Condensed Statements of Stockholders’ Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit
Balance, beginning (in shares) at Dec. 31, 2020		42,196,296
Balance, beginning at Dec. 31, 2020	$ 191,216		$ 524,022	$ (332,806)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued upon exercises of stock options (in shares)	91,737	91,737
Shares issued upon exercises of stock options	$ 282		282
Shares issued upon vesting of restricted stock units (in shares)		38,000
Shares issued upon vesting of restricted stock units	0
Stock-based compensation	2,420		2,420
Net loss	(14,950)			(14,950)
Balance, ending (in shares) at Mar. 31, 2021		42,326,033
Balance, ending at Mar. 31, 2021	178,968		526,724	(347,756)
Balance, beginning (in shares) at Dec. 31, 2021		42,457,471
Balance, beginning at Dec. 31, 2021	$ 142,864		536,362	(393,498)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued upon exercises of stock options (in shares)	36,500	36,500
Shares issued upon exercises of stock options	$ 134		134
Stock-based compensation	2,446		2,446
Net loss	(15,351)			(15,351)
Balance, ending (in shares) at Mar. 31, 2022		42,493,971
Balance, ending at Mar. 31, 2022	$ 130,093		$ 538,942	$ (408,849)