Document and Entity Information (USD $)
In Millions, except Share data, unless otherwise specified
12 Months Ended
Sep. 30, 2014
Dec. 05, 2014
Mar. 31, 2014
Document and Entity Information [Abstract]      
Entity Registrant Name EMCORE CORPORATION    
Entity Central Index Key 0000808326    
Document Type 10-K    
Document Period End Date Sep. 30, 2014    
Document Fiscal Period Focus FY    
Document Fiscal Year Focus 2014    
Current Fiscal Year End Date --09-30    
Entity Filer Category Accelerated Filer    
Amendment Flag false    
Entity Common Stock, Shares Outstanding   31,149,792  
Entity Well-known Seasoned Issuer No    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Public Float     $ 142.1