Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017	Dec. 31, 2016
Accumulated Other Comprehensive Income [Abstract]
Accumulated other comprehensive income	$ 309	$ (122)	$ 307	$ (260)
Foreign currency translation adjustments	2	138
Translation Adjustment Functional to Reporting Currency, Tax Benefit (Expense)	0	0
Total other comprehensive income, net of tax	$ 2	$ 138