Note 11 - Income Taxes - Reconciliation of Income Tax Rate (Details)	12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016
Federal statutory tax rate	27.60%	34.00%	35.00%
State and local taxes, net of federal benefit	1.10%	2.40%	2.20%
Federal and state tax credits	0.90%	(5.30%)	(2.60%)
Valuation allowance	3.50%	(18.90%)
Domestic production activities deduction	0.60%	(4.10%)	(4.20%)
Uncertain tax position activity	0.40%	(5.50%)	(0.60%)
Shared based compensation	(1.30%)	0.00%	2.50%
Tax rate changes	(14.20%)
Other	(2.30%)
Effective tax rate	16.30%	2.60%	32.30%