Note 15 - Segment and Geographic Information - Revenue by Product Line (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Power Semiconductors [Member]
Net Revenues									$ 213,347	$ 219,445	$ 222,813
Integrated Circuits [Member]
Net Revenues									84,078	95,547	91,189
Systems and RF Power Semiconductors [Member]
Net Revenues									19,784	23,775	22,328
Net Revenues	$ 79,772	$ 75,133	$ 80,257	$ 82,047	$ 82,926	$ 81,326	$ 86,435	$ 88,080	$ 317,209	$ 338,767	$ 336,330