Options and RSUs granted during the year (Detail) - shares	3 Months Ended	12 Months Ended
	Jun. 30, 2022	Dec. 31, 2022
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (Shares)		18,408
RSUs | Option Grant Contingent upon Continued Employment or Service as a Director and Achievement of Performance Metric
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of options vesting rights		25.00%
Granted (Shares)		3,168
RSUs | Option Grant Solely Contingent upon Continued Employment or Continued Service as a Director
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of options vesting rights		50.00%
Granted (Shares)		5,261
RSUs | Share-based Compensation Award, Tranche Three [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of options vesting rights		50.00%
Granted (Shares)		596
RSUs | Share-Based Payment Arrag
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of options vesting rights		25.00%
Granted (Shares)		123
RSUs | Share-Based Payment Arrangement, Tranche Five
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of options vesting rights		50.00%
Granted (Shares)		79
Options | Share-based Compensation Award, Tranche Three [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of options vesting rights		50.00%
Employee Performance Based Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of options vesting rights		50.00%
Granted (Shares)		86,160
Employee Performance Based Stock Option [Member] | Option Grant Contingent upon Continued Employment or Service as a Director and Achievement of Performance Metric
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of options vesting rights		50.00%
Granted (Shares)		16,415
Employee Performance Based Stock Option [Member] | Option Grant Solely Contingent upon Continued Employment or Continued Service as a Director
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of options vesting rights		25.00%
Granted (Shares)		64,195
Employee Performance Based Stock Option [Member] | Share-based Compensation Award, Tranche Three [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of options vesting rights		25.00%
Granted (Shares)		3,100
Employee Performance Based Stock Option [Member] | Share-Based Payment Arrag
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of options vesting rights		50.00%
Granted (Shares)		2,210
Employee Performance Based Stock Option [Member] | Share-Based Payment Arrangement, Tranche Five
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of options vesting rights		50.00%
Granted (Shares)		240
Employee Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (Shares)		177,486
Employee Stock | Option Grant Contingent upon Continued Employment or Service as a Director and Achievement of Performance Metric
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of options vesting rights		50.00%
Granted (Shares)		16,415
Employee Stock | Option Grant Solely Contingent upon Continued Employment or Continued Service as a Director
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of options vesting rights		25.00%
Granted (Shares)		69,361
Employee Stock | Share-based Compensation Award, Tranche Three [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of options vesting rights		25.00%
Granted (Shares)		3,100
Employee Stock | Share-Based Payment Arrag
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of options vesting rights		50.00%
Granted (Shares)		2,210
Employee Stock | Share-Based Payment Arrangement, Tranche Five
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (Shares)		240
Share-Based Payment Arrangement
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (Shares)		91,326
Performance Based Restricted Stock Unit [Member] | Option Grant Contingent upon Continued Employment or Service as a Director and Achievement of Performance Metric
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (Shares)		3,168
Performance Based Restricted Stock Unit [Member] | Option Grant Solely Contingent upon Continued Employment or Continued Service as a Director
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of options vesting rights		50.00%
Granted (Shares)		5,215
Performance Based Restricted Stock Unit [Member] | Share-based Compensation Award, Tranche Three [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of options vesting rights		50.00%
Granted (Shares)		596
Performance Based Restricted Stock Unit [Member] | Share-Based Payment Arrag
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of options vesting rights		25.00%
Granted (Shares)		123
Performance Based Restricted Stock Unit [Member] | Share-Based Payment Arrangement, Tranche Five
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of options vesting rights		50.00%
Granted (Shares)		79
2014 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (Shares)		115,270
Granted (Shares)		0
2014 Plan | RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (Shares)		0
2014 Plan | Employee Performance Based Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (Shares)		57,635
2014 Plan | Employee Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (Shares)		57,635
2014 Plan | Performance Based Restricted Stock Unit [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (Shares)		0
2018 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (Shares)		62,216
Granted (Shares)		18,408
2018 Plan | RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (Shares)	16,864	9,227
2018 Plan | Employee Performance Based Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (Shares)		28,525
2018 Plan | Employee Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (Shares)		33,691
2018 Plan | Performance Based Restricted Stock Unit [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (Shares)		9,181