Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Net (loss) income	$ (11,034)	$ (7,517)	$ 2,253
Unrealized loss on marketable securities	(1)	(1)	(3)
Foreign currency translation adjustment	5,404	(9,288)	(4,207)
Unrealized gain on derivative instruments, net	89	80	57
Other comprehensive income (loss), net of tax (1)	5,492	(9,209)	(4,153)
Total comprehensive loss	$ (5,542)	$ (16,726)	$ (1,900)