Quarterly report pursuant to Section 13 or 15(d)

Document and Entity Information

v3.20.2
Document and Entity Information - shares
 9 Months Ended
Sep. 30, 2020
Nov. 03, 2020
Document Information [Line Items]    
Document Type 10-Q  
Document Quarterly Report true  
Document Transition Report false  
Document Period End Date Sep. 30, 2020  
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 2 Gansevoort Street  
Entity Address, Address Line Two 9th Floor  
Entity Address, City or Town New York  
Entity Address, State or Province NY  
Entity Address, Postal Zip Code 10014  
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 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 2020  
Document Fiscal Period Focus Q3  
Amendment Flag false  
Common Shares [Member]    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding   60,883,303
Class A Common Shares [Member]    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding   7,000,000