Note 10 - Marketable Securities - Summary of Investments (Details) - USD ($)	Jun. 30, 2025	Mar. 31, 2024
Equity Securities, FV-NI, Cost	$ 643,419	$ 634,705
Equity Securities, FV-NI, Current	710,829	663,682
Equity Securities, FV-NI, Accumulated Unrealized Gain (Loss)	67,410	28,977
Other Short-term Investments, cost		6,858,943
Other Short-term Investments, fair value		6,858,943
Marketable securities, cost	6,585,234	7,493,648
Marketable securities, fair value	6,652,644	7,522,625
Marketable securities, unrealized gain	67,410	28,977
Certificates of Deposit [Member]
Other Short-term Investments, cost		570,000
Other Short-term Investments, fair value		570,000
US Treasury Bill Securities [Member]
Other Short-term Investments, cost	5,941,815	6,288,943
Other Short-term Investments, fair value	$ 5,941,815	$ 6,288,943