Note 5 - Intangible Assets (Tables)

12 Months Ended

Mar. 31, 2020

Notes Tables

Schedule of Finite-Lived Intangible Assets [Table Text Block]

	March 31, 2020										March 31, 2019
	Cost		Accumulated Amortization			Net Carrying Amount		Amortization Period (Years)			Cost		Accumulated Amortization			Net Carrying Amount		Amortization Period (Years)
Patents & Trademarks	$	35,794	$	(14,091	)	$	21,703	10	-	15	$	20,934	$	(12,035	)	$	8,899		15

Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block]

For the fiscal years ended March 31,
2021	$	2,882
2022		2,882
2023		2,882
2024		2,882
2025		2,465
Thereafter		7,710
	$	21,703