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Balance Sheet Components - Additional Information (Detail) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]    
Depreciation expense $ 1.8 $ 1.3
Employer contributions under the plan $ 0.9 $ 0.6