Note 12 - Stock-based Compensation - Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Stock-based compensation expense	$ 76,855	$ 63,884	$ 44,833
Cost of Sales [Member]
Stock-based compensation expense	6,208	2,527	2,045
Research and Development Expense [Member]
Stock-based compensation expense	42,265	37,397	28,846
Selling and Marketing Expense [Member]
Stock-based compensation expense	15,561	13,470	8,340
General and Administrative Expense [Member]
Stock-based compensation expense	$ 12,821	$ 10,490	$ 5,602