Note 5 - Stock-based Compensation - Schedule of Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
General and administrative expense	$ 560	$ 484	$ 1,136	$ 1,469
General and Administrative Expense [Member]
General and administrative expense	$ 560	$ 484	$ 1,136	$ 1,469