Note 11 - Common Stock and Stock-based Compensation Plans - Equity-based Compensation Expense Included in Interim Condensed Consolidated Statements of Income (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Total equity-based compensation expense	$ 2,906	$ 3,417	$ 6,104	$ 6,524
Cost of Revenues [Member]
Total equity-based compensation expense	119	156	262	314
Research and Development, Net [Member]
Total equity-based compensation expense	1,743	1,722	3,428	3,345
Sales and Marketing [Member]
Total equity-based compensation expense	367	512	785	963
General and Administrative [Member]
Total equity-based compensation expense	$ 677	$ 1,027	$ 1,629	$ 1,902