Onto Innovation (ONTO) 10-Q 29 Apr 21 2021 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information Document - shares	3 Months Ended
	Mar. 27, 2021	Apr. 14, 2021
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	Mar. 27, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q1
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		49,039,653
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
	Mar. 27, 2021	Mar. 28, 2020
Income Statement [Abstract]
Revenue	$ 169,279	$ 139,928
Cost of revenue	78,810	77,297
Gross profit	90,469	62,631
Operating expenses:
Research and development	21,964	20,927
Sales and marketing	13,104	13,071
General and administrative	15,559	20,147
Amortization	12,357	13,732
Total operating expenses	62,984	67,877
Operating income (loss)	27,485	(5,246)
Interest income, net	361	1,210
Other (expense) income, net	(1,244)	32
Income (loss) before provision for income taxes	26,602	(4,004)
Provision for income taxes	2,489	400
Net income (loss)	$ 24,113	$ (4,404)
Earnings (loss) per share:
Basic	$ 0.49	$ (0.09)
Diluted	$ 0.49	$ (0.09)
Weighted average shares outstanding:
Basic	49,000	50,121
Diluted	49,572	50,121

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 27, 2021	Mar. 28, 2020
Statement Of Income And Comprehensive Income [Abstract]
Net income (loss)	$ 24,113	$ (4,404)
Other comprehensive loss, net of tax:
Change in net unrealized losses on available-for-sale marketable securities	(131)	(526)
Change in currency translation adjustments	(1,899)	(2,231)
Total other comprehensive loss, net of tax	(2,030)	(2,757)
Total comprehensive income (loss)	$ 22,083	$ (7,161)

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 27, 2021	Dec. 26, 2020
Current Assets:
Cash and cash equivalents	$ 126,450	$ 136,720
Marketable securities	266,450	237,002
Accounts receivable, less allowance of $1,018 and $784	141,876	149,251
Inventories, net	200,896	191,217
Prepaid expenses and other current assets	19,156	17,471
Total current assets	754,828	731,661
Property, plant and equipment, net	87,679	87,950
Goodwill	313,891	306,632
Identifiable intangible assets, net	318,210	318,357
Deferred income taxes	2,332	2,235
Other assets	26,779	21,337
Total assets	1,503,719	1,468,172
Current liabilities:
Accounts payable	45,622	40,183
Accrued liabilities	28,925	37,075
Deferred revenue	21,424	14,334
Other current liabilities	30,441	28,499
Total current liabilities	126,412	120,091
Deferred and other tax liabilities	56,258	55,623
Other non-current liabilities	28,737	27,712
Total liabilities	211,407	203,426
Commitments and contingencies
Stockholders’ equity:
Common stock	49	49
Additional paid-in capital	1,239,450	1,233,967
Accumulated other comprehensive income	2,538	4,568
Retained earnings	50,275	26,162
Total stockholders’ equity	1,292,312	1,264,746
Total liabilities and stockholders’ equity	$ 1,503,719	$ 1,468,172

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) (Unaudited) - USD ($) $ in Thousands	Mar. 27, 2021	Dec. 26, 2020
Statement Of Financial Position [Abstract]
Allowances for doubtful accounts	$ 1,018	$ 784

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 27, 2021	Mar. 28, 2020
Cash flows from operating activities:
Net income (loss)	$ 24,113	$ (4,404)
Adjustments to reconcile net income to net cash and cash equivalents provided by operating activities:
Amortization of intangibles	12,357	13,732
Depreciation	3,618	3,103
Share-based compensation	4,890	3,955
Acquired inventory step-up amortization	252	9,898
Provision for inventory valuation	2,267	928
Other, net	2,173	(144)
Changes in operating assets and liabilities, net of effects of business acquired	1,329	(18,170)
Net cash and cash equivalents provided by operating activities	50,999	8,898
Cash flows from investing activities:
Purchases of marketable securities	(83,652)	(76,460)
Proceeds from sales of marketable securities	53,973	74,857
Purchase of business, net of cash acquired	(26,795)
Purchases of property, plant and equipment	(3,875)	(997)
Net cash and cash equivalents used in investing activities	(60,349)	(2,600)
Cash flows from financing activities:
Purchase of common stock		(33,614)
Tax payments related to shares withheld for share-based compensation plans	(2,492)	(1,565)
Issuance of shares through share-based compensation plans	3,085	164
Net cash and cash equivalents provided by (used in) financing activities	593	(35,015)
Effect of exchange rate changes on cash and cash equivalents	(1,513)	(636)
Net decrease in cash and cash equivalents	(10,270)	(29,353)
Cash and cash equivalents at beginning of period	136,720	130,673
Cash and cash equivalents at end of period	126,450	101,320
Supplemental disclosure of cash flow information:
Income taxes paid	$ 1,799	$ 588

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, 2019	$ 1,264,026	$ 50	$ 1,269,437	$ (598)	$ (4,863)
Balance, Shares at Dec. 31, 2019		50,184
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
Issuance of shares through share-based compensation plans	164		164
Issuance of shares through share-based compensation plans, Shares		240
Share-based compensation plan withholdings	(1,565)		(1,565)
Share-based compensation plan withholdings, Shares		(42)
Currency translation	(2,231)			(2,231)
Unrealized 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. 26, 2020	1,264,746	$ 49	1,233,967	4,568	26,162
Balance, Shares at Dec. 26, 2020		48,758
Net income (loss)	24,113				24,113
Share-based compensation	4,890		4,890
Issuance of shares through share-based compensation plans	3,085		3,085
Issuance of shares through share-based compensation plans, Shares		240
Share-based compensation plan withholdings	(2,492)		(2,492)
Share-based compensation plan withholdings, Shares		(41)
Currency translation	(1,899)			(1,899)
Unrealized loss on investments	(131)			(131)
Balance at Mar. 27, 2021	$ 1,292,312	$ 49	$ 1,239,450	$ 2,538	$ 50,275
Balance, shares at Mar. 27, 2021		48,957

Basis of Presentation

Basis of Presentation	3 Months Ended
	Mar. 27, 2021
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Basis of Presentation	NOTE 1. Basis of Presentation The Company operates on a 52- or 53-week fiscal year ending on the Saturday closest to December 31 st 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 months ended March 27, 2021 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 26, 2020 (the “2020 Form 10-K”) filed with the Securities and Exchange Commission (“SEC”) on February 19, 2021. The accompanying Condensed Consolidated Balance Sheet at December 26, 2020 has been derived from the audited consolidated financial statements included in the 2020 Form 10-K. 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 credit losses, 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, recoverability of goodwill, recoverability of deferred tax assets, liabilities for product warranty and 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, fair value of assets acquired and liabilities assumed in a business combination and stock awards. 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 March 27, 2021 and through the date of this report. While there was not a material impact as of and for the quarter ended March 27, 2021, future actual magnitude and duration of the COVID-19 pandemic, as well as other associated factors, could result in material negative impacts to the Company’s condensed consolidated financial statements in future reporting periods. Recent Accounting Pronouncements Recently Adopted Effective December 27, 2020, the Company adopted Accounting Standards Update (“ASU”) No. 2019-12, “Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes.” This standard simplified 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 simplified aspects of the accounting for franchise 2019-12 did not have a significant impact on the Company’s consolidated financial position, results of operations, and cash flows.

