| Select Balance Sheet Details |
Select Balance Sheet Details Accounts Receivable, net Accounts receivable, net consist of the following (in thousands): | | | | | | | | | | March 31, 2014 | | December 31, 2013 | Accounts receivable | $ | 39,968 |
| | $ | 42,443 |
| Allowance for doubtful accounts | (1,130 | ) | | (1,048 | ) | Accounts receivables, net | $ | 38,838 |
| | $ | 41,395 |
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Inventories, net Inventories, net consist of the following (in thousands): | | | | | | | | | | | | | | | | | | | | | | | | | | March 31, 2014 | | December 31, 2013 | | Gross | | Reserve for excess and obsolete | | Net | | Gross | | Reserve for excess and obsolete | | Net | Raw materials | $ | 3,996 |
| | $ | — |
| | $ | 3,996 |
| | $ | 4,375 |
| | $ | — |
| | $ | 4,375 |
| Work-in-process | 645 |
| | — |
| | 645 |
| | 531 |
| | — |
| | 531 |
| Finished goods | 60,852 |
| | (22,951 | ) | | 37,901 |
| | 60,979 |
| | (23,946 | ) | | 37,033 |
| Inventories | $ | 65,493 |
| | $ | (22,951 | ) | | $ | 42,542 |
| | $ | 65,885 |
| | $ | (23,946 | ) | | $ | 41,939 |
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Property and Equipment, net Property and equipment, net consist of the following (in thousands except as indicated): | | | | | | | | | | | | Useful lives (in years) | | March 31, 2014 | | December 31, 2013 | Surgical instruments | 4 | | $ | 62,602 |
| | $ | 62,636 |
| Machinery and equipment | 7 | | 14,414 |
| | 14,692 |
| Computer equipment | 3 | | 3,143 |
| | 3,357 |
| Office furniture and equipment | 5 | | 3,861 |
| | 3,703 |
| Leasehold improvements | various | | 3,733 |
| | 4,161 |
| Building | 39 | | 77 |
| | 52 |
| Land | n/a | | 11 |
| | 10 |
| Construction in progress | n/a | | 1,270 |
| | 1,228 |
| | | | 89,111 |
| | 89,839 |
| Less accumulated depreciation and amortization | | | (60,975 | ) | | (61,809 | ) | Property and equipment, net | | | $ | 28,136 |
| | $ | 28,030 |
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Total depreciation expense was $3.3 million and $3.5 million for the three months ended March 31, 2014 and 2013, respectively. At March 31, 2014, assets recorded under capital leases of $2.4 million were included in the machinery and equipment balance. At December 31, 2013, assets recorded under capital leases of $1.8 million were included in the machinery and equipment balance and $0.6 million in construction in progress balance. Amortization of assets under capital leases was included in depreciation expense. Intangible Assets, net Intangible assets, net consist of the following (in thousands except for useful lives): | | | | | | | | | | | | Useful lives (in years) | | March 31, 2014 | | December 31, 2013 | Developed product technology | 3-8 | | $ | 23,641 |
| | $ | 23,633 |
| Distribution rights | 3 | | 2,388 |
| | 2,343 |
| Intellectual property | 5 | | 1,004 |
| | 1,004 |
| License agreements | 1-7 | | 16,716 |
| | 17,686 |
| Core technology | 10 | | 5,140 |
| | 5,137 |
| Trademarks and trade names | 3-9 | | 3,922 |
| | 3,920 |
| Customer-related | 12-15 | | 22,171 |
| | 22,161 |
| Distribution network | 10-12 | | 4,027 |
| | 4,027 |
| Physician education programs | 10 | | 3,163 |
| | 3,160 |
| Supply agreement | 10 | | 225 |
| | 225 |
| | | | 82,397 |
| | 83,296 |
| Less accumulated amortization | | | (45,221 | ) | | (44,232 | ) | Intangible assets, net | | | $ | 37,176 |
| | $ | 39,064 |
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Total amortization expense was $1.6 million and $2.7 million for the three months ended March 31, 2014 and 2013, respectively. Future amortization expense related to intangible assets subject to amortization are as follows (in thousands): | | | | | Year Ending December 31, | | Remainder of 2014 | $ | 4,739 |
| 2015 | 6,060 |
| 2016 | 5,537 |
| 2017 | 5,240 |
| 2018 | 3,288 |
| Thereafter | 12,312 |
| | $ | 37,176 |
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Accrued Expenses Accrued expenses consist of the following (in thousands): | | | | | | | | | | March 31, 2014 | | December 31, 2013 | Legal | $ | 1,376 |
| | $ | 2,139 |
| Accounting | 782 |
| | 928 |
| Severance | 173 |
| | 297 |
| Restructuring | 9,307 |
| | 9,170 |
| Sales milestones | 1,958 |
| | 1,828 |
| Accrued taxes | 924 |
| | 1,120 |
| Deferred rent | 1,073 |
| | 1,163 |
| Royalties | 2,436 |
| | 2,347 |
| Commissions | 4,376 |
| | 6,180 |
| Payroll and related | 10,196 |
| | 9,369 |
| Litigation settlements | 22,708 |
| | 22,600 |
| Other | 7,145 |
| | 5,855 |
| Total accrued expenses | $ | 62,454 |
| | $ | 62,996 |
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Goodwill The changes in the carrying amount of goodwill from December 31, 2013 through March 31, 2014 are as follows (in thousands): | | | | | | | Balance at December 31, 2013 | $ | 183,004 |
| Effect of foreign exchange rate on goodwill | 84 |
| Balance at March 31, 2014 | $ | 183,088 |
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