Share capital - Common shares issued and outstanding (Details) - Share capital - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Feb. 28, 2021	Nov. 30, 2020
Beginning balance, Number of shares	144,137,850	140,427,761
Beginning balance, Ascribed value	$ 179,746	$ 177,971
Exercise of options, Number of shares	76,635	3,297,588
Exercise of options, Ascribed value	$ 334	$ 1,133
Restricted share units, Number of shares		412,501
Restricted share units, Ascribed value		$ 642
Ending balance, Number of shares	144,214,485	144,137,850
Ending balance, Ascribed value	$ 180,080	$ 179,746