Note 6 - Short-term Investments - Marketable Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Mar. 31, 2021
Total short-term investments	$ 13,322	$ 9,789
Deposits [Member]
Total short-term investments	11,893	7,542
Canadian Deposits [Member]
Total short-term investments	$ 1,429	$ 2,247