Note 5 - Basic and Diluted Net Income Per Share - Basic and Diluted Weighted Average Common Shares Outstanding (Details) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Weighted average common shares outstanding, basic (in shares)	5,523	5,514	5,520	5,510
Dilutive common equivalent shares (in shares)		9		25
Weighted average common shares outstanding, diluted (in shares)	5,523	5,523	5,520	5,535