Consolidated Statements of Comprehensive Loss (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Statement Of Partners Capital [Abstract]
Net loss	$ (116,389)	$ (83,132)	$ (53,901)
Other comprehensive income (loss), net:
Change in unrealized gain/loss on available-for-sale securities	(240)	642	(276)
Foreign currency translation adjustment	(3,155)	(252)	(473)
Other comprehensive income (loss)	(3,395)	390	(749)
Total comprehensive loss	$ (119,784)	$ (82,742)	$ (54,650)