Condensed 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, 2019	$ 464	$ 548,304	$ (530,389)	$ (5,168)	$ 13,211
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	0	0	(1,418)	0	(1,418)
Balance at Mar. 31, 2020	464	548,304	(531,807)	(5,168)	11,793
Balance at Dec. 31, 2020	464	548,304	(535,993)	(5,168)	7,607
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	0	0	(1,635)	0	(1,635)
Balance at Mar. 31, 2021	$ 464	$ 548,304	$ (537,628)	$ (5,168)	$ 5,972