Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2021	Nov. 12, 2021
Document and Entity Information [Abstract]
Document Type	10-Q
Document Period End Date	Sep. 30, 2021
Entity Registrant Name	AVENUE THERAPEUTICS, INC.
Document Quarterly Report	true
Document Transition Report	false
Entity File Number	001-38114
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	47-4113275
Entity Address, Address Line One	1140 Avenue of the Americas, Floor 9
Entity Address, City or Town	New York
Entity Address, State or Province	NY
Entity Address, Postal Zip Code	10036
City Area Code	781
Local Phone Number	652-4500
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		18,700,480
Entity Central Index Key	0001644963
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
Amendment Flag	false
Title of 12(b) Security	Common Stock
Trading Symbol	ATXI
Security Exchange Name	NASDAQ
Entity Ex Transition Period	true