Note 3 - Stock-based Compensation - Stock-based Compensation Plan Expenses (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Share based compensation expense	$ 14,843	$ 13,969	$ 45,765	$ 40,759
Tax benefit related to stock-based compensation	764		2,723
Cost of Sales [Member]
Share based compensation expense	471	453	1,384	1,264
Research and Development Expense [Member]
Share based compensation expense	3,979	3,838	12,168	11,297
Selling, General and Administrative Expenses [Member]
Share based compensation expense	$ 10,393	$ 9,678	$ 32,213	$ 28,198

Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
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