Security	Conv. / exercise price	Date	Code	Shares	A/D	Exercisable	Expires	Underlying	Underlying shares	Owned after	D/I
Series A Preferred Stock^F1,F2,F3	—	Apr 2, 2018	C	4,683,238	D	—	—	Common Stock	4,683,238	0	I
Series B Preferred Stock^F1,F2,F3	—	Apr 2, 2018	C	1,385,457	D	—	—	Common Stock	1,385,457	0	I

Explanation of responses

F1Following the transactions reported herein, includes 1,196,827 shares of common stock held of record by ARCH Venture Fund VIII Overage, L.P. ("ARCH Fund Overage") and 4,871,868 shares of common stock held of record by ARCH Venture Fund VIII, L.P. ("ARCH Fund VIII").
F2The sole general partner of ARCH Fund VIII is ARCH Venture Partners VIII, L.P. ("ARCH Partners VIII"). The sole general partner of ARCH Partners VIII and ARCH Fund Overage is ARCH Venture Partners VIII, LLC ("ARCH VIII LLC"). ARCH Partners VIII may therefore be deemed to beneficially own the securities held by ARCH Fund VIII and ARCH VIII LLC may be deemed to beneficially own the securities held by ARCH Fund VIII and ARCH Fund Overage. ARCH Partners VIII and ARCH VIII LLC disclaim beneficial ownership of such securities, except to the extent of any pecuniary interest therein. The managing directors of ARCH VIII LLC are Keith L. Crandell, Clinton Bybee and Robert Nelsen, and they may be deemed to beneficially own the shares held by ARCH Fund VIII and ARCH Fund Overage. Messrs. Crandell, Bybee and Nelsen disclaim beneficial ownership of such shares, except to the extent of any pecuniary interest therein.
F3Upon closing of the Issuer's initial public offering, each share of preferred stock was automatically converted into one share of the Issuer's common stock.