Document and Entity Information (USD $) In Billions, except Share data, unless otherwise specified	12 Months Ended
	May 03, 2015	Jun. 12, 2015	Oct. 26, 2014
Document and Entity Information [Abstract]
Entity Registrant Name	FINISAR CORP
Entity Central Index Key	0001094739
Current Fiscal Year End Date	--05-03
Entity Filer Category	Large Accelerated Filer
Document Type	10-K
Document Period End Date	May 03, 2015
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Common Stock, Shares Outstanding		104,151,047
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 1.6