Income Taxes - Income (Loss) From Continuing Operations Before Income Tax (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income (Loss) from Operations before Income Tax Expense (Benefit) [Abstract]
Income (loss) before income taxes	$ (9,938)	$ (1,970)	$ 2,666
United States
Income (Loss) from Operations before Income Tax Expense (Benefit) [Abstract]
Income (loss) before income taxes	(13,271)	(7,775)	(570)
Foreign Tax Authority
Income (Loss) from Operations before Income Tax Expense (Benefit) [Abstract]
Income (loss) before income taxes	$ 3,333	$ 5,805	$ 3,236