Document and Entity Information - USD ($)
$ in Millions
12 Months Ended
May 01, 2016
Jun. 10, 2016
Nov. 01, 2015
Document and Entity Information [Abstract]      
Entity Registrant Name FINISAR CORP    
Entity Central Index Key 0001094739    
Current Fiscal Year End Date --05-01    
Entity Filer Category Large Accelerated Filer    
Document Type 10-K    
Document Period End Date May 01, 2016    
Document Fiscal Year Focus 2016    
Document Fiscal Period Focus FY    
Amendment Flag false    
Entity Common Stock, Shares Outstanding   107,706,776  
Entity Well-known Seasoned Issuer Yes    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Public Float     $ 905