Note A - Basis of Presentation and Summary of Significant Accounting Policies - Calculation of Basic and Diluted Net Income Per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Numerator
Net income	$ 2,559	$ 1,434
Denominator
Basic weighted average common shares outstanding (in shares)	6,764,962	6,606,518
Dilutive effect of stock options (in shares)	200,000	224,000
Diluted weighted average common shares outstanding (in shares)	6,964,942	6,831,230
Basic net income per common share (in dollars per share)	$ 0.38	$ 0.22
Diluted net income per common share (in dollars per share)	$ 0.37	$ 0.21