Commitments and Contingencies - Additional Information (Detail)	1 Months Ended	3 Months Ended
	Oct. 31, 2017 USD ($) ft²	Mar. 31, 2022 USD ($)	Mar. 31, 2021 USD ($)	Dec. 31, 2021
Other Commitments [Line Items]
Rent expense recognized for company's operating leases		$ 100,000	$ 200,000
Variable lease payments for operating leases		23,000	23,000
Operating cash outflows for operating lease liabilities		$ 200,000	$ 200,000
Weighted-average remaining lease term		10 months 24 days		1 year 2 months 12 days
Weighted-average discount rate		9.15%		9.15%
Palo Alto, California [Member]
Other Commitments [Line Items]
Total leased space | ft²	8,029
Lease commencement date	Mar. 01, 2018
Long-term operating lease expiry period month and year	2023-02
Lease renewal term	3 years
Security deposit of collateral for lease	$ 300,000