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Accounts Receivable, net

Accounts receivable, net consist of the following (in thousands):



	September 30, 2013			December 31, 2012
Accounts receivable	$	42,717		$	42,086
Allowance for doubtful accounts	(979		)	(1,074		)
Accounts receivables, net	$	41,738		$	41,012

Inventories, net

Inventories, net consist of the following (in thousands):



	September 30, 2013							December 31, 2012
	Gross		Reserve for excess and obsolete			Net		Gross		Reserve for excess and obsolete			Net
Raw materials	$	5,291	$	—		$	5,291	$	5,863	$	—		$	5,863
Work-in-process	519		—			519		1,350		—			1,350
Finished goods	61,439		(24,110		)	37,329		59,864		(17,222		)	42,642
Inventories	$	67,249	$	(24,110	)	$	43,139	$	67,077	$	(17,222	)	$	49,855

Property and Equipment, net

Property and equipment, net consist of the following (in thousands except as indicated):



	Useful lives (in years)	September 30, 2013			December 31, 2012
Surgical instruments	4	$	63,119		$	56,712
Machinery and equipment	7	14,630			13,996
Computer equipment	3	3,352			3,269
Office furniture and equipment	5	3,714			3,528
Leasehold improvements	various	4,177			4,092
Building	39	56			64
Land	n/a	11			13
Construction in progress	n/a	336			1,045
		89,395			82,719
Less accumulated depreciation and amortization		(59,880		)	(52,316		)
Property and equipment, net		$	29,515		$	30,403

Total depreciation expense was $3.7 million and $3.5 million for the three months ended September 30, 2013 and 2012, respectively. Total depreciation expense was $10.9 million and $10.5 million for the nine months ended September 30, 2013 and 2012, respectively.

Intangible Assets, net

Intangible assets, net consist of the following (in thousands except as indicated):



	Useful lives (in years)	September 30, 2013			December 31, 2012
Developed product technology	3-8	$	23,475		$	23,253
Distribution rights	3	2,480			4,281
Intellectual property	5	1,004			1,004
License agreements	1-7	17,186			17,423
Core technology	10	5,053			4,940
Trademarks and trade names	3-9	3,868			3,796
Customer-related	12-15	21,923			19,221
Distribution network	10-12	4,027			3,906
Physician education programs	10	3,109			3,039
Supply agreement	10	225			225
		82,350			81,088
Less accumulated amortization		(41,606		)	(34,232		)
Intangible assets, net		$	40,744		$	46,856

Total amortization expense was $3.7 million and $2.3 million for the three months ended September 30, 2013 and 2012, respectively. Total amortization expense was $9.1 million and $6.9 million for the nine months ended September 30, 2013 and 2012, respectively.

Future amortization expense related to intangible assets subject to amortization are as follows (in thousands):



Year Ending December 31,
Remainder of 2013	$	3,266
2014	6,121
2015	5,638
2016	5,320
2017	4,945
Thereafter	15,454
	$	40,744

Goodwill

The changes in the carrying amount of goodwill from December 31, 2012 through September 30, 2013 are as follows (in thousands):




Balance at December 31, 2012	$	180,838
Change in Phygen goodwill	(1,610		)
Effect of foreign exchange rate on goodwill	2,162
Balance at September 30, 2013	$	181,390