Quarterly report pursuant to Section 13 or 15(d)

Stock Plans - Additional Information (Detail)

v3.20.2
Stock Plans - Additional Information (Detail)
1 Months Ended 9 Months Ended
Aug. 31, 2020
USD ($)
Customer
Sep. 30, 2020
USD ($)
$ / shares
shares
Sep. 30, 2019
USD ($)
$ / shares
Employee Stock Purchase Plan [Member]      
Class of Stock [Line Items]      
Common stock were purchased under ESPP | shares   126,550  
Accrued employee contributions   $ 72,000  
2018 Performance Base Stock Incentive Plan [Member]      
Class of Stock [Line Items]      
Number of employees | Customer 215    
Incremental compensation cost $ 3,011,000    
Timebased Stock Option [Member]      
Class of Stock [Line Items]      
Options granted | shares   610,000  
Restricted Stock [Member]      
Class of Stock [Line Items]      
Unrecognized cost of share-based compensation awards   $ 14,000  
Cost of share-based compensation awards, recognition period   1 month 6 days  
Restricted Stock Units [Member]      
Class of Stock [Line Items]      
Unrecognized cost of share-based compensation awards   $ 5,641,000  
Cost of share-based compensation awards, recognition period   8 months 12 days  
Performance-based Stock Options [Member]      
Class of Stock [Line Items]      
Cost of share-based compensation awards, recognition period   2 years  
Weighted Average Grant Date Fair Value, Granted | $ / shares     $ 2.55
Total grant date fair value of stock options granted   $ 0  
Total grant date fair value of stock options vested   0 $ 0
Unrecognized compensation expense related to stock options   $ 18,092,000  
Stock Options [Member]      
Class of Stock [Line Items]      
Options granted | shares   610,000  
Cost of share-based compensation awards, recognition period   2 years 3 months 18 days  
Weighted Average Grant Date Fair Value, Granted | $ / shares   $ 2.46 $ 3.65
Total grant date fair value of stock options vested   $ 4,659,000 $ 8,056,000
Unrecognized compensation expense related to stock options   4,744,000  
Aggregate intrinsic value of the options exercised   $ 484,000 $ 183,000