Note 6 - Goodwill and Acquisition-related Intangible Assets, Net (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Goodwill, Period Increase (Decrease)	$ 0	$ 0
Goodwill, Impairment Loss	0	0	$ 0
Cost Of Revenue [Member]
Amortization of Intangible Assets	$ 2,100	$ 2,100	$ 1,800