Note 8 - Segment and Geographic Information (Tables)

6 Months Ended

Jun. 30, 2019

Notes Tables

Schedules of Concentration of Risk, by Risk Factor [Table Text Block]

	Revenue												Accounts Receivable
	Three Months Ended June 30,						Six Months Ended June 30,						June 30,			December 31,
Customer	2019			2018			2019			2018			2019			2018
Company A (distributor)		22	%		20	%		22	%		20	%		21	%		25	%
Company B (distributor)		*			10	%		*			10	%		12	%		16	%
Company A (direct)		13	%		*			10	%		*			16	%		*

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

	Three Months Ended June 30,				Six Months Ended June 30,
Country or Region	2019		2018		2019		2018
China	$	94,837	$	81,207	$	171,035	$	154,072
Taiwan		16,018		18,150		37,365		34,541
Europe		13,040		12,651		26,024		24,116
Korea		9,623		8,853		19,234		18,640
Southeast Asia		7,122		7,977		15,794		17,002
Japan		6,292		6,486		12,934		12,100
United States		4,013		4,274		9,819		8,029
Other		62		163		165		411
Total	$	151,007	$	139,761	$	292,370	$	268,911

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

	Three Months Ended June 30,				Six Months Ended June 30,
Product Family	2019		2018		2019		2018
DC to DC	$	139,691	$	127,496	$	272,402	$	246,765
Lighting Control		11,316		12,265		19,968		22,146
Total	$	151,007	$	139,761	$	292,370	$	268,911

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

	June 30,		December 31,
Country	2019		2018
China	$	101,872	$	93,096
United States		94,296		39,054
Taiwan		16,795		16,972
Other		867		879
Total	$	213,830	$	150,001