v3.7.0.1
Document and Entity Information - shares
9 Months Ended
Jan. 29, 2017
Mar. 03, 2017
Document and Entity Information [Abstract]    
Entity Registrant Name FINISAR CORP  
Entity Central Index Key 0001094739  
Current Fiscal Year End Date --04-30  
Entity Filer Category Large Accelerated Filer  
Document Type 10-Q  
Document Period End Date Jan. 29, 2017  
Document Fiscal Year Focus 2017  
Document Fiscal Period Focus Q3  
Amendment Flag false  
Entity Common Stock, Shares Outstanding   111,387,722