Note 4 - Intangible Assets (Tables)

9 Months Ended

Dec. 31, 2022

Notes Tables

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

	December 31, 2022											March 31, 2022
	Cost		Weighted Average Amortization Period (Years)				Accumulated Amortization			Net Carrying Amount		Cost		Weighted Average Amortization Period (Years)				Accumulated Amortization			Net Carrying Amount
Patents & Trademarks	$	35,794		10	-	15	$	(21,911	)	$	13,883	$	35,794		10	-	15	$	(19,751	)	$	16,043

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

For the fiscal years ended March 31,
2023		721
2024		2,883
2025		2,466
2026		1,980
2027		1,725
Thereafter		4,108
	$	13,883