Note 4 - Intangible Assets - Intangible Assets (Details) - USD ($)	9 Months Ended	12 Months Ended
	Dec. 31, 2024	Mar. 31, 2024
Cost	$ 50,309	$ 50,309
Accumulated amortization	33,121	27,936
Net carrying amount	17,188	22,373
Accumulated amortization	(33,121)	(27,936)
Intangible assets, net of accumulated amortization of $31,792 and $27,936 at September 30, 2024 and March 31, 2024, respectively	17,188	$ 22,373
Patents And Trademarks [Member]
Cost	35,794
Acquired Finite-Lived Intangible Assets, Weighted Average Useful Life (Year)		15 years
Accumulated amortization	27,071	$ 25,516
Net carrying amount		10,278
Accumulated amortization	$ (27,071)	(25,516)
Intangible assets, net of accumulated amortization of $31,792 and $27,936 at September 30, 2024 and March 31, 2024, respectively		10,278
Patents And Trademarks [Member] | Minimum [Member]
Cost		$ 35,794
Acquired Finite-Lived Intangible Assets, Weighted Average Useful Life (Year)	10 years
Net carrying amount	$ 8,723
Intangible assets, net of accumulated amortization of $31,792 and $27,936 at September 30, 2024 and March 31, 2024, respectively	$ 8,723
Patents And Trademarks [Member] | Maximum [Member]
Acquired Finite-Lived Intangible Assets, Weighted Average Useful Life (Year)	15 years	10 years
Software [Member]
Cost	$ 14,515	$ 14,515
Acquired Finite-Lived Intangible Assets, Weighted Average Useful Life (Year)	3 years	3 years
Accumulated amortization	$ 6,050	$ (2,420)
Net carrying amount	8,465	12,095
Accumulated amortization	(6,050)	2,420
Intangible assets, net of accumulated amortization of $31,792 and $27,936 at September 30, 2024 and March 31, 2024, respectively	$ 8,465	$ 12,095