Note 6 - Segment and Geographic Information - Revenue by Region (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Revenue	$ 128,939	$ 106,456	$ 341,499	$ 285,047
CHINA
Revenue	66,645	67,372	185,054	180,689
TAIWAN, PROVINCE OF CHINA
Revenue	27,387	12,786	59,548	31,801
Europe [Member]
Revenue	10,726	7,193	28,227	21,232
KOREA, REPUBLIC OF
Revenue	9,279	7,405	25,594	21,522
South East Asia [Member]
Revenue	7,179	5,370	20,476	13,210
JAPAN
Revenue	4,813	4,084	14,584	9,771
UNITED STATES
Revenue	2,781	2,164	7,711	6,613
Other Region [Member]
Revenue	$ 129	$ 82	$ 305	$ 209