Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Treasury Stock [Member]	Total
Balance (in shares) at Dec. 31, 2018	84,742,000				(200,000)
Balance at Dec. 31, 2018	$ 110	$ 713,019	$ (609,208)	$ (105)	$ (2,741)	$ 101,075
Net loss			(18,735)			(18,735)
Foreign currency translation adjustments				(42)		(42)
Stock-based compensation expense		1,077				$ 1,077
Exercise of stock options (in shares)						0
Balance (in shares) at Mar. 31, 2019	84,742,000				(200,000)
Balance at Mar. 31, 2019	$ 110	714,096	(627,943)	(147)	$ (2,741)	$ 83,375
Balance (in shares) at Dec. 31, 2019	86,760,000				(200,000)
Balance at Dec. 31, 2019	$ 113	727,089	(677,760)	(148)	$ (2,741)	46,553
Net loss			(16,801)			(16,801)
Foreign currency translation adjustments				(179)		(179)
Stock-based compensation expense		878				$ 878
Exercise of stock options (in shares)	36,000					36,000
Exercise of stock options		162				$ 162
Balance (in shares) at Mar. 31, 2020	86,796,000				(200,000)
Balance at Mar. 31, 2020	$ 113	$ 728,129	$ (694,561)	$ (327)	$ (2,741)	$ 30,613