Note 9 - Leases - Summary of Components of Lease Costs (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Lease cost
Operating lease cost	$ 45	$ 48	$ 90	$ 100
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	37	42	83	95
Right-of-use assets obtained in exchange for lease obligations:
Right-of-use assets obtained in exchange for new operating lease liabilities	0	313	0	313
Right-of-use assets obtained in exchange for new finance lease liabilities	$ 0	$ 6	$ 0	$ 6