Note 6 - Segment and Geographic Information (Tables)

3 Months Ended

Mar. 31, 2017

Notes Tables

Schedule of Revenue by Major Customers by Reporting Segments [Table Text Block]

	Three Months Ended March 31,
Customer	2017			2016
Distributor A		18	%		20	%
Distributor B		10	%		*

Schedule of Accounts Receivable by Major Customers by Reporting Segments [Table Text Block]

	March 31,			December 31,
Customer	2017			2016
Distributor A		20	%		19	%
Distributor B		13	%		17	%

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

	Three Months Ended March 31,
Country or Region	2017		2016
China	$	56,084	$	52,388
Taiwan		14,875		8,855
Korea		8,161		7,093
Europe		7,907		6,985
Southeast Asia		6,372		4,338
Japan		4,825		2,650
United States		2,042		2,146
Other		96		57
Total	$	100,362	$	84,512

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

	Three Months Ended March 31,
Product Family	2017		2016
DC to DC	$	91,424	$	77,118
Lighting Control		8,938		7,394
Total	$	100,362	$	84,512

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

	March 31,		December 31,
Country	2017		2016
United States	$	52,270	$	50,242
China		45,339		45,728
Bermuda		9,060		9,573
Taiwan		9,576		8,919
Other		433		571
Total	$	116,678	$	115,033