Quarterly report pursuant to Section 13 or 15(d)

Summary of Unvested Stock Option Activity (Detail)

v3.21.2
Summary of Unvested Stock Option Activity (Detail) - $ / shares
shares in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2021
Jun. 30, 2020
Jun. 30, 2021
Jun. 30, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Ending Balance 95   95  
Granted $ 0 $ 0.29 $ 1.07 $ 0.29
Ending Balance $ 0.83   $ 0.83  
Stock Options        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Beginning Balance     1,323  
Granted     20  
Vested     (1,248)  
Beginning Balance     $ 0.34  
Granted     1.07  
Vested     $ 0.31