Note 2 - Summary of Significant Accounting Policies - Basic and Diluted Weighted Average Common Shares Outstanding (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Weighted average common shares outstanding, basic (in shares)	5,626	5,549	5,524
Dilutive common equivalent shares (in shares)	0	0	0
Weighted average common shares outstanding, assuming dilution (in shares)	5,626	5,549	5,524