Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2019	May 03, 2019
Document and Entity Information [Abstract]
Entity Registrant Name	Axsome Therapeutics, Inc.
Entity Central Index Key	0001579428
Document Type	10-Q
Document Period End Date	Mar. 31, 2019
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
Entity Common Stock, Shares Outstanding		33,305,310
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q1