Annual report pursuant to Section 13 and 15(d)

Fair Value - Carrying and Fair Value Amounts (Details)

v3.20.4
Fair Value - Carrying and Fair Value Amounts (Details) - USD ($)
Dec. 31, 2020
Dec. 31, 2019
Aug. 15, 2019
Aug. 12, 2019
Jun. 29, 2015
Carrying Amount | Level 1          
Financial Assets:          
Cash and cash equivalents $ 99,596,907 $ 120,863,643      
Carrying Amount | Level 2          
Financial Liabilities:          
Secured credit facilities 0 33,785,930      
Carrying Amount | Level 3          
Financial Assets:          
Financing notes receivable 1,209,736 1,235,000      
Fair Value | Level 1          
Financial Assets:          
Cash and cash equivalents 99,596,907 120,863,643      
Fair Value | Level 2          
Financial Liabilities:          
Secured credit facilities 0 33,785,930      
Fair Value | Level 3          
Financial Assets:          
Financing notes receivable 1,209,736 1,235,000      
7.00% Unsecured convertible senior notes | Carrying Amount | Level 1          
Financial Liabilities:          
Unsecured convertible senior notes 0 2,084,178      
7.00% Unsecured convertible senior notes | Fair Value | Level 1          
Financial Liabilities:          
Unsecured convertible senior notes 0 2,820,832      
5.875% Unsecured Convertible Senior Notes | Carrying Amount | Level 2          
Financial Liabilities:          
Unsecured convertible senior notes 115,008,130 116,239,318      
5.875% Unsecured Convertible Senior Notes | Fair Value | Level 2          
Financial Liabilities:          
Unsecured convertible senior notes $ 84,409,292 $ 122,508,000      
Convertible Debt | 7.00% Unsecured convertible senior notes          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Effective interest rate 0.00% 7.00%     7.00%
Convertible Debt | 5.875% Unsecured Convertible Senior Notes          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Effective interest rate 5.875% 5.875% 5.875% 5.875%