Annual report pursuant to Section 13 and 15(d)

Debt - Convertible Debt (Details)

v3.10.0.1
Debt - Convertible Debt (Details) - Convertible Debt - USD ($)
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Jun. 29, 2015
Debt Instrument [Line Items]        
Interest expense $ 8,766,306 $ 8,767,188 $ 8,800,842  
Discount amortization 738,912 738,912 744,081  
Deferred debt issuance amortization 48,276 48,276 48,566  
Convertible Senior Notes Due 2020        
Debt Instrument [Line Items]        
Interest expense $ 7,979,118 $ 7,980,000 $ 8,008,195  
Interest Rate 7.00% 7.00%   7.00%