Business Combination

Business Combination	3 Months Ended
	Mar. 27, 2021
Business Combinations [Abstract]
Business Combination	NOTE 2. Business Combination Inspectrology, LLC On December 31, 2020, the Company acquired Inspectrology, LLC (“Inspectrology”), a leading supplier of overlay metrology for controlling lithography and etch processes in the compound semiconductor market for $27,015 in cash and a potential earnout of $10,000, subject to achievement of certain revenue targets earned for fiscal 2021 and 2022. Certain payments, including the earnout, are subject to the principals remaining with the Company for a period of one to three years The following table summarizes the preliminary fair values of assets acquired and liabilities assumed at the date of acquisition: Cash and cash equivalents $ 220 Account receivables 4,071 Inventories 2,587 Prepaid expenses and other current assets 104 Property, plant and equipment 86 Identifiable intangible assets 12,210 Other assets 3,000 Total assets acquired 22,278 Accounts payable (1,048 ) Payroll and related expenses (512 ) Deferred revenue (386 ) Other current liabilities (576 ) Net assets acquired 19,756 Goodwill 7,259 Total purchase consideration $ 27,015

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 27, 2021
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 March 27, 2021 and December 26, 2020: 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) March 27, 2021 Assets: Available-for-sale debt securities: Municipal notes and bonds $ 136,538 $ — $ 136,538 $ — Asset-backed securities 9,180 — 9,180 — Certificates of deposit 36,472 — 36,472 — Commercial paper 51,789 — 51,789 — Corporate bonds 32,471 — 32,471 — Total assets $ 266,450 $ — $ 266,450 $ — Liabilities: Foreign currency forward contracts 229 — 229 — Total liabilities $ 229 $ — $ 229 $ — December 26, 2020 Assets: Available-for-sale debt securities: Municipal notes and bonds $ 124,640 $ — $ 124,640 $ — Asset-backed securities 11,708 — 11,708 — Certificates of deposit 36,373 — 36,373 — Commercial paper 32,699 — 32,699 — Corporate bonds 31,582 — 31,582 — Total assets $ 237,002 $ — $ 237,002 $ — Liabilities: Foreign currency forward contracts 36 — 36 — Total liabilities $ 36 $ — $ 36 $ — 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. See Note 4 for additional discussion regarding the fair value of the Company’s marketable securities.

Marketable Securities

Marketable Securities	3 Months Ended
	Mar. 27, 2021
Marketable Securities [Abstract]
Marketable Securities	NOTE 4. Marketable Securities At March 27, 2021 and December 26, 2020, marketable securities are categorized as follows: Amortized Cost Gross Unrealized Holding Gains Gross Unrealized Holding Losses Fair Value March 27, 2021 Municipal notes and bonds $ 136,345 $ 202 $ 9 $ 136,538 Asset-backed securities 9,169 11 — 9,180 Certificates of deposit 36,449 23 — 36,472 Commercial paper 51,769 21 1 51,789 Corporate bonds 32,496 15 40 32,471 Total marketable securities $ 266,228 $ 272 $ 50 $ 266,450 December 26, 2020 Municipal notes and bonds $ 124,387 $ 257 $ 4 $ 124,640 Asset-backed securities 11,679 29 — 11,708 Certificates of deposit 36,349 24 — 36,373 Commercial paper 32,690 12 3 32,699 Corporate bonds 31,544 50 12 31,582 Total marketable securities $ 236,649 $ 372 $ 19 $ 237,002 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 March 27, 2021 and December 26, 2020: March 27, 2021 December 26, 2020 Amortized Cost Fair Value Amortized Cost Fair Value Due within one year $ 201,075 $ 201,236 $ 170,099 $ 170,321 Due after one through five years 65,153 65,214 66,550 66,681 Due after five through ten years — — — — Due after ten years — — — — Total marketable securities $ 266,228 $ 266,450 $ 236,649 $ 237,002 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 March 27, 2021 and December 26, 2020: 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 March 27, 2021 Municipal notes and bonds $ 15,472 $ 9 $ — $ — Commercial paper 5,991 1 — — Corporate bonds 20,577 40 — — Total $ 42,040 $ 50 $ — $ — December 26, 2020 Municipal notes and bonds $ 8,641 $ 4 $ — $ — Commercial paper 8,862 3 — — Corporate bonds 14,947 12 — — Total $ 32,450 $ 19 $ — $ — 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	3 Months Ended
	Mar. 27, 2021
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 March 27, 2021 and December 26, 2020, these contracts included the future sale of British pound sterling, euro, Israeli shekel, Japanese yen, Korean won, Singapore dollar, Taiwanese dollar, and Chinese 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 March 27, 2021 and December 26, 2020 were as follows: March 27, 2021 December 26, 2020 Notional amount $ 33,436 $ 37,580 Fair value of liability $ (229 ) $ (36 )

Goodwill and Purchased Intangib

Goodwill and Purchased Intangible Assets	3 Months Ended
	Mar. 27, 2021
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill and Purchased Intangible Assets	NOTE 6. Goodwill and Purchased Intangible Assets Goodwill The changes in the carrying amount of goodwill are as follows: Balance at December 26, 2020 $ 306,632 Goodwill acquired during the period (Note 2) 7,259 Balance at March 27, 2021 $ 313,891 Intangible Assets Purchased intangible assets as of March 27, 2021 and December 26, 2020 are as follows: Gross Carrying Amount Accumulated Amortization Net March 27, 2021 Finite-lived intangibles: Developed technology $ 331,747 $ 121,569 $ 210,178 Customer and distributor relationships 74,701 21,969 52,732 Trademarks and trade names 14,361 5,661 8,700 Total finite-lived intangible assets 420,809 149,199 271,610 In-process research and development 46,600 — 46,600 Total identifiable intangible assets $ 467,409 $ 149,199 $ 318,210 December 26, 2020 Finite-lived intangibles: Developed technology $ 326,877 $ 110,851 $ 216,026 Customer and distributor relationships 69,261 20,654 48,607 Trademarks and trade names 12,461 5,337 7,124 Total finite-lived intangible assets 408,599 136,842 271,757 In-process research and development 46,600 — 46,600 Total identifiable intangible assets $ 455,199 $ 136,842 $ 318,357 Assuming no change in the gross carrying value of identifiable intangible assets and estimated lives, future estimated amortization expenses are: Expected Amortization Fiscal Year: Expense 2021 (remainder) $ 36,872 2022 48,830 2023 48,355 2024 42,669 2025 26,119 2026 24,926 Thereafter 43,839 Total $ 271,610

