Property and Equipment, net - Property and Equipment, Net (Detail) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Property, Plant and Equipment [Line Items]
Total property and equipment, at cost	$ 349	$ 387
Less: Accumulated depreciation and amortization	(180)	(171)
Property and equipment, net	169	216
Computers and software [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment, at cost	26	31
Office furniture and equipment [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment, at cost	15	27
Laboratory equipment [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment, at cost	251	221
Leasehold improvement [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment, at cost	57	88
Assets in progress [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment, at cost	$ 0	$ 20