Balance Sheet Components - Summary of Prepaid Expenses and Other Current Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Prepaid Expense And Other Assets Current [Abstract]
Prepaid insurance	$ 1,282	$ 1,236
Prepaid research and development costs	3,002	1,039
Other prepaid expenses	231	527
Other receivables		3
Other current assets	463
Total prepaid expenses and other current assets	$ 4,978	$ 2,805