Condensed Consolidated Statements of Changes in Equity Statement - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Treasury Stock	Accumulated Other Comprehensive Loss	Accumulated Deficit	Total Equity	Non-controlling interest
Beginning balance (in shares) at Dec. 31, 2016		397,979,772		2,282,700
Beginning balance at Dec. 31, 2016	$ 975,770	$ 4,003	$ 1,226,206	$ (19,485)	$ (767)	$ (234,187)	$ 975,770	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation and related tax effects	43,795		45,192			(1,397)	43,795
Issuances under equity incentive plans, net of tax (in shares)		12,181,123
Issuances under equity incentive plans, net of tax	9,003	$ 122	8,881				9,003
ESPP purchase shares (in shares)		565,701
ESPP purchase shares	2,855	$ 5	2,850				2,855
Net unrealized gain (loss) on available for sale securities, net of tax	171				171		171
Contribution of interests in consolidated VIE	7,722						0	7,722
Net loss	(55,298)					(55,298)	(55,298)	10
Net loss, including portion attributable to noncontrolling interest	(55,288)
Ending balance (in shares) at Jun. 30, 2017		410,726,596		2,282,700
Ending balance at Jun. 30, 2017	984,028	$ 4,130	1,283,129	$ (19,485)	(596)	(290,882)	976,296	7,732
Beginning balance (in shares) at Dec. 31, 2017		417,473,846		2,282,700
Beginning balance at Dec. 31, 2017	927,757	$ 4,198	1,327,206	$ (19,485)	(5)	(389,419)	922,495	5,262
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation and related tax effects	42,535		42,535			0	42,535
Issuances under equity incentive plans, net of tax (in shares)		4,772,667
Issuances under equity incentive plans, net of tax	(4,357)	$ 48	(4,405)				(4,357)
ESPP purchase shares (in shares)		937,607
ESPP purchase shares	2,773	$ 9	2,764				2,773
Net unrealized gain (loss) on available for sale securities, net of tax	(371)				(388)		(388)	17
Dividends paid and return of capital to noncontrolling interests	(2,125)							(2,125)
Net loss	(92,042)					(92,042)	(92,042)	50
Net loss, including portion attributable to noncontrolling interest	(91,992)
Ending balance (in shares) at Jun. 30, 2018		423,184,120		2,282,700
Ending balance at Jun. 30, 2018	$ 874,220	$ 4,255	$ 1,368,100	$ (19,485)	$ (393)	$ (481,461)	$ 871,016	$ 3,204