Quarterly report pursuant to Section 13 or 15(d)

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

v3.20.1
Stock Plans - Summary of Fair Value Assumptions of Stock Purchase Plan (Detail) - Employee Stock Purchase Plan [Member]
3 Months Ended
Mar. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Expected volatility, minimum 65.00%
Expected volatility, maximum 81.00%
Risk-free interest rate, minimum 1.30%
Risk-free interest rate, maximum 1.50%
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