Share capital - Stock options outstanding (Details)	12 Months Ended
	Nov. 30, 2020 $ / shares shares
Number of outstanding options | shares	8,647,500
Weighted average years to expiry	3 years 5 months 4 days
Weighted average exercise price options outstanding	$ 2.39
Number of exercisable options | shares	6,154,163
Weighted average exercise price exercisable	$ 2.22
Number of unvested options | shares	2,493,337
Range 1
Exercise price lower range limit	$ 0.44
Exercise price upper range limit	$ 0.50
Number of outstanding options | shares	20,000
Weighted average years to expiry	21 days
Weighted average exercise price options outstanding	$ 0.44
Number of exercisable options | shares	20,000
Weighted average exercise price exercisable	$ 0.44
Range 2
Exercise price lower range limit	0.51
Exercise price upper range limit	$ 1.00
Number of outstanding options | shares	770,000
Weighted average years to expiry	1 year 21 days
Weighted average exercise price options outstanding	$ 0.72
Number of exercisable options | shares	770,000
Weighted average exercise price exercisable	$ 0.72
Range 3
Exercise price lower range limit	1.01
Exercise price upper range limit	$ 1.50
Number of outstanding options | shares	1,070,000
Weighted average years to expiry	2 years 7 days
Weighted average exercise price options outstanding	$ 1.04
Number of exercisable options | shares	1,070,000
Weighted average exercise price exercisable	$ 1.04
Range 4
Exercise price lower range limit	2.01
Exercise price upper range limit	$ 2.50
Number of outstanding options | shares	865,000
Weighted average years to expiry	3 years 11 months 23 days
Weighted average exercise price options outstanding	$ 2.37
Number of exercisable options | shares	865,000
Weighted average exercise price exercisable	$ 2.37
Range 5
Exercise price lower range limit	2.51
Exercise price upper range limit	$ 3.00
Number of outstanding options | shares	3,835,000
Weighted average years to expiry	3 years 10 months 6 days
Weighted average exercise price options outstanding	$ 2.77
Number of exercisable options | shares	2,121,665
Weighted average exercise price exercisable	$ 2.82
Number of unvested options | shares	1,713,335
Range 6
Exercise price lower range limit	$ 3.01
Exercise price upper range limit	$ 3.41
Number of outstanding options | shares	2,087,500
Weighted average years to expiry	4 years 18 days
Weighted average exercise price options outstanding	$ 3.03
Number of exercisable options | shares	1,307,498
Weighted average exercise price exercisable	$ 3.04
Number of unvested options | shares	780,002