Property and Equipment - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Depreciation	$ 938	$ 1,090
Impairment charges, property and equipment	238	76
Capitalized Software
Property, Plant and Equipment [Line Items]
Impairment charges, property and equipment	$ 232	$ 64