Property and equipment - Summary of Property and Equipment (Detail) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Property Plant And Equipment [Line Items]
Total, at cost	$ 14,089	$ 14,014
Accumulated depreciation	(11,292)	(10,755)
Total, net	2,797	3,259
Leasehold improvements [Member]
Property Plant And Equipment [Line Items]
Total, at cost	6,101	6,101
Lab equipment [Member]
Property Plant And Equipment [Line Items]
Total, at cost	5,905	5,830
Computer equipment [Member]
Property Plant And Equipment [Line Items]
Total, at cost	1,051	1,051
Furniture and office equipment [Member]
Property Plant And Equipment [Line Items]
Total, at cost	732	732
Vehicles and equipment [Member]
Property Plant And Equipment [Line Items]
Total, at cost	296	296
Asset under construction [Member]
Property Plant And Equipment [Line Items]
Total, at cost	$ 4	$ 4