AGREEMENT TO FILE JOINTLY AND STATEMENT APPOINTING DESIGNATED FILER AND
                              AUTHORIZED SIGNATORY


     Each of the undersigned entities and individuals (collectively, the
"Reporting Persons") hereby authorizes and designates Benchmark Capital
Management Co. VII, L.L.C. or such other person or entity as is designated in
writing by Steven M. Spurlock (the "Designated Filer") as the beneficial owner
to prepare and file on behalf of such Reporting Person individually, or jointly
together with the other Reporting Persons, any and all reports, notices,
communications and other documents (including, but not limited to, reports on
Schedule 13D, Schedule 13G, Form 3, Form 4 and Form 5) that such Reporting
Person may be required to file with the United States Securities and Exchange
Commission pursuant to the Securities Act of 1933, as amended (together with the
implementing regulations thereto, the "Act"), the Securities Exchange Act of
1934, as amended (together with the implementing regulations thereto, the
"Exchange Act") or any other state or federal agency (collectively, the
"Reports") with respect to the Reporting Person's ownership of, or transactions
in, securities of any entity whose securities are beneficially owned (directly
or indirectly) by such Reporting Person (collectively, the "Companies").

     Each Reporting Person hereby further authorizes and designates Steven M.
Spurlock (the "Authorized Signatory") to execute and file on behalf of such
Reporting Person the Reports and to perform any and all other acts, which in the
opinion of the Designated Filer or Authorized Signatory may be necessary or
incidental to the performance of the foregoing powers herein granted.

     The authority of the Designated Filer and the Authorized Signatory under
this Document with respect to each Reporting Person shall continue until such
Reporting Person is no longer required to file any Reports with respect to the
Reporting Person's ownership of, or transactions in, the securities of the
Companies, unless earlier revoked in writing.  Each Reporting Person
acknowledges that the Designated Filer and the Authorized Signatory are not
assuming any of the Reporting Person's responsibilities to comply with the Act
or the Exchange Act.

December 11, 2014             BENCHMARK CAPITAL MANAGEMENT CO. VII, L.L.C.,
                              a Delaware Limited Liability Company


                              By: /s/ Steven M. Spurlock
                                  ------------------------------------
                                  Steven M. Spurlock, Managing Member


December 11, 2014             BENCHMARK CAPITAL PARTNERS VII, L.P.,
                              a Delaware Limited Partnership

                              By: Benchmark Capital Management Co. VII, L.L.C.,
                              a Delaware Limited Liability Company,
                              Its General Partner

                              By: /s/ Steven M. Spurlock
                                  ------------------------------------
                                  Steven M. Spurlock, Managing Member




December 11, 2014             BENCHMARK FOUNDERS' FUND VII, L.P.,
                              a Delaware Limited Partnership

                              By: Benchmark Capital Management Co. VII, L.L.C.,
                              a Delaware Limited Liability Company,
                              Its General Partner

                              By: /s/ Steven M. Spurlock
                                  ------------------------------------
                                  Steven M. Spurlock, Managing Member


December 11, 2014             BENCHMARK FOUNDERS' FUND VII-B, L.P.,
                              a Delaware Limited Partnership

                              By: Benchmark Capital Management Co. VII, L.L.C.,
                              a Delaware Limited Liability Company,
                              Its General Partner

                              By: /s/ Steven M. Spurlock
                                  ------------------------------------
                                  Steven M. Spurlock, Managing Member


December 11, 2014             By: /s/ Bruce W. Dunlevie
                                  ------------------------------------
                                  Bruce W. Dunlevie


December 11, 2014             By: /s/ J. William Gurley
                                  ------------------------------------
                                  William Gurley


December 11, 2014             By: /s/ Kevin R. Harvey
                                  ------------------------------------
                                  Kevin R. Harvey


December 11, 2014             By: /s/ Mitchell H. Lasky
                                  ------------------------------------
                                  Mitchell H. Lasky


December 11, 2014             By: /s/ Peter H. Fenton
                                  -------------------------------------
                                  Peter H. Fenton


December 11, 2014             By: /s/ Matthew R. Cohler
                                  -------------------------------------
                                  Matthew R. Cohler