Quarterly report pursuant to Section 13 or 15(d)

Debt - Convertible Debt Information (Details)

v3.10.0.1
Debt - Convertible Debt Information (Details) - USD ($)
3 Months Ended 6 Months Ended
May 23, 2016
Jun. 30, 2018
Jun. 30, 2017
Jun. 30, 2018
Jun. 30, 2017
Dec. 31, 2017
Jun. 29, 2015
Debt Instrument [Line Items]              
Repurchases of convertible debt $ 1,000,000            
Convertible Senior Notes Due 2020 [Member]              
Debt Instrument [Line Items]              
Amount of underwriter's discount   $ 1,477,798   $ 1,477,798   $ 1,847,254  
Convertible Debt [Member]              
Debt Instrument [Line Items]              
Amount of underwriter's discount   $ 3,700,000   $ 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%