Fixed Assets - Schedule of Fixed Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Total cost	$ 1,826	$ 1,848
Less: accumulated depreciation	(1,774)	(1,755)
Fixed assets, net of accumulated depreciation and amortization	52	93
Computer equipment and software, office equipment and furniture
Property, Plant and Equipment [Line Items]
Total cost	$ 1,297	1,346
Computer equipment and software, office equipment and furniture | Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life (in years)	3 years
Computer equipment and software, office equipment and furniture | Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life (in years)	5 years
Leasehold improvements
Property, Plant and Equipment [Line Items]
Total cost	$ 529	$ 502
Property, plant and equipment, useful life (in years)	5 years