Document and Entity Information (USD $)
12 Months Ended
Jun. 30, 2012
Aug. 13, 2012
Document and Entity Information [Abstract]    
Entity Registrant Name SYNAPTICS INC  
Entity Central Index Key 0000817720  
Document Type 10-K  
Document Period End Date Jun. 30, 2012  
Amendment Flag false  
Document Fiscal Year Focus 2012  
Document Fiscal Period Focus FY  
Current Fiscal Year End Date --06-30  
Entity Well-known Seasoned Issuer Yes  
Entity Voluntary Filers No  
Entity Current Reporting Status Yes  
Entity Filer Category Large Accelerated Filer  
Entity Public Float $ 761,620,959  
Entity Common Stock, Shares Outstanding   33,004,709