Transaction Details

Footnotes

The shares represent fully vested restricted stock units (RSUs) issued in lieu of quarterly cash retainer(s) payable under the issuer's Outsider Director Compensation Policy. The RSUs immediately converted into shares of the issuer's Class A Common Stock. | Includes shares to be issued in connection with the vesting of one or more RSUs. | These shares are held by Potomac Investments L.P. - Fund 1. The Reporting Person disclaims Section 16 beneficial ownership over the securities reported herein except to the extent of his pecuniary interest therein, if any, and this report shall not be deemed an admission that the Reporting Person is the beneficial owner of such securities for Section 16 or any other purpose. | These shares are held by The Potomac Trust, dated 9/21/2001, of which the Reporting Person is a co-trustee. The Reporting Person disclaims Section 16 beneficial ownership over the securities reported herein except to the extent of his pecuniary interest therein, if any, and this report shall not be deemed an admission that the Reporting Person is the beneficial owner of such securities for Section16 or any other purpose. | These shares are held by The Potomac 2011 Irrevocable Trust, of which the Reporting Person is a co-trustee. The Reporting Person disclaims Section 16 beneficial ownership over the securities reported herein except to the extent of his pecuniary interest therein, if any, and this report shall not be deemed an admission that the Reporting Person is the beneficial owner of such securities for Section16 or any other purpose. | These shares are held by Accel Leaders Fund L.P. Accel Leaders Fund Associates L.L.C. ("Accel Leaders Fund GP") is the general partner of Accel Leaders Fund L.P. (the "Accel Leader Fund Entity"). Accel Leaders Fund GP has sole voting and dispositive power with regard to the shares held by the Accel Leaders Fund Entity. The Reporting Person is one of five Managing Members of Accel Leaders Fund GP, who share voting and dispositive powers over the shares held by the Accel Leaders Fund Entity. Each of such Managing Members, the Reporting Person and Accel Leaders Fund GP disclaims Section 16 beneficial ownership over the securities reported herein except to the extent of its pecuniary interest therein, if any, and this report shall not be deemed an admission that any such Managing Member, the Reporting Person or Accel Leaders Fund GP is the beneficial owner of such securities for Section 16 or any other purpose. | These shares are held by Accel Leaders Fund Investors 2016 L.L.C. The Reporting Person is one of five Managing Members of Accel Leaders Fund Investors 2016 L.L.C. who share voting and dispositive powers over such shares. Each of such Managing Members and the Reporting Person disclaims beneficial ownership over the securities herein except to the extent of their pecuniary interest therein, if any, and this report shall not be deemed an admission that any such Managing Member or the Reporting Person is the beneficial owner of such securities for Section 16 or any other purpose. | These shares are held by The Potomac 2011 Nonexempt Trust dated 10/31/2011, of which the Reporting Person is a co-trustee. The Reporting Person disclaims Section 16 beneficial ownership over the securities reported herein except to the extent of his pecuniary interest therein, if any, and this report shall not be deemed an admission that the Reporting Person is the beneficial owner of such securities for Section 16 or any other purpose. | These shares are held by Accel Growth Fund II L.P. Accel Growth Fund II Associates L.L.C. ("Accel Growth Fund II GP") is the general partner of each of Accel Growth Fund II L.P. and Accel Growth Fund II Strategic Partners L.P. (together, the "Accel Growth Fund II Entities"). Accel Growth Fund II GP has sole voting and dispositive power with regard to the shares held by the Accel Growth Fund II Entities. The Reporting Person is one of five Managing Members of Accel Growth Fund II GP, who share voting and dispositive powers over the shares held by the Accel Growth Fund II Entities (continued on Footnote 10). | (continued from Footnote 9) Each of such Managing Members, the Reporting Person and Accel Growth Fund II GP disclaims Section 16 beneficial ownership over the securities reported herein except to the extent of its pecuniary interest therein, if any, and this report shall not be deemed an admission that any such Managing Member, the Reporting Person or Accel Growth Fund II GP is the beneficial owner of such securities for Section 16 or any other purpose. | These shares are held by Accel Growth Fund II Strategic Partners L.P. | The Reporting Person is one of five Managing Members of Accel Growth Fund Investors 2013 L.L.C. who share voting and dispositive powers over such shares. Each of such Managing Members and the Reporting Person disclaims beneficial ownership over the securities herein except to the extent of their pecuniary interest therein, if any, and this report shall not be deemed an admission that any such Managing Member or the Reporting Person is the beneficial owner of such securities for Section 16 or any other purpose.