EXHIBIT 24

         LIMITED POWER OF ATTORNEY FOR SECTION 16 REPORTING OBLIGATIONS

       Know all by these present that the undersigned hereby makes, constitutes
and appoints each of Kimberly Totah and Neal Bhadkamkar, 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 its capacity as
trustee of KC Trust UTA dated December 17, 1999 (the "Trust"), 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 the Trust has made an investment (each
and any of such entities, the "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 any of the undersigned's
responsibilities to comply with Section 16 of the Exchange Act.  The undersigned
acknowledges that neither of 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
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 13th day of June, 2014.

                                           KC TRUST UTA DATED DECEMBER 17, 1999

                                           By:  /s/ Peter J. Randazzo
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                                              Name:  Peter J. Randazzo
                                                   ------------------------
                                              Title: Managing Director
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