Consolidated Statements of Changes in Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Loss, Net [Member]	Accumulated Deficit [Member]	Total
Balances at Dec. 31, 2018	$ 155	$ 2,735,125		$ (73,177)	$ (2,371,364)	$ 290,739
Beginning balance, shares at Dec. 31, 2018	15,488,542
Net loss					(47,705)	(47,705)
Foreign currency translation adjustment				1,073		1,073
Stock-based compensation expense, net of forfeitures		5,625				5,625
Transactions under stock plans, value	$ 1	(1,667)				(1,666)
Transactions under stock plans, shares	107,118
Balances at Mar. 31, 2019	$ 156	2,739,083		(72,104)	(2,419,069)	248,066
Ending balance, shares at Mar. 31, 2019	15,595,660
Balances at Dec. 31, 2018	$ 155	2,735,125		(73,177)	(2,371,364)	290,739
Beginning balance, shares at Dec. 31, 2018	15,488,542
Balances at Dec. 31, 2019	$ 16	2,752,859	$ (4,290)	(71,927)	(2,627,085)	49,573
Ending balance, shares at Dec. 31, 2019	15,689,463
Net loss					(79,464)	(79,464)
Foreign currency translation adjustment				(4,538)		(4,538)
Stock-based compensation expense, net of forfeitures		2,527				2,527
Transactions under stock plans, value		(208)				(208)
Transactions under stock plans, shares	108,965
Balances at Mar. 31, 2020	$ 16	$ 2,755,178	$ (4,290)	$ (76,465)	$ (2,706,549)	$ (32,110)
Ending balance, shares at Mar. 31, 2020	15,798,428