Quarterly report pursuant to Section 13 or 15(d)

Stockholders' equity - Schedule of equity awards (Detail)

v3.22.4
Stockholders' equity - Schedule of equity awards (Detail) - Employee stock option - USD ($)
6 Months Ended
Jun. 30, 2022
Dec. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Stock Options,Outstanding, beginning of period   738,064
Stock Options, Expired   5,665
Stock Options, Granted   36,000
Stock Options, Outstanding, end of period 738,064 768,399
Stock Options, Exercisable, end of period   456,688
Weighted-average Exercise price, beginning of period   $ 6.95
Weighted-average Exercise Price, Expired   45.92
Weighted-average Exercise Price, Granted   0.17
Weighted-average Exercise Price, Exercise price, end of period $ 6.95 6.35
Weighted-average Exercise Price, Exercisable, end of period   $ 8.58
Weighted-average Remaining Contractual Term, Outstanding 7 years 2 months 4 days 6 years 10 months 20 days
Weighted-average Remaining Contractual Term, Granted   9 years 11 months 4 days
Weighted-average Remaining Contractual Term, Exercisable   6 years 8 months 15 days
Aggregate Intrinsic Value, Outstanding at December 31, 2022   $ 64,800