Receivables (Tables)

12 Months Ended

Sep. 30, 2012

Receivables

Receivables at September 30, 2012 and 2011 consisted of the following:

	September 30,
	2012			2011
	(In thousands)
Billed	$	113,514		$	80,858
Unbilled (1)		32,487			27,830
		146,001			108,688
Less: allowance for doubtful accounts		(3,406	)		(3,714	)
Receivables, net	$	142,595		$	104,974

(1) Unbilled receivables represent revenue recorded in excess of amounts billable pursuant to contract provisions and generally become billable at contractually specified dates or upon the attainment of milestones. Unbilled amounts are expected to be realized within one year.

Activity of Allowance for Doubtful Accounts

Activity in the allowance for doubtful accounts was as follows:

	Years Ended September 30,
	2012			2011
	(in thousands)
Balance, beginning of period	$	3,714		$	5,981
Less: reversal of expense		(122	)		(583	)
Less: write-offs (net of recoveries)		(186	)		(1,684	)
Balance, end of period	$	3,406		$	3,714