AGREEMENT TO FILE JOINTLY AND STATEMENT APPOINTING DESIGNATED FILER
ANDAUTHORIZED SIGNATORY

Each of the undersigned entities and individuals (collectively, the "Reporting
Persons") hereby authorizes and designates Benchmark Capital Management Co. VI,
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. VI, L.L.C.,
a Delaware Limited Liability Company

/s/ Steven M. Spurlock, Managing Member

BENCHMARK CAPITAL PARTNERS VI, L.P.,
a Delaware Limited Partnership

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

/s/ Steven M. Spurlock, Managing Member

BENCHMARK FOUNDERS' FUND VI, L.P.,
a Delaware Limited Partnership

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

/s/ Steven M. Spurlock, Managing Member

BENCHMARK FOUNDERS' FUND VI-B, L.P.,
a Delaware Limited Partnership

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

/s/ Steven M. Spurlock, Managing Member

/s/ Alexandre Balkanski
/s/ Bruce W. Dunlevie
/s/ J. William Gurley
/s/ Kevin R. Harvey
/s/ Robert C. Kagle
/s/ Mitchell H. Lasky
/s/ Peter H. Fenton
/s/ Matthew R. Cohler