Note 17 - Segment and Geographic Information - Revenue by Region (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenue	$ 103,618	$ 106,456	$ 94,079	$ 84,512	$ 86,918	$ 91,194	$ 81,416	$ 73,538	$ 388,665	$ 333,067	$ 282,535
CHINA
Revenue									245,169	213,119	181,050
TAIWAN, PROVINCE OF CHINA
Revenue									45,414	41,521	38,460
KOREA, REPUBLIC OF
Revenue									27,710	20,519	14,362
Europe [Member]
Revenue									27,554	22,603	19,830
South East Asia [Member]
Revenue									19,645	18,592	13,993
JAPAN
Revenue									14,318	9,727	8,251
UNITED STATES
Revenue									8,567	6,732	6,392
Other Region [Member]
Revenue									$ 288	$ 254	$ 197