Condensed Consolidated Statements of Comprehensive Loss (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Statement of Comprehensive Income [Abstract]
Net loss	$ (39,677)	$ (30,703)	$ (117,275)	$ (83,053)
Other comprehensive income (loss), net:
Change in unrealized gain/loss on available-for-sale securities	(154)	98	(206)	(235)
Foreign currency translation adjustment	(4,878)	(75)	(2,668)	(492)
Other comprehensive income (loss)	(5,032)	23	(2,874)	(727)
Total comprehensive loss	$ (44,709)	$ (30,680)	$ (120,149)	$ (83,780)