Note 4 - Segment Information - Geographical Segment Revenue (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2024	Mar. 31, 2023
Revenue		$ 9,938	$ 7,843
UNITED STATES
Revenue		2,874	2,767
Non-US [Member]
Revenue	[1]	$ 7,064	$ 5,076

[1] Revenue from the Central Banks, consisting of a consortium of central banks around the world, is classified as international revenue. Reporting revenue by country for this customer is not practicable.