The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation.

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The aggregate amount of write-downs for impairments recognized during the period for long-lived assets held for abandonment, exchange or sale.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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Describes the basis at which an entity records its property, plant and equipment (for example at cost, fair value).

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Description of the methodology for computing depreciation for classes of depreciable assets.

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Describes the periods of time over which an entity anticipates to receive utility from its property, plant and equipment (that is, the periods of time over which an entity allocates the initial cost of its property, plant and equipment).

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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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 - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Property Plant And Equipment [Line Items]
Property plant and equipment basis of valuation	cost
Property plant and equipment depreciation methods	the straight-line method over the estimated useful lives of the assets
Depreciation expense	$ 1,948,000	$ 1,567,000	$ 1,294,000
Impairment of long-lived assets	$ 0
Minimum
Property Plant And Equipment [Line Items]
Property plant and equipment useful life	2 years
Maximum
Property Plant And Equipment [Line Items]
Property plant and equipment useful life	5 years
Leasehold improvements
Property Plant And Equipment [Line Items]
Property plant and equipment estimated useful lives	shorter of their estimated useful lives or the related lease term