The following table provides details of selected balance sheet items (in thousands):



	December 27, 2014			December 28, 2013
Inventory:
Raw materials	$	15,169		$	14,311
Work in process	50,046			49,172
Finished goods⁽¹⁾	81,285			60,202
Total⁽²⁾	$	146,500		$	123,685
Property, plant and equipment, net:
Computer hardware	$	8,785		$	9,692
Computer software⁽³⁾	17,684			16,988
Laboratory and manufacturing equipment	162,004			146,834
Furniture and fixtures	1,340			1,347
Leasehold improvements	37,825			35,913
Construction in progress	14,726			8,950
Subtotal	$	242,364		$	219,724
Less accumulated depreciation and amortization⁽⁴⁾	(160,798		)	(140,056		)
Total	$	81,566		$	79,668
Accrued expenses:
Loss contingency related to non-cancelable purchase commitments	$	5,390		$	5,120
Professional and other consulting fees	1,831			1,411
Taxes payable	3,993			2,372
Royalties	2,648			1,540
Accrued rebate and customer prepay liability	941			3,807
Accrued interest on convertible senior notes	219			219
Other accrued expenses	11,419			7,962
Total	$	26,441		$	22,431


⁽¹⁾	Included in finished goods inventory at December 27, 2014 and December 28, 2013 were $10.2 million and $9.2 million, respectively, of inventory at customer locations for which product acceptance had not occurred.


⁽²⁾	As of December 27, 2014 and December 28, 2013, the Company’s inventory value had been reduced by $10.1 million and $8.7 million, respectively, for excess and obsolescence, and $7.1 million and $5.0 million, respectively, for LCM adjustments.


⁽³⁾	Included in computer software at December 27, 2014 and December 28, 2013 were $7.9 million and $7.9 million, respectively, related to an enterprise resource planning (“ERP”) system that the Company implemented during 2012. The unamortized ERP costs at December 27, 2014 and December 28, 2013 were $5.2 million and $6.3 million, respectively.


₍₄₎	Depreciation expense was $25.9 million, $24.5 million and $23.5 million (which includes depreciation of capitalized ERP costs of $1.1 million, $1.1 million and $0.4 million, respectively) for 2014, 2013 and 2012, respectively.