Document and Entity Information	9 Months Ended
	Sep. 27, 2014
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 27, 2014
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	Q3
Trading Symbol	COHU
Entity Registrant Name	COHU INC
Entity Central Index Key	0000021535
Current Fiscal Year End Date	--12-27
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding	25,534,807