Commitments and Contingencies - Information Related to Right-of-use Assets and Lease Liabilities (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Operating Leases Future Minimum Payments Due [Abstract]
Operating lease costs	$ 456	$ 464
Short-term lease costs	1	7
Variable lease costs	225	211
Total lease costs	682	682
Operating cash used for operating leases	508	509
Right-of-use assets obtained in exchange for operating lease liabilities	$ 479	$ 421
Weighted-average remaining lease term (years)	4 years 5 months 1 day	3 years 10 months 24 days
Weighted-average discount rate	13.48%	17.05%