Note 10 - Share Option and Equity Incentive Plan - Expense Recognized During the Year Related to Share-based Compensation Transactions (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based compensation	$ 5,019	$ 3,485	$ 2,521
Cost of Revenue [Member]
Share-based compensation	57	529	330
Research and Development Expense [Member]
Share-based compensation	548	86	87
Selling and Marketing Expense [Member]
Share-based compensation	1,725	1,045	949
General and Administrative Expense [Member]
Share-based compensation	$ 2,689	$ 1,825	$ 1,155