Condensed Statements of Stockholders' Equity - USD ($) $ in Thousands	Common Stock At The Market Equity Offering Program	Common Stock	Additional Paid-in Capital At The Market Equity Offering Program	Additional Paid-in Capital	Accumulated Deficit At The Market Equity Offering Program	Accumulated Deficit	At The Market Equity Offering Program	Total
Beginning Balance at Dec. 31, 2020		$ 19		$ 218,020		$ (200,527)		$ 17,512
Beginning Balance, Shares at Dec. 31, 2020		193,378,996
Issuance of common stock for services		$ 0		80		0		80
Issuance of common stock for services (Shares)		54,052
Share-based compensation, net of forfeitures		$ 0		166		0		166
Stock options exercised, net		$ 0		33		0		33
Stock options exercised, net (Shares)		129,500
Shares held back in settlement of tax obligation for shares issued in connection with restricted stock awards				(40)		0		(40)
Shares held back in settlement of tax obligation for shares issued in connection with restricted stock awards (Shares)		(28,562)
Warrants exercised, net		$ 0		114		0		114
Warrants exercised, net (Shares)		306,705
Issuance of common stock in connection with the "at-the-market" equity offering program	$ 0		$ 2,705		$ 0		$ 2,705
Issuance of common stock in connection with the "at-the-market" equity offering program (Shares)	1,848,437
Offering costs related to the issuance of common stock in connection with the "at-the-market" equity offering program		$ 0		(126)		0		(126)
Net loss		0		0		(3,667)		(3,667)
Ending Balance at Mar. 31, 2021		$ 19		220,952		(204,194)		16,777
Ending Balance, Shares at Mar. 31, 2021		195,689,128
Beginning Balance at Dec. 31, 2020		$ 19		218,020		(200,527)		17,512
Beginning Balance, Shares at Dec. 31, 2020		193,378,996
Net loss								(7,222)
Ending Balance at Jun. 30, 2021		$ 20		228,091		(207,750)		20,361
Ending Balance, Shares at Jun. 30, 2021		(200,070,419)
Beginning Balance at Mar. 31, 2021		$ 19		220,952		(204,194)		16,777
Beginning Balance, Shares at Mar. 31, 2021		195,689,128
Share-based compensation, net of forfeitures		$ 0		67		0		67
Stock options exercised, net		$ 0		127		0		127
Stock options exercised, net (Shares)		314,162
Shares held back in settlement of tax obligation for shares issued in connection with restricted stock awards		$ 0		0		0		0
Shares held back in settlement of tax obligation for shares issued in connection with restricted stock awards (Shares)		(28,802)
Warrants exercised, net		$ 0		0		0		0
Warrants exercised, net (Shares)		29,158
Issuance of common stock in connection with the "at-the-market" equity offering program	$ 1		$ 7,266		$ 0		$ 7,267
Issuance of common stock in connection with the "at-the-market" equity offering program (Shares)	4,066,773
Offering costs related to the issuance of common stock in connection with the "at-the-market" equity offering program		$ 0		(321)		0		(321)
Net loss		0		0		(3,556)		(3,556)
Ending Balance at Jun. 30, 2021		$ 20		228,091		(207,750)		20,361
Ending Balance, Shares at Jun. 30, 2021		(200,070,419)
Beginning Balance at Dec. 31, 2021		$ 23		244,863		(217,602)		27,284
Beginning Balance, Shares at Dec. 31, 2021		227,325,381
Share-based compensation, net of forfeitures		$ 0		716		0		716
Shares held back in settlement of tax obligation for shares issued in connection with restricted stock awards		$ 0		(79)		0		(79)
Shares held back in settlement of tax obligation for shares issued in connection with restricted stock awards (Shares)		(138,514)
Costs related to the sale of common stock and warrants in connection with the registered direct offering		$ 0		(32)		0		(32)
Net loss		0		0		(5,636)		(5,636)
Ending Balance at Mar. 31, 2022		$ 23		245,468		(223,238)		22,253
Ending Balance, Shares at Mar. 31, 2022		227,186,867
Beginning Balance at Dec. 31, 2021		$ 23		244,863		(217,602)		27,284
Beginning Balance, Shares at Dec. 31, 2021		227,325,381
Net loss								(7,706)
Ending Balance at Jun. 30, 2022		$ 23		245,382		(225,308)		20,097
Ending Balance, Shares at Jun. 30, 2022		226,286,867
Beginning Balance at Mar. 31, 2022		$ 23		245,468		(223,238)		22,253
Beginning Balance, Shares at Mar. 31, 2022		227,186,867
Share-based compensation, net of forfeitures		$ 0		423		0		423
Restricted stock award forfeitures		$ 0		(509)		0		(509)
Restricted stock award forfeitures (Shares)		(900,000)
Net loss		$ 0		0		(2,070)		(2,070)
Ending Balance at Jun. 30, 2022		$ 23		$ 245,382		$ (225,308)		$ 20,097
Ending Balance, Shares at Jun. 30, 2022		226,286,867