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. Our fiscal year ending January 1, 2022 (“fiscal year 2021”) is a 53-week fiscal year. The first quarter of the Company’s fiscal year 2021 ended on March 27, 2021 (“first quarter 2021”), the second quarter ends on June 26, 2021 and the third quarter ends on September 25, 2021. Our fiscal year ended December 26, 2020 (“fiscal year 2020”) was a 52-week fiscal year. 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 taxes and enacted changes in tax laws or rates and clarified the accounting for transactions that resulted in a step-up in the tax basis of goodwill and allocating consolidated income taxes to separate financial statements of entities not subject to income tax. The adoption of ASU No. 2019-12 did not have a significant impact on the Company’s consolidated financial position, results of operations, and cash flows.

Basis of Presentation

3 Months Ended

Mar. 27, 2021

Organization Consolidation And Presentation Of Financial Statements [Abstract]

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. Our fiscal year ending January 1, 2022 (“fiscal year 2021”) is a 53-week fiscal year. The first quarter of the Company’s fiscal year 2021 ended on March 27, 2021 (“first quarter 2021”), the second quarter ends on June 26, 2021 and the third quarter ends on September 25, 2021. Our fiscal year ended December 26, 2020 (“fiscal year 2020”) was a 52-week fiscal year.

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 taxes and enacted changes in tax laws or rates and clarified the accounting for transactions that resulted in a step-up in the tax basis of goodwill and allocating consolidated income taxes to separate financial statements of entities not subject to income tax. The adoption of ASU No.

2019-12 did not have a significant impact on the Company’s consolidated financial position, results of operations, and cash flows.