Balance Sheet Details

Balance Sheet Details	3 Months Ended
	Mar. 27, 2021
Balance Sheet Detail [Abstract]
Balance Sheet Details	NOTE 7. Balance Sheet Details Inventories Inventories, net are comprised of the following: March 27, 2021 December 26, 2020 Materials $ 122,785 $ 124,926 Work-in-process 52,272 44,829 Finished goods 25,839 21,462 Total inventories, net $ 200,896 $ 191,217 Property, Plant and Equipment Property, plant and equipment, net is comprised of the following: March 27, 2021 December 26, 2020 Machinery and equipment $ 54,811 $ 52,833 Land and building 47,702 47,544 Computer equipment and software 15,616 15,549 Leasehold improvements 13,170 12,927 Furniture and fixtures 3,883 4,013 135,182 132,866 Accumulated depreciation (47,503 ) (44,916 ) Total property, plant and equipment, net $ 87,679 $ 87,950 Other assets Other assets is comprised of the following: March 27, 2021 December 26, 2020 Operating lease right-of-use assets $ 21,887 $ 19,669 Other 4,892 1,668 Total other assets $ 26,779 $ 21,337 Accrued liabilities Accrued liabilities is comprised of the following: March 27, 2021 December 26, 2020 Payroll and related expenses $ 21,051 $ 30,270 Warranty 6,932 6,062 Other 942 743 Total accrued liabilities $ 28,925 $ 37,075 Other current liabilities Other current liabilities is comprised of the following: March 27, 2021 December 26, 2020 Customer deposits $ 17,106 $ 15,177 Current operating lease obligations 5,605 4,470 Income tax payable 2,543 4,109 Accrued professional fees 1,261 1,184 Other 3,926 3,559 Total other current liabilities $ 30,441 $ 28,499 Other non-current liabilities Other non-current liabilities is comprised of the following: March 27, 2021 December 26, 2020 Non-current operating lease obligations $ 17,203 $ 16,455 Unrecognized tax benefits (including interest) 4,002 3,812 Deferred revenue 1,005 1,292 Other 6,527 6,153 Total other non-current liabilities $ 28,737 $ 27,712

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 27, 2021
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	NOTE 8. 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 $2,670 of receivables during the three months ended March 27, 2021. 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 March 27, 2021. 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: Three Months Ended March 27, March 28, 2021 2020 Balance, beginning of the period $ 6,485 $ 6,348 Accruals 2,652 2,313 Warranty liability assumed in acquisition 407 — Usage (2,039 ) (2,277 ) Balance, end of the period $ 7,505 $ 6,384 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. The relief sought is the award of damages in an amount to be proven at trial, attorney’s fees and cost as well as other relief the court deems just and proper. 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. The relief sought is the award of damages in an amount to be proven at trial including pre- and post-judgment interest, punitive damages, restitution for benefits unjustly received by OSI, attorney’s fees and cost as well as other relief the court deems just and proper. 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 March 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 regard 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. On December 1, 2020, the Northern District of California denied this final motion to dismiss and as a result the Company filed its Answer in this matter on December 22, 2020. This matter is currently in discovery. The Northern District of California granted a joint stipulation that discovery cutoff is September 3, 2022 and the trial date is set for December 4, 2023. 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 March 27, 2021 was approximately $82.0 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	3 Months Ended
	Mar. 27, 2021
Revenue From Contract With Customer [Abstract]
Revenue	NOTE 9. Revenue The following table represents a disaggregation of revenue by timing of revenue: Three Months Ended March 27, March 28, 2021 2020 Point-in-time $ 161,161 $ 133,745 Over-time 8,118 6,183 Total revenue $ 169,279 $ 139,928 See Note 15 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 March 27, March 28, 2021 2020 Balance, beginning of the period $ 15,626 $ 15,093 Deferred revenue assumed in acquisition 385 — Deferral of revenue 19,232 14,434 Recognition of deferred revenue (12,814 ) (11,495 ) Balance, end of the period $ 22,429 $ 18,032

Share-Based Compensation

Share-Based Compensation	3 Months Ended
	Mar. 27, 2021
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Share-Based Compensation	NOTE 10. Share-Based Compensation Restricted Stock Unit Activity A summary of the Company’s restricted stock unit activity with respect to the three months ended March 27, 2021 is as follows: Number of Shares Weighted Average Grant Date Fair Value Nonvested at December 26, 2020 964 $ 31.37 Granted 104 $ 69.94 Vested (124 ) $ 28.85 Forfeited (10 ) $ 31.51 Nonvested at March 27, 2021 934 $ 36.62 As of March 27, 2021 and December 26, 2020, there was $21,789 and $19,135 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 1.6 years and 1.7 years for March 27, 2021 and December 26, 2020, respectively.

Other (Expense) Income, Net

Other (Expense) Income, Net	3 Months Ended
	Mar. 27, 2021
Other Income Expense [Abstract]
Other (Expense) Income, Net	NOTE 11. Other (Expense) Income, Net Other (expense) income, net, is comprised of the following: Three Months Ended March 27, March 28, 2021 2020 Foreign currency exchange losses, net $ (1,271 ) $ (35 ) Other 27 67 Total other (expense) income, net $ (1,244 ) $ 32

Income Taxes

Income Taxes	3 Months Ended
	Mar. 27, 2021
Income Tax Disclosure [Abstract]
Income Taxes	NOTE 12. Income Taxes The following table provides details of income taxes: Three Months Ended March 27, March 28, 2021 2020 Income (loss) before income taxes $ 26,602 $ (4,004 ) Provision for income taxes $ 2,489 $ 400 Effective tax rate 9 % (10 %) The income tax provision for the three months ended March 27, 2021 was computed based on the Company’s annual forecast of profit by jurisdiction and forecasted effective tax rate for the year. The increase in the Company’s effective tax rate for the three months ended March 27, 2021 as compared to the three months ended March 28, 2020 is primarily due to (i) an increase in quarterly earnings, offset by an increase in the Foreign Derived Intangible Income (“FDII”) deduction and (ii) an increase in the excess tax benefit associated with equity compensation. 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 $14,249 and $14,238 as of March 27, 2021 and December 26, 2020, respectively.

Earnings Per Share

Earnings Per Share	3 Months Ended
	Mar. 27, 2021
Earnings Per Share [Abstract]
Earnings Per Share	NOTE 13. Earnings (Loss) Per Share Basic earnings (loss) per share is calculated using the weighted average number of shares of common stock outstanding during the period. Restricted stock units, employee stock purchase grants and stock options are included in the calculation of diluted earnings per share, except when their effect would be anti-dilutive. The Company’s basic and diluted earnings (loss) per share amounts are as follows: Three Months Ended March 27, March 28, 2021 2020 Numerator: Net income (loss) $ 24,113 $ (4,404 ) Denominator: Basic earnings (loss) per share - weighted average shares outstanding 49,000 50,121 Effect of potential dilutive securities: Employee stock options, employee stock purchase grants and restricted stock units - dilutive shares 572 — Diluted earnings (loss) per share - weighted average shares outstanding 49,572 50,121 Earnings (loss) per share: Basic $ 0.49 $ (0.09 ) Diluted $ 0.49 $ (0.09 )

Accumulated Other Comprehensive

Accumulated Other Comprehensive (Income) Loss	3 Months Ended
	Mar. 27, 2021
Accumulated Other Comprehensive Income Loss Net Of Tax [Abstract]
Accumulated Other Comprehensive (Income) Loss	NOTE 14. Accumulated Other Comprehensive (Income) Loss The components of accumulated other comprehensive (income) loss, net of tax at March 27, 2021, as well as the activity for the three months ended March 27, 2021, were as follows: Foreign currency translation adjustments Net unrealized (gains) losses on available-for-sale marketable securities Accumulated other comprehensive (income) loss Balance at December 26, 2020 $ (4,479 ) $ (89 ) $ (4,568 ) Net current period other comprehensive loss 1,899 131 2,030 Reclassifications — — — Balance at March 27, 2021 $ (2,580 ) $ 42 $ (2,538 )

Segment Reporting and Geographi

Segment Reporting and Geographic Information	3 Months Ended
	Mar. 27, 2021
Segment Reporting [Abstract]
Segment Reporting and Geographic Information	NOTE 15. Segment Reporting and Geographic Information The Company is engaged in the design, development, manufacture and support of high-performance control metrology, defect inspection, lithography and data analysis systems used by microelectronics device manufacturers. 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, 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 March 27, March 28, 2021 2020 Systems and software $ 141,509 84 % $ 114,330 82 % Parts 17,418 10 % 13,575 10 % Services 10,352 6 % 12,023 8 % Total revenue $ 169,279 100 % $ 139,928 100 % 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 March 27 March 28 2021 2020 Revenue from third parties: South Korea $ 50,530 $ 20,757 Taiwan 36,293 35,181 China 25,779 31,383 United States 25,480 19,648 Europe 17,385 15,069 Japan 7,865 15,027 Southeast Asia 5,947 2,863 Total revenue $ 169,279 $ 139,928 The following customers accounted for 10% or more of total revenue for the indicated periods: Three Months Ended March 27, March 28, 2021 2020 Samsung Semiconductor 25 % 18 % Taiwan Semiconductor Manufacturing Co. Ltd. 13 % 17 % SK Hynix Inc. 12 % ^ ^ The customer accounted for less than 10% of total revenue during the period.

Share Repurchase Authorization

Share Repurchase Authorization	3 Months Ended
	Mar. 27, 2021
Share Repurchase Program [Abstract]
Share Repurchase Authorization	NOTE 16. Share Repurchase Authorization In November 2020, the Onto Innovation Board of Directors approved a new share repurchase authorization, which allows the Company to repurchase up to $100,000 worth of shares of its common stock. This share repurchase authorization replaced the remaining balance of $28,000 from the prior share repurchase authorization. Repurchases may be made through both public market and private transactions from time to time with shares purchased being subsequently retired. At March 27, 2021, there was $100,000 available for future share repurchases under this share repurchase authorization. The following table summarizes the Company’s share repurchases for the periods indicated: Three Months Ended March 27, March 28, 2021 2020 Shares of common stock repurchased — 1,250 Cost of shares repurchased $ — $ 33,614 Average price paid per share $ — $ 26.89

Basis of Presentation (Policies

Basis of Presentation (Policies)	3 Months Ended
	Mar. 27, 2021
Organization Consolidation And Presentation Of Financial Statements [Abstract]
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 credit losses, 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, recoverability of goodwill, recoverability of deferred tax assets, liabilities for product warranty and 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, fair value of assets acquired and liabilities assumed in a business combination and stock awards. 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 March 27, 2021 and through the date of this report. While there was not a material impact as of and for the quarter ended March 27, 2021, future actual magnitude and duration of the COVID-19 pandemic, as well as other associated factors, could result in material negative impacts to the Company’s condensed consolidated financial statements in future reporting periods.
Recent Accounting Pronouncements	Recent Accounting Pronouncements Recently Adopted Effective December 27, 2020, the Company adopted Accounting Standards Update (“ASU”) No. 2019-12, “Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes.” This standard simplified 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 simplified aspects of the accounting for franchise 2019-12 did not have a significant impact on the Company’s consolidated financial position, results of operations, and cash flows.

Business Combination (Tables)

Business Combination (Tables)	3 Months Ended
	Mar. 27, 2021
Business Combinations [Abstract]
Summary of Preliminary Fair Values of Assets Acquired and Liabilities Assumed	The following table summarizes the preliminary fair values of assets acquired and liabilities assumed at the date of acquisition: Cash and cash equivalents $ 220 Account receivables 4,071 Inventories 2,587 Prepaid expenses and other current assets 104 Property, plant and equipment 86 Identifiable intangible assets 12,210 Other assets 3,000 Total assets acquired 22,278 Accounts payable (1,048 ) Payroll and related expenses (512 ) Deferred revenue (386 ) Other current liabilities (576 ) Net assets acquired 19,756 Goodwill 7,259 Total purchase consideration $ 27,015

Fair Value Measurements - (Tabl

Fair Value Measurements - (Tables)	3 Months Ended
	Mar. 27, 2021
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 March 27, 2021 and December 26, 2020: 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) March 27, 2021 Assets: Available-for-sale debt securities: Municipal notes and bonds $ 136,538 $ — $ 136,538 $ — Asset-backed securities 9,180 — 9,180 — Certificates of deposit 36,472 — 36,472 — Commercial paper 51,789 — 51,789 — Corporate bonds 32,471 — 32,471 — Total assets $ 266,450 $ — $ 266,450 $ — Liabilities: Foreign currency forward contracts 229 — 229 — Total liabilities $ 229 $ — $ 229 $ — December 26, 2020 Assets: Available-for-sale debt securities: Municipal notes and bonds $ 124,640 $ — $ 124,640 $ — Asset-backed securities 11,708 — 11,708 — Certificates of deposit 36,373 — 36,373 — Commercial paper 32,699 — 32,699 — Corporate bonds 31,582 — 31,582 — Total assets $ 237,002 $ — $ 237,002 $ — Liabilities: Foreign currency forward contracts 36 — 36 — Total liabilities $ 36 $ — $ 36 $ —

Marketable Securities - (Tables

Marketable Securities - (Tables)	3 Months Ended
	Mar. 27, 2021
Marketable Securities [Abstract]
Schedule of Marketable Securities by Category	At March 27, 2021 and December 26, 2020, marketable securities are categorized as follows: Amortized Cost Gross Unrealized Holding Gains Gross Unrealized Holding Losses Fair Value March 27, 2021 Municipal notes and bonds $ 136,345 $ 202 $ 9 $ 136,538 Asset-backed securities 9,169 11 — 9,180 Certificates of deposit 36,449 23 — 36,472 Commercial paper 51,769 21 1 51,789 Corporate bonds 32,496 15 40 32,471 Total marketable securities $ 266,228 $ 272 $ 50 $ 266,450 December 26, 2020 Municipal notes and bonds $ 124,387 $ 257 $ 4 $ 124,640 Asset-backed securities 11,679 29 — 11,708 Certificates of deposit 36,349 24 — 36,373 Commercial paper 32,690 12 3 32,699 Corporate bonds 31,544 50 12 31,582 Total marketable securities $ 236,649 $ 372 $ 19 $ 237,002
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 March 27, 2021 and December 26, 2020: March 27, 2021 December 26, 2020 Amortized Cost Fair Value Amortized Cost Fair Value Due within one year $ 201,075 $ 201,236 $ 170,099 $ 170,321 Due after one through five years 65,153 65,214 66,550 66,681 Due after five through ten years — — — — Due after ten years — — — — Total marketable securities $ 266,228 $ 266,450 $ 236,649 $ 237,002
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 March 27, 2021 and December 26, 2020: 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 March 27, 2021 Municipal notes and bonds $ 15,472 $ 9 $ — $ — Commercial paper 5,991 1 — — Corporate bonds 20,577 40 — — Total $ 42,040 $ 50 $ — $ — December 26, 2020 Municipal notes and bonds $ 8,641 $ 4 $ — $ — Commercial paper 8,862 3 — — Corporate bonds 14,947 12 — — Total $ 32,450 $ 19 $ — $ —

Derivative Instruments and He_2

Derivative Instruments and Hedging Activities (Tables)	3 Months Ended
	Mar. 27, 2021
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 March 27, 2021 and December 26, 2020 were as follows: March 27, 2021 December 26, 2020 Notional amount $ 33,436 $ 37,580 Fair value of liability $ (229 ) $ (36 )

