Balance sheet components - Property and equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2025	Dec. 31, 2024
Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, after Accumulated Depreciation and Amortization [Abstract]
Property, plant and equipment, gross	$ 21,006	$ 14,862
Less accumulated depreciation and amortization	(6,370)	(4,749)
Property and equipment, net	14,636	10,113
Lab equipment
Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, after Accumulated Depreciation and Amortization [Abstract]
Property, plant and equipment, gross	10,580	9,501
Construction in progress
Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, after Accumulated Depreciation and Amortization [Abstract]
Property, plant and equipment	5,548	3,297
Leasehold improvements
Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, after Accumulated Depreciation and Amortization [Abstract]
Property, plant and equipment	4,164	1,636
Computer equipment
Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, after Accumulated Depreciation and Amortization [Abstract]
Property, plant and equipment	502	270
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	$ 212	$ 158