Share capital - Stock options plans and changes (Details) - $ / shares	3 Months Ended	6 Months Ended	9 Months Ended
	Aug. 31, 2022	May 31, 2022	Aug. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Balance - end of period, number of options	12,187,150		12,187,150
Balance - end of period, weighted average exercise price	$ 2.50		$ 2.50
Stock option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Balance - beginning of the year, number of options		10,539,324	10,539,324
Balance - beginning of the year, weighted average exercise price		$ 2.54	$ 2.54
Number of options, Granted			1,734,500
Weighted average exercise price, Granted			$ 2.21
Number of options, Exercised	0	(81,674)	(81,674)
Weighted average exercise price, Exercised			$ 0.85
Number of options, Expired			(5,000)
Weighted average exercise price, Expired			$ 2.52
Balance - end of period, number of options	12,187,150		12,187,150
Balance - end of period, weighted average exercise price	$ 2.50		$ 2.50