Quarterly report pursuant to Section 13 or 15(d)

Fair Value of Warrants - Assumptions Used in Computing Fair Value of Derivative Warrants (Details)

v3.20.2
Fair Value of Warrants - Assumptions Used in Computing Fair Value of Derivative Warrants (Details) - $ / shares
9 Months Ended 12 Months Ended
Sep. 30, 2020
Dec. 31, 2019
Class of Warrant or Right [Line Items]    
Exercise price (usd per share) $ 104.18  
2016 Offering    
Class of Warrant or Right [Line Items]    
Exercise price (usd per share) $ 67.50 $ 67.50
Expected life (years) 1 year 3 months 29 days 2 years 29 days
Expected volatility | 2016 Offering    
Class of Warrant or Right [Line Items]    
Measurement input assumption (as a percent) 164.40% 150.69%
Risk-free interest rate | 2016 Offering    
Class of Warrant or Right [Line Items]    
Measurement input assumption (as a percent) 0.12% 1.58%
Expected dividend yield | 2016 Offering    
Class of Warrant or Right [Line Items]    
Measurement input assumption (as a percent) 0.00% 0.00%