Balance Sheet Components - Summary of Prepaid Expenses and Other Current Assets (Detail) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]
Prepaid insurance	$ 572	$ 991
Prepaid software and subscription fees	362	376
Other receivables	214	311
Prepaid research and development project costs	186	321
Other	676	416
Total prepaid expenses and other current assets	$ 2,010	$ 2,415