POWERS OF ATTORNEY

    KNOW ALL MEN BY THESE PRESENTS, that each person whose signature appears
below hereby constitutes and appoints Mark McDonnell his true and lawful
attorney-in-fact, with full power of substitution, to sign any and all
instruments, certificates and documents that may be necessary, desirable or
appropriate to be executed on behalf of himself as an individual or in his
capacity as a direct or indirect general partner, member, director, officer or
manager of any partnership, corporation or limited liability company, pursuant
to section 13 or 16 of the Securities Exchange Act of 1934, as amended (the
"Exchange Act"), and any and all regulations promulgated thereunder, and to file
the same, with all exhibits thereto, and any other documents in connection
therewith, with the Securities and Exchange Commission, and with any other
entity when and if such is mandated by the Exchange Act or by the Financial
Industry Regulatory Authority, granting unto said attorney-in-fact full power
and authority to do and perform each and every act and thing necessary,
desirable or appropriate, fully to all intents and purposes as he might or could
do in person, thereby ratifying and confirming all that said attorney-in-fact,
or his substitutes, may lawfully do or cause to be done by virtue hereof. This
Power of Attorney shall remain in full force and effect with respect to each
undersigned person unless and until six months after such person is both no
longer a Managing Director of ARCH Venture Partners and no longer serving on the
board of directors of any portfolio company of any ARCH Venture Partners fund.

    IN WITNESS WHEREOF, this Power of Attorney has been signed as of the 9th day
of March, 2015.

                          ARCH VENTURE FUND VIII, L.P.

                          By:  ARCH Venture Partners VIII, L.P.
                               its General Partner

                               By:  ARCH Venture Partners VIII, LLC.
                                    its General Partner

                                    By:  /s/ Keith Crandell
                                         -----------------------
                                         Managing Director

                          ARCH VENTURE PARTNERS VIII, L.P.

                          By:  ARCH Venture Partners VIII, LLC
                               its General Partner

                               By:  /s/ Keith Crandell
                                    ----------------------------
                                    Managing Director

                          ARCH VENTURE PARTNERS VIII, LLC

                          By:  /s/ Keith Crandell
                               -----------------------
                               Managing Director

                          /s/ Keith Crandell
                          -----------------------
                          Keith Crandell

                          /s/ Robert Nelsen
                          -----------------------
                          Robert Nelsen

                          /s/ Clinton Bybee
                          -----------------------
                          Clinton Bybee

                          /s/ Kristina Burow
                          -----------------------
                          Kristina Burow

                          /s/ Paul Thurk
                          -----------------------
                          Paul Thurk




                               POWERS OF ATTORNEY

    KNOW ALL MEN BY THESE PRESENTS, that each person whose signature appears
below hereby constitutes and appoints Mark McDonnell his true and lawful
attorney-in-fact, with full power of substitution, to sign any and all
instruments, certificates and documents that may be necessary, desirable or
appropriate to be executed on behalf of himself as an individual or in his
capacity as a direct or indirect general partner, member, director, officer or
manager of any partnership, corporation or limited liability company, pursuant
to section 13 or 16 of the Securities Exchange Act of 1934, as amended (the
"Exchange Act"), and any and all regulations promulgated thereunder, and to file
the same, with all exhibits thereto, and any other documents in connection
therewith, with the Securities and Exchange Commission, and with any other
entity when and if such is mandated by the Exchange Act or by the Financial
Industry Regulatory Authority, granting unto said attorney-in-fact full power
and authority to do and perform each and every act and thing necessary,
desirable or appropriate, fully to all intents and purposes as he might or could
do in person, thereby ratifying and confirming all that said attorney-in-fact,
or his substitutes, may lawfully do or cause to be done by virtue hereof. This
Power of Attorney shall remain in full force and effect with respect to each
undersigned person unless and until six months after such person is both no
longer a Managing Director of ARCH Venture Partners and no longer serving on the
board of directors of any portfolio company of any ARCH Venture Partners fund.

    IN WITNESS WHEREOF, this Power of Attorney has been signed as of the 26th
day of July, 2017.


                          ARCH VENTURE FUND VIII OVERAGE, L.P.

                          By:  ARCH Venture Partners VIII, LLC
                               its General Partner

                               By:  /s/ Keith Crandell
                                    -----------------------
                                    Managing Director

                          ARCH VENTURE PARTNERS VIII, L.P.

                          By:  ARCH Venture Partners VIII, LLC
                               its General Partner

                               By:  /s/ Keith Crandell
                                    -----------------------
                                    Managing Director