Note 9 - Leases - Summary of Components of Lease Costs (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Lease cost
Operating lease cost	$ 48	$ 52	$ 100	$ 89
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	42	43	95	80
Right-of-use assets obtained in exchange for lease obligations:
Right-of-use assets obtained in exchange for new operating lease liabilities	313	248	313	248
Right-of-use assets obtained in exchange for new finance lease liabilities	$ 6	$ 0	$ 6	$ 0