Quarterly report pursuant to Section 13 or 15(d)

Document and Entity Information

v3.21.2
Document and Entity Information - shares
 6 Months Ended
Jun. 30, 2021
Aug. 31, 2021
Aug. 03, 2021
Document Information [Line Items]      
Document Type 10-Q    
Document Quarterly Report true    
Document Transition Report false    
Document Period End Date Jun. 30, 2021    
Entity File Number 001-38128    
Entity Registrant Name Checkpoint Therapeutics, Inc.    
Entity Incorporation, State or Country Code DE    
Entity Tax Identification Number 47-2568632    
Entity Address, Address Line One 95 Sawyer Road    
Entity Address, Address Line Two Suite 110    
Entity Address, City or Town Waltham    
Entity Address, State or Province MA    
Entity Address, Postal Zip Code 02453    
City Area Code 781    
Local Phone Number 652-4500    
Title of 12(b) Security Common Stock, par value $0.0001 per share    
Trading Symbol CKPT    
Security Exchange Name NASDAQ    
Entity Current Reporting Status Yes    
Entity Interactive Data Current Yes    
Entity Filer Category Non-accelerated Filer    
Entity Small Business true    
Entity Emerging Growth Company true    
Entity Ex Transition Period true    
Entity Shell Company false    
Entity Central Index Key 0001651407    
Current Fiscal Year End Date --12-31    
Document Fiscal Year Focus 2021    
Document Fiscal Period Focus Q2    
Amendment Flag false    
Class A Common Shares [Member]      
Document Information [Line Items]      
Entity Common Stock, Shares Outstanding     7,000,000
Common Shares [Member]      
Document Information [Line Items]      
Entity Common Stock, Shares Outstanding   75,741,873