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 aggregate net amount of depreciation, amortization, and accretion recognized during an accounting period. As a noncash item, the net amount is added back to net income when calculating cash provided by or used in operations using the indirect method.

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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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Supplemental Balance Sheet Information - Property and Equipment, Net (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 6,108		$ 6,108		$ 3,416
Less: accumulated depreciation	(1,644)		(1,644)		(1,317)
Property and equipment, net	4,464		4,464		2,099
Depreciation and amortization	187	$ 87	335	$ 174
Scientific equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	3,315		3,315		2,795
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	192		192		192
Computers and software
Property, Plant and Equipment [Line Items]
Property and equipment, gross	48		48		32
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property and equipment, gross	41		41		41
Construction in process
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 2,512		$ 2,512		$ 356