Quarterly report pursuant to Section 13 or 15(d)

Summary of Unvested Stock Option Activity (Detail)

v3.20.2
Summary of Unvested Stock Option Activity (Detail) - $ / shares
shares in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2020
Jun. 30, 2019
Jun. 30, 2020
Jun. 30, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Granted $ 0.29 $ 1.53 $ 0.29 $ 1.53
Stock Options        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Beginning Balance     254  
Granted     1,242  
Vested     (82)  
Forfeited or cancelled     (15)  
Ending Balance 1,399   1,399  
Beginning Balance     $ 1.44  
Granted     0.29  
Vested     1.62  
Forfeited or cancelled     2.55  
Ending Balance $ 0.40   $ 0.40