
Deferred revenue	1,764	2,464
Other	5,323	2,953
Total other non-current liabilities	$ 31,523	$ 31,771

Commitments and Contingencies -

Commitments and Contingencies - Textual (Details)	3 Months Ended	9 Months Ended
	Sep. 26, 2020USD ($)	Sep. 26, 2020USD ($)
Commitments And Contingencies [Line Items]
Sold receivables amount	$ 7,738,000
Due from unrelated third parties	0	$ 0
Liabilities recorded for obligations	0	$ 0
Percentage of maximum borrowing capacity of value of eligible securities		70.00%
Available line of credit	$ 71,200,000	$ 71,200,000
Available interest rate on line of credit	1.80%	1.80%
Minimum [Member]
Commitments And Contingencies [Line Items]
Warranty period		12 months
Maximum [Member]
Commitments And Contingencies [Line Items]
Warranty period		14 months

Commitments and Contingencies_2

Commitments and Contingencies - Schedule of Changes in Warranty Reserves (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 26, 2020	Sep. 30, 2019
Commitments And Contingencies Disclosure [Abstract]
Balance, beginning of the period	$ 6,348	$ 2,441
Accruals	5,646	2,078
Usage	(5,710)	(2,477)
Balance, end of the period	$ 6,284	$ 2,042

Revenue - Schedule of Disaggreg

Revenue - Schedule of Disaggregation of Revenue by Timing of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 30, 2019	Sep. 26, 2020	Sep. 30, 2019
Disaggregation Of Revenue [Line Items]
Total revenue	$ 126,492	$ 62,935	$ 401,368	$ 185,338
Transferred at Point in Time [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	122,015	58,663	387,556	172,562
Transferred over Time [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	$ 4,477	$ 4,272	$ 13,812	$ 12,776

Revenue - Schedule of Changes i

Revenue - Schedule of Changes in Deferred Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 30, 2019	Sep. 26, 2020	Sep. 30, 2019
Deferred Revenue Disclosure [Abstract]
Balance, beginning of the period	$ 17,894	$ 9,349	$ 15,093	$ 8,080
Deferral of revenue	10,137	5,860	33,389	17,492
Recognition of deferred revenue	(10,396)	(7,937)	(30,847)	(18,300)
Balance, end of the period	$ 17,635	$ 7,272	$ 17,635	$ 7,272

Share-Based Compensation - Summ

Share-Based Compensation - Summary of Restricted Stock Unit Activity (Details) - Restricted Stock Units (RSUs) [Member]	9 Months Ended
	Sep. 26, 2020$ / sharesshares
Activity for RSUs [Roll Forward]
Number of Shares, Beginning balance (in shares) | shares	1,107,000
Number of Shares, Granted (in shares) | shares	490,000
Number of Shares, Vested (in shares) | shares	(470,000)
Number of Shares, Forfeited (in shares) | shares	(116,000)
Number of Shares, Ending balance (in shares) | shares	1,011,000
Weighted Average Grant Date Fair Value for RSUs [Roll Forward]
Weighted Average Grant Date Fair Value, Beginning balance (in dollars per share) | $ / shares	$ 28.89
Weighted Average Grant Date Fair Value, Granted (in dollars per share) | $ / shares	34.66
Weighted Average Grant Date Fair Value, Vested (in dollars per share) | $ / shares	29.37
Weighted Average Grant Date Fair Value, Forfeited (in dollars per share) | $ / shares	29.86
Weighted Average Grant Date Fair Value, Ending balance (in dollars per share) | $ / shares	$ 31.28

Share-Based Compensation - Text

Share-Based Compensation - Textual (Details) - Restricted Stock Units (RSUs) [Member] - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 26, 2020	Dec. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total unrecognized compensation cost related to restricted stock units granted	$ 23,128	$ 22,230
Unrecognized compensation cost related to restricted stock units, weighted average period	1 year 10 months 24 days	1 year 10 months 24 days

Other (Expense) Income, Net - S

Other (Expense) Income, Net - Schedule of Other (Expense) Income, Net (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 30, 2019	Sep. 26, 2020	Sep. 30, 2019
Other Income Expense [Abstract]
Foreign currency exchange gains (losses), net	$ (1,005)	$ 552	$ (2,311)	$ 774
Other	106	65	246	67
Total other (expense) income, net	$ (899)	$ 617	$ (2,065)	$ 841

Income Taxes - Details of Incom

Income Taxes - Details of Income Tax (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 30, 2019	Sep. 26, 2020	Sep. 30, 2019
Income Tax Disclosure [Abstract]
Income before income taxes	$ 8,927	$ 6,908	$ 12,341	$ 21,824
Provision for income taxes	$ 836	$ 348	$ 1,230	$ 2,162
Effective tax rate	9.00%	5.00%	10.00%	10.00%

Income Taxes - Textual (Details

Income Taxes - Textual (Details) - USD ($) $ in Thousands	Sep. 26, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Deferred tax assets, valuation allowance	$ 14,150	$ 14,160

Earnings Per Share - Schedule o

Earnings Per Share - Schedule of Weighted Average Number of Restricted Stock Units Excluded from Calculation of Diluted Earnings Per Share (Details) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 30, 2019	Sep. 26, 2020	Sep. 30, 2019
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Total	4	56	23	92
Restricted Stock Units (RSUs) [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Total	4	56	23	92

Earnings Per Share - Schedule_2

Earnings Per Share - Schedule of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 26, 2020	Jun. 27, 2020	Mar. 28, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 26, 2020	Sep. 30, 2019
Earnings Per Share [Abstract]
Net income	$ 8,091	$ 7,424	$ (4,404)	$ 6,560	$ 5,526	$ 7,576	$ 11,111	$ 19,662
Basic	48,900			25,079			49,231	25,012
Employee stock options, employee stock purchase grants and restricted stock units - dilutive shares	231			226			320	242
Diluted earnings per share - weighted average shares outstanding	49,131			25,305			49,551	25,254
Basic	$ 0.17			$ 0.26			$ 0.23	$ 0.79
Diluted	$ 0.16			$ 0.26			$ 0.22	$ 0.78

