Balance Sheet Details

The detail of certain assets in the Consolidated Balance Sheets consists of the following (in millions).

Cash and cash equivalents

The Company's cash equivalents consist of overnight cash sweep accounts that are invested on a daily basis. Cash and cash equivalents at December 30, 2012 and December 29, 2013 were $49.0 million and $55.7 million, respectively and approximated their fair value.

Net unrealized and realized gains recorded during the years ended December 30, 2012 and December 29, 2013 were immaterial.

Accounts receivable, net

Receivables including amounts due under long-term contracts are summarized as follows:



	December 30, 2012			December 29, 2013
Billed, current	$	137.9		$	150.2
Unbilled, current	135.4			117.9
Total current accounts receivable	273.3			268.1
Allowance for doubtful accounts	(1.4		)	(2.3		)
Total current accounts receivable, net	271.9			265.8
Unbilled, long-term (included in other assets)	0.3			0.1
Total accounts receivable, net	$	272.2		$	265.9

Unbilled receivables represent the balance of recoverable costs and accrued profit, composed principally of revenue recognized on contracts for which billings have not been presented to the customer because the amounts were earned but not contractually billable as of the balance sheet date. Retainages receivable were $3.5 million as of December 30, 2012 and $6.2 million as of December 29, 2013 and are included in accounts receivable, net in the Consolidated Balance Sheets.

U.S. Government contract receivables (included in accounts receivable, net)



	December 30, 2012		December 29, 2013
Billed	$	24.6	$	19.8
Unbilled	39.4		31.6
Total U.S. Government contract receivables	$	64.0	$	51.4

Inventoried costs, net of progress payments



	December 30, 2012			December 29, 2013
Raw materials	$	48.4		$	44.5
Work in process	36.5			24.3
Finished goods	7.3			4.6
Supplies and other	2.2			1.9
Subtotal inventoried costs	94.4			75.3
Less customer advances and progress payments	(0.1		)	(0.7		)
Total inventoried costs	$	94.3		$	74.6

Property and equipment, net



	December 30, 2012			December 29, 2013
Land and buildings	$	20.8		$	21.0
Computer equipment and software	17.2			20.0
Machinery and equipment	49.9			59.0
Furniture and office equipment	12.2			15.4
Facility under capital lease	1.0			1.0
Leasehold improvements	13.9			13.7
Construction in progress	5.8			4.8
Property and equipment	120.8			134.9
Accumulated depreciation and amortization	(35.2		)	(50.1		)
Total property and equipment, net	$	85.6		$	84.8

Depreciation expense was $10.0 million, $14.1 million and $17.2 million for the years ended December 25, 2011, December 30, 2012, and December 29, 2013, respectively.