LIMITED POWER OF ATTORNEY FOR SECTION 16 REPORTING OBLIGATIONS

      Know all by these present that the undersigned hereby makes, constitutes
and appoints each of Samir Kaul, John Demeter and Kimberly Totah, signing singly
and each acting individually, as the undersigned's true and lawful
attorney-in-fact with full power and authority as hereinafter described to:

      (1)     prepare, execute in the undersigned's name and on the
undersigned's behalf, and submit to the U.S. Securities and Exchange Commission
(the "SEC") a Form ID, including amendments thereto, and any other application
materials necessary or appropriate to obtain codes and passwords enabling the
undersigned to gain or maintain access to the Electronic Data Gathering,
Analysis and Retrieval system of the SEC and make electronic filings with the
SEC of reports required by Section 16(a) of the Securities Exchange Act of 1934
(the "Exchange Act") or any rule or regulation of the SEC;

      (2)     execute for and on behalf of the undersigned, in his own capacity
and in the undersigned's capacity as managing manager of VK Services, LLC,
Forms 3, 4, and 5 (including any amendments thereto) in accordance with
Section 16(a) of the Exchange Act;

      (3)     do and perform any and all acts for and on behalf of the
undersigned which may be necessary or desirable to prepare, complete and
execute any such Form 3, 4, or 5, or other form or report, prepare, complete and
execute any amendment or amendments thereto, and timely deliver and file such
form or report with the SEC and any stock exchange or similar authority;

      (4)     seek or obtain, as the undersigned's representative and on the
undersigned's behalf, information regarding transactions in any of the
securities issued by entities in which any of Khosla Ventures I, L.P., Khosla
Ventures II, L.P., Khosla Ventures III, L.P., Khosla Ventures IV, L.P., Khosla
Ventures IV (CF), L.P., Khosla Ventures V, L.P., Khosla Ventures Seed, L.P.,
Khosla Ventures Seed Side Fund, L.P., Khosla Ventures Seed B, L.P., Khosla
Ventures Seed B (CF), L.P. or Khosla Ventures Seed C, L.P. has made an
investment (each and any of such entities, the "Khosla Portfolio Companies")
from any third party, including brokers, employee benefit plan administrators
and trustees, and the undersigned hereby authorizes any such person to release
any such information to such attorney-in-fact and approves and ratifies any such
release of information; and

      (5)     take any other action of any type whatsoever in connection with
the foregoing which, in the opinion of such attorney-in-fact, may be of benefit
to, in the best interest of, or legally required by, the undersigned, it being
understood that the documents executed by such attorney-in-fact on behalf of the
undersigned pursuant to this Power of Attorney shall be in such form and shall
contain such terms and conditions as such attorney-in-fact may approve in such
attorney-in-fact's discretion.

      The undersigned hereby grants to each such attorney-in-fact full power
and authority to do and perform any and every act and thing whatsoever
requisite, necessary, or proper to be done in the exercise of any of the rights
and powers herein granted, as fully to all intents and purposes as the
undersigned might or could do if personally present, with full power of
substitution or revocation, hereby ratifying and confirming all that such
attorney-in-fact, or such attorney-in-fact's substitute or substitutes, shall
lawfully do or cause to be done by virtue of this power of attorney and the
rights and powers herein granted.  The undersigned acknowledges that the
foregoing attorneys-in-fact, in serving in such capacity at the request of the
undersigned, are not assuming or relieving, nor is VK Services, LLC assuming or
relieving, any of the undersigned's responsibilities to comply with Section 16
of the Exchange Act.  The undersigned acknowledges that neither VK Services, LLC
nor the foregoing attorneys-in-fact assumes (i) any liability for the
undersigned's responsibility to comply with the requirements of the Exchange
Act, (ii) any liability of the undersigned for any failure to comply with such
requirements, or (iii) any obligation or liability of the undersigned for profit
disgorgement under Section 16(b) of the Exchange Act.

      This Power of Attorney shall remain in full force and effect until the
undersigned is no longer required to file Forms 3, 4, or 5 with respect to the
undersigned's holdings of and transactions in securities issued by any of the
Khosla Portfolio Companies, unless earlier revoked by the undersigned in a
signed writing delivered to the foregoing attorneys-in-fact.

      IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to
be executed as of this 22nd day of September, 2016.


                                             /s/ Vinod Khosla
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                                             Signature

                                             Vinod Khosla
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