Note 9 - Related-party Transactions (Details Textual) - General and Administrative Expense [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Overhead Charged Related to Office Expenses [Member]
Related Party Transaction, Amounts of Transaction	$ 0	$ 64	$ 198	$ 192
Reimbursable Payroll Expense [Member]
Related Party Transaction, Amounts of Transaction	$ (23)	$ 2	$ (53)	$ (16)