CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (unaudited) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement Of Income And Comprehensive Income [Abstract]
Net loss		$ (18,478)	$ (12,463)	$ (36,255)	$ (27,180)
Other comprehensive income (loss):
Foreign currency translation gains (losses)	[1]	807	(255)	788	(262)
Total other comprehensive income (loss)	[1]	807	(255)	788	(262)
Total comprehensive loss		$ (17,671)	$ (12,718)	$ (35,467)	$ (27,442)

[1] Net of tax effect which was not material.