v3.25.2
Cover Page - shares
6 Months Ended
Jun. 30, 2025
Aug. 06, 2025
Cover [Abstract]    
Document Type 10-Q  
Amendment Flag false  
Document Period End Date Jun. 30, 2025  
Document Fiscal Year Focus 2025  
Document Fiscal Period Focus Q2  
Current Fiscal Year End Date --12-31  
Entity Registrant Name Karyopharm Therapeutics Inc.  
Trading Symbol KPTI  
Entity Central Index Key 0001503802  
Entity Filer Category Accelerated Filer  
Entity Small Business true  
Entity Emerging Growth Company false  
Entity Common Stock, Shares Outstanding   8,671,278
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity File Number 001-36167  
Entity Incorporation, State or Country Code DE  
Entity Tax Identification Number 26-3931704  
Entity Address, Address Line One 85 Wells Avenue, 2nd Floor  
Entity Address, City or Town Newton  
Entity Address, Postal Zip Code 02459  
City Area Code 617  
Local Phone Number 658-0600  
Document Quarterly Report true  
Document Transition Report false  
Entity Shell Company false  
Entity Address, State or Province MA  
Title of 12(b) Security Common Stock  
Security Exchange Name NASDAQ