Property and equipment, net (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, after Accumulated Depreciation and Amortization [Abstract]
Property, plant and equipment, gross	$ 3,805	$ 3,219
Less accumulated depreciation and amortization	(2,274)	(1,519)
Property and equipment, net	1,531	1,700
Lab equipment
Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, after Accumulated Depreciation and Amortization [Abstract]
Property, plant and equipment, gross	3,506	2,942
Leasehold improvements
Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, after Accumulated Depreciation and Amortization [Abstract]
Property, plant and equipment	185	184
Computer equipment
Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, after Accumulated Depreciation and Amortization [Abstract]
Property, plant and equipment	96	76
Office equipment and furniture and fixtures
Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, after Accumulated Depreciation and Amortization [Abstract]
Property, plant and equipment	$ 18	$ 17