Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	AOCI Attributable to Parent [Member]	Retained Earnings [Member]	Total
Balance (in shares) at Dec. 31, 2021	29,716
Balance at Dec. 31, 2021	$ 29	$ 271,861	$ 0	$ (236,200)	$ 35,690
Issuance of shares under employee stock purchase plan (in shares)	86
Issuance of shares under employee stock purchase plan	$ 0	372	0	0	372
Stock-based compensation expense	0	2,007	0	0	2,007
Net loss	$ 0		0	(17,273)	(17,273)
Balance (in shares) at Mar. 31, 2022	29,802
Balance at Mar. 31, 2022	$ 29	274,240	0	(253,473)	20,796
Balance (in shares) at Dec. 31, 2022	37,235
Balance at Dec. 31, 2022	$ 37	292,420	0	(294,705)	(2,248)
Issuance of shares under employee stock purchase plan (in shares)	262
Issuance of shares under employee stock purchase plan	$ 0	291	0	0	291
Issuance of shares upon exercise of warrants (in shares)	96
Issuance of shares upon exercise of warrants	$ 0	194	0	0	194
Stock-based compensation expense	0	896	0	0	896
Net loss	$ 0	0	0	(9,801)	(9,801)
Balance (in shares) at Mar. 31, 2023	37,593
Balance at Mar. 31, 2023	$ 37	$ 293,801	$ 0	$ (304,506)	$ (10,668)