Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Loss [Member]
Balances at beginning of period at Dec. 31, 2020	$ 15,815	$ 10	$ 308,065	$ (291,163)	$ (1,097)
Balances at beginning of period (in shares) at Dec. 31, 2020		9,743,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net proceeds from common stock sold	41,642	$ 5	41,637
Common stock sold under agreement | shares		5,502,000
Issuance of common stock from vesting of restricted stock units (in shares)		264,000
Tax withholding related to vesting of restricted stock units	(444)		(444)
Issuance of common stock under employee stock purchase plan	28		28
Issuance of common stock under employee stock purchase plan (in shares)		23,000
Stock-based compensation expense	2,108		2,108
Net loss	(12,944)			(12,944)
Foreign currency translation adjustments	53				53
Balances at end of period at Dec. 31, 2021	46,258	$ 15	351,394	(304,107)	(1,044)
Balances at end of period (in shares) at Dec. 31, 2021		15,532,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net proceeds from common stock sold	1,333	$ 1	1,332
Common stock sold under agreement | shares		1,073,000
Issuance of common stock from vesting of restricted stock units (in shares)		594,000
Tax withholding related to vesting of restricted stock units	(434)		(434)
Issuance of common stock under employee stock purchase plan	37	$ 1	36
Issuance of common stock under employee stock purchase plan (in shares)		27,000
Stock-based compensation expense	3,668		3,668
Net loss	(18,227)			(18,227)
Foreign currency translation adjustments	79				79
Balances at end of period at Dec. 31, 2022	$ 32,714	$ 17	$ 355,996	$ (322,334)	$ (965)
Balances at end of period (in shares) at Dec. 31, 2022		17,226,000