Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Mar. 13, 2025	Jun. 30, 2024
Document and Entity Information
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2024
Document Transition Report	false
Securities Act File Number	001-38899
Entity Registrant Name	Milestone Pharmaceuticals Inc.
Entity Incorporation, State or Country Code	A8
Entity Tax Identification Number	00-0000000
Entity Address, Address Line One	1111 Dr. Frederik-Phillips Boulevard
Entity Address, Address Line Two	Suite 420
Entity Address, City or Town	Montréal
Entity Address, State or Province	QC
Entity Address, Country	CA
Entity Address, Postal Zip Code	H4M 2X6
City Area Code	514
Local Phone Number	336-0444
Title of 12(b) Security	Common Shares
Trading Symbol	MIST
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	false
Document Financial Statement Error Correction [Flag]	false
Entity Shell Company	false
Entity Public Float			$ 69.8
Entity Common Stock, Shares Outstanding		53,353,984
Auditor Firm ID	271
Auditor Name	PricewaterhouseCoopers LLP
Auditor Location	Montreal, Canada
Entity Central Index Key	0001408443
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	FY
Amendment Flag	false