Condensed Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Net loss	$ (43,114)	$ (34,503)
Other comprehensive income (loss), net of tax:
Change in foreign currency translation and other comprehensive income (loss)	4,865	2,592
Investments:
Change in unrealized loss, net of tax	0	(536)
Reclassification adjustment due to adoption of ASU 2016-01	(4,876)	0
Comprehensive loss	$ (43,125)	$ (32,447)