Goodwill and Purchased Intang_2

Goodwill and Purchased Intangible Assets (Tables)	3 Months Ended
	Mar. 27, 2021
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 26, 2020 $ 306,632 Goodwill acquired during the period (Note 2) 7,259 Balance at March 27, 2021 $ 313,891
Schedule of Purchased Intangible Assets	Intangible Assets Purchased intangible assets as of March 27, 2021 and December 26, 2020 are as follows: Gross Carrying Amount Accumulated Amortization Net March 27, 2021 Finite-lived intangibles: Developed technology $ 331,747 $ 121,569 $ 210,178 Customer and distributor relationships 74,701 21,969 52,732 Trademarks and trade names 14,361 5,661 8,700 Total finite-lived intangible assets 420,809 149,199 271,610 In-process research and development 46,600 — 46,600 Total identifiable intangible assets $ 467,409 $ 149,199 $ 318,210 December 26, 2020 Finite-lived intangibles: Developed technology $ 326,877 $ 110,851 $ 216,026 Customer and distributor relationships 69,261 20,654 48,607 Trademarks and trade names 12,461 5,337 7,124 Total finite-lived intangible assets 408,599 136,842 271,757 In-process research and development 46,600 — 46,600 Total identifiable intangible assets $ 455,199 $ 136,842 $ 318,357
Schedule of Estimated Future Amortization Expenses	Assuming no change in the gross carrying value of identifiable intangible assets and estimated lives, future estimated amortization expenses are: Expected Amortization Fiscal Year: Expense 2021 (remainder) $ 36,872 2022 48,830 2023 48,355 2024 42,669 2025 26,119 2026 24,926 Thereafter 43,839 Total $ 271,610

Balance Sheet Details (Tables)

Balance Sheet Details (Tables)	3 Months Ended
	Mar. 27, 2021
Balance Sheet Detail [Abstract]
Schedule of Inventories	Inventories, net are comprised of the following: March 27, 2021 December 26, 2020 Materials $ 122,785 $ 124,926 Work-in-process 52,272 44,829 Finished goods 25,839 21,462 Total inventories, net $ 200,896 $ 191,217
Schedule of Property, Plant and Equipment, Net	Property, plant and equipment, net is comprised of the following: March 27, 2021 December 26, 2020 Machinery and equipment $ 54,811 $ 52,833 Land and building 47,702 47,544 Computer equipment and software 15,616 15,549 Leasehold improvements 13,170 12,927 Furniture and fixtures 3,883 4,013 135,182 132,866 Accumulated depreciation (47,503 ) (44,916 ) Total property, plant and equipment, net $ 87,679 $ 87,950
Schedule of Other Assets	Other assets is comprised of the following: March 27, 2021 December 26, 2020 Operating lease right-of-use assets $ 21,887 $ 19,669 Other 4,892 1,668 Total other assets $ 26,779 $ 21,337
Schedule of Accrued Liabilities	Accrued liabilities is comprised of the following: March 27, 2021 December 26, 2020 Payroll and related expenses $ 21,051 $ 30,270 Warranty 6,932 6,062 Other 942 743 Total accrued liabilities $ 28,925 $ 37,075
Schedule of Other Current Liabilities	Other current liabilities is comprised of the following: March 27, 2021 December 26, 2020 Customer deposits $ 17,106 $ 15,177 Current operating lease obligations 5,605 4,470 Income tax payable 2,543 4,109 Accrued professional fees 1,261 1,184 Other 3,926 3,559 Total other current liabilities $ 30,441 $ 28,499
Schedule of Other Non-Current Liabilities	Other non-current liabilities is comprised of the following: March 27, 2021 December 26, 2020 Non-current operating lease obligations $ 17,203 $ 16,455 Unrecognized tax benefits (including interest) 4,002 3,812 Deferred revenue 1,005 1,292 Other 6,527 6,153 Total other non-current liabilities $ 28,737 $ 27,712

Commitments and Contingencies (

Commitments and Contingencies (Tables)	3 Months Ended
	Mar. 27, 2021
Commitments And Contingencies Disclosure [Abstract]
Schedule of Changes in Warranty Reserves	Changes in the Company’s warranty reserves are as follows: Three Months Ended March 27, March 28, 2021 2020 Balance, beginning of the period $ 6,485 $ 6,348 Accruals 2,652 2,313 Warranty liability assumed in acquisition 407 — Usage (2,039 ) (2,277 ) Balance, end of the period $ 7,505 $ 6,384

Revenue (Tables)

Revenue (Tables)	3 Months Ended
	Mar. 27, 2021
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 March 27, March 28, 2021 2020 Point-in-time $ 161,161 $ 133,745 Over-time 8,118 6,183 Total revenue $ 169,279 $ 139,928
Schedule of Changes in Deferred Revenue	Changes in deferred revenue were as follows: Three Months Ended March 27, March 28, 2021 2020 Balance, beginning of the period $ 15,626 $ 15,093 Deferred revenue assumed in acquisition 385 — Deferral of revenue 19,232 14,434 Recognition of deferred revenue (12,814 ) (11,495 ) Balance, end of the period $ 22,429 $ 18,032

Share-Based Compensation - (Tab

Share-Based Compensation - (Tables)	3 Months Ended
	Mar. 27, 2021
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 three months ended March 27, 2021 is as follows: Number of Shares Weighted Average Grant Date Fair Value Nonvested at December 26, 2020 964 $ 31.37 Granted 104 $ 69.94 Vested (124 ) $ 28.85 Forfeited (10 ) $ 31.51 Nonvested at March 27, 2021 934 $ 36.62

Other (Expense) Income, Net (Ta

Other (Expense) Income, Net (Tables)	3 Months Ended
	Mar. 27, 2021
Other Income Expense [Abstract]
Schedule of Other (Expense) Income, Net	Other (expense) income, net, is comprised of the following: Three Months Ended March 27, March 28, 2021 2020 Foreign currency exchange losses, net $ (1,271 ) $ (35 ) Other 27 67 Total other (expense) income, net $ (1,244 ) $ 32

Income Taxes - (Tables)

Income Taxes - (Tables)	3 Months Ended
	Mar. 27, 2021
Income Tax Disclosure [Abstract]
Details of Income Tax	The following table provides details of income taxes: Three Months Ended March 27, March 28, 2021 2020 Income (loss) before income taxes $ 26,602 $ (4,004 ) Provision for income taxes $ 2,489 $ 400 Effective tax rate 9 % (10 %)

Earnings Per Share (Tables)

Earnings Per Share (Tables)	3 Months Ended
	Mar. 27, 2021
Earnings Per Share [Abstract]
Schedule of Basic and Diluted Earnings Per Share	The Company’s basic and diluted earnings (loss) per share amounts are as follows: Three Months Ended March 27, March 28, 2021 2020 Numerator: Net income (loss) $ 24,113 $ (4,404 ) Denominator: Basic earnings (loss) per share - weighted average shares outstanding 49,000 50,121 Effect of potential dilutive securities: Employee stock options, employee stock purchase grants and restricted stock units - dilutive shares 572 — Diluted earnings (loss) per share - weighted average shares outstanding 49,572 50,121 Earnings (loss) per share: Basic $ 0.49 $ (0.09 ) Diluted $ 0.49 $ (0.09 )

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive (Income) Loss (Tables)	3 Months Ended
	Mar. 27, 2021
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 March 27, 2021, as well as the activity for the three months ended March 27, 2021, were as follows: Foreign currency translation adjustments Net unrealized (gains) losses on available-for-sale marketable securities Accumulated other comprehensive (income) loss Balance at December 26, 2020 $ (4,479 ) $ (89 ) $ (4,568 ) Net current period other comprehensive loss 1,899 131 2,030 Reclassifications — — — Balance at March 27, 2021 $ (2,580 ) $ 42 $ (2,538 )

