Note 3 - Revenue - Components of Accounts Receivable (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Trade receivables	$ 2,681	$ 2,122
Unbilled receivables	2,222	1,277
Other short-term receivables	90	83
Allowance for doubtful accounts	(198)	(223)
Total accounts receivable	$ 4,795	$ 3,259