Share capital - Stock options outstanding (Details)	3 Months Ended
	Feb. 29, 2020 $ / shares shares
Number of outstanding options | shares	10,998,933
Weighted average years to expiry	2 years 10 months 2 days
Weighted average exercise price options outstanding	$ 1.27
Number of exercisable options | shares	9,545,595
Weighted average exercise price exercisable	$ 2.60
Number of unvested options | shares	1,453,338
Range 1 [Member]
Exercise price lower range limit	$ 0.33
Exercise price upper range limit	$ 0.50
Number of outstanding options | shares	2,676,433
Weighted average years to expiry	8 months 23 days
Weighted average exercise price options outstanding	$ 0.36
Number of exercisable options | shares	2,676,433
Weighted average exercise price exercisable	$ 0.73
Number of unvested options | shares	0
Range 2 [Member]
Exercise price lower range limit	$ 0.51
Exercise price upper range limit	$ 1.00
Number of outstanding options | shares	3,195,000
Weighted average years to expiry	2 years 4 months 6 days
Weighted average exercise price options outstanding	$ 0.66
Number of exercisable options | shares	3,195,000
Weighted average exercise price exercisable	$ 2.35
Number of unvested options | shares	0
Range 3 [Member]
Exercise price lower range limit	$ 1.01
Exercise price upper range limit	$ 1.50
Number of outstanding options | shares	225,000
Weighted average years to expiry	3 years 1 month 13 days
Weighted average exercise price options outstanding	$ 1.32
Number of exercisable options | shares	175,000
Weighted average exercise price exercisable	$ 3.08
Number of unvested options | shares	50,000
Range 4 [Member]
Exercise price lower range limit	$ 1.51
Exercise price upper range limit	$ 2.00
Number of outstanding options | shares	640,000
Weighted average years to expiry	4 years 5 months 16 days
Weighted average exercise price options outstanding	$ 1.81
Number of exercisable options | shares	623,333
Weighted average exercise price exercisable	$ 4.49
Number of unvested options | shares	16,667
Range 5 [Member]
Exercise price lower range limit	$ 2.01
Exercise price upper range limit	$ 2.54
Number of outstanding options | shares	4,262,500
Weighted average years to expiry	4 years 3 months 11 days
Weighted average exercise price options outstanding	$ 2.23
Number of exercisable options | shares	2,875,829
Weighted average exercise price exercisable	$ 4.17
Number of unvested options | shares	1,386,671