Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Deficit [Member]
Balance at Dec. 31, 2020	$ 16,006	$ 1,334	$ 558,309	$ (543,637)
Balance (in shares) at Dec. 31, 2020		13,380
Exercise of stock options	239		239
Exercise of stock options (in shares)		30
Stock-based compensation	397		397
Net loss	(2,455)			(2,455)
Balance at Dec. 31, 2021	14,187	$ 1,334	558,945	(546,092)
Balance (in shares) at Dec. 31, 2021		13,410
Exercise of stock options	$ 6,533	$ 8	6,525
Exercise of stock options (in shares)	805	805
Stock-based compensation	$ 71		71
Net loss	(1,544)			(1,544)
Balance at Dec. 31, 2022	$ 19,247	$ 1,342	$ 565,541	$ (547,636)
Balance (in shares) at Dec. 31, 2022		14,215