Note 10 - Equity, Share-based Compensation, Warrants and Securities Offerings - Share-based Compensation Expenses Related to Employees and Directors (Details) - The 2014 Equity Incentive Plan [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Compensation expense related to common stock awards issued under equity incentive plans	$ 1,261	$ 1,114
Restricted Stock Units (RSUs) [Member]
Compensation expense related to common stock awards issued under equity incentive plans	1,160	866
Share-Based Payment Arrangement, Option [Member]
Compensation expense related to common stock awards issued under equity incentive plans	101	140
Common Stock, Vested at Issuance and Nonvested at Issuance [Member]
Compensation expense related to common stock awards issued under equity incentive plans	$ 0	$ 108