v3.26.1
Cover
 3 Months Ended
Mar. 31, 2026
Entity Addresses [Line Items]  
Document Type S-4
Amendment Flag false
Entity Registrant Name PULMATRIX, INC.
Entity Central Index Key 0001574235
Entity Primary SIC Number 2834
Entity Tax Identification Number 46-1821392
Entity Incorporation, State or Country Code DE
Entity Address, Address Line One 945 Concord Street
Entity Address, Address Line Two Suite 1217
Entity Address, City or Town Framingham
Entity Address, State or Province MA
Entity Address, Postal Zip Code 01701
City Area Code (888)
Local Phone Number 355-4440
Entity Filer Category Non-accelerated Filer
Entity Small Business true
Entity Emerging Growth Company false
Business Contact [Member]  
Entity Addresses [Line Items]  
Entity Address, Address Line One 945 Concord Street
Entity Address, Address Line Two Suite 1217
Entity Address, City or Town Framingham
Entity Address, State or Province MA
Entity Address, Postal Zip Code 01701
City Area Code (888)
Local Phone Number 355-4440
Contact Personnel Name Peter Ludlum