Note 13 - Stock-based Compensation - Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Stock-based compensation expense	$ 63,884	$ 44,833	$ 30,192
Cost of Sales [Member]
Stock-based compensation expense	2,527	2,045	1,796
Research and Development Expense [Member]
Stock-based compensation expense	37,397	28,846	17,390
Selling and Marketing Expense [Member]
Stock-based compensation expense	13,470	8,340	4,405
General and Administrative Expense [Member]
Stock-based compensation expense	10,490	5,602	4,407
Net income (Loss) from Discontinued Operations [Member]
Stock-based compensation expense			$ 2,194