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 29, 2013 and December 28, 2014 were $55.7 million and $34.7 million, respectively and approximated their fair value.

Accounts receivable, net (in millions)

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



	December 29, 2013			December 28, 2014
Billed, current	$	150.2		$	133.6
Unbilled, current	117.9			116.6
Total current accounts receivable	268.1			250.2
Allowance for doubtful accounts	(2.3		)	(2.0		)
Total current accounts receivable, net	265.8			248.2
Unbilled, long-term (included in other assets)	0.1			—
Total accounts receivable, net	$	265.9		$	248.2

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 $6.2 million as of December 29, 2013 and $6.1 million as of December 28, 2014 and are included in accounts receivable, net in the Consolidated Balance Sheets.

U.S. Government contract receivables where the Company is the prime contractor included in accounts receivable, net (in millions)



	December 29, 2013		December 28, 2014
Billed	$	19.8	$	19.1
Unbilled	31.6		21.2
Total U.S. Government contract receivables	$	51.4	$	40.3

Inventoried costs, net of progress payments (in millions)



	December 29, 2013			December 28, 2014
Raw materials	$	44.5		$	39.8
Work in process	24.3			22.3
Finished goods	4.6			4.7
Supplies and other	1.9			2.1
Subtotal inventoried costs	75.3			68.9
Less customer advances and progress payments	(0.7		)	(0.9		)
Total inventoried costs	$	74.6		$	68.0

Property and equipment, net (in millions)



	December 29, 2013			December 28, 2014
Land and buildings	$	21.0		$	21.8
Computer equipment and software	20.0			27.0
Machinery and equipment	59.0			59.8
Furniture and office equipment	15.4			12.9
Facility under capital lease	1.0			—
Leasehold improvements	13.7			13.8
Construction in progress	4.8			8.0
Property and equipment	134.9			143.3
Accumulated depreciation and amortization	(50.1		)	(60.7		)
Total property and equipment, net	$	84.8		$	82.6

Depreciation expense was $14.1 million, $17.2 million and $16.6 million for the years ended December 30, 2012, December 29, 2013, and December 28, 2014, respectively.