Note 7 - Income Tax Expense - Income Tax Rate Reconciliation (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statutory Federal income tax rate	21.00%	21.00%	34.00%
State and local income taxes, net of Federal income tax benefit	4.80%	2.00%	1.50%
Rate impacts due to foreign operations	(3.90%)	(2.70%)	(5.10%)
Changes in uncertain tax positions	1.70%	0.40%
Compensation related	(0.20%)	1.40%	(6.10%)
R&D tax credits	(0.90%)	(0.40%)	(0.50%)
Other	(1.40%)	(1.00%)	(0.10%)
Impact of the Tax Act			15.70%
Effective income tax rate	21.10%	20.70%	39.40%