Note 3 - Segment Information - Assets and Capital Expenditures (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Assets	$ 41,951	$ 41,850
Operating Segments [Member] | Electronic Instruments [Member]
Assets	710	843
Operating Segments [Member] | Merchant Investment [Member]
Assets	23,819	23,530
Segment Reporting, Reconciling Item, Corporate Nonsegment [Member]
Assets	$ 17,422	$ 17,477