

Note 7	Allowance for Doubtful Accounts Receivable and Sales Returns

Activity in the allowance for doubtful accounts receivable and sales returns (in thousands):



	Allowance For
	Doubtful Accounts Receivable			Sales Returns
Balances, December 31, 2015	$	765		$	158
Addition (reduction) to allowance	52			15
Amounts written off	(6		)	(3		)
Foreign currency translation	29			—
Balances, September 30, 2016	$	840		$	170

One customer accounted for 57% and one other customer accounted for 14% of trade accounts receivable as of September 30, 2016. At December 31, 2015, one customer accounted for 52% and one other customer accounted for 12% of trade accounts receivable.

One customer accounted for 32% or $9.9 million of consolidated revenue during the quarter ended September 30, 2016 and 31% or $27.9 million during the nine months ended September 30, 2016, which is reflected in our Mobile Services segment.

One customer accounted for 28% of consolidated revenue or $8.7 million during the quarter ended September 30, 2015 and for 25% of consolidated revenue or $24.2 million during the nine months ended September 30, 2015, which is reflected in our Mobile Services segment.