Leases - Summary of Lease, Cost (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Operating leases
Operating lease cost	$ 38,000		$ 114,000
Less: sublease income	(12,000)	$ (19,000)	(44,000)	$ (47,000)
Operating lease expense	26,000		70,000
Short-term lease rent expense	1,000		11,000
Total rent expense	$ 27,000	$ 40,000	$ 81,000	$ 107,000