Consolidated Statements Of Changes In Stockholders' Equity - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Loss, Net [Member]	Retained Deficit [Member]	Total
Beginning balance, value at Dec. 31, 2016	$ 152	$ 2,691,553		$ (80,248)	$ (1,307,537)	$ 1,303,920
Beginning balance, shares at Dec. 31, 2016	151,861,661
Net loss					(205,921)	(205,921)
Foreign currency translation adjustment				12,821		12,821
Stock-based compensation expense, net of forfeitures		26,221				26,221
Exercise of stock options, value		99				99
Exercise of stock options, shares	5,998
Transactions under stock plans	$ 1	(8,327)				(8,326)
Transactions under stock plans, shares	1,034,973
Shares issued under Employee Stock Purchase Plan, value		3,615				$ 3,615
Shares issued under Employee Stock Purchase Plan	360,465					360,465
Ending balance, value at Dec. 31, 2017	$ 153	2,713,161		(67,427)	(1,513,458)	$ 1,132,429
Ending balance, shares at Dec. 31, 2017	153,263,097
Net loss					(858,115)	(858,115)
Foreign currency translation adjustment				(5,750)		(5,750)
Forfeited dividends					209	209
Stock-based compensation expense, net of forfeitures		24,076				24,076
Transactions under stock plans	$ 2	(5,200)				(5,198)
Transactions under stock plans, shares	1,071,371
Shares issued under Employee Stock Purchase Plan, value		3,088				$ 3,088
Shares issued under Employee Stock Purchase Plan	550,950					550,950
Ending balance, value at Dec. 31, 2018	$ 155	2,735,125		(73,177)	(2,371,364)	$ 290,739
Ending balance, shares at Dec. 31, 2018	154,885,418
Net loss					(255,721)	(255,721)
Foreign currency translation adjustment				1,250		1,250
Purchases of treasury stock			$ (4,290)			(4,290)
Stock-based compensation expense, net of forfeitures		18,459				18,459
Transactions under stock plans	$ 2	(1,677)				(1,675)
Transactions under stock plans, shares	1,187,961
Shares issued under Employee Stock Purchase Plan, value		811				$ 811
Shares issued under Employee Stock Purchase Plan	532,292					532,292
1-for-10 Reverse Stock Split	$ (141)	141
1-for-10 Reverse Stock Split, shares	(140,916,208)
Ending balance, value 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