| TOP INSTITUTIONAL HOLDERS |
| Holder | Shares | % Out | Value* | Reported | | PRIMECAP MANAGEMENT COMPANY | 8,738,614 | 8.68 | $157,994,141 | 30-Sep-09 | | PRICE (T.ROWE) ASSOCIATES INC | 8,152,590 | 8.09 | $147,398,827 | 30-Sep-09 | | SECTORAL ASSET MANAGEMENT, INC. | 5,800,746 | 5.76 | $104,877,487 | 30-Sep-09 | | HEALTHCOR MANAGEMENT LP | 4,900,000 | 4.86 | $88,592,000 | 30-Sep-09 | | COLUMBIA WANGER ASSET MANAGEMENT, L.P. | 4,745,576 | 4.71 | $85,800,014 | 30-Sep-09 | | MUNDER CAPITAL MANAGEMENT, INC. | 4,448,294 | 4.42 | $80,425,155 | 30-Sep-09 | | VANGUARD GROUP, INC. (THE) | 3,876,304 | 3.85 | $70,083,576 | 30-Sep-09 | | FEDERATED INVESTORS, INC. | 3,845,273 | 3.82 | $69,522,535 | 30-Sep-09 | | Barclays Global Investors UK Holdings Ltd | 3,735,446 | 3.71 | $67,536,863 | 30-Sep-09 | | ORBIMED ADVISORS LLC. | 3,108,800 | 3.09 | $56,207,104 | 30-Sep-09 |
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| Holder | Shares | % Out | Value* | Reported | | VANGUARD HORIZON FUND-CAPITAL OPPORTUNITY PORTFOLIO | 4,969,100 | 4.93 | $77,567,651 | 30-Jun-09 | | FEDERATED KAUFMANN FUND | 3,250,000 | 3.23 | $53,332,500 | 31-Jul-09 | | COLUMBIA ACORN FD | 3,000,000 | 2.98 | $46,830,000 | 30-Jun-09 | | Munder Mid-Cap Core Growth Fund | 2,648,825 | 2.63 | $41,348,158 | 30-Jun-09 | | PRICE (T.ROWE) MID CAP GROWTH FUND | 2,500,000 | 2.48 | $45,200,000 | 30-Sep-09 | | PRICE (T.ROWE) HEALTH SCIENCES FUND | 1,750,000 | 1.74 | $27,317,500 | 30-Jun-09 | | FIDELITY SELECT PORTFOLIOS - BIOTECHNOLOGY | 1,582,778 | 1.57 | $28,616,626 | 30-Sep-09 | | PRICE (T.ROWE) NEW HORIZONS FUND | 1,312,000 | 1.30 | $23,720,960 | 30-Sep-09 | | EATON VANCE WORLDWIDE HEALTH SCIENCES FD | 1,302,000 | 1.29 | $23,540,160 | 30-Sep-09 | | VANGUARD EXPLORER FUND, INC. | 1,264,719 | 1.26 | $20,754,038 | 31-Jul-09 |
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Value shown is computed using the security's price on the report date given.
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1.48% Nasdaq 
Major Holders
