Quarterly report pursuant to Section 13 or 15(d)

Stock Plans - Schedule of Fair Value Assumptions (Detail)

v3.19.2
Stock Plans - Schedule of Fair Value Assumptions (Detail) - Timebased Stock Option [Member]
6 Months Ended
Jun. 30, 2019
Minimum [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Expected term (in years) 6 years
Expected volatility 66.00%
Risk-free interest rate 1.80%
Maximum [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Expected term (in years) 6 years 1 month 6 days
Expected volatility 68.00%
Risk-free interest rate 2.50%