Exhibit 24.1

                          SUBSTITUTE POWER OF ATTORNEY

Under the terms of a power of attorney (the "Power of Attorney") previously
filed with the U.S. Securities and Exchange Commission, the undersigned was
appointed an attorney-in-fact for the following individual to, among other
things, execute for and on behalf of the following individual any Forms 3, 4 and
5 or any amendments thereto, in accordance with Section 16(a) of the Securities
Exchange Act of 1934, as amended, and the rules and regulations promulgated
thereunder:

Anil C. Patel

In accordance with the authority granted under the Power of Attorney, including
the power of substitution, the undersigned hereby appoints Nathanael P. Kibler
as substitute attorney-in-fact, on behalf of the individual listed above, with
the power to exercise and execute all of the powers granted or conferred in the
original Power of Attorney. This Substitute Power of Attorney shall not revoke
the powers granted to the undersigned in the original Power of Attorney.

This Substitute Power of Attorney shall remain in full force and effect until
the underlying Power of Attorney is revoked or terminated, unless earlier
revoked by the undersigned in a signed writing.

Dated: July 17, 2018.

/s/ Mandy Garland
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Name: Mandy Garland
Title: Attorney-in-Fact