4. Select Balance Sheet Details

Accounts Receivable, net

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


	June 30, 2013			December 31, 2012
Accounts receivable	$	42,092		$	42,086
Allowance for doubtful accounts		(1,061	)		(1,074	)

Accounts receivables, net	$	41,031		$	41,012

Inventories, net

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


	June 30, 2013							December 31, 2012
	Gross		Reserve for excess and obsolete			Net		Gross		Reserve for excess and obsolete			Net
Raw materials	$	5,746	$	—		$	5,746	$	5,863	$	—		$	5,863
Work-in-process		859		—			859		1,350		—			1,350
Finished goods		61,659		(17,650	)		44,009		59,864		(17,222	)		42,642

Inventories, net	$	68,264	$	(17,650	)	$	50,614	$	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)		June 30, 2013			December 31, 2012
Surgical instruments		4	$	61,131		$	56,712
Machinery and equipment		7		14,594			13,996
Computer equipment		5		3,310			3,269
Office furniture and equipment		5		3,696			3,528
Leasehold improvements		various		4,109			4,092
Building		39		56			64
Land		n/a		11			13
Construction in progress		n/a		302			1,045

				87,209			82,719
Less accumulated depreciation and amortization				(56,738	)		(52,316	)

Property and equipment, net			$	30,471		$	30,403

Total depreciation expense was $3.7 million and $3.5 million for the three months ended June 30, 2013 and 2012, respectively. Total depreciation expense was $7.2 million and $7.0 million for the six months ended June 30, 2013 and 2012, respectively.

Intangible Assets, net

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


	Useful lives (in years)		June 30, 2013			December 31, 2012
Developed product technology		3-8	$	23,136		$	23,253
Distribution rights		3		3,967			4,281
Intellectual property		5		1,004			1,004
License agreements		1-7		17,436			17,423
Core technology		10		4,875			4,940
Trademarks and trade names		3-9		3,757			3,796
Customer-related		12-15		21,411			19,221
Distribution network		10-12		4,027			3,906
Physician education programs		10		2,999			3,039
Supply agreement		10		225			225

				82,837			81,088
Less accumulated amortization				(39,226	)		(34,232	)

Intangible assets, net			$	43,611		$	46,856

Total amortization expense was $2.7 million and $2.3 million for the three months ended June 30, 2013 and 2012, respectively. Total amortization expense was $5.4 million and $4.6 million for the six months ended June 30, 2013 and 2012, respectively.

Goodwill

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


	2013
Balance at December 31, 2012	$	180,838
Change in Phygen goodwill		(1,610	)
Effect of foreign exchange rate on goodwill		(1,396	)

Balance at June 30, 2013	$	177,832