Quarterly report pursuant to Section 13 or 15(d)

Stockholders' equity - Schedule of equity awards (Detail)

v3.20.4
Stockholders' equity - Schedule of equity awards (Detail) - Employee stock option - $ / shares
3 Months Ended 12 Months Ended
Dec. 31, 2020
Sep. 30, 2020
Jun. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Stock Options,Outstanding, beginning of period 69,717 70,161  
Stock Options, Granted 525,546    
Stock Options, Forfeited (7,967) (444)  
Stock Options, Outstanding, end of period 587,296 69,717 70,161
Stock Options, Exercisable, end of period 35,473 43,273  
Exercise price, beginning of period $ 60.00 $ 60.42  
Weighted-average Exercise Price, Granted 2.98    
Weighted-average Exercise Price, Forfeited 153.78 69.32  
Weighted-average Exercise Price, Exercise price, end of period 7.64 60.00 $ 60.42
Weighted-average Exercise Price, Exercisable, end of period $ 48.18 $ 68.53  
Weighted-average Remaining Contractual Term, Outstanding 9 years 2 months 12 days 2 years 7 months 24 days 2 years 10 months 20 days
Weighted-average Remaining Contractual Term, Exercisable 2 years 4 months 24 days 2 years 3 months 3 days