v3.25.2
Cover Page - shares
6 Months Ended
Jun. 30, 2025
Aug. 01, 2025
Cover [Abstract]    
Document Type 10-Q  
Document Quarterly Report true  
Document Period End Date Jun. 30, 2025  
Document Transition Report false  
Entity File Number 000-30739  
Entity Registrant Name INSMED INC  
Entity Incorporation, State or Country Code VA  
Entity Tax Identification Number 54-1972729  
Entity Address, Address Line One 700 US Highway 202/206  
Entity Address, City or Town Bridgewater  
Entity Address, State or Province NJ  
Entity Address, Postal Zip Code 08807  
City Area Code 908  
Local Phone Number 977-9900  
Title of 12(b) Security Common stock, par value $0.01 per share  
Trading Symbol INSM  
Security Exchange Name NASDAQ  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Filer Category Large Accelerated Filer  
Entity Small Business false  
Entity Emerging Growth Company false  
Entity Shell Company false  
Entity Common Stock, Shares Outstanding   211,374,786
Entity Central Index Key 0001104506  
Amendment Flag false  
Current Fiscal Year End Date --12-31  
Document Fiscal Year Focus 2025  
Document Fiscal Period Focus Q2