Note H - Income Taxes (Details Textual) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Mar. 31, 2017	Jun. 30, 2018
Effective Income Tax Rate Reconciliation, Percent, Total	21.10%	29.00%	69.40%	29.90%
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	28.06%		28.06%
Income Tax Expense (Benefit), Continuing Operations, Adjustment of Transition Tax Liability			$ 1,800,000
Undistributed Earnings of Foreign Subsidiaries	$ 0		0
Effective Income Tax Rate Reconciliation, Repatriation of Foreign Earnings, Amount			775,000
Income Tax Expense (Benefit), Continuing Operations, Adjustment of Deferred Tax (Asset) Liability			664,000
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount	$ 0		$ 0
Earliest Tax Year [Member] | Domestic Tax Authority [Member] | Internal Revenue Service (IRS) [Member]
Open Tax Year			2015
Earliest Tax Year [Member] | State and Local Jurisdiction [Member]
Open Tax Year			2007
Earliest Tax Year [Member] | Foreign Tax Authority [Member] | Swiss Federal Tax Administration (FTA) [Member]
Open Tax Year			2015
Scenario, Forecast [Member]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent					28.06%