Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement of Comprehensive Income [Abstract]
Net loss	$ (28,808)	$ (25,123)	$ (85,058)	$ (80,277)
Other comprehensive (loss) income:
Foreign currency translation adjustment	(12)	13	(22)	34
Comprehensive loss	$ (28,820)	$ (25,110)	$ (85,080)	$ (80,243)