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 of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

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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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Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services 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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Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

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Balance Sheet Components - Property (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Property and Equipment, net
Property and equipment, gross	$ 58,633	$ 56,652
Less: Accumulated depreciation and amortization	(34,297)	(26,985)
Total Property and Equipment, net	24,336	29,667
Impairment of assets	1,544	576	$ 2,138
Machinery and equipment
Property and Equipment, net
Property and equipment, gross	35,400	31,825
Machinery and equipment \| Cost of product revenues
Property and Equipment, net
Impairment of assets		1,900
Machinery and equipment \| General and administrative expense
Property and Equipment, net
Impairment of assets		200
Machinery and equipment \| Maintenance service contract
Property and Equipment, net
Impairment of assets		300
Furniture and fixtures
Property and Equipment, net
Property and equipment, gross	$ 1,319	1,216
Useful Life	3 years
Computer equipment
Property and Equipment, net
Property and equipment, gross	$ 2,117	1,958
Useful Life	3 years
Capitalized software held for internal use
Property and Equipment, net
Property and equipment, gross	$ 4,868	4,465
Useful Life	3 years
Leasehold improvements
Property and Equipment, net
Property and equipment, gross	$ 10,916	10,691
Construction-in-process
Property and Equipment, net
Property and equipment, gross	$ 4,013	$ 6,497
Minimum \| Machinery and equipment
Property and Equipment, net
Useful Life	3 years
Maximum \| Machinery and equipment
Property and Equipment, net
Useful Life	5 years