Note 3—Balance sheet details

The components of accounts receivable are as follows (in thousands):

	December 31, 2012			September 30, 2012



Trade and other receivables	$	19,701		$	17,543
Long-term contracts:
Billed		84,961			91,132
Unbilled		276,520			264,555
Allowance for doubtful accounts		(421	)		(463	)

Total accounts receivable		380,761			372,767
Less estimated amounts not currently due		(21,460	)		(22,070	)

Current accounts receivable	$	359,301		$	350,697

The amount classified as not currently due is an estimate of the amount of long-term contract accounts receivable that will not be collected within one year from December 31, 2012 under transportation systems contracts in the U.S. and Australia. The non-current balance at September 30, 2012 represented non-current amounts due from customers under transportation systems contracts in the same locations.

Inventories consist of the following (in thousands):

	December 31, 2012			September 30, 2012



Work in process and inventoried costs under long-term contracts	$	85,411		$	78,796
Customer advances		(33,086	)		(27,288	)
Raw material and purchased parts		770			858

Net inventories	$	53,095		$	52,366

At December 31, 2012, work in process and inventoried costs under long-term contracts includes approximately $2.5 million in costs incurred outside the scope of work or in advance of a contract award, compared to $1.9 million at September 30, 2012. We believe it is probable that we will recover these costs, plus a profit margin, under contract change orders or awards within the next year.

Long-term capitalized contract costs include costs incurred on a contract to develop and manufacture a transportation fare system for a customer for which revenue will not begin to be recognized until the system has been delivered.