| Document And Entity Information | Sep. 30, 2023 |
| Document Information [Line Items] | |
| Entity, Registrant Name | Avenue Therapeutics, Inc. |
| Document, Type | 8-K |
| Document, Period End Date | Nov. 13, 2023 |
| Entity, Incorporation, State or Country Code | DE |
| Entity, File Number | 001-38114 |
| Entity, Tax Identification Number | 47-4113275 |
| Entity, Address, Address Line One | 1111 Kane Concourse, Suite 301 |
| Entity, Address, City or Town | Bay Harbor Islands |
| Entity, Address, State or Province | FL |
| Entity, Address, Postal Zip Code | 33154 |
| City Area Code | 781 |
| Local Phone Number | 652-4500 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock |
| Trading Symbol | ATXI |
| Security Exchange Name | NASDAQ |
| Entity, Emerging Growth Company | false |
| Amendment Flag | false |
| Entity, Central Index Key | 0001644963 |
