Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net loss	$ (52,604)	$ (10,251)	$ (14,678)
Other comprehensive loss:
Translation adjustments	1,722	(952)	(1,255)
Adjustment for fair value of hedge derivatives, net of tax	350	292	(67)
Other comprehensive income (loss)	2,072	(660)	(1,322)
Comprehensive loss	$ (50,532)	$ (10,911)	$ (16,000)