Note 4 - Intangible Assets - Intangible Assets (Details) - USD ($)	9 Months Ended	12 Months Ended
	Dec. 31, 2023	Mar. 31, 2023	Sep. 30, 2023
Cost	$ 50,309	$ 35,794
Accumulated amortization	(26,001)	(22,631)
Net carrying amount	24,308	13,163	$ 24,308
Intangible assets, accumulated amortization	26,001	22,631
Intangible assets, net of accumulated amortization of $24,071 and $22,631 at September 30, 2023 and March 31, 2023, respectively	24,308	13,163	$ 24,308
Patents And Trademarks [Member]
Cost	35,794	35,794
Accumulated amortization	(24,791)	(22,631)
Net carrying amount		13,163
Intangible assets, accumulated amortization	$ 24,791	22,631
Intangible assets, net of accumulated amortization of $24,071 and $22,631 at September 30, 2023 and March 31, 2023, respectively		$ 13,163
Patents And Trademarks [Member] | Minimum [Member]
Acquired Finite-Lived Intangible Assets, Weighted Average Useful Life (Year)	10 years	10 years
Net carrying amount	$ 11,003
Intangible assets, net of accumulated amortization of $24,071 and $22,631 at September 30, 2023 and March 31, 2023, respectively	11,003
Patents And Trademarks [Member] | Maximum [Member]
Acquired Finite-Lived Intangible Assets, Weighted Average Useful Life (Year)		15 years
Software [Member]
Cost	$ 14,515	$ 0
Acquired Finite-Lived Intangible Assets, Weighted Average Useful Life (Year)	3 years
Accumulated amortization	$ 1,210	0
Net carrying amount	13,305	0
Intangible assets, accumulated amortization	(1,210)	0
Intangible assets, net of accumulated amortization of $24,071 and $22,631 at September 30, 2023 and March 31, 2023, respectively	$ 13,305	$ 0