Quarterly report pursuant to Section 13 or 15(d)

Summary of Unvested Stock Option Activity (Detail)

v3.19.3
Summary of Unvested Stock Option Activity (Detail) - $ / shares
shares in Thousands
 3 Months Ended 9 Months Ended
Sep. 30, 2018
Sep. 30, 2019
Sep. 30, 2018
Weighted Average Grant Date Fair Value      
Granted $ 1.02 $ 1.53 $ 1.38
Stock Options      
Shares      
Beginning Balance   522  
Granted   70  
Vested   (229)  
Forfeited or cancelled   (84)  
Ending Balance   279  
Weighted Average Grant Date Fair Value      
Beginning Balance   $ 2.11  
Granted   1.51  
Vested   2.55  
Forfeited or cancelled   2.39  
Ending Balance   $ 1.59