Security	Date	Code	Shares	Price	A/D	Owned after	D/I
Common Stock^F1,F2	Dec 11, 2017	C	398,257	—	A	398,257	D
Common Stock^F1,F2	Dec 11, 2017	C	1,045,426	—	A	1,443,683	D
Common Stock^F1,F2	Dec 11, 2017	C	477,042	—	A	1,920,725	D
Common Stock^F1,F2	Dec 11, 2017	C	109,769	—	A	2,030,494	D
Common Stock^F1,F2	Dec 11, 2017	C	381,507	—	A	2,412,001	D
Common Stock^F1,F3	Dec 11, 2017	C	1,271,684	—	A	1,271,684	D
Common Stock^F4,F3	Dec 11, 2017	P	266,000	$15.00	A	1,537,684	D

Table II — derivative securities

Security	Conv. / exercise price	Date	Code	Shares	A/D	Exercisable	Expires	Underlying	Underlying shares	D/I
Series A-1 Preferred Stock^F1,F2,F5,F6	—	Dec 11, 2017	C	1,280,000	D	—	—	Common Stock	398,257	D
Series A-2 Preferred Stock^F1,F2,F5,F6	—	Dec 11, 2017	C	3,360,000	D	—	—	Common Stock	1,045,426	D
Series B Preferred Stock^F1,F2,F5,F6	—	Dec 11, 2017	C	1,533,214	D	—	—	Common Stock	477,042	D
Series C Preferred Stock^F1,F2,F5,F6	—	Dec 11, 2017	C	352,800	D	—	—	Common Stock	109,769	D
Series D Preferred Stock^F1,F2,F5,F6	—	Dec 11, 2017	C	1,226,158	D	—	—	Common Stock	381,507	D
Series D Preferred Stock^F1,F3,F5,F6	—	Dec 11, 2017	C	4,087,193	D	—	—	Common Stock	1,271,684	D

Explanation of responses

F1The shares of preferred stock automatically converted into common stock immediately prior to the closing of the Issuer's initial public offering using a calculation defined in the Issuer's Restated Certificate of Incorporation, as amended, based on the initial purchase price and the conversion rate in effect at the time of conversion. The shares of preferred stock automatically converted on a 1-for-3.214 basis and such conversion rate is reflected in the amount of common stock underlying the security.
F2The shares are held of record by ARCH Venture Fund VI, L.P. ("ARCH Fund VI"). The sole general partner of ARCH Fund VI is ARCH Venture Partners VI, L.P. ("ARCH Partners VI"), which may be deemed to beneficially own the shares held by ARCH Fund VI. The sole general partner of ARCH Partners VI is ARCH Venture Partners VI, LLC ("ARCH VI LLC"), which may be deemed to beneficially own the shares held by ARCH Fund VI. ARCH Partners VI and ARCH VI LLC disclaim beneficial ownership of such shares, except to the extent of any pecuniary interest therein. As a managing director of ARCH VI LLC, the Reporting Person may be deemed to beneficially own the shares held by ARCH Fund VI. The Reporting Person disclaims beneficial ownership of such shares, except to the extent of any pecuniary interest therein.
F3The shares are held of record by ARCH Venture Fund VIII Overage, L.P. ("ARCH Fund Overage"). The sole general partner of ARCH Fund Overage is ARCH Venture Partners VIII, LLC ("ARCH VIII LLC"), which may be deemed to beneficially own the shares held by ARCH Fund Overage. ARCH VIII LLC disclaims beneficial ownership of such shares, except to the extent of any pecuniary interest therein. As a managing director of ARCH VIII LLC, the Reporting Person may be deemed to beneficially own the shares held by ARCH Fund Overage. The Reporting Person disclaims beneficial ownership of such shares, except to the extent of any pecuniary interest therein.
F4Reflects shares purchased in the Issuer's initial public offering.
F5These shares were convertible into the Issuer's common stock in accordance with the Issuer's Restated Certificate of Incorporation, as amended, at any time after the issuance of such shares, at the holder's election.
F6Not applicable.