Note 6 - Accrued Expenses and Other Current Liabilities - Summary of Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Accrued expenses	$ 111	$ 157
Accrued salaries and employee benefits	715	899
Accrued clinical trial costs	821	548
Grant liability	501	534
Customer deposits	90	90
Total	2,257	2,246
Related Party [Member]
Payable to related party	$ 19	$ 18