Note 6 - Accrued Expenses and Other Current Liabilities - Summary of Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Accrued expenses	$ 34	$ 240
Accrued salaries and employee benefits	895	861
Accrued clinical trial costs	304	334
Grant liability	587	590
Customer deposits	96	96
Payable to Related Party	4	0
Total	$ 1,920	$ 2,121