Accounts Receivable

6 Months Ended

Mar. 31, 2013

Receivables [Abstract]

Accounts Receivable

Accounts Receivable

The components of accounts receivable consisted of the following:

	As of			As of
(in thousands)	March 31, 2013			September 30, 2012
Accounts receivable	$	32,167		$	33,893
Accounts receivable – unbilled	10,651			6,325
Accounts receivable, gross	42,818			40,218
Allowance for doubtful accounts	(3,281		)	(3,279		)
Accounts receivable, net	$	39,537		$	36,939

Unbilled accounts receivable represents revenue recognized but not yet billed as of the period ended. Billings on contracts using the percentage-of-completion method usually occur upon completion of predetermined contract milestones or other contract terms, such as customer approval. The allowance for doubtful accounts is based on the age of receivables and a specific identification of receivables considered at risk of collection.

As of March 31, 2013 and September 30, 2012, we had $9.3 million and $6.3 million, respectively, of accounts receivable recorded using the percentage of completion method. Of these amounts, $0.6 million was invoiced and $8.7 million was unbilled as of March 31, 2013 and $1.9 million was invoiced and $4.4 million was unbilled as of September 30, 2012.

Included in accounts receivable, net at March 31, 2013 and September 30, 2012 is $3.6 million and $2.3 million, respectively, from sales to Suncore. See Note 15 - Suncore Joint Venture for additional disclosures related to Suncore.