Balance Sheet Information - Property, Equipment and Software Development, Net (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Property, equipment, and software development, at cost	$ 27,286	$ 28,236
Accumulated depreciation and amortization	(21,872)	(22,792)
Property, equipment, and software development, net	5,414	5,444
Automobiles
Property, Plant and Equipment [Line Items]
Property, equipment, and software development, at cost	12	13
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property, equipment, and software development, at cost	167	168
Computer, communications, and network equipment
Property, Plant and Equipment [Line Items]
Property, equipment, and software development, at cost	16,936	21,009
Software
Property, Plant and Equipment [Line Items]
Property, equipment, and software development, at cost	3,834	5,311
Software development
Property, Plant and Equipment [Line Items]
Property, equipment, and software development, at cost	6,208	1,735
Leasehold Improvements
Property, Plant and Equipment [Line Items]
Property, equipment, and software development, at cost	$ 129	$ 0

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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