Note 12 - Income Taxes (Details Textual) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		12 Months Ended
	Apr. 30, 2015	Dec. 31, 2017	Jun. 30, 2015	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Apr. 30, 2011
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent					35.00%	34.00%	34.00%
Income Tax Expense (Benefit), Continuing Operations, Adjustment of Deferred Tax (Asset) Liability					$ 9,800
Deemed repatriation tax					41,900
Utilization of R&D tax credit					18,000
Transition Tax Payable		$ 23,900			23,900
Undistributed Earnings of Foreign Subsidiaries		390,200			390,200
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount		(21,600)
Unrecognized Tax Benefits		16,272			16,272	$ 14,431	$ 12,093	$ 16,406
Unrecognized Tax Benefits that Would Impact Effective Tax Rate		9,100			9,100	3,500
Unrecognized Tax Benefits, Interest on Income Taxes Accrued		500			500	$ 300
Income Tax Examination, Liability (Refund) Adjustment from Settlement with Taxing Authority									$ 10,500
Tax Adjustments, Settlements, and Unusual Provisions			$ 2,700
Income Tax Examination, Tax Payment			1,600
Income Tax Examination, Interest Expense			$ 1,100
Domestic Tax Authority [Member]
Operating Loss Carryforwards		0			$ 0
Domestic Tax Authority [Member] | Internal Revenue Service (IRS) [Member]
Income Tax Examination, Year under Examination						2014
Income Taxes Paid	$ 1,200						100
Interest Paid							$ 1,000
Domestic Tax Authority [Member] | Internal Revenue Service (IRS) [Member] | Earliest Tax Year [Member]
Income Tax Examination, Year under Examination					2005
Domestic Tax Authority [Member] | Internal Revenue Service (IRS) [Member] | Latest Tax Year [Member]
Income Tax Examination, Year under Examination					2007
Domestic Tax Authority [Member] | Research Tax Credit Carryforward [Member]
Tax Credit Carryforward, Amount		800			$ 800
State and Local Jurisdiction [Member]
Operating Loss Carryforwards		19,700			19,700
State and Local Jurisdiction [Member] | Research Tax Credit Carryforward [Member]
Tax Credit Carryforward, Amount		21,000			21,000
Accounts Payable and Accrued Liabilities [Member]
Transition Tax Payable		1,900			1,900
Income Tax Liabilites [Member]
Transition Tax Payable		$ 22,000			$ 22,000
Scenario, Forecast [Member]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent				21.00%