Share capital - Stock options outstanding (Details)	9 Months Ended
	Aug. 31, 2019 $ / shares shares
Number of outstanding options | shares	11,042,502
Weighted average years to expiry	2 years 3 months 15 days
Weighted average exercise price options outstanding	$ 0.96
Number of exercisable options | shares	9,267,497
Weighted average exercise price exercisable	$ 0.80
Number of unvested options | shares	1,775,005
Range 1 [Member]
Exercise price lower range limit	$ 0.33
Exercise price upper range limit	$ 0.50
Number of outstanding options | shares	3,876,433
Weighted average years to expiry	11 months 19 days
Weighted average exercise price options outstanding	$ 0.39
Number of exercisable options | shares	3,876,433
Weighted average exercise price exercisable	$ 0.39
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	4,333,569
Weighted average years to expiry	2 years 2 months 16 days
Weighted average exercise price options outstanding	$ 0.72
Number of exercisable options | shares	3,885,233
Weighted average exercise price exercisable	$ 0.71
Number of unvested options | shares	448,336
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 7 months 13 days
Weighted average exercise price options outstanding	$ 1.32
Number of exercisable options | shares	175,000
Weighted average exercise price exercisable	$ 1.29
Number of unvested options | shares	50,000
Range Four [Member]
Exercise price lower range limit	$ 1.51
Exercise price upper range limit	$ 2.00
Number of outstanding options | shares	90,000
Weighted average years to expiry	3 years 10 months 13 days
Weighted average exercise price options outstanding	$ 1.83
Number of exercisable options | shares	73,333
Weighted average exercise price exercisable	$ 1.82
Number of unvested options | shares	16,667
Range Five [Member]
Exercise price lower range limit	$ 2.01
Exercise price upper range limit	$ 2.52
Number of outstanding options | shares	2,517,500
Weighted average years to expiry	4 years 3 months 7 days
Weighted average exercise price options outstanding	$ 2.21
Number of exercisable options | shares	1,257,498
Weighted average exercise price exercisable	$ 2.22
Number of unvested options | shares	1,260,002