Note 5 - Short-term Investments - Marketable Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Mar. 31, 2022
Total short-term investments	$ 16	$ 13,322
Canadian Deposits [Member]
Total short-term investments		1,429
US Deposits [Member]
Total short-term investments		$ 11,893

Amount of investment in marketable security.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.4)
-URI https://asc.fasb.org/extlink&oid=126897435&loc=d3e534808-122878

Name:	us-gaap_MarketableSecurities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant