Cover Page
Jun. 02, 2021
Cover [Abstract]  
Document Type 8-K
Document Period End Date Jun. 02, 2021
Entity Registrant Name CTI BIOPHARMA CORP.
Entity Incorporation, State or Country Code DE
Entity File Number 000-28386
Entity Tax Identification Number 91-1533912
Entity Address, Address Line One 3101 Western Avenue
Entity Address, Address Line Two Suite 800
Entity Address, City or Town Seattle
Entity Address, State or Province WA
Entity Address, Postal Zip Code 98121
City Area Code 206
Local Phone Number 282-7100
Written Communications false
Soliciting Material false
Pre-commencement Tender Offer false
Pre-commencement Issuer Tender Offer false
Title of 12(b) Security Common Stock, par value $0.001
Trading Symbol CTIC
Entity Emerging Growth Company false
Entity Central Index Key 0000891293
Amendment Flag false