Note 5 - Prepaid Expenses - Schedule of Prepaid Expenses (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Prepaid research and development	$ 2,927	$ 1,853
Prepaid insurance	613	461
Professional services	293	124
Other	41	50
Total prepaid expenses	$ 3,874	$ 2,488