Share capital - Stock options outstanding (Details)	3 Months Ended
	Feb. 28, 2021 $ / shares shares
Number of outstanding options | shares	11,520,277
Weighted average years to expiry	3 years 7 months 28 days
Weighted average exercise price options outstanding	$ 1.90
Number of exercisable options | shares	8,215,940
Weighted average exercise price exercisable	$ 1.82
Number of unvested options | shares	3,304,337
Range 1
Exercise price lower range limit	$ 0.55
Exercise price upper range limit	$ 1.00
Number of outstanding options | shares	1,705,627
Weighted average years to expiry	1 year 4 months 2 days
Weighted average exercise price options outstanding	$ 0.69
Number of exercisable options | shares	1,705,627
Weighted average exercise price exercisable	$ 0.69
Number of unvested options | shares	0
Range 2
Exercise price lower range limit	$ 1.01
Exercise price upper range limit	$ 1.50
Number of outstanding options | shares	75,000
Weighted average years to expiry	1 year 9 months 21 days
Weighted average exercise price options outstanding	$ 1.15
Number of exercisable options | shares	75,000
Weighted average exercise price exercisable	$ 1.15
Number of unvested options | shares	0
Range 3
Exercise price lower range limit	$ 1.51
Exercise price upper range limit	$ 2.00
Number of outstanding options | shares	4,277,150
Weighted average years to expiry	4 years 6 months 14 days
Weighted average exercise price options outstanding	$ 1.95
Number of exercisable options | shares	2,779,483
Weighted average exercise price exercisable	$ 1.94
Number of unvested options | shares	1,497,667
Range 4
Exercise price lower range limit	$ 2.01
Exercise price upper range limit	$ 2.50
Number of outstanding options | shares	5,425,000
Weighted average years to expiry	3 years 8 months 19 days
Weighted average exercise price options outstanding	$ 2.24
Number of exercisable options | shares	3,618,330
Weighted average exercise price exercisable	$ 2.28
Number of unvested options | shares	1,806,670
Range 5
Exercise price lower range limit	$ 2.51
Exercise price upper range limit	$ 3.00
Number of outstanding options | shares	37,500
Weighted average years to expiry	3 years 2 months 23 days
Weighted average exercise price options outstanding	$ 2.68
Number of exercisable options | shares	37,500
Weighted average exercise price exercisable	$ 2.68
Number of unvested options | shares	0