Statements of Convertible Preferred Stock and Stockholders' Equity - USD ($)		Convertible Preferred Stock [Member]	Common Stock [Member]	Additional Paid-In Capital [Member]	Treasury Stock [Member]	Accumulated Deficit [Member]	Total
Beginning Balance at Dec. 31, 2016		$ 5,960,475	$ 22,064	$ 449,939,406	$ (205,999)	$ (471,245,398)	$ (21,489,927)
Beginning Balance, Shares at Dec. 31, 2016		23,900	22,063,582
Share-based compensation				768,682			768,682
Restricted stock vesting			$ 675	(552)			123
Restricted stock vesting, Shares			675,473
Components of comprehensive Income (loss): net Income (loss)						(5,887,410)	(5,887,410)
Employee stock purchase plan			$ 67	40,867			40,934
Employee stock purchase plan, Shares			66,676
Ending Balance at Dec. 31, 2017		$ 5,960,475	$ 22,806	450,748,403	(205,999)	(477,132,808)	(26,567,598)
Ending Balance, Shares at Dec. 31, 2017		23,900	22,805,731
Share-based compensation				561,115			561,115
Restricted stock vesting			$ 294	(294)
Restricted stock vesting, Shares			293,912
Components of comprehensive Income (loss): net Income (loss)						116,756	116,756
Employee stock purchase plan			$ 74	56,917			56,991
Employee stock purchase plan, Shares			74,367
Issuance of common stock and warrants			$ 35,793	26,813,524			26,849,317
Issuance of common stock and warrants, Shares			35,792,593
Grant of restricted shares, net of forfeitures			$ 91	(91)			0
Grant of restricted shares, net of forfeitures, Shares			91,694
Cumulative Catchup for Adoption of ASC 606	[1]					294,562	294,562
Ending Balance at Dec. 31, 2018		$ 5,960,475	$ 59,058	$ 478,179,574	$ (205,999)	$ (476,721,490)	$ 1,311,143
Ending Balance, Shares at Dec. 31, 2018		23,900	59,058,297

[1] Represents the adjustments related to the adoption of new accounting standards. See Note 2 for details.