XML 11 R1.htm IDEA: XBRL DOCUMENT v3.25.3
Cover - shares
 9 Months Ended
Sep. 30, 2025
Oct. 31, 2025
Document Type 10-Q  
Document Quarterly Report true  
Document Period End Date Sep. 30, 2025  
Document Transition Report false  
Entity File Number 001-39264  
Entity Registrant Name KEROS THERAPEUTICS, INC.  
Entity Incorporation, State or Country Code DE  
Entity Tax Identification Number 81-1173868  
Entity Address, Address Line One 1050 Waltham Street,  
Entity Address, Address Line Two Suite 302  
Entity Address, City or Town Lexington,  
Entity Address, State or Province MA  
Entity Address, Postal Zip Code 02421  
City Area Code 617  
Local Phone Number 314-6297  
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 (in shares)   30,466,069
Amendment Flag false  
Document Fiscal Year Focus 2025  
Document Fiscal Period Focus Q3  
Current Fiscal Year End Date --12-31  
Entity Central Index Key 0001664710  
Common stock    
Title of 12(b) Security Common Stock, $0.0001 par value per share  
Trading Symbol KROS  
Security Exchange Name NASDAQ  
Preferred Stock    
Title of 12(b) Security Preferred Share Purchase Rights  
Security Exchange Name NASDAQ  
No trading symbol true