Note 1 - Description of Business and Accounting Policies - Earnings Per Share (Details) - shares	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019
Basic (in shares)	13,225	13,165	13,110	13,055	12,997	12,934	12,855	12,795	13,139	12,896
Dilutive potential common shares (in shares)
Diluted (in shares)	13,225	13,165	13,110	13,055	12,997	12,934	12,855	12,795	13,139	12,896