Property and Equipment - Property and Equipment, Net (Detail) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Total property and equipment, at cost	$ 331	$ 349
Less accumulated depreciation and amortization	(188)	(180)
Property and equipment, net	143	169
Computers and software [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment, at cost	26	26
Office furniture and equipment [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment, at cost	15	15
Laboratory equipment [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment, at cost	233	251
Leasehold improvement [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment, at cost	$ 57	$ 57