Cover Page - shares	3 Months Ended
	Mar. 31, 2024	May 03, 2024
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2024
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q1
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	false
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		117,710,263
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