Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net loss	$ (126,710)	$ (52,870)	$ (23,009)
Other comprehensive income (loss):
Foreign currency translation	1,215	(382)	0
Other comprehensive income (loss)	1,215	(382)	0
Comprehensive loss	$ (125,495)	$ (53,252)	$ (23,009)