Balance sheet components - Summary of Property and Equipment (Detail) - USD ($) $ in Thousands	Jun. 30, 2026	Dec. 31, 2025
Property Plant And Equipment [Line Items]
Total, at cost	$ 14,647	$ 14,579
Accumulated depreciation	(13,313)	(12,712)
Total, net	1,334	1,867
Leasehold improvements [Member]
Property Plant And Equipment [Line Items]
Total, at cost	6,264	6,264
Lab equipment [Member]
Property Plant And Equipment [Line Items]
Total, at cost	6,258	6,209
Computer equipment [Member]
Property Plant And Equipment [Line Items]
Total, at cost	1,075	1,075
Furniture and office equipment [Member]
Property Plant And Equipment [Line Items]
Total, at cost	770	751
Vehicles and equipment [Member]
Property Plant And Equipment [Line Items]
Total, at cost	$ 280	$ 280

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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