Note 9 - Prepaid and Other Current Assets (Details Textual) - USD ($) $ in Millions	3 Months Ended			12 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2023
Employee Retention Credits Receivable				$ 3.3
Cost of Sales [Member]
Employee Retention Credits Benefit				1.8
Selling, General and Administrative Expenses [Member]
Employee Retention Credits Benefit				0.8
Research and Development Expense [Member]
Employee Retention Credits Benefit				0.7
Prepaid Expenses and Other Current Assets [Member]
Employee Retention Credits Receivable				$ 3.3
Maximum [Member]
Percentage of Qualified Wages Paid	70.00%	70.00%	50.00%