Quarterly report pursuant to Section 13 or 15(d)

Related Party Transactions - Additional Information (Details)

v3.20.2
Related Party Transactions - Additional Information (Details) - USD ($)
 3 Months Ended 9 Months Ended
Jun. 12, 2020
Sep. 13, 2019
Sep. 30, 2020
Sep. 30, 2019
Sep. 30, 2020
Sep. 30, 2019
Dec. 31, 2019
Related Party Transaction [Line Items]              
TGTX     $ 28,000 $ 280,000 $ 1,042,000 $ 1,683,000  
Total notes payable, long-term     $ 60,000,000   $ 60,000,000   $ 89,742,000
Debt Instrument, Interest Rate, Stated Percentage     2.50%   2.50%    
Opus Credit Facility [Member]              
Related Party Transaction [Line Items]              
Common Shares Issued For Opus Debt, In Shares           91,767  
Common Shares Issued For Opus Debt, Issue Price           $ 1.80  
2019 Notes (formerly the Opus Credit Facility Agreement)              
Related Party Transaction [Line Items]              
Maturity extended period   2 years          
Debt pay off     $ 9,000,000.0        
Interet paid         $ 500,000    
Payments of Loan Costs           $ 200,000  
Total notes payable, long-term             9,000,000.0
Debt Instrument, Interest Rate, Stated Percentage     12.00%   12.00%    
DAK Capital Inc [Member] | 2019 Notes (formerly the Opus Credit Facility Agreement)              
Related Party Transaction [Line Items]              
Total notes payable, long-term             3,800,000
Chief Executive Officer [Member]              
Related Party Transaction [Line Items]              
Interest own in percent by principal stockholder or director     10.10%   10.10%    
Executives Vice Chairman [Member]              
Related Party Transaction [Line Items]              
Interest own in percent by principal stockholder or director     10.90%   10.90%    
Fortress's Chairman, President and Chief Executive Officer (Lindsay A. Rosenwald) [Member] | 2019 Notes (formerly the Opus Credit Facility Agreement)              
Related Party Transaction [Line Items]              
Total notes payable, long-term             300,000
Fortress's Executive Vice President, Strategic Development (Michael S. Weiss) [Member] | 2019 Notes (formerly the Opus Credit Facility Agreement)              
Related Party Transaction [Line Items]              
Total notes payable, long-term             2,000,000.0
Credit Facility Provided | Avenue [Member]              
Related Party Transaction [Line Items]              
Maximum borrowing capacity $ 2,000,000            
Maximum aggregate lending up agreement 800,000            
Aggregate lending up agreement $ 1,200,000            
Interest rate per annum (as a percent) 7.00%            
Repayment period following the termination of the SPMA 30 days            
Amounts drawn     $ 0   $ 0    
Dr Rosenwald and Mr Weiss | 2019 Notes (formerly the Opus Credit Facility Agreement)              
Related Party Transaction [Line Items]              
Total notes payable, long-term             $ 2,900,000
Shared Services Agreement [Member] | TG Therapeutics, Inc [Member]              
Related Party Transaction [Line Items]              
TGTX     100,000 100,000 300,000 $ 300,000  
Due from Related Parties, Current     69,000   69,000    
Desk Share Agreements [Member]              
Related Party Transaction [Line Items]              
Payments for Rent     700,000 700,000      
Desk Share Agreements [Member] | TG Therapeutics, Inc [Member]              
Related Party Transaction [Line Items]              
TGTX     400,000   400,000    
Due from Related Parties, Current     0   0    
Desk Share Agreements [Member] | OPPM [Member]              
Related Party Transaction [Line Items]              
TGTX     0 $ 24,000      
Due from Related Parties, Current     $ 400,000   $ 400,000