Note H - Income Taxes (Details Textual) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Jun. 30, 2018
Effective Income Tax Rate Reconciliation, Percent, Total	20.70%	153.10%	20.60%	97.31%
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent			21.00%	28.06%	28.06%
Income Tax Expense (Benefit), Continuing Operations, Discrete Tax Items Due to Tax Act, Amount, Total		$ 3,300,000		$ 3,300,000
Income Tax Expense (Benefit), Continuing Operations, Adjustment of Transition Tax Liability		1,800,000		1,800,000
Effective Income Tax Rate Reconciliation, Repatriation of Foreign Earnings, Amount		775,000		775,000
Income Tax Expense (Benefit), Continuing Operations, Adjustment of Deferred Tax (Asset) Liability		$ 664,000		$ 664,000
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount	$ 0		$ 0
Domestic Tax Authority [Member]
Open Tax Year			2015 2016 2017
State and Local Jurisdiction [Member]
Open Tax Year			2007 2008 2009 2014 2015 2016 2017
Foreign Tax Authority [Member] | Swiss Federal Tax Administration (FTA) [Member]
Open Tax Year			2015 2016 2017