Quarterly report pursuant to Section 13 or 15(d)

Fair Value - Carrying and Fair Value Amounts (Details)

v3.7.0.1
Fair Value - Carrying and Fair Value Amounts (Details) - USD ($)
Mar. 31, 2017
Dec. 31, 2016
Carrying Amount [Member] | Level 1 [Member]    
Financial Assets:    
Cash and cash equivalents $ 11,375,702 $ 7,895,084
Financial Liabilities:    
Unsecured convertible senior notes 111,441,691 111,244,895
Carrying Amount [Member] | Level 2 [Member]    
Financial Liabilities:    
Long-term debt 86,992,738 89,387,985
Carrying Amount [Member] | Level 3 [Member]    
Financial Assets:    
Financing notes receivable 1,500,000 1,500,000
Fair Value [Member] | Level 1 [Member]    
Financial Assets:    
Cash and cash equivalents 11,375,702 7,895,084
Financial Liabilities:    
Unsecured convertible senior notes 127,300,380 129,527,940
Fair Value [Member] | Level 2 [Member]    
Financial Liabilities:    
Long-term debt 86,992,738 89,387,985
Fair Value [Member] | Level 3 [Member]    
Financial Assets:    
Financing notes receivable $ 1,500,000 $ 1,500,000