Note 5 - Operating Lease Right-of-use Asset, Net - Future Minimum Lease Payments Under Operating Lease (Details) $ in Thousands	Dec. 31, 2022 USD ($)
Lessee, Operating Lease, Liability, to be Paid, Year One	$ 471
Lessee, Operating Lease, Liability, to be Paid, Year Two	485
Lessee, Operating Lease, Liability, to be Paid, Year Three	499
Lessee, Operating Lease, Liability, to be Paid, Year Four	514
Lessee, Operating Lease, Liability, to be Paid, Year Five	44
Total undiscounted lease payments	2,013
Less imputed interest	382
Total operating lease liabilities	$ 1,631