Balance Sheet Components - Schedule of Prepaid Expenses and Other Current Assets (Detail) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Balance Sheet Related Disclosures [Abstract]
Prepaid research and development	$ 5,500	$ 2,462
Prepaid bonus	800	409
Prepaid clinical trial	779	944
Prepaid insurance	144	2,480
Other	1,162	331
Total prepaid expenses and other current assets	$ 8,385	$ 6,626

Amount of asset related to consideration paid in advance for insurance that provides economic benefits within a future period of one year or the normal operating cycle, if longer.

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Name:	us-gaap_PrepaidInsurance
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant