Note 3 - Revenue - Components of Accounts Receivable (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Trade receivables	$ 3,769	$ 4,300
Unbilled receivables	1,507	2,285
Receivable for employee retention credit	1,677	0
Other short-term receivables	262	255
Allowance for credit losses	(111)	(111)	$ (110)
Total accounts receivable	$ 7,104	$ 6,729