Note 4 - Accrued Expenses and Other Current Liabilities - Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Accrued research and development	$ 1,005	$ 907
Accrued payroll and bonuses	606	426
Accrued legal, regulatory, professional and other	442	262
Accrued liabilities due to related party	109	78
Total accrued expenses and other current liabilities	2,258	1,791
Accounts Payable and Accrued Liabilities [Member]
Operating lease liability - current	$ 96	$ 118