Annual report pursuant to Section 13 and 15(d)

Stock Plans - Schedule of Performance Options Activity (Detail)

v3.20.1
Stock Plans - Schedule of Performance Options Activity (Detail) - Performance-based Stock Options [Member]
12 Months Ended
Dec. 31, 2019
$ / shares
shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Options, Outstanding, Beginning Balance | shares 3,167,325
Options Granted | shares 1,619,175
Options Forfeited | shares (301,761)
Options, Outstanding, Ending Balance | shares 4,484,739
Weighted-Average Exercise Price, Outstanding, Beginning Balance | $ / shares $ 21.25
Weighted-Average Exercise Price, Options Granted | $ / shares 5.69
Weighted-Average Exercise Price, Options Forfeited | $ / shares 5.66
Weighted-Average Exercise Price, Outstanding, Ending Balance | $ / shares $ 16.68
Weighted-Average Remaining Contractual Term, Outstanding 8 years 7 months 2 days