Statements of Convertible Preferred Stock and Stockholders' Equity (Unaudited) - USD ($)	Convertible Preferred Stock Series A [Member]	Convertible Preferred Stock Series B [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Retained Earnings [Member]	Total
Beginning balance, value at Dec. 31, 2018	$ 5,960,475		$ 59,058	$ 478,179,574	$ (205,999)	$ (476,721,490)	$ 1,311,143
Beginning Balance, Shares at Dec. 31, 2018	23,900	(0)	59,058,297
Issuance of common stock and warrants			$ 47	(50,479)			(50,432)
Issuance of common stock and warrants, Shares			46,484
Share-based compensation			$ 174	954,808			954,982
Share-based compensation, shares			174,462
Components of net loss						$ (3,550,538)	(3,550,538)
Employee stock purchase plan			$ 24	$ 31,934			$ 31,958
Employee stock purchase plan, Shares			23,757
Issuance of common stock, Shares
Preferred stock conversion	$ (11,522)		$ 80	$ 11,442			$ 11,522
Preferred stock conversion, shares	(45)		80,038
Ending balance, value at Jun. 30, 2019	$ 5,948,953		$ 59,383	479,127,279	(205,999)	$ (480,272,028)	(1,291,365)
Ending Balance, Shares at Jun. 30, 2019	23,855	(0)	59,383,038
Beginning balance, value at Mar. 31, 2019	$ 5,955,354		$ 59,308	478,363,886	(205,999)	(478,844,310)	(627,115)
Beginning Balance, Shares at Mar. 31, 2019	23,880		59,308,237
Issuance of common stock and warrants			$ 14	(66,869)			(66,855)
Issuance of common stock and warrants, Shares			13,397
Share-based compensation			$ 7	807,021			807,028
Share-based compensation, shares			7,500
Components of net loss						(1,427,718)	(1,427,718)
Employee stock purchase plan			$ 9	16,885			16,894
Employee stock purchase plan, Shares			9,132
Issuance of common stock
Issuance of common stock, Shares
Preferred stock conversion	$ (6,401)		$ 45	6,356			6,401
Preferred stock conversion, shares	(25)		44,772
Ending balance, value at Jun. 30, 2019	$ 5,948,953		$ 59,383	479,127,279	(205,999)	(480,272,028)	(1,291,365)
Ending Balance, Shares at Jun. 30, 2019	23,855	(0)	59,383,038
Beginning balance, value at Dec. 31, 2019	$ 5,758,190	$ 5,610	$ 68,530	504,211,040	$ (205,999)	(481,312,774)	22,766,407
Beginning Balance, Shares at Dec. 31, 2019	23,110	5,610,121	68,529,623
Issuance of common stock and warrants			$ 3,815	15,004,554			15,008,369
Issuance of common stock and warrants, Shares			3,815,092
Share-based compensation			$ 117	1,657,604			1,657,721
Share-based compensation, shares			116,989
Components of net loss						$ (3,892,637)	(3,892,637)
Employee stock purchase plan			$ 18	$ 65,006			$ 65,024
Employee stock purchase plan, Shares			17,835
Issuance of common stock, Shares
Preferred stock conversion	$ (76,049)		$ 551	$ 75,498			$ 76,049
Preferred stock conversion, shares	(297)		551,285
Ending balance, value at Jun. 30, 2020	$ 5,682,141	$ 5,610	$ 73,031	521,013,702	(205,999)	$ (485,205,411)	35,680,933
Ending Balance, Shares at Jun. 30, 2020	22,813	5,610,121	73,030,824
Beginning balance, value at Mar. 31, 2020	$ 5,709,027	$ 5,610	$ 69,041	504,990,377	(205,999)	(483,284,305)	21,574,724
Beginning Balance, Shares at Mar. 31, 2020	22,918	5,610,121	69,040,781
Share-based compensation			$ 8	935,401			935,409
Share-based compensation, shares			7,500
Components of net loss						(1,921,106)	(1,921,106)
Employee stock purchase plan			$ 11	32,790			32,801
Employee stock purchase plan, Shares			11,429
Issuance of common stock			$ 3,774	15,028,445			15,032,219
Issuance of common stock, Shares			3,774,276
Preferred stock conversion	$ (26,886)		$ 197	26,689			26,886
Preferred stock conversion, shares	(105)		196,838
Ending balance, value at Jun. 30, 2020	$ 5,682,141	$ 5,610	$ 73,031	$ 521,013,702	$ (205,999)	$ (485,205,411)	$ 35,680,933
Ending Balance, Shares at Jun. 30, 2020	22,813	5,610,121	73,030,824