Property and equipment, net - Schedule of Property Plant and Equipment (Details) - USD ($)	Dec. 31, 2021	Dec. 31, 2020
Property Plant And Equipment [Line Items]
Laboratory equipment	$ 0	$ 955,000
Less accumulated depreciation	0	661,000
Property and equipment, net	0	294,000
Laboratory Equipment
Property Plant And Equipment [Line Items]
Laboratory equipment	0	808,000
Computer Equipment
Property Plant And Equipment [Line Items]
Laboratory equipment	0	29,000
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Laboratory equipment	0	53,000
Leasehold Improvements [Member]
Property Plant And Equipment [Line Items]
Laboratory equipment	$ 0	$ 65,000

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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