Note 15 - Stock-based Compensation - Compensation Related to Stock-based Awards (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Total stock-based compensation expense	$ 9,359	$ 10,218	$ 8,760
Tax effect on stock-based compensation expense	736	668	604
Net effect of stock-based compensation expense	8,623	9,550	8,156
Cost of Sales [Member]
Total stock-based compensation expense	3,633	3,488	3,369
Selling and Marketing Expense [Member]
Total stock-based compensation expense	4,810	792	452
General and Administrative Expense [Member]
Total stock-based compensation expense	$ 916	$ 5,938	$ 4,939