| Cover | Jan. 03, 2025 | Aug. 06, 2024 |
| Cover [Abstract] | ||
| Document Type | 8-K | |
| Document Period End Date | Jan. 03, 2025 | |
| Entity Registrant Name | EMCORE CORP | |
| Entity Incorporation, State or Country Code | NJ | |
| Entity File Number | 001-36632 | |
| Entity Tax Identification Number | 22-2746503 | |
| Entity Address, Address Line One | 50 Clark Drive | |
| Entity Address, City or Town | Budd Lake | |
| Entity Address, State or Province | NJ | |
| Entity Address, Postal Zip Code | 07828 | |
| City Area Code | 626 | |
| Local Phone Number | 293-3400 | |
| Written Communications | false | |
| Soliciting Material | false | |
| Pre-commencement Tender Offer | false | |
| Pre-commencement Issuer Tender Offer | false | |
| Title of 12(b) Security | Common stock, no par value | |
| Trading Symbol | EMKR | |
| Security Exchange Name | NASDAQ | |
| Entity Emerging Growth Company | false | |
| Entity Central Index Key | 0000808326 | |
| Amendment Flag | false | |
| Entity Information [Line Items] | ||
| Entity Registrant Name | EMCORE CORP |
