Consolidated Statements of Stockholders’ Equity - USD ($)	Total	Preferred Stock [Member]	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]
Balance at Dec. 31, 2015	$ (6,087,441)	$ 0	$ 325,252	$ (8,034,244)	$ 434,099,890	$ (432,478,339)
Balance (in Shares) at Dec. 31, 2015		0	32,445,811
Issuance of common stock and warrants pursuant to financing agreements	28,100,000	$ 0	$ 231,276	0	27,868,724	0
Issuance of common stock and warrants pursuant to financing agreements (in shares)		0	23,127,566
Issuance of common stock from exercise of contingent purchase right	$ 46,232	$ 0	$ 46,232	0	0	0
Issuance of common stock from exercise of contingent purchase right (in shares)	0		4,623,197
Partial settlement of contingent purchase rights derivative	$ 5,279,744	0	$ 0	0	5,279,744	0
Stock issuance costs	(96,512)	0	0	0	(96,512)	0
Stock-based compensation expense, net of forfeitures	2,995,240	0	0	0	2,995,240	0
Net loss	(9,453,488)	0	0	0	0	(9,453,488)
Balance at Dec. 31, 2016	20,783,775	$ 0	$ 602,760	(8,034,244)	470,147,086	(441,931,827)
Balance (in shares) at Dec. 31, 2016		0	60,196,574
Issuance of common stock and warrants pursuant to financing agreements	23,884,475	$ 0	$ 79,519	0	23,804,956	0
Issuance of common stock and warrants pursuant to financing agreements (in shares)		0	7,951,865
Issuance of common stock from exercise of contingent purchase right	15,191	$ 0	$ 15,191	0	0	0
Issuance of common stock from exercise of contingent purchase right (in shares)		0	1,519,096
Issuance of common stock for options exercised	325,999	$ 0	$ 1,545	0	324,454	0
Issuance of common stock for options exercised (in shares)		0	154,545
Partial settlement of contingent purchase rights derivative	4,142,157	$ 0	$ 0	0	4,142,157	0
Stock issuance costs	(491,721)	0	0	0	(491,721)	0
Stock-based compensation expense, net of forfeitures	650,440	0	0	0	650,440	0
Net loss	(10,770,202)	0	0	0	0	(10,770,202)
Balance at Dec. 31, 2017	$ 38,540,114	$ 0	$ 699,015	$ (8,034,244)	$ 498,577,372	$ (452,702,029)
Balance (in shares) at Dec. 31, 2017		0	69,822,080