Security	Date	Code	Shares	Price	A/D	Owned after	D/I	Nature of ownership
Common Stock^F2	Oct 24, 2016	C	437,247	—	A	676,895	I	Footnote
Common Stock^F2	Oct 24, 2016	C	3,100,477	—	A	3,777,372	I	Footnote
Common Stock^F2	Oct 24, 2016	C	231,077	—	A	4,008,449	I	Footnote
Common Stock^F2	Oct 24, 2016	P	95,596	$14.00	A	4,104,045	I	Footnote
Common Stock^F2,F3	Oct 24, 2016	C	2,754	—	A	2,754	I	Footnote
Common Stock^F2,F3	Oct 24, 2016	C	19,524	—	A	22,278	I	Footnote
Common Stock^F2,F3	Oct 24, 2016	C	1,454	—	A	23,732	I	Footnote
Common Stock^F3	Oct 24, 2016	P	602	$14.00	A	24,334	I	Footnote
Common Stock^F2,F4	Oct 24, 2016	C	2,210,417	—	A	2,210,417	I	Footnote
Common Stock^F2,F4	Oct 24, 2016	C	173,167	—	A	2,383,584	I	Footnote
Common Stock^F4	Oct 24, 2016	P	60,219	$14.00	A	2,443,803	I	Footnote
Common Stock^F2,F5	Oct 24, 2016	C	66,490	—	A	66,490	I	Footnote
Common Stock^F2,F5	Oct 24, 2016	C	5,210	—	A	71,700	I	Footnote
Common Stock^F2,F6	Oct 24, 2016	C	168,224	—	A	168,224	I	Footnote
Common Stock^F2,F6	Oct 24, 2016	C	13,180	—	A	181,404	I	Footnote
Common Stock^F6	Oct 24, 2016	P	4,583	$14.00	A	185,987	I	Footnote
Common Stock^F2,F7	Oct 24, 2016	C	73,704	—	A	73,704	I	Footnote
Common Stock^F2,F7	Oct 24, 2016	C	5,774	—	A	79,478	I	Footnote

Table II — derivative securities

Security	Conv. / exercise price	Date	Code	Shares	A/D	Exercisable	Expires	Underlying	Underlying shares	D/I
Series A-1 Preferred Shares^F1,F2	—	Oct 24, 2016	C	437,247	D	—	—	Common Stock	437,247	I
Series A-1 Preferred Shares^F1,F3	—	Oct 24, 2016	C	2,754	D	—	—	Common Stock	2,754	I
Series A-2 Preferred Shares^F1,F2	—	Oct 24, 2016	C	3,100,477	D	—	—	Common Stock	3,100,477	I
Series A-2 Preferred Shares^F1,F3	—	Oct 24, 2016	C	19,524	D	—	—	Common Stock	19,524	I
Series A-3 Preferred Shares^F1,F4	—	Oct 24, 2016	C	2,210,417	D	—	—	Common Stock	2,210,417	I
Series A-3 Preferred Shares^F1,F5	—	Oct 24, 2016	C	66,490	D	—	—	Common Stock	66,490	I
Series A-3 Preferred Shares^F1,F6	—	Oct 24, 2016	C	168,224	D	—	—	Common Stock	168,224	I
Series A-3 Preferred Shares^F1,F7	—	Oct 24, 2016	C	73,704	D	—	—	Common Stock	73,704	I
Series B Preferred Shares^F1,F2	—	Oct 24, 2016	C	231,077	D	—	—	Common Stock	231,077	I
Series B Preferred Shares^F1,F3	—	Oct 24, 2016	C	1,454	D	—	—	Common Stock	1,454	I
Series B Preferred Shares^F1,F4	—	Oct 24, 2016	C	173,167	D	—	—	Common Stock	173,167	I
Series B Preferred Shares^F1,F5	—	Oct 24, 2016	C	5,210	D	—	—	Common Stock	5,210	I
Series B Preferred Shares^F1,F6	—	Oct 24, 2016	C	13,180	D	—	—	Common Stock	13,180	I
Series B Preferred Shares^F1,F7	—	Oct 24, 2016	C	5,774	D	—	—	Common Stock	5,774	I

Explanation of responses

F1Each share of the Issuer's Series A-1 Preferred Stock, Series A-2 Preferred Stock, Series A-3 Preferred Stock and Series B Preferred Stock automatically converted into 1 share of the Issuer's Common Stock in its firm commitment initial public offering pursuant to the Issuer's prospectus (Form 424B4) filed with the Securities and Exchange Commission on October 19, 2016.
F2These securities are held of record by Versant Venture Capital IV, L.P. ("VVC IV"). Versant Ventures IV, LLC ("VV IV") is the sole general partner of VVC IV and may be deemed to have voting and investment power over the securities held by VVC IV and as a result may be deemed to have beneficial ownership over such securities, however, VV IV disclaims beneficial ownership of the securities held by VVC IV, except to the extent of its pecuniary interests therein.
F3These securities are held of record by Versant Side Fund IV, L.P. ("VSF IV"). VV IV is the sole general partner of VSF IV and may be deemed to have voting and investment power over the securities held by VSF IV and as a result may be deemed to have beneficial ownership over such securities, however, VV IV disclaims beneficial ownership of the securities held by VSF IV, except to the extent of its pecuniary interests therein.
F4These securities are held of record by Versant Venture Capital V, L.P. ("VVC V"). Versant Ventures V, LLC ("VV V") is the sole general partner of VVC V and may be deemed to have voting and investment power over the securities held by VVC V and as a result may be deemed to have beneficial ownership over such securities, however, VV V disclaims beneficial ownership of the securities held by