Balance Sheet Components - Schedule of Property and Equipment, Net (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Property Plant And Equipment [Line Items]
Less: accumulated amortization and depreciation	$ (996)	$ (959)
Property and equipment, net	230	263
Computer Equipment
Property Plant And Equipment [Line Items]
Property and equipment	52	53
Lab Equipment
Property Plant And Equipment [Line Items]
Property and equipment	528	528
Finance Lease Right of Use Assets
Property Plant And Equipment [Line Items]
Property and equipment	557	557
Leasehold Improvement
Property Plant And Equipment [Line Items]
Property and equipment	63	58
Office Furniture
Property Plant And Equipment [Line Items]
Property and equipment	$ 26	$ 26

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 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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