Quarterly report pursuant to Section 13 or 15(d)

Stockholders' Equity - Additional Information (Detail)

v3.19.1
Stockholders' Equity - Additional Information (Detail) - USD ($)
1 Months Ended 3 Months Ended
Nov. 30, 2017
Mar. 31, 2019
Mar. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Adjustments To Additional Paid In Capital At Market Offering Costs     $ (6,000)
Market Offering [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Available-for-sale Securities   $ 10,200,000  
Common Stock [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Issuance of Common Stock for At the Market Offering in shares   2,927,427 64,797
Adjustments To Additional Paid In Capital At Market Offering Costs     $ 0
Common Stock [Member] | Market Offering [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Shares Issued, Price Per Share   $ 2.14  
Proceeds from issuance of Common stock   $ 6,300,000  
Issuance of Common Stock for At the Market Offering in shares   2.9  
Adjustments To Additional Paid In Capital At Market Offering Costs   $ 100,000  
Checkpoint Therapeutics, Inc [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Shares Issued, Price Per Share   $ 4.05  
Proceeds from issuance of Common stock   $ 400,000  
Stock Issued During Period, Shares, New Issues   90,269  
Percentage of Placement of Agent Fee 3.00%    
Maximum Authorized Amount Of Shares To Be Sold $ 100,000,000    
Available-for-sale Securities   $ 68,600,000  
Checkpoint Therapeutics, Inc [Member] | Market Offering [Member] | Founder Agreement [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Stock Issued During Period, Shares, New Issues   2,254  
Research and Development Expense [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Allocated Share-based Compensation Expense   $ 600,000 2,300,000
General and Administrative Expense [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Allocated Share-based Compensation Expense   $ 2,700,000 $ 2,500,000
Restricted Stock Units (RSUs) [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition   5 years 4 months 24 days 2 years 4 months 24 days
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Stock Options   $ 14,800,000 $ 2,500,000
Employee Stock Option [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Employee Stock Purchase Plan to eligible employees, Reckoning fair value percentage during offering period   85.00%  
Common Stock issued in connection with the first ESPP offering   356,507  
Allocated Share-based Compensation Expense   $ 20,000 $ 38,000
Common Stock, Capital Shares Reserved for Future Issuance   643,493