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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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	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Property and Equipment, net
Property and equipment, gross	$ 60,265		$ 58,633
Less: Accumulated depreciation and amortization	(38,226)		(34,297)
Total Property and Equipment, net	22,039		24,336
Impairment of assets		$ 1,544
Machinery and equipment
Property and Equipment, net
Property and equipment, gross	36,614		35,400
Furniture and fixtures
Property and Equipment, net
Property and equipment, gross	$ 1,376		1,319
Useful Life	3 years
Computer equipment
Property and Equipment, net
Property and equipment, gross	$ 1,949		2,117
Useful Life	3 years
Capitalized software held for internal use
Property and Equipment, net
Property and equipment, gross	$ 5,545		4,868
Useful Life	3 years
Leasehold improvements
Property and Equipment, net
Property and equipment, gross	$ 12,580		10,916
Construction-in-process
Property and Equipment, net
Property and equipment, gross	$ 2,201		$ 4,013
Minimum \| Machinery and equipment
Property and Equipment, net
Useful Life	3 years
Maximum \| Machinery and equipment
Property and Equipment, net
Useful Life	5 years