Property and Equipment, Net - Schedule of Property and Equipment, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Total cost	$ 20,083	$ 21,201
Less: accumulated depreciation	(12,909)	(11,288)
Property and equipment, net	7,174	9,913
Equipment [Member]
Property, Plant and Equipment [Line Items]
Total cost	4,145	4,471
Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Total cost	481	489
Computer Software [Member]
Property, Plant and Equipment [Line Items]
Total cost	570	524
Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Total cost	164	215
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Total cost	3,941	4,030
Vehicles [Member]
Property, Plant and Equipment [Line Items]
Total cost	10	10
Surgical Instruments [Member]
Property, Plant and Equipment [Line Items]
Total cost	$ 10,772	$ 11,461