Annual report pursuant to Section 13 and 15(d)

Stock Plans and Stock-Based Compensation - Additional Information (Detail)

v3.21.1
Stock Plans and Stock-Based Compensation - Additional Information (Detail) - USD ($)
$ / shares in Units, $ in Thousands
1 Months Ended 12 Months Ended
Sep. 30, 2013
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2013
Jan. 01, 2021
Jun. 30, 2014
Apr. 30, 2014
Jan. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Shares available for grant   917,159                
Intrinsic value of options exercised   $ 400 $ 400              
Fair value of options vested   3,300 $ 9,900              
Unamortized employee and non-employee stock-based compensation expense   $ 17,900                
Unamortized employee and non-employee stock-based compensation expense recognized period   2 years 9 months 18 days                
Options exercised   3,611,593                
Share reserved for issue   9,830,230 9,143,863              
Stock-based compensation expense   $ 7,135 $ 9,558              
Stock options outstanding   8,811,630 6,726,695              
Equity Incentive Plan Two Thousand and Twenty Plan [Member]                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Share based compensation arrangement by share based payment award, exercise price percentage   85.00%                
Shares available for grant   750,000                
Options exercised   0                
Share reserved for issue   750,000                
2013 Equity Incentive Plan [Member]                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Share based compensation arrangement by share based payment award, expiration period 10 years                  
Share based compensation arrangement percentage increase in share reserved 5.00%                  
Shares available for grant   167,159                
Share reserved for issue   9,080,230 9,143,863       2,757,843      
2013 Equity Incentive Plan [Member] | Incentive Stock Options for Employees and Directors [Member]                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Share based compensation arrangement by share based payment award, exercise price percentage 100.00%                  
2013 Equity Incentive Plan [Member] | Nonqualified Options to Employees, Directors and Consultants [Member]                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Share based compensation arrangement by share based payment award, exercise price percentage 85.00%                  
2013 Equity Incentive Plan [Member] | Restricted Stock [Member]                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Share based compensation arrangement by share based payment award, exercise price percentage 85.00%                  
Share based compensation arrangement by share based payment award, award vesting period 4 years                  
2013 Equity Incentive Plan [Member] | Stock Options to 10% Stockholders [Member]                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Share based compensation arrangement by share based payment award, exercise price percentage         110.00%          
Share based compensation arrangement by share based payment award, award vesting period         5 years          
Incentive Awards [Member]                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Share based compensation arrangement by share based payment award, expiration period       10 years            
Share based compensation arrangement by share based payment award, award vesting period           4 years        
Share reserved for issue               500,000 252,752  
Exercisable weighted average price per share                   $ 5.21
Stock option plan, Description   vest monthly over four years effective from their grant date                
Stock-based compensation expense   $ 0 $ 0              
Stock options outstanding   101,441 101,441              
Incentive Awards [Member] | First Tranche [Member]                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Percentage of vesting of shares           100.00%        
Maximum [Member] | 2013 Equity Incentive Plan [Member]                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Percentage of vesting of shares   5.00%                
Minimum [Member] | 2013 Equity Incentive Plan [Member]                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Percentage of vesting of shares   4.00%