v3.10.0.1
Document and Entity Information - shares
9 Months Ended
Sep. 30, 2018
Oct. 19, 2018
Document Document And Entity Information [Abstract]    
Document Type 10-Q  
Amendment Flag false  
Document Period End Date Sep. 30, 2018  
Document Fiscal Year Focus 2018  
Document Fiscal Period Focus Q3  
Trading Symbol CY  
Entity Registrant Name CYPRESS SEMICONDUCTOR CORP /DE/  
Entity Central Index Key 0000791915  
Current Fiscal Year End Date --12-30  
Entity Filer Category Large Accelerated Filer  
Entity Common Stock, Shares Outstanding   361,950,039
Entity Emerging Growth Company false  
Entity Small Business false