Condensed Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (16,918)	$ (3,437)	$ (29,260)	$ (9,639)
Other comprehensive income (loss):
Foreign currency translation adjustment, net of taxes	(2,384)	85	(2,651)	126
Total comprehensive loss	$ (19,302)	$ (3,352)	$ (31,911)	$ (9,513)