Note 9 - Related-party Transactions (Details Textual) - USD ($) $ in Thousands		3 Months Ended			9 Months Ended
	Sep. 30, 2021	Sep. 30, 2022	Jun. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Overhead Charged Related to Office Expenses [Member] | General and Administrative Expense [Member]
Related Party Transaction, Amounts of Transaction		$ 64		$ 66	$ 192	$ 200
Reimbursable Payroll Expense [Member] | General and Administrative Expense [Member]
Related Party Transaction, Amounts of Transaction		2	$ 9	8	16	$ 25
Firms in Which Two Directors Were Principals or Partners [Member]
Related Party Transaction, Amounts of Transaction	$ 604	$ 0		$ 200	$ 0