Statements of Convertible Preferred Stock and Stockholders' Equity - USD ($)		Convertible Preferred Stock Series A (Mezzanine) [Member]	Convertible Preferred Stock Series B [Member]	Common Stock [Member]	Additional Paid-In Capital [Member]	Treasury Stock [Member]	Accumulated Deficit [Member]	Total
Beginning Balance at Dec. 31, 2017		$ 5,960,475		$ 22,806	$ 450,748,403	$ (205,999)	$ (477,132,808)	$ (26,567,598)
Beginning Balance, Shares at Dec. 31, 2017		23,900		22,805,731
Issuance of common stock and warrants				$ 35,793	26,813,524			26,849,317
Issuance of common stock and warrants, Shares				35,792,593
Share-based compensation					561,115			561,115
Restricted stock vesting				$ 385	(385)			0
Restricted stock vesting, shares				385,606
Components of net income (loss)							116,756	116,756
Employee stock purchase plan				$ 74	56,917			56,991
Employee stock purchase plan, Shares				74,367
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
Issuance of common stock and warrants				$ 7,779	13,312,405			13,320,184
Issuance of common stock and warrants, Shares				7,778,806
Share-based compensation				$ 207	1,811,877			1,812,084
Share-based compensation, shares				207,212
Components of net income (loss)							$ (4,591,284)	(4,591,284)
Employee stock purchase plan				$ 40	80,017			80,057
Employee stock purchase plan, Shares				39,648
Preferred stock issuance			$ 5,610		10,626,328			10,631,938
Preferred stock issuance, shares			5,610,121
Preferred stock conversion		$ (202,285)		$ 1,446	$ 200,839			$ 202,285
Preferred stock conversion, shares		(790)		1,445,660
Ending Balance at Dec. 31, 2019		$ 5,758,190	$ 5,610	$ 68,530	$ 504,211,040	$ (205,999)	$ (481,312,774)	$ 22,766,407
Ending Balance, Shares at Dec. 31, 2019		23,110	5,610,121	68,529,623

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