Balance Sheet Components (Inventories, Property and Equipment) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Inventories
Finished goods	$ 37,801	$ 33,050
Component parts	3,773	4,025
Work-in-process	47	96
Total inventories	41,621	37,171
Property and equipment, net
Property and equipment, gross	25,728	23,537
Less: accumulated depreciation	(17,044)	(16,200)
Property and equipment, net	8,684	7,337
Computer equipment and software
Property and equipment, net
Property and equipment, gross	5,137	5,030
Manufacturing tooling and test equipment
Property and equipment, net
Property and equipment, gross	4,297	4,894
Lab and warehouse equipment
Property and equipment, net
Property and equipment, gross	5,692	4,869
Leasehold improvements
Property and equipment, net
Property and equipment, gross	5,059	3,960
Furniture and fixtures
Property and equipment, net
Property and equipment, gross	4,457	3,698
Other
Property and equipment, net
Property and equipment, gross	$ 1,086	$ 1,086

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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