Document and Entity Information (USD $)
9 Months Ended
Oct. 01, 2011
Nov. 01, 2011
Jul. 03, 2010
Document and Entity Information [Abstract]      
Entity Registrant Name INTEVAC INC    
Entity Central Index Key 0001001902    
Document Type 10-Q    
Document Period End Date Oct. 01, 2011    
Amendment Flag false    
Document Fiscal Year Focus 2011    
Document Fiscal Period Focus Q3    
Current Fiscal Year End Date --12-31    
Entity Well-known Seasoned Issuer No    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Filer Category Accelerated Filer    
Entity Public Float     $ 146,965,844
Entity Common Stock, Shares Outstanding   23,080,356