Condensed Statements of Stockholders' Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit
Balances at Dec. 31, 2020	$ 21,147	$ 7	$ 174,342	$ (153,202)
Balance (in shares) at Dec. 31, 2020		3,189
Common stock issued, net	65		65
Common stock issued, net (in shares)		35
Stock-based compensation	1,169		1,169
Stock-based compensation (In shares)		35
Net loss	(7,236)			(7,236)
Balances at Mar. 31, 2021	15,145	$ 7	175,576	(160,438)
Balance (in shares) at Mar. 31, 2021		3,259
Balances at Dec. 31, 2020	21,147	$ 7	174,342	(153,202)
Balance (in shares) at Dec. 31, 2020		3,189
Net loss	(12,485)
Balances at Jun. 30, 2021	21,263	$ 7	186,943	(165,687)
Balance (in shares) at Jun. 30, 2021		5,903
Balances at Mar. 31, 2021	15,145	$ 7	175,576	(160,438)
Balance (in shares) at Mar. 31, 2021		3,259
Common stock issued, net	10,645		10,645
Common stock issued, net (in shares)		2,582
Common stock issued pursuant to the vesting of restricted stock units and purchases under the employee stock purchase plan	26		26
Common stock issued pursuant to the vesting of restricted stock units and purchases under the employee stock purchase plan (in shares)		6
Stock-based compensation	696		696
Stock-based compensation (In shares)		56
Net loss	(5,249)			(5,249)
Balances at Jun. 30, 2021	21,263	$ 7	186,943	(165,687)
Balance (in shares) at Jun. 30, 2021		5,903
Balances at Dec. 31, 2021	13,673	$ 8	191,937	(178,272)
Balance (in shares) at Dec. 31, 2021		7,010
Common stock and warrants issued, net	9,740	$ 2	9,738
Common stock and warrants issued, net (in shares)		25,248
Warrants exercised	25		25
Warrants exercised (in shares)		50
Restricted stock awards cancelled		(7)
Stock-based compensation	165		165
Net loss	(5,495)			(5,495)
Balances at Mar. 31, 2022	18,108	$ 10	201,865	(183,767)
Balance (in shares) at Mar. 31, 2022		32,301
Balances at Dec. 31, 2021	13,673	$ 8	191,937	(178,272)
Balance (in shares) at Dec. 31, 2021		7,010
Net loss	(13,943)
Balances at Jun. 30, 2022	9,791	$ 10	201,996	(192,215)
Balance (in shares) at Jun. 30, 2022		32,279
Balances at Mar. 31, 2022	18,108	$ 10	201,865	(183,767)
Balance (in shares) at Mar. 31, 2022		32,301
Common stock issued pursuant to the vesting of restricted stock units and purchases under the employee stock purchase plan	5		5
Common stock issued pursuant to the vesting of restricted stock units and purchases under the employee stock purchase plan (in shares)		19
Restricted stock awards cancelled		(41)
Stock-based compensation	126		126
Net loss	(8,448)			(8,448)
Balances at Jun. 30, 2022	$ 9,791	$ 10	$ 201,996	$ (192,215)
Balance (in shares) at Jun. 30, 2022		32,279