9. Concentration of Credit Risk, Segment, and Geographic Information

We operate in two segments, products and services, as disclosed within our condensed consolidated Statements of Operations. We do not identify assets on a segment basis. We attribute revenues to individual countries and geographic areas based upon location of our selling operating subsidiaries. A summary of our revenues by geographic area is as follows (dollars in thousands):


		Three Months Ended				Six Months Ended
		December 31,				December 31,
		2011		2010		2011		2010
United States	$	10,934	$	11,604	$	19,222	$	23,334

Japan		3,637		5,225		6,826		7,441
Other Asia Pacific countries		22		83		53		488
Total Asia Pacific		3,659		5,308		6,879		7,929
Europe		1,817		940		3,197		2,135
Total revenue	$	16,410	$	17,852	$	29,298	$	33,398

In addition, the following summarizes revenues by significant customer where such revenue accounted for 10% or more of total revenues for any one of the indicated periods:


		Three Months Ended						Six Months Ended
		December 31,						December 31,
		2011			2010			2011			2010
Customer A		17	%		24	%		17	%		17	%
Customer B		12	%	<	10	%		10	%	<	10	%
Customer C		12	%		13	%	<	10	%		13	%
Customer D	<	10	%	<	10	%		12	%	<	10	%

We assess credit risk through ongoing credit evaluations of customers' financial condition, and collateral is generally not required. Three customers accounted for $1,792,000 or 15%, $1,628,000 or 14%, and $1,208,000 or 10% of trade receivables, respectively, at December 31, 2011. Three customers accounted for $1,024,000 or 13%, $1,011,000 or 12%, and $973,000 or 12% of trade receivables, respectively, at June 30, 2011. No other customers accounted for 10% or more of trade receivables as of December 31, 2011 or June 30, 2011.

The following summarizes purchases from significant vendors where such purchases accounted for 10% or more of total purchases for any one of the indicated periods:


		Three Months Ended						Six Months Ended
		December 31,						December 31,
		2011			2010			2011			2010
Vendor A		31	%	<	10	%		26	%	<	10	%
Vendor B	<	10	%		25	%	<	10	%		22	%
Vendor C	<	10	%		21	%	<	10	%		20	%