Note 11 - Capital Stock - Warrants Outstanding and Exercisable (Details) - $ / shares	9 Months Ended
	Apr. 30, 2019	Jul. 31, 2018
Weighted Average Exercise Price (in dollars per share)	$ 1.94	$ 1.97
Number of Warrants Outstanding (in shares)	19,443,910	30,923,489
Warrants 1 [Member]
Weighted Average Exercise Price (in dollars per share)	$ 1.20
Number of Warrants Outstanding (in shares)	2,450,000
Expiry Date	Jan. 30, 2020
Weighted Average Remaining Contractual Life (Year)	273 days
Warrants 2 [Member]
Weighted Average Exercise Price (in dollars per share)	$ 1.35
Number of Warrants Outstanding (in shares)	50,000
Expiry Date	May 21, 2023
Weighted Average Remaining Contractual Life (Year)	4 years 21 days
Warrants 3 [Member]
Weighted Average Exercise Price (in dollars per share)	$ 1.64
Number of Warrants Outstanding (in shares)	9,571,929
Expiry Date	Jan. 20, 2020
Weighted Average Remaining Contractual Life (Year)	266 days
Warrants 4 [Member]
Weighted Average Exercise Price (in dollars per share)	$ 2
Number of Warrants Outstanding (in shares)	7,063,253
Expiry Date	Apr. 03, 2021
Weighted Average Remaining Contractual Life (Year)	1 year 339 days
Warrants 5 [Member]
Weighted Average Exercise Price (in dollars per share)	$ 2.05
Number of Warrants Outstanding (in shares)	308,728
Expiry Date	Aug. 09, 2022
Weighted Average Remaining Contractual Life (Year)	3 years 102 days
Warrants 6 [Member]
Weighted Average Exercise Price (in dollars per share)	$ 2.30
Number of Warrants Outstanding (in shares)	19,443,910
Weighted Average Remaining Contractual Life (Year)	1 year 76 days