Share capital - Authorized unlimited common shares, no par value (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended				6 Months Ended	12 Months Ended
	May 31, 2022	Feb. 28, 2022	May 31, 2021	Feb. 28, 2021	May 31, 2022	Nov. 30, 2021
Class of Stock [Line Items]
Unlimited common shares authorized					Unlimited	Unlimited
Common Stock, No Par Value	$ 0				$ 0	$ 0
Joint venture contribution		$ 51
Share capital
Class of Stock [Line Items]
Beginning balance, Number of shares		145,009,811			145,009,811
Beginning balance, Ascribed value		$ 180,820			$ 180,820
Exercise of options, Number of shares	276,961	31,674	232,000	76,635	328,635
Exercise of options, Ascribed value					$ 76
Restricted share units, Number of shares	110,000	391,332			501,332
Restricted share units, Ascribed value					$ 763
Joint venture equity contribution (note 3(b)), Number of shares		31,469			31,469
Joint venture contribution	$ 51	$ 51			$ 51
Ending balance, Number of shares	145,871,247				145,871,247	145,009,811
Ending balance, Ascribed value	$ 181,710				$ 181,710	$ 180,820