Note 6 - Income Taxes - Reconciliation of Income Taxes Rates (Details)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Statutory rate	21.00%	21.00%
State and local taxes, net of federal benefit	5.80%	4.70%
Equity compensation	0.30%	0.30%
Research and development credit	(2.60%)	(2.50%)
Foreign tax credit	(1.30%)	(2.70%)
GILTI income inclusion	0.00%	1.80%
Other	0.00%	0.60%
Effective rate	23.20%	23.20%