Quarterly report pursuant to Section 13 or 15(d)

Debt - Convertible Debt Information (Details)

v3.19.2
Debt - Convertible Debt Information (Details)
1 Months Ended 3 Months Ended 6 Months Ended
Jan. 16, 2019
USD ($)
$ / shares
shares
Aug. 01, 2019
USD ($)
shares
Jun. 30, 2019
USD ($)
$ / shares
shares
Jun. 30, 2018
USD ($)
Jun. 30, 2019
USD ($)
$ / shares
Jun. 30, 2018
USD ($)
Dec. 31, 2018
USD ($)
$ / shares
Jun. 29, 2015
USD ($)
Debt Instrument [Line Items]                
Amount converted     $ 584,000          
Number of shares issued in conversion | shares     17,690          
Capital stock non-convertible, par value (in dollars per share) | $ / shares     $ 0.001   $ 0.001   $ 0.001  
Loss on extinguishment of debt     $ 0 $ 0 $ 5,039,731 $ 0    
Convertible Senior Notes Due 2020 [Member]                
Debt Instrument [Line Items]                
Amount of underwriter's discount     449,034   449,034   $ 1,108,342  
Convertible Debt [Member]                
Debt Instrument [Line Items]                
Interest expense     1,351,369 2,191,797 2,899,817 4,383,594    
Write off of debt discount     117,139 184,728 250,049 369,456    
Write off of deferred debt costs     $ 7,650 $ 12,069 $ 16,331 $ 24,138    
Amount of underwriter's discount               $ 3,700,000
Effective percentage     7.70% 7.70% 7.70% 7.70%    
Convertible Debt [Member] | Convertible Senior Notes Due 2020 [Member]                
Debt Instrument [Line Items]                
Face amount     $ 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             $ 114,000,000  
Conversion ratio         0.0303030      
Conversion price (in dollars per share) | $ / shares     $ 33.00   $ 33.00      
Amount converted $ 43,800,000              
Number of shares issued in conversion | shares 837,040              
Capital stock non-convertible, par value (in dollars per share) | $ / shares $ 0.001              
Repurchases of convertible debt $ 19,800,000              
Interest expense $ 315,000   $ 1,226,580 $ 1,995,000 $ 2,633,437 $ 3,990,000    
Loss on extinguishment of debt         5,000,000      
Write off of debt discount         409,000      
Write off of deferred debt costs         $ 27,000      
Subsequent Event [Member]                
Debt Instrument [Line Items]                
Amount converted   $ 70,000            
Number of shares issued in conversion | shares   2,121