Allowance for Doubtful Accounts Receivable and Sales Returns

12 Months Ended

Dec. 31, 2011

Allowance for Doubtful Accounts Receivable and Sales Returns

Note 6. Allowance for Doubtful Accounts Receivable and Sales Returns

Activity in the allowance for doubtful accounts receivable is as follows (in thousands):

	Years Ended December 31,
	2011			2010			2009
Balance, beginning of year	$	1,529		$	2,912		$	3,532
Additions charged to expenses		693			114			1,523
Amounts written off		(742	)		(1,364	)		(2,117	)
Effects of foreign currency translation		(35	)		(133	)		(28	)
Balance, end of year	$	1,445		$	1,529		$	2,912

Activity in the allowance for sales returns is as follows (in thousands):

	Years Ended December 31,
	2011			2010			2009
Balance, beginning of year	$	1,039		$	1,012		$	1,099
Additions charged to revenue		939			3,175			2,840
Amounts written off		(1,311	)		(3,149	)		(2,927	)
Effects of foreign currency translation		1			1			—
Balance, end of year	$	668		$	1,039		$	1,012

One customer accounted for 17% of trade accounts receivable as of December 31, 2011. One customer accounted for 15% of trade accounts receivable as of December 31, 2010.

No one customer accounted for more than 10% of total revenue during the years ended December 31, 2011, 2010 and 2009.