Annual report pursuant to Section 13 and 15(d)

Debt - Convertible Debt (Details)

v3.20.4
Debt - Convertible Debt (Details)
3 Months Ended 12 Months Ended
Jun. 12, 2020
USD ($)
Apr. 29, 2020
USD ($)
Aug. 15, 2019
USD ($)
shares
Jan. 16, 2019
USD ($)
$ / shares
shares
May 23, 2016
USD ($)
Dec. 31, 2020
USD ($)
$ / shares
Sep. 30, 2020
USD ($)
Jun. 30, 2020
USD ($)
Mar. 31, 2020
USD ($)
shares
Dec. 31, 2019
USD ($)
$ / shares
Sep. 30, 2019
USD ($)
Jun. 30, 2019
USD ($)
Mar. 31, 2019
USD ($)
Dec. 31, 2020
USD ($)
tradingDay
$ / shares
Dec. 31, 2019
USD ($)
$ / shares
shares
Dec. 31, 2018
USD ($)
shares
Aug. 12, 2019
USD ($)
Jun. 29, 2015
USD ($)
$ / shares
Debt Instrument [Line Items]                                    
Deferred debt financing costs, net           $ 0       $ 158,070       $ 0 $ 158,070      
Repurchases of convertible debt                           $ 1,316,250 $ 0 $ 0    
Common stock, par value (in dollars per share) | $ / shares           $ 0.001       $ 0.001       $ 0.001 $ 0.001      
Gain (loss) on extinguishment of debt           $ 0 $ 0 $ 11,549,968 $ 0 $ 0 $ (28,920,834) $ 0 $ (5,039,731) $ 11,549,968 $ (33,960,565) 0    
7.00% Unsecured convertible senior notes                                    
Debt Instrument [Line Items]                                    
Amount of underwriter's discount           0       6,681       0 6,681      
5.875% Unsecured Convertible Senior Notes                                    
Debt Instrument [Line Items]                                    
Amount of underwriter's discount           2,656,739       $ 3,284,542       2,656,739 3,284,542      
Convertible Debt                                    
Debt Instrument [Line Items]                                    
Interest expense                           7,697,403 $ 6,675,037 8,766,306    
Convertible Debt | 7.00% Unsecured convertible senior notes                                    
Debt Instrument [Line Items]                                    
Face amount     $ 63,900,000     $ 115,000,000               $ 115,000,000       $ 115,000,000.0
Effective interest rate           0.00%       7.00%       0.00% 7.00%     7.00%
Conversion ratio                           0.030303        
Conversion price (in dollars per share) | $ / shares                                   $ 33.00
Repurchases of convertible debt $ 1,700,000   $ 60,200,000 $ 19,800,000 $ 1,000,000.0                          
Principal amount       $ 43,800,000         $ 416,000           $ 4,200,000 $ 42,000    
Shares issued (in shares) | shares     703,432 837,040         12,605           127,143 1,271    
Common stock, par value (in dollars per share) | $ / shares       $ 0.001                            
Interest expense $ 59,000   $ 733,000 $ 315,000                   $ 63,153 $ 3,696,003 $ 8,766,306    
Gain (loss) on extinguishment of debt                     $ (28,900,000)   $ (5,000,000.0)          
Write-off of underwriter's discount     360,000 409,000                   6,682 320,821 738,912    
Amortization of debt issuance costs     24,000 $ 27,000                   1,140 21,004 $ 48,276    
Debt conversion, exchanged instrument, amount     $ 93,200,000                              
Convertible debt outstanding                   $ 2,100,000         $ 2,100,000      
Effective percentage                             7.70% 7.70%    
Convertible Debt | 5.875% Unsecured Convertible Senior Notes                                    
Debt Instrument [Line Items]                                    
Face amount           $ 120,000,000               $ 120,000,000     $ 120,000,000.0  
Effective interest rate     5.875%     5.875%       5.875%       5.875% 5.875%   5.875%  
Amount of underwriter's discount                                 $ 3,500,000  
Conversion ratio                           0.02        
Conversion price (in dollars per share) | $ / shares           $ 50.00               $ 50.00        
Repurchases of convertible debt   $ 1,300,000                                
Interest expense   24,000                       $ 7,634,250 $ 2,979,034 $ 0    
Gain (loss) on extinguishment of debt                           576,000        
Write-off of underwriter's discount                           577,539 225,458 0    
Amortization of debt issuance costs                           83,723 $ 31,493 $ 0    
Convertible debt outstanding           $ 118,100,000               $ 118,100,000        
Redemption price in percentage                           100.00%        
Deferred debt costs                                 $ 508,000  
Sale price of common stock, percentage                           125.00%        
Number of trading days | tradingDay                           20        
Number of consecutive trading days | tradingDay                           30        
Minimum balance to trigger default upon qualified event           $ 25,000,000.0               $ 25,000,000.0        
Debt instrument, repurchased face amount   $ 2,000,000.0                                
Effective percentage                           6.40% 6.40%