Equity Transactions - At-The-Market Equity Offering (Details) shares in Millions, $ in Millions	1 Months Ended		3 Months Ended	12 Months Ended
	Aug. 31, 2022 USD ($) day	Jan. 31, 2021 USD ($)	Jun. 30, 2022 USD ($)	Dec. 31, 2022 USD ($) shares
At-The Market Equity Offering
Class of Stock [Line Items]
Gross proceeds from offering				$ 45.5
Sale of stock, agent commissions				1.4
August 2022 Sale Agreement
Class of Stock [Line Items]
Gross proceeds from offering				9.7
Sale of stock, agent commissions				$ 0.3
Common Stock \| At-The Market Equity Offering
Class of Stock [Line Items]
Expected proceeds from common stock offering, net of issuance costs		$ 50.0
Shares available for future conversion (in shares) \| shares				9.4
Common Stock \| January 2021 Sale Agreement
Class of Stock [Line Items]
Expected proceeds from common stock offering, net of issuance costs			$ 50.0
Common Stock \| August 2022 Sale Agreement
Class of Stock [Line Items]
Expected proceeds from common stock offering, net of issuance costs	$ 100.0
Shares available for future conversion (in shares) \| shares				1.7
Number of trading days \| day	1
Number of trading day's prior notice \| day	1
Percent of gross proceeds, underwriter commission	3.00%
Remaining Available Proceeds From Issuance Of Common Stock				$ 90.0

CTI BIOPHARMA CORP 10-K