Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (20,977)	$ (15,681)	$ (14,232)
Other comprehensive loss:
Effect of currency translation	(20)	(1)	7
Comprehensive net loss	$ (20,997)	$ (15,682)	$ (14,225)