Balance Sheet Components - Summary of Prepaid Expenses and Other Current Assets (Detail) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]
Prepaid research and development project costs	$ 2,341	$ 321
Prepaid insurance	1,517	991
Prepaid software and subscription fees	695	376
Other receivables	360	311
Other	734	416
Total prepaid expenses and other current assets	$ 5,647	$ 2,415