Incentive Stock Options and Employee Stock Purchase Plan - Summary of Assumptions Used in Black-Scholes Option-Pricing Model to Determine Grant-Date Fair Value of Stock Option Granted (Detail) - Employees And Directors [Member] - Stock Options [Member]	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Risk-free interest rate	1.03%	0.79%
Expected term (in years)	6 years 1 month 6 days	6 years 1 month 6 days
Expected volatility	69.70%	68.60%
Expected dividend yield	0.00%	0.00%