Restructuring (Additional Information) (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 28, 2024	Dec. 30, 2023	Dec. 31, 2022
Restructuring Charges [Abstract]
Restructuring cost in operating expenses	$ 9,009	$ 3,572
Restructuring cost in cost of goods sold	14,068	7,027
RestructuringCost	$ 23,077	$ 10,599

Restructuring cost recored to cost of goods sold for inventory write-downs.

No definition available.

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Namespace Prefix:	onto_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration