Note 16 - Stockholders' Equity - Stock-based Compensation Expense by Financial Statement Line Item (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Total stock-based compensation expense	$ 4,652	$ 4,729
Cost of Sales [Member]
Total stock-based compensation expense	293	283
Research and Development Expense [Member]
Total stock-based compensation expense	627	865
Selling, General and Administrative Expenses [Member]
Total stock-based compensation expense	$ 3,732	$ 3,581