v3.26.1
Document and Entity Information Document - shares
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2026
Jul. 31, 2026
Cover [Abstract]      
Entity Registrant Name   ONTO INNOVATION INC.  
Trading Symbol ONTO    
Entity Central Index Key   0000704532  
Current Fiscal Year End Date   --12-31  
Entity Filer Category   Large Accelerated Filer  
Document Type   10-Q  
Document Period End Date   Jun. 30, 2026  
Document Fiscal Year Focus   2026  
Document Fiscal Period Focus   Q2  
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     49,074,247
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