Note 12 - Capital Stock - Warrants Outstanding and Exercisable (Details) - $ / shares	12 Months Ended
	Jul. 31, 2019	Mar. 14, 2019	Jul. 31, 2018	Jul. 31, 2017	Jul. 31, 2016
Weighted Average Exercise Price (in dollars per share)	$ 1.94	$ 1.33	$ 1.97	$ 1.78	$ 1.65
Number of Warrants Outstanding (in shares)	19,443,910		30,923,489	19,676,560	13,953,872
Warrants 1 [Member]
Weighted Average Exercise Price (in dollars per share)	$ 2
Number of Warrants Outstanding (in shares)	9,571,929
Expiry Date	Jan. 20, 2020
Weighted Average Remaining Contractual Life (Year)	171 days
Warrants 2 [Member]
Weighted Average Exercise Price (in dollars per share)	$ 1.35
Number of Warrants Outstanding (in shares)	2,450,000
Expiry Date	Jan. 30, 2020
Weighted Average Remaining Contractual Life (Year)	182 days
Warrants 3 [Member]
Weighted Average Exercise Price (in dollars per share)	$ 2.05
Number of Warrants Outstanding (in shares)	7,063,253
Expiry Date	Apr. 03, 2021
Weighted Average Remaining Contractual Life (Year)	1 year 248 days
Warrants 4 [Member]
Weighted Average Exercise Price (in dollars per share)	$ 2.30
Number of Warrants Outstanding (in shares)	308,728
Expiry Date	Aug. 09, 2022
Weighted Average Remaining Contractual Life (Year)	3 years 10 days
Warrants 5 [Member]
Weighted Average Exercise Price (in dollars per share)	$ 1.64
Number of Warrants Outstanding (in shares)	50,000
Expiry Date	May 21, 2023
Weighted Average Remaining Contractual Life (Year)	3 years 295 days
Warrants 6 [Member]
Weighted Average Exercise Price (in dollars per share)	$ 1.94
Number of Warrants Outstanding (in shares)	19,443,910
Weighted Average Remaining Contractual Life (Year)	350 days