Note 11 - Income Taxes - Reconciliation of Federal Tax Calculated at Statutory Rate (Details)	12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2019
Income tax expense at federal statutory rate	21.00%	21.00%	21.00%
State income taxes, net of federal benefit	0.60%	2.30%	(1.50%)
Research and development tax credit	(1.80%)	(0.70%)	(1.60%)
Contingent consideration adjustment	0.80%	(0.20%)	(0.40%)
Foreign tax rate differences	0.80%	(0.20%)	0.20%
Option exercises	(16.90%)	(5.70%)	(5.80%)
U.S. taxation of foreign earnings	(0.10%)	0.90%	3.70%
Foreign derived intangible income	(5.10%)	(0.90%)	(2.00%)
Executive compensation limitations	6.50%	1.60%	0.40%
Other, net	0.00%	(1.00%)	0.20%
Effective tax rate	5.80%	17.10%	14.20%