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Income (Loss) - Components of Accumulated Other Comprehensive Income (Loss), Net of Tax (Details) $ in Thousands	9 Months Ended
	Sep. 26, 2020USD ($)
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	$ 1,264,026
Balance	1,237,683
Accumulated Foreign Currency Translation Adjustment [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	(564)
Net current period other comprehensive gain	2,067
Reclassifications	0
Balance	1,503
Accumulated Net Unrealized Gain (Loss) on Available-For-Sale Marketable Securities [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	(34)
Net current period other comprehensive gain	197
Reclassifications	0
Balance	163
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	(598)
Net current period other comprehensive gain	2,264
Reclassifications	0
Balance	$ 1,666

Segment Reporting and Geograp_3

Segment Reporting and Geographic Information - Additional Information (Details)	9 Months Ended
	Sep. 26, 2020Segment
Segment Reporting [Abstract]
Number of reportable segments	1

Segment Reporting and Geograp_4

Segment Reporting and Geographic Information - Schedule of Revenue from External Customers by Products and Services (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 30, 2019	Sep. 26, 2020	Sep. 30, 2019
Segment Reporting Information [Line Items]
Total revenue	$ 126,492	$ 62,935	$ 401,368	$ 185,338
Sales [Member] | Product [Member]
Segment Reporting Information [Line Items]
Concentration risk, percentage	100.00%	100.00%	100.00%	100.00%
Systems and Software [Member]
Segment Reporting Information [Line Items]
Total revenue	$ 97,774	$ 52,786	$ 321,062	$ 154,207
Systems and Software [Member] | Sales [Member] | Product [Member]
Segment Reporting Information [Line Items]
Concentration risk, percentage	77.00%	84.00%	80.00%	83.00%
Parts Revenue [Member]
Segment Reporting Information [Line Items]
Total revenue	$ 18,815	$ 7,142	$ 48,719	$ 22,292
Parts Revenue [Member] | Sales [Member] | Product [Member]
Segment Reporting Information [Line Items]
Concentration risk, percentage	15.00%	11.00%	12.00%	12.00%
Service Revenue [Member]
Segment Reporting Information [Line Items]
Total revenue	$ 9,903	$ 3,007	$ 31,587	$ 8,839
Service Revenue [Member] | Sales [Member] | Product [Member]
Segment Reporting Information [Line Items]
Concentration risk, percentage	8.00%	5.00%	8.00%	5.00%

Segment Reporting and Geograp_5

Segment Reporting and Geographic Information - Schedule of Revenue from External Customers Attributed to Foreign Countries by Geographic Area (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 30, 2019	Sep. 26, 2020	Sep. 30, 2019
Segment Reporting Information [Line Items]
Total revenue	$ 126,492	$ 62,935	$ 401,368	$ 185,338
United States [Member]
Segment Reporting Information [Line Items]
Total revenue	16,036	8,816	58,062	26,879
Taiwan [Member]
Segment Reporting Information [Line Items]
Total revenue	30,028	14,304	97,206	32,446
Japan [Member]
Segment Reporting Information [Line Items]
Total revenue	13,698	8,962	42,632	16,330
China [Member]
Segment Reporting Information [Line Items]
Total revenue	31,911	14,666	90,295	54,887
South Korea [Member]
Segment Reporting Information [Line Items]
Total revenue	13,250	8,481	56,971	30,027
Singapore [Member]
Segment Reporting Information [Line Items]
Total revenue	5,690	2,396	14,619	6,007
Other Asia [Member]
Segment Reporting Information [Line Items]
Total revenue	3,706	1,386	4,252	3,425
Germany [Member]
Segment Reporting Information [Line Items]
Total revenue	3,760	735	12,352	3,260
Other Europe [Member]
Segment Reporting Information [Line Items]
Total revenue	$ 8,413	$ 3,189	$ 24,979	$ 12,077

Segment Reporting and Geograp_6

Segment Reporting and Geographic Information - Schedule of Revenue by Major Customer by Reporting Segments (Details) - Sales [Member] - Customer Concentration Risk [Member]	9 Months Ended
	Sep. 26, 2020	Sep. 30, 2019
Customer A [Member]
Segment Reporting Information [Line Items]
Entity-wide revenue, major customer, percentage	16.20%	7.80%
Customer B [Member]
Segment Reporting Information [Line Items]
Entity-wide revenue, major customer, percentage	14.40%	6.10%
Customer C [Member]
Segment Reporting Information [Line Items]
Entity-wide revenue, major customer, percentage	7.40%	17.60%

Share Repurchase Authorizatio_2

Share Repurchase Authorization - Textual (Details) - USD ($)	9 Months Ended
	Sep. 26, 2020	Mar. 14, 2019
Shares Repurchase Authorization [Line Items]
Amount available for future repurchase	$ 28,000,000
Stock repurchase, authorization termination date	Oct. 25, 2019
Maximum [Member]
Shares Repurchase Authorization [Line Items]
Stock repurchase, authorized amount		$ 80,000,000

Share Repurchase Authorizatio_3

Share Repurchase Authorization - Summary of Stock Repurchases (Details) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 26, 2020	Sep. 30, 2019
Disclosure Share Repurchase Authorization Summary Of Stock Repurchases Details [Abstract]
Shares of common stock repurchased	1,882,000	30,000
Cost of shares repurchased	$ 52,000	$ 744
Average price paid per share	$ 27.62	$ 24.68