CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Unaudited) - 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]
Issuance of common stock through equity distribution agreement, net of offering costs	3,025		$ 1	3,024
Issuance of common stock through equity distribution agreement, net of offering costs (in shares)			1,186,000
Issuance of common stock from vesting of restricted stock units (in shares)			12,000
Tax withholding related to vesting of restricted stock units	(23)			(23)
Stock-based compensation expense	276			276
Net loss	(2,212)				(2,212)
Foreign currency translation adjustments	(51)					(51)
Balances at end of period at Mar. 31, 2021	16,830		$ 11	311,342	(293,375)	(1,148)
Balances at end of period (in shares) at Mar. 31, 2021			10,941,000
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 loss	12,944
Balances at end of period at Dec. 31, 2021	46,258	[1]	$ 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]
Issuance of common stock from vesting of restricted stock units (in shares)			11,000
Tax withholding related to vesting of restricted stock units	(29)			(29)
Stock-based compensation expense	883			883
Net loss	(1,999)				(1,999)
Foreign currency translation adjustments	3					3
Balances at end of period at Mar. 31, 2022	$ 45,116		$ 15	$ 352,248	$ (306,106)	$ (1,041)
Balances at end of period (in shares) at Mar. 31, 2022			15,543,000

[1] Derived from the Company’s audited consolidated financial statements as of December 31, 2021.