Consolidated Statements of Comprehensive (Loss) Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement Of Income And Comprehensive Income [Abstract]
Net (loss) income	$ (2,060)	$ 5,951	$ (1,496)
Other comprehensive loss components:
Foreign currency translation	1,871	(3,866)	(1,099)
Total other comprehensive loss	1,871	(3,866)	(1,099)
Comprehensive (loss) income	$ (189)	$ 2,085	$ (2,595)