Note 4 - Investments - Marketable Securities (Details) $ in Thousands, $ in Thousands	Dec. 31, 2020 USD ($)	Dec. 31, 2020 CAD ($)	Mar. 31, 2020 USD ($)	Mar. 31, 2020 CAD ($)
Total Investments - US	$ 1,372
Total short-term investments	1,372
Deposits [Member]
Total Investments - US	536
Total short-term investments	$ 536
Canadian Deposits [Member]
Total Investments - US		$ 836
Total short-term investments		$ 836