Segment Reporting and Geograp_2

Segment Reporting and Geographic Information - (Tables)	3 Months Ended
	Mar. 27, 2021
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 March 27, March 28, 2021 2020 Systems and software $ 141,509 84 % $ 114,330 82 % Parts 17,418 10 % 13,575 10 % Services 10,352 6 % 12,023 8 % Total revenue $ 169,279 100 % $ 139,928 100 %
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 March 27 March 28 2021 2020 Revenue from third parties: South Korea $ 50,530 $ 20,757 Taiwan 36,293 35,181 China 25,779 31,383 United States 25,480 19,648 Europe 17,385 15,069 Japan 7,865 15,027 Southeast Asia 5,947 2,863 Total revenue $ 169,279 $ 139,928
Schedule of Revenue by Major Customer by Reporting Segments	The following customers accounted for 10% or more of total revenue for the indicated periods: Three Months Ended March 27, March 28, 2021 2020 Samsung Semiconductor 25 % 18 % Taiwan Semiconductor Manufacturing Co. Ltd. 13 % 17 % SK Hynix Inc. 12 % ^ ^ The customer accounted for less than 10% of total revenue during the period.

Share Repurchase Authorization

Share Repurchase Authorization (Tables)	3 Months Ended
	Mar. 27, 2021
Share Repurchase Program [Abstract]
Summary of Share Repurchases	The following table summarizes the Company’s share repurchases for the periods indicated: Three Months Ended March 27, March 28, 2021 2020 Shares of common stock repurchased — 1,250 Cost of shares repurchased $ — $ 33,614 Average price paid per share $ — $ 26.89

Business Combination - Textual

Business Combination - Textual (Details) - Inspectrology, LLC [Member] - USD ($) $ in Thousands	Dec. 31, 2020	Mar. 27, 2021
Business Acquisition [Line Items]
Business acquisition, date of acquisition	Dec. 31, 2020
Business acquisition, cash consideration	$ 27,015
Business combination potential earnout payment	$ 10,000
Minimum [Member]
Business Acquisition [Line Items]
Business combination potential earnout subject to principal remaining period		1 year
Maximum [Member]
Business Acquisition [Line Items]
Business combination potential earnout subject to principal remaining period		3 years

Business Combination - Summary

Business Combination - Summary of Preliminary Fair Values of Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	Mar. 27, 2021	Dec. 31, 2020	Dec. 26, 2020
Business Acquisition [Line Items]
Goodwill	$ 313,891		$ 306,632
Inspectrology, LLC [Member]
Business Acquisition [Line Items]
Cash and cash equivalents		$ 220
Account receivables		4,071
Inventories		2,587
Prepaid expenses and other current assets		104
Property, plant and equipment		86
Identifiable intangible assets		12,210
Other assets		3,000
Total assets acquired		22,278
Accounts payable		(1,048)
Payroll and related expenses		(512)
Deferred revenue		(386)
Other current liabilities		(576)
Net assets acquired		19,756
Goodwill		7,259
Total purchase consideration		$ 27,015

Fair Value Measurements - Asset

Fair Value Measurements - Assets and Liabilities Carried at Fair Value Measured on a Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 27, 2021	Dec. 26, 2020
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale debt securities	$ 266,450	$ 237,002
Carrying Value [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets	266,450	237,002
Foreign currency forward contracts	229	36
Total liabilities	229	36
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	136,538	124,640
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	9,180	11,708
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	36,472	36,373
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	51,789	32,699
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	32,471	31,582
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]
Total assets	0	0
Foreign currency forward contracts	0	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]
Total assets	266,450	237,002
Foreign currency forward contracts	229	36
Total liabilities	229	36
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	136,538	124,640
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	9,180	11,708
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	36,472	36,373
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	51,789	32,699
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	32,471	31,582
Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets	0	0
Foreign currency forward contracts	0	0
Total liabilities	0	0
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

Marketable Securities - Schedul

Marketable Securities - Schedule of Marketable Securities by Category (Details) - USD ($) $ in Thousands	Mar. 27, 2021	Dec. 26, 2020
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 266,228	$ 236,649
Gross Unrealized Holding Gains	272	372
Gross Unrealized Holding Losses	50	19
Fair Value	266,450	237,002
Municipal notes and bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	136,345	124,387
Gross Unrealized Holding Gains	202	257
Gross Unrealized Holding Losses	9	4
Fair Value	136,538	124,640
Asset-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	9,169	11,679
Gross Unrealized Holding Gains	11	29
Gross Unrealized Holding Losses	0	0
Fair Value	9,180	11,708
Certificates of deposits [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	36,449	36,349
Gross Unrealized Holding Gains	23	24
Gross Unrealized Holding Losses	0	0
Fair Value	36,472	36,373
Commercial paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	51,769	32,690
Gross Unrealized Holding Gains	21	12
Gross Unrealized Holding Losses	1	3
Fair Value	51,789	32,699
Corporate bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	32,496	31,544
Gross Unrealized Holding Gains	15	50
Gross Unrealized Holding Losses	40	12
Fair Value	$ 32,471	$ 31,582

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	Mar. 27, 2021	Dec. 26, 2020
Available For Sale Securities Debt Maturities Fair Value [Abstract]
Amortized Cost, Due within one year	$ 201,075	$ 170,099
Amortized Cost, Due after one through five years	65,153	66,550
Amortized Cost, Due after five through ten years	0	0
Amortized Cost, Due after ten years	0	0
Amortized Cost	266,228	236,649
Fair Value, Due within one year	201,236	170,321
Fair Value, Due after one through five years	65,214	66,681
Fair Value, Due after five through ten years	0	0
Fair Value, Due after ten years	0	0
Fair Value, Total marketable securities	$ 266,450	$ 237,002

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	Mar. 27, 2021	Dec. 26, 2020
Schedule of Available-for-sale Securities [Line Items]
In Unrealized Loss Position For Less Than 12 Months, Fair Value	$ 42,040	$ 32,450
In Unrealized Loss Position For Less Than 12 Months, Gross Unrealized Losses	50	19
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	15,472	8,641
In Unrealized Loss Position For Less Than 12 Months, Gross Unrealized Losses	9	4
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	5,991	8,862
In Unrealized Loss Position For Less Than 12 Months, Gross Unrealized Losses	1	3
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
Corporate bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
In Unrealized Loss Position For Less Than 12 Months, Fair Value	20,577	14,947
In Unrealized Loss Position For Less Than 12 Months, Gross Unrealized Losses	40	12
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

Derivative Instruments and He_3

Derivative Instruments and Hedging Activities - Forward Contracts and Related Fair Values (Details) - USD ($) $ in Thousands	Mar. 27, 2021	Dec. 26, 2020
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Notional amount	$ 33,436	$ 37,580
Fair value of liability	$ (229)	$ (36)

Goodwill and Purchased Intang_3

Goodwill and Purchased Intangible Assets - Changes in the Carrying Amount of Goodwill (Details) $ in Thousands	3 Months Ended
	Mar. 27, 2021USD ($)
Goodwill Roll Forward
Beginning balance	$ 306,632
Goodwill acquired during the period (Note 2)	7,259
Ending balance	$ 313,891

