Annual report pursuant to Section 13 and 15(d)


Cover - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2021
Mar. 28, 2022
Jun. 30, 2021
Cover [Abstract]      
Document Type 10-K    
Amendment Flag false    
Document Annual Report true    
Document Transition Report false    
Document Period End Date Dec. 31, 2021    
Document Fiscal Period Focus FY    
Document Fiscal Year Focus 2021    
Current Fiscal Year End Date --12-31    
Entity File Number 001-40023    
Entity Registrant Name GT BIOPHARMA, INC.    
Entity Central Index Key 0000109657    
Entity Tax Identification Number 94-1620407    
Entity Incorporation, State or Country Code DE    
Entity Address, Address Line One 8000 Marina Blvd.    
Entity Address, Address Line Two Suite 100    
Entity Address, City or Town Brisbane    
Entity Address, State or Province CA    
Entity Address, Postal Zip Code 94005    
City Area Code (415)    
Local Phone Number 919-4040    
Title of 12(b) Security Common Stock, $.001 Par Value    
Trading Symbol GTBP    
Security Exchange Name NASDAQ    
Entity Well-known Seasoned Issuer No    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Interactive Data Current Yes    
Entity Filer Category Non-accelerated Filer    
Entity Small Business true    
Entity Emerging Growth Company false    
Entity Shell Company false    
Entity Public Float     $ 372.3
Entity Common Stock, Shares Outstanding   32,122,844  
Documents Incorporated by Reference In Part III, portions of the registrant’s 2022    
Auditor Name Weinberg & Company, P.A    
Auditor Location Los Angeles, California    
Auditor Firm ID 572