Document and Entity Information
Jul. 17, 2020
Cover [Abstract]  
Security Exchange Name NASDAQ
Amendment Flag false
Entity Central Index Key 0001260990
Document Type 8-K
Document Period End Date Jul. 17, 2020
Entity Registrant Name Oncternal Therapeutics, Inc.
Entity Incorporation State Country Code DE
Entity File Number 000-50549
Entity Tax Identification Number 62-1715807
Entity Address, Address Line One 12230 El Camino Real
Entity Address, Address Line Two Suite 300
Entity Address, City or Town San Diego
Entity Address, State or Province CA
Entity Address, Postal Zip Code 92130
City Area Code (858)
Local Phone Number 434-1113
Written Communications false
Soliciting Material false
Pre Commencement Tender Offer false
Pre Commencement Issuer Tender Offer false
Security 12b Title Common Stock, par value $0.001 per share
Trading Symbol ONCT
Entity Emerging Growth Company false