Goodwill and Purchased Intang_4

Goodwill and Purchased Intangible Assets - Schedule of Purchased Intangible Assets (Details) - USD ($) $ in Thousands	Mar. 27, 2021	Dec. 26, 2020
Finite Lived Intangible Assets [Line Items]
Finite-lived intangibles assets, Gross Carrying Amount	$ 420,809	$ 408,599
Finite-lived intangibles assets, Accumulated Amortization	149,199	136,842
Finite-lived intangibles assets, Net	271,610	271,757
Identifiable intangibles assets, Gross Carrying Amount	467,409	455,199
Identifiable intangibles assets, Accumulated Amortization	149,199	136,842
Identifiable intangibles assets, Net	318,210	318,357
Developed technology [Member]
Finite Lived Intangible Assets [Line Items]
Finite-lived intangibles assets, Gross Carrying Amount	331,747	326,877
Finite-lived intangibles assets, Accumulated Amortization	121,569	110,851
Finite-lived intangibles assets, Net	210,178	216,026
Customer and distributor relationships [Member]
Finite Lived Intangible Assets [Line Items]
Finite-lived intangibles assets, Gross Carrying Amount	74,701	69,261
Finite-lived intangibles assets, Accumulated Amortization	21,969	20,654
Finite-lived intangibles assets, Net	52,732	48,607
Trademarks and trade names [Member]
Finite Lived Intangible Assets [Line Items]
Finite-lived intangibles assets, Gross Carrying Amount	14,361	12,461
Finite-lived intangibles assets, Accumulated Amortization	5,661	5,337
Finite-lived intangibles assets, Net	8,700	7,124
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

Goodwill and Purchased Intang_5

Goodwill and Purchased Intangible Assets - Schedule of Estimated Future Amortization Expenses (Details) - USD ($) $ in Thousands	Mar. 27, 2021	Dec. 26, 2020
Finite Lived Intangible Assets Future Amortization Expense [Abstract]
2021 (remainder)	$ 36,872
2022	48,830
2023	48,355
2024	42,669
2025	26,119
2026	24,926
Thereafter	43,839
Finite-lived intangibles assets, Net	$ 271,610	$ 271,757

Balance Sheet Details - Schedul

Balance Sheet Details - Schedule of Inventories (Details) - USD ($) $ in Thousands	Mar. 27, 2021	Dec. 26, 2020
Inventory Details [Abstract]
Materials	$ 122,785	$ 124,926
Work-in-process	52,272	44,829
Finished goods	25,839	21,462
Total inventories, net	$ 200,896	$ 191,217

Balance Sheet Details - Sched_2

Balance Sheet Details - Schedule of Property, Plant and Equipment, Net (Details) - USD ($) $ in Thousands	Mar. 27, 2021	Dec. 26, 2020
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 135,182	$ 132,866
Accumulated depreciation	(47,503)	(44,916)
Total property, plant and equipment, net	87,679	87,950
Land and building [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	47,702	47,544
Machinery and equipment [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	54,811	52,833
Furniture and fixtures [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	3,883	4,013
Computer equipment and software [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	15,616	15,549
Leasehold improvements [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 13,170	$ 12,927

Balance Sheet Details - Sched_3

Balance Sheet Details - Schedule of Other Assets (Details) - USD ($) $ in Thousands	Mar. 27, 2021	Dec. 26, 2020
Other Assets [Abstract]
Operating lease right-of-use assets	$ 21,887	$ 19,669
Other	4,892	1,668
Total other assets	$ 26,779	$ 21,337

Balance Sheet Details - Sched_4

Balance Sheet Details - Schedule of Accrued Liabilities (Details) - USD ($) $ in Thousands	Mar. 27, 2021	Dec. 26, 2020
Accrued Liabilities Current [Abstract]
Payroll and related expenses	$ 21,051	$ 30,270
Warranty	6,932	6,062
Other	942	743
Total accrued liabilities	$ 28,925	$ 37,075

Balance Sheet Details - Sched_5

Balance Sheet Details - Schedule of Other Current Liabilities (Details) - USD ($) $ in Thousands	Mar. 27, 2021	Dec. 26, 2020
Other Liabilities Current [Abstract]
Customer deposits	$ 17,106	$ 15,177
Current operating lease obligations	$ 5,605	$ 4,470
Operating Lease Liability Current Statement Of Financial Position [Extensible List]	onto:OperatingLeaseLiabilityCurrentMember	onto:OperatingLeaseLiabilityCurrentMember
Income tax payable	$ 2,543	$ 4,109
Accrued professional fees	1,261	1,184
Other	3,926	3,559
Total other current liabilities	$ 30,441	$ 28,499

Balance Sheet Details - Sched_6

Balance Sheet Details - Schedule of Other Non-Current Liabilities (Details) - USD ($) $ in Thousands	Mar. 27, 2021	Dec. 26, 2020
Other Liabilities Noncurrent [Abstract]
Non-current operating lease obligations	$ 17,203	$ 16,455
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	onto:OperatingLeaseLiabilityNonCurrentMember	onto:OperatingLeaseLiabilityNonCurrentMember
Unrecognized tax benefits (including interest)	$ 4,002	$ 3,812
Deferred revenue	1,005	1,292
Other	6,527	6,153
Total other non-current liabilities	$ 28,737	$ 27,712

Commitments and Contingencies -

Commitments and Contingencies - Textual (Details)	3 Months Ended
	Mar. 27, 2021USD ($)
Commitments And Contingencies [Line Items]
Sold receivables amount	$ 2,670,000
Due from unrelated third parties	0
Liabilities recorded for obligations	$ 0
Percentage of maximum borrowing capacity of value of eligible securities	70.00%
Available line of credit	$ 82,000,000
Available interest rate on line of credit	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	3 Months Ended
	Mar. 27, 2021	Mar. 28, 2020
Commitments And Contingencies Disclosure [Abstract]
Balance, beginning of the period	$ 6,485	$ 6,348
Accruals	2,652	2,313
Warranty liability assumed in acquisition	407
Usage	(2,039)	(2,277)
Balance, end of the period	$ 7,505	$ 6,384

Revenue - Schedule of Disaggreg

Revenue - Schedule of Disaggregation of Revenue by Timing of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 27, 2021	Mar. 27, 2021	Mar. 28, 2020	Mar. 28, 2020
Disaggregation Of Revenue [Line Items]
Total revenue	$ 169,279	$ 169,279	$ 139,928	$ 139,928
Transferred at Point in Time [Member]
Disaggregation Of Revenue [Line Items]
Total revenue		161,161		133,745
Transferred over Time [Member]
Disaggregation Of Revenue [Line Items]
Total revenue		$ 8,118		$ 6,183

Revenue - Schedule of Changes i

Revenue - Schedule of Changes in Deferred Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 27, 2021	Mar. 28, 2020
Deferred Revenue Disclosure [Abstract]
Balance, beginning of the period	$ 15,626	$ 15,093
Deferred revenue assumed in acquisition	385
Deferral of revenue	19,232	14,434
Recognition of deferred revenue	(12,814)	(11,495)
Balance, end of the period	$ 22,429	$ 18,032

Share-Based Compensation - Summ

Share-Based Compensation - Summary of Restricted Stock Unit Activity (Details) - Restricted Stock Units (RSUs) [Member]	3 Months Ended
	Mar. 27, 2021$ / sharesshares
Activity for RSUs [Roll Forward]
Number of Shares, Beginning balance (in shares) | shares	964,000
Number of Shares, Granted (in shares) | shares	104,000
Number of Shares, Vested (in shares) | shares	(124,000)
Number of Shares, Forfeited (in shares) | shares	(10,000)
Number of Shares, Ending balance (in shares) | shares	934,000
Weighted Average Grant Date Fair Value for RSUs [Roll Forward]
Weighted Average Grant Date Fair Value, Beginning balance (in dollars per share) | $ / shares	$ 31.37
Weighted Average Grant Date Fair Value, Granted (in dollars per share) | $ / shares	69.94
Weighted Average Grant Date Fair Value, Vested (in dollars per share) | $ / shares	28.85
Weighted Average Grant Date Fair Value, Forfeited (in dollars per share) | $ / shares	31.51
Weighted Average Grant Date Fair Value, Ending balance (in dollars per share) | $ / shares	$ 36.62

Share-Based Compensation - Text

Share-Based Compensation - Textual (Details) - Restricted Stock Units (RSUs) [Member] - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 27, 2021	Dec. 26, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total unrecognized compensation cost related to restricted stock units granted	$ 21,789	$ 19,135
Unrecognized compensation cost related to restricted stock units, weighted average period	1 year 7 months 6 days	1 year 8 months 12 days

Other (Expense) Income, Net - S

Other (Expense) Income, Net - Schedule of Other (Expense) Income, Net (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 27, 2021	Mar. 28, 2020
Other Income Expense [Abstract]
Foreign currency exchange losses, net	$ (1,271)	$ (35)
Other	27	67
Total other (expense) income, net	$ (1,244)	$ 32

Income Taxes - Details of Incom

Income Taxes - Details of Income Tax (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 27, 2021	Mar. 28, 2020
Income Tax Disclosure [Abstract]
Income (loss) before income taxes	$ 26,602	$ (4,004)
Provision for income taxes	$ 2,489	$ 400
Effective tax rate	9.00%	(10.00%)

Income Taxes - Textual (Details

Income Taxes - Textual (Details) - USD ($) $ in Thousands	Mar. 27, 2021	Dec. 26, 2020
Income Tax Disclosure [Abstract]
Deferred tax assets, valuation allowance	$ 14,249	$ 14,238

Earnings Per Share - Schedule o

Earnings Per Share - Schedule of Basic and Diluted Earnings (Loss) Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 27, 2021	Mar. 27, 2021	Mar. 28, 2020	Mar. 28, 2020
Earnings Per Share [Abstract]
Net income (loss)	$ 24,113	$ 24,113	$ (4,404)	$ (4,404)
Basic earnings (loss) per share - weighted average shares outstanding	49,000	49,000	50,121	50,121
Employee stock options, employee stock purchase grants and restricted stock units - dilutive shares	572
Diluted earnings (loss) per share - weighted average shares outstanding	49,572	49,572	50,121	50,121
Earnings (loss) per share:
Basic	$ 0.49	$ 0.49	$ (0.09)	$ (0.09)
Diluted	$ 0.49	$ 0.49	$ (0.09)	$ (0.09)

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive (Income) Loss - Components of Accumulated Other Comprehensive (Income) Loss, Net of Tax (Details) $ in Thousands	3 Months Ended
	Mar. 27, 2021USD ($)
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	$ (1,264,746)
Balance	(1,292,312)
Accumulated Foreign Currency Translation Adjustments [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	(4,479)
Net current period other comprehensive loss	1,899
Reclassifications	0
Balance	(2,580)
Accumulated Net Unrealized (Gains) Losses on Available-for-sale Marketable Securities [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	(89)
Net current period other comprehensive loss	131
Reclassifications	0
Balance	42
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	(4,568)
Net current period other comprehensive loss	2,030
Reclassifications	0
Balance	$ (2,538)

Segment Reporting and Geograp_3

Segment Reporting and Geographic Information - Additional Information (Details)	3 Months Ended
	Mar. 27, 2021Segment
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
	Mar. 27, 2021	Mar. 27, 2021	Mar. 28, 2020	Mar. 28, 2020
Segment Reporting Information [Line Items]
Total revenue	$ 169,279	$ 169,279	$ 139,928	$ 139,928
Sales [Member] | Product [Member]
Segment Reporting Information [Line Items]
Concentration risk, percentage		100.00%		100.00%
Systems and Software [Member]
Segment Reporting Information [Line Items]
Total revenue		$ 141,509		$ 114,330
Systems and Software [Member] | Sales [Member] | Product [Member]
Segment Reporting Information [Line Items]
Concentration risk, percentage		84.00%		82.00%
Parts Revenue [Member]
Segment Reporting Information [Line Items]
Total revenue		$ 17,418		$ 13,575
Parts Revenue [Member] | Sales [Member] | Product [Member]
Segment Reporting Information [Line Items]
Concentration risk, percentage		10.00%		10.00%
Service Revenue [Member]
Segment Reporting Information [Line Items]
Total revenue		$ 10,352		$ 12,023
Service Revenue [Member] | Sales [Member] | Product [Member]
Segment Reporting Information [Line Items]
Concentration risk, percentage		6.00%		8.00%

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
	Mar. 27, 2021	Mar. 27, 2021	Mar. 28, 2020	Mar. 28, 2020
Segment Reporting Information [Line Items]
Total revenue	$ 169,279	$ 169,279	$ 139,928	$ 139,928
South Korea [Member]
Segment Reporting Information [Line Items]
Total revenue	50,530		20,757
Taiwan [Member]
Segment Reporting Information [Line Items]
Total revenue	36,293		35,181
China [Member]
Segment Reporting Information [Line Items]
Total revenue	25,779		31,383
United States [Member]
Segment Reporting Information [Line Items]
Total revenue	25,480		19,648
Europe [Member]
Segment Reporting Information [Line Items]
Total revenue	17,385		15,069
Japan [Member]
Segment Reporting Information [Line Items]
Total revenue	7,865		15,027
Southeast Asia [Member]
Segment Reporting Information [Line Items]
Total revenue	$ 5,947		$ 2,863

Segment Reporting and Geograp_6

Segment Reporting and Geographic Information - Schedule of Revenue by Major Customer by Reporting Segments (Details) - Customer Concentration Risk [Member] - Sales [Member]	3 Months Ended
	Mar. 27, 2021	Mar. 28, 2020
Samsung Semiconductor [Member]
Concentration Risk [Line Items]
Customer concentration risk percentage	25.00%	18.00%
Taiwan Semiconductor Manufacturing Co. Ltd. [Member]
Concentration Risk [Line Items]
Customer concentration risk percentage	13.00%	17.00%
SK Hynix Inc. [Member]
Concentration Risk [Line Items]
Customer concentration risk percentage	12.00%

Share Repurchase Authorizatio_2

Share Repurchase Authorization - Textual (Details) - USD ($)	Mar. 27, 2021	Nov. 30, 2020
Shares Repurchase Authorization [Line Items]
Amount available for future repurchase	$ 100,000,000	$ 28,000,000
Maximum [Member]
Shares Repurchase Authorization [Line Items]
Stock repurchase, authorized amount		$ 100,000,000

Share Repurchase Authorizatio_3

Share Repurchase Authorization - Summary of Share Repurchases (Details) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 28, 2020USD ($)$ / sharesshares
Disclosure Share Repurchase Authorization Summary Of Stock Repurchases Details [Abstract]
Shares of common stock repurchased | shares	1,250,000
Cost of shares repurchased | $	$ 33,614
Average price paid per share | $ / shares	$ 26.89