Document and Entity Information - USD ($)	12 Months Ended
	Jul. 31, 2015	Oct. 20, 2015	Jan. 24, 2015
Document Information [Line Items]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Jul. 31, 2015
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	FY
Trading Symbol	SCMR
Entity Registrant Name	SYCAMORE NETWORKS INC
Entity Central Index Key	0001092367
Current Fiscal Year End Date	--07-31
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Smaller Reporting Company
Entity Common Stock, Shares Outstanding		28,882,093
Entity Public Float			$ 7,329,659