CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	At-the-Market Offering	Equity Offering	Common Stock	Common Stock At-the-Market Offering	Common Stock Equity Offering	Additional Paid-In Capital	Additional Paid-In Capital At-the-Market Offering	Additional Paid-In Capital Equity Offering	Accumulated Other Comprehensive Loss	Accumulated Deficit
Balance (in shares) at Dec. 31, 2021				4,881,851
Balance at Dec. 31, 2021	$ 16,026			$ 49			$ 402,283			$ (175)	$ (386,131)
Increase (decrease) in stockholders' equity
Stock-based compensation expense	1,903						1,903
Issuance of common stock for 401k match (in shares)				36,706
Issuance of common stock for 401(k) match	128						128
Issuance of common stock upon vesting of restricted stock units (in shares)				25,645
Taxes paid on employees' behalf related to vesting of stock awards	(37)						(37)
Effect of foreign currency translation and unrelated loss on investments	(54)									(54)
Net loss	(13,566)										(13,566)
Balance (in shares) at Dec. 31, 2022				4,944,202
Balance at Dec. 31, 2022	4,400			$ 49			404,277			(229)	(399,697)
Increase (decrease) in stockholders' equity
Stock-based compensation expense	1,544						1,544
Issuance of common stock for 401k match (in shares)				119,971
Issuance of common stock for 401(k) match	111			$ 1			110
Issuance of common stock upon vesting of restricted stock units (in shares)				17,640
Taxes paid on employees' behalf related to vesting of stock awards	$ (41)						(41)
Issuance of stock (in shares)					94,665	6,756,710
Issuance of stock		$ 103	$ 5,842		$ 1	$ 68		$ 102	$ 5,774
Issuance of common stock for director compensation (in shares)	99,237			99,237
Issuance of common stock for director compensation	$ 49			$ 1			48
Effect of foreign currency translation and unrelated loss on investments	(36)									(36)
Net loss	(14,455)										(14,455)
Balance (in shares) at Dec. 31, 2023				12,032,425
Balance at Dec. 31, 2023	$ (2,483)			$ 120			$ 411,814			$ (265)	$ (414,152)