Consolidated Statements Of Changes In Stockholders' Equity (Deficit) - USD ($)	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Loss, Net [Member]	Accumulated Deficit [Member]	Total
Beginning balance, value at Dec. 31, 2017	$ 153,000	$ 2,713,161,000		$ (67,427,000)	$ (1,513,458,000)	$ 1,132,429,000
Beginning balance, shares at Dec. 31, 2017	153,263,097
Net loss					(858,115,000)	(858,115,000)
Foreign currency translation adjustment				(5,750,000)		(5,750,000)
Forfeited dividends					209,000	209,000
Stock-based compensation expense, net of forfeitures		24,076,000				24,076,000
Transactions under stock plans	$ 2,000	(5,200,000)				(5,198,000)
Transactions under stock plans, shares	1,071,371
Shares issued under Employee Stock Purchase Plan, value		3,088,000				3,088,000
Shares issued under Employee Stock Purchase Plan, shares	550,950
Ending balance, value at Dec. 31, 2018	$ 155,000	2,735,125,000		(73,177,000)	(2,371,364,000)	290,739,000
Ending balance, shares at Dec. 31, 2018	154,885,418
Net loss					(255,721,000)	(255,721,000)
Foreign currency translation adjustment				1,250,000		1,250,000
Purchases of treasury stock			$ (4,290,000)			(4,290,000)
Stock-based compensation expense, net of forfeitures		18,459,000				18,459,000
Transactions under stock plans	$ 2,000	(1,677,000)				(1,675,000)
Transactions under stock plans, shares	1,187,961
Shares issued under Employee Stock Purchase Plan, value	$ 532,292	811,000				$ 811,000
Shares issued under Employee Stock Purchase Plan, shares						550,950
1-for-10 Reverse Stock Split	$ (141,000)	141,000
1-for-10 Reverse Stock Split, shares	(140,916,208)
Ending balance, value at Dec. 31, 2019	$ 16,000	2,752,859,000	(4,290,000)	(71,927,000)	(2,627,085,000)	$ 49,573,000
Ending balance, shares at Dec. 31, 2019	15,689,463
Net loss					(396,230,000)	(396,230,000)
Foreign currency translation adjustment				3,980,000		3,980,000
Stock-based compensation expense, net of forfeitures		4,238,000				4,238,000
Transactions under stock plans		(208,000)				$ (208,000)
Transactions under stock plans, shares	109,855
Shares issued under Employee Stock Purchase Plan, shares						532,292
Ending balance, value at Dec. 31, 2020	$ 16,000	$ 2,756,889,000	$ (4,290,000)	$ (67,947,000)	$ (3,023,315,000)	$ (338,647,000)
Ending balance, shares at Dec. 31, 2020	15,799,318