Quarterly report pursuant to Section 13 or 15(d)

Stock Plans - Summary of Fair Value Assumptions of Stock Purchase Plan (Detail)

v3.21.2
Stock Plans - Summary of Fair Value Assumptions of Stock Purchase Plan (Detail) - Employee Stock Purchase Plan [Member]
9 Months Ended
Sep. 30, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]  
Expected volatility, minimum 67.00%
Expected volatility, maximum 119.00%
Risk-free interest rate 0.10%
Minimum [Member]  
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]  
Expected term (in years) 6 months
Maximum [Member]  
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]  
Expected term (in years) 2 years