Note 15 - Reconciliation of Federal Statutory Income Tax Rate to Effective Tax Rate (Details)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Federal tax statutory rate	35.00%	35.00%	35.00%
State tax (net of federal benefit)	0.50%	0.50%	0.60%
Qualified subsidiary election	0.60%	0.20%	(0.80%)
Valuation allowance against deferred tax assets	(0.30%)	(0.20%)	0.80%
Research and development credit	(2.90%)	(0.80%)	(1.80%)
Foreign rate differential	(1.80%)	(2.10%)	(1.60%)
Tax reserves	1.50%	0.40%	0.60%
Domestic manufacturing deduction	(1.40%)	(2.10%)	(1.10%)
Miscellaneous	0.30%	0.30%	(0.10%)
Effective Income Tax Rate Reconciliation, Percent	31.50%	31.20%	31.60%