Note 6 - Share Capital - Stock Options Outstanding (Details) - $ / shares		May 31, 2019	May 31, 2018	May 31, 2017
Exercise Price (in CAD per share)		$ 1.40	$ 0.85	$ 0.87
Number of Options (in shares)		10,000,000	9,861,900	8,846,900
Exercisable at Year- End (in shares)		3,952,720	7,659,510
Employee Stock Option, Expiring on September 19, 2017 [Member]
Exercise Price (in CAD per share)	[1]	$ 0.96	$ 0.96
Number of Options (in shares)	[1]		1,966,900
Exercisable at Year- End (in shares)	[1]		1,966,900
Employee Stock Option, Expiring on August 16, 2018 [Member]
Exercise Price (in CAD per share)	[1]	$ 0.76	$ 0.76
Number of Options (in shares)	[1]		2,095,000
Exercisable at Year- End (in shares)	[1]		2,095,000
Employee Stock Option, Expiring on September 8, 2019 [Member]
Exercise Price (in CAD per share)		$ 1.40	$ 1.40
Number of Options (in shares)		635,000	1,250,000
Exercisable at Year- End (in shares)		635,000	1,250,000
Employee Stock Option, Expiring on September 9, 2020 [Member]
Exercise Price (in CAD per share)		$ 0.46	$ 0.46
Number of Options (in shares)		620,000	625,000
Exercisable at Year- End (in shares)		620,000	625,000
Employee Stock Option, Expiring on November 13, 2020 [Member]
Exercise Price (in CAD per share)		$ 0.49	$ 0.49
Number of Options (in shares)		1,000,000	1,000,000
Exercisable at Year- End (in shares)		1,000,000	1,000,000
Employee Stock Option, Expiring on September 15, 2021 [Member]
Exercise Price (in CAD per share)		$ 0.91	$ 0.91
Number of Options (in shares)		1,085,000	1,085,000
Exercisable at Year- End (in shares)		1,085,000	722,610
Employee Stock Option, Expiring on July 31, 2022 [Member]
Exercise Price (in CAD per share)		$ 0.77	$ 0.77
Number of Options (in shares)		1,840,000	1,840,000
Exercisable at Year- End (in shares)		612,720
Employee Stock Options, Expiring on November 19, 2023 [Member]
Exercise Price (in CAD per share)		$ 2.06
Number of Options (in shares)		4,420,000
Exercisable at Year- End (in shares)
Employee Stock Option, Expiring on April 9, 2024 [Member]
Exercise Price (in CAD per share)		$ 2.04
Number of Options (in shares)		400,000
Exercisable at Year- End (in shares)

[1] The Company's share trading policy (the "Policy") requires that all restricted persons and others who are subject to the Policy refrain from conducting any transactions involving the purchase or sale of the Company's securities, during the period in any quarter commencing 30 days prior to the scheduled issuance of the next quarter or year-end public disclosure of the financial results as well as when there is material data on hand. In accordance with the terms of the Amended 2010 Plan, if stock options are set to expire during a restricted period and are not exercised prior to any such restriction, they will not expire but instead will be available for exercise for ten days after such restrictions are lifted.