Transaction Details

Footnotes

These securities are fully vested restricted stock units. Each restricted stock unit represents a contingent right to receive one share of the Issuer's common stock. The amount reflects payment to Mr. Michael Lee of a quarterly retainer in common stock pursuant to the Issuer's Outside Director Compensation Policy. | These securities were granted to Mr. Lee, a managing director of Redmile Group, LLC ("Redmile"), in connection with his service as a member of the Board of Directors of the Issuer. Pursuant to the policies of Redmile, Mr. Lee holds these securities as a nominee on behalf, and for the sole benefit, of Redmile and has assigned all economic, pecuniary and voting rights in respect of the securities to Redmile. Mr. Lee disclaims beneficial ownership of the securities, and the filing of this Form 4 shall not be deemed an admission that Mr. Lee is the beneficial owner of the securities for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose. | The reported securities may also be deemed beneficially owned by Jeremy Green as the principal of Redmile (collectively with Redmile, the "Reporting Persons"). The Reporting Persons disclaim beneficial ownership of the reported securities except to the extent of their pecuniary interest therein, if any, and this Form 4 shall not be deemed an admission that either Reporting Person is the beneficial owner of the securities for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose.