Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Treasury Stock [Member]	Total
Balance at Dec. 31, 2018	$ 464	$ 548,304	$ (525,463)	$ (5,168)	$ 18,137
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	0	0	(4,926)	0	(4,926)
Balance at Dec. 31, 2019	464	548,304	(530,389)	(5,168)	13,211
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	0	0	(5,604)	0	(5,604)
Balance at Dec. 31, 2020	$ 464	$ 548,304	$ (535,993)	$ (5,168)	$ 7,607