v3.26.1
Document and Entity Information
Sep. 08, 2026
Document And Entity Information [Line Items]  
Document Type 8-K
Document Period End Date Sep. 08, 2026
Entity Registrant Name Korsana Biosciences, Inc.
Entity Incorporation State Country Code MA
Entity File Number 001-38787
Entity Tax Identification Number 83-1895370
Entity Address Address Line 1 203 Crescent Street
Entity Address Address Line 2 Bldgs. #3/3A/4
Entity Address Address Line 3 Suite 503
Entity Address City Or Town Waltham
Entity Address State Or Province MA
Entity Address Postal Zip Code 02453
City Area Code 781
Local Phone Number 516-2325
Entity Information Former Legal Or Registered Name Cyclerion Therapeutics, Inc.
Written Communications false
Soliciting Material false
Pre Commencement Tender Offer false
Pre Commencement Issuer Tender Offer false
Security 12b Title Common Stock, no par value per share
Trading Symbol KRSA
Security Exchange Name NASDAQ
Entity Emerging Growth Company false
Amendment Flag false
Current Fiscal Year End Date --12-31
Entity Central Index Key 0001755237
Former Address [Member]  
Document And Entity Information [Line Items]  
Entity Address Address Line 1 245 First Street
Entity Address Address Line 2 18th Floor
Entity Address City Or Town Cambridge
Entity Address State Or Province MA
Entity Address Postal Zip Code 02142