Share Based Compensation - Share Based Compensation Allocation (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2026	Jun. 28, 2025	Jun. 30, 2026	Jun. 28, 2025
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-Based Payment Arrangement, Expense	$ 10,015	$ 6,678	$ 17,026	$ 13,492
Disaggregation of Income Statement Expense, Caption, Identifier [Axis]: us-gaap:CostOfRevenue
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-Based Payment Arrangement, Expense	1,226	895	2,168	2,002
Disaggregation of Income Statement Expense, Caption, Identifier [Axis]: us-gaap:GeneralAndAdministrativeExpense
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-Based Payment Arrangement, Expense	5,552	3,362	9,576	6,668
Disaggregation of Income Statement Expense, Caption, Identifier [Axis]: us-gaap:ResearchAndDevelopmentExpense
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-Based Payment Arrangement, Expense	1,911	1,292	2,927	2,354
Disaggregation of Income Statement Expense, Caption, Identifier [Axis]: us-gaap:SellingAndMarketingExpense
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-Based Payment Arrangement, Expense	$ 1,326	651	$ 2,355	1,990
Disaggregation of Income Statement Expense, Caption, Identifier [Axis]: onto:Restructuringcost
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-Based Payment Arrangement, Expense		$ 478		$ 478