Quarterly report pursuant to Section 13 or 15(d)

Summary of Option Activity (Detail)

v3.21.2
Summary of Option Activity (Detail)
$ / shares in Units, shares in Thousands, $ in Thousands
 9 Months Ended 12 Months Ended
Sep. 30, 2021
USD ($)
$ / shares
shares
Dec. 31, 2020
USD ($)
$ / shares
shares
Equity [Abstract]    
Beginning Balance | shares 2,398  
Granted at fair market value | shares 50  
Exercised | shares (176)  
Forfeited, cancelled, or expired | shares (102)  
Ending Balance | shares 2,170 2,398
Options exercisable at September 30, 2021 | shares 2,052  
Vested options expired during the period ended September 30, 2021 | shares 91  
Beginning Balance | $ / shares $ 2.96  
Granted at fair market value | $ / shares 0.87  
Exercised | $ / shares 0.38  
Forfeited, cancelled, or expired | $ / shares 7.78  
Ending Balance | $ / shares 2.89 $ 2.96
Options exercisable at September 30, 2021 | $ / shares 3.00  
Vested options expired during the period ended September 30, 2021 | $ / shares $ 8.48  
Weighted-Average Remaining Contractual Term (Years)    
Options outstanding 6 years 7 months 6 days 7 years 2 months 12 days
Options exercisable 6 years 6 months  
Options outstanding | $ $ 286 [1] $ 53 [1]
Options exercisable | $ $ 277 [1]  
[1] The intrinsic value calculation does not include negative values, which can occur when the fair market value on the reporting date is less than the exercise price of the award.