Condensed Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Net loss	$ (27,655)	$ (35,917)	$ (76,969)	$ (87,336)
Other comprehensive income (loss), net of tax:
Change in foreign currency translation and other comprehensive income (loss)	(134)	8,557	(7,734)	21,646
Investments:
Change in unrealized loss, net of tax	0	(6)	0	(749)
Reclassification adjustment due to adoption of ASU 2016-01	0	0	(4,876)	0
Reclassification adjustments for losses included in net loss, net of tax	0	96	0	690
Comprehensive loss	$ (27,789)	$ (27,270)	$ (89,579)	$ (65,749)