| Top Institutional Holders |
|---|
| Holder | Shares | % Out | Value* | Reported |
|---|
| RA Capital Management, LLC | 6,698,558 | 8.08 | 23,377,967 | 31-Mar-2013 | | FMR, LLC | 6,108,500 | 7.37 | 21,318,665 | 31-Mar-2013 | | Orbimed Advisors LLC. | 2,796,827 | 3.37 | 9,760,926 | 31-Mar-2013 | | BlackRock Fund Advisors | 2,789,097 | 3.36 | 9,733,948 | 31-Mar-2013 | | BlackRock Institutional Trust Company, N.A. | 2,554,399 | 3.08 | 8,914,852 | 31-Mar-2013 | | Artal Group S.A. | 2,500,000 | 3.02 | 8,725,000 | 31-Mar-2013 | | Baker Brothers Advisors, LLC | 20,274,581 | 24.46 | 70,758,287 | 31-Mar-2013 | | Vanguard Group, Inc. (The) | 2,263,462 | 2.73 | 7,899,482 | 31-Mar-2013 | | Driehaus Capital Management, Inc. | 1,698,953 | 2.05 | 5,929,345 | 31-Mar-2013 | | State Street Corporation | 1,160,541 | 1.40 | 4,050,288 | 31-Mar-2013 |
|
| Holder | Shares | % Out | Value* | Reported |
|---|
| Fidelity Small Cap Growth Fund | 2,500,000 | 3.02 | 6,725,000 | 31-Jan-2013 | | Fidelity Small Cap Opportunities Fund | 2,391,541 | 2.89 | 6,433,245 | 31-Jan-2013 | | iShares Russell 2000 Index Fund | 1,321,168 | 1.59 | 4,610,876 | 31-Mar-2013 | | Fidelity Stock Selector Small Cap Fund | 1,216,959 | 1.47 | 3,273,619 | 31-Jan-2013 | | Vanguard Total Stock Market Index Fund | 1,032,232 | 1.25 | 2,477,356 | 31-Dec-2012 | | iShares NASDAQ Biotechnology Index Fund | 707,167 | 0.85 | 2,468,012 | 31-Mar-2013 | | Vanguard Extended Market Index Fund | 625,463 | 0.75 | 1,501,111 | 31-Dec-2012 | | iShares Russell 2000 Growth Index Fund | 536,100 | 0.65 | 1,870,989 | 31-Mar-2013 | | Master Value Opportunities LLC | 534,800 | 0.65 | 1,283,520 | 31-Dec-2012 | | College Retirement Equities Fund-Stock Account | 340,839 | 0.41 | 818,013 | 31-Dec-2012 |
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View Transactions for Insiders & Institutional Holders Value shown is computed using the security's price on the report date given. Currency in USD. |