Document and Entity Information (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Sep. 30, 2011	Dec. 21, 2011	Mar. 31, 2011
Entity Registrant Name	EMCORE CORPORATION
Entity Central Index Key	0000808326
Document Type	10-K
Document Period End Date	Sep. 30, 2011
Document Fiscal Period Focus	FY
Document Fiscal Year Focus	2011
Current Fiscal Year End Date	--09-30
Entity Filer Category	Accelerated Filer
Amendment Flag	false
Entity Common Stock, Shares Outstanding		94,067,694
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 185.6