Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement of Comprehensive Income [Abstract]
Net loss	$ (101,556)	$ (141,447)	$ (162,141)
Other comprehensive income (loss), net:
Change in unrealized gain/loss on available-for-sale securities	(2)	228	(312)
Foreign currency translation adjustment	5,525	(11,545)	(6,908)
Other comprehensive income (loss)	5,523	(11,317)	(7,220)
Total comprehensive loss	$ (96,033)	$ (152,764)	$ (169,361)