Quarterly report pursuant to Section 13 or 15(d)

Debt - Convertible Debt Information (Details)

v3.19.3
Debt - Convertible Debt Information (Details)
3 Months Ended 9 Months Ended
Aug. 15, 2019
USD ($)
shares
Jan. 16, 2019
USD ($)
$ / shares
shares
Sep. 30, 2019
USD ($)
$ / shares
shares
Sep. 30, 2018
USD ($)
Sep. 30, 2019
USD ($)
$ / shares
shares
Sep. 30, 2018
USD ($)
Aug. 12, 2019
USD ($)
Dec. 31, 2018
USD ($)
$ / shares
Jun. 29, 2015
USD ($)
Debt Instrument [Line Items]                  
Capital stock non-convertible, par value (in dollars per share) | $ / shares     $ 0.001   $ 0.001     $ 0.001  
Loss on extinguishment of debt     $ 28,920,834 $ 0 $ 33,960,565 $ 0      
7.00% Convertible Senior Notes                  
Debt Instrument [Line Items]                  
Unamortized discount     26,986   26,986     $ 1,108,342  
5.875% Convertible Senior Notes                  
Debt Instrument [Line Items]                  
Unamortized discount     3,430,522   3,430,522     $ 0  
Convertible Debt                  
Debt Instrument [Line Items]                  
Interest expense     1,747,954 2,191,650 4,647,771 6,575,244      
Convertible Debt | 7.00% Convertible Senior Notes                  
Debt Instrument [Line Items]                  
Face amount $ 63,900,000   $ 115,000,000   $ 115,000,000       $ 115,000,000.0
Debt instrument coupon rate     7.00%   7.00%     7.00% 7.00%
Convertible debt outstanding     $ 5,500,000   $ 5,500,000     $ 114,000,000  
Conversion ratio         0.0303030        
Conversion price (in dollars per share) | $ / shares     $ 33.00   $ 33.00        
Amount converted   $ 43,800,000 $ 178,000   $ 762,000        
Debt conversion, exchanged instrument, amount $ 93,200,000                
Number of shares issued in conversion (in shares) | shares 703,432 837,040 5,393   23,083        
Capital stock non-convertible, par value (in dollars per share) | $ / shares   $ 0.001              
Repurchases of convertible debt $ 60,200,000 $ 19,800,000              
Interest expense 733,000 315,000 $ 698,270 2,191,650 $ 3,598,087 6,575,244      
Loss on extinguishment of debt 28,900,000 5,000,000     34,000,000        
Discount amortization 360,000 409,000 62,030 184,728 312,079 554,184      
Deferred debt cost amortization expense $ 24,000 $ 27,000 $ 4,051 12,069 20,382 36,207      
Effective interest rate in percentage     7.70%            
Convertible Debt | 5.875% Convertible Senior Notes                  
Debt Instrument [Line Items]                  
Face amount     $ 120,000,000   $ 120,000,000   $ 120,000,000.0    
Debt instrument coupon rate     5.875%   5.875%   5.875% 0.00%  
Conversion ratio         0.0200000        
Conversion price (in dollars per share) | $ / shares     $ 50.00   $ 50.00        
Interest expense     $ 1,049,684 0 $ 1,049,684 0      
Discount amortization     79,478 0 79,478 0      
Deferred debt cost amortization expense     10,623 $ 0 10,623 $ 0      
Unamortized discount             $ 3,500,000    
Debt issuance costs, gross     $ 494,000   $ 494,000        
Number of trading days         20        
Number of consecutive trading days         30        
Redemption price in percentage         100.00%        
Sale price of common stock, percentage         125.00%        
Effective interest rate in percentage     6.40%