Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
U.S. operations	$ (21,938)	$ (9,514)	$ 6,911
Foreign operations	6,662	(2,184)	(208)
(Loss) income before income tax expense	$ (15,276)	$ (11,698)	$ 6,703