Note 16 - Segment and Geographic Information (Tables)

12 Months Ended

Dec. 31, 2015

Segment Reporting [Abstract]

Schedule of Revenue from External Customers Attributed to Foreign Countries by Geographic Area [Table Text Block]

	Year Ended December 31,
Country or Region	2015		2014		2013
China	$	213,119	$	181,050	$	141,400
Taiwan		41,521		38,460		34,248
Europe		22,603		19,830		15,351
Korea		20,519		14,362		9,992
Southeast Asia		18,592		13,993		21,760
Japan		9,727		8,251		7,495
United States		6,732		6,392		7,525
Other		254		197		320
Total	$	333,067	$	282,535	$	238,091

Revenue from External Customers by Products and Services [Table Text Block]

	Year Ended December 31,
Product Family	2015		2014		2013
DC to DC products	$	299,726	$	253,083	$	211,337
Lighting control products		33,341		29,452		26,754
Total	$	333,067	$	282,535	$	238,091

Schedule of Disclosure on Geographic Areas, Long-Lived Assets in Individual Foreign Countries by Country [Table Text Block]

	December 31,
Country	2015		2014
China	$	40,738	$	37,147
United States		40,405		33,913
Bermuda		11,624		13,383
Other		557		339
Total	$	93,324	$	84,782