Fixed Assets - Schedule of Fixed Assets, Net (Detail) - USD ($) $ in Thousands	9 Months Ended
Sep. 30, 2021	Dec. 31, 2020
Fixed assets, gross	$ 1,645	$ 1,375
Less: Accumulated depreciation	(510)	(335)
Fixed assets, net	1,135	1,040
Computer Equipment [Member]
Fixed assets, gross	$ 66	66
Fixed assets, useful life	5 years
Lab Equipment [Member]
Fixed assets, gross	$ 1,092	849
Fixed assets, useful life	5 years
Furniture and Fixtures [Member]
Fixed assets, gross	$ 456	$ 460
Fixed assets, useful life	7 years
Lease hold Improvements [Member]
Fixed assets, gross	$ 31
Fixed assets, useful life	lease term

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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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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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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