Note 8 - Stock-based Compensation - Stock-based Compensation Plan Expenses (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share based compensation expense		$ 85,551	$ 78,699	$ 60,607
Tax benefit related to stock-based compensation	[1]	1,855	2,754	4,383
Cost of Sales [Member]
Share based compensation expense		2,592	2,409	1,888
Research and Development Expense [Member]
Share based compensation expense		20,033	19,584	15,990
Selling, General and Administrative Expenses [Member]
Share based compensation expense		$ 62,926	$ 56,706	$ 42,729

[1] Amount reflects the tax benefit related to stock-based compensation recorded for equity awards that are expected to generate tax deductions when they vest in future periods.