Note 17 - Stockholders' Equity - Stock-based Compensation Expense by Financial Statement Line Item (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Total stock-based compensation expense	$ 4,729	$ 4,661
Cost of Sales [Member]
Total stock-based compensation expense	283	209
Research and Development Expense [Member]
Total stock-based compensation expense	865	820
Selling, General and Administrative Expenses [Member]
Total stock-based compensation expense	$ 3,581	$ 3,632