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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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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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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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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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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Property and Equipment, Net (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Property and Equipment, Net
Property and equipment, gross	$ 5,754		$ 5,754		$ 2,639
Accumulated depreciation	(1,345)		(1,345)		(480)
Property and equipment, net	4,409		4,409		2,159
Depreciation	366	$ 103	865	$ 208
Computer equipment
Property and Equipment, Net
Property and equipment, gross	1,338		1,338		650
Fleet vehicles
Property and Equipment, Net
Property and equipment, gross	2,076		2,076
Manufacturing equipment
Property and Equipment, Net
Property and equipment, gross	562		562		511
Lab equipment
Property and Equipment, Net
Property and equipment, gross	928		928		721
Furniture and fixtures
Property and Equipment, Net
Property and equipment, gross	524		524		327
Leasehold improvements
Property and Equipment, Net
Property and equipment, gross	$ 326		$ 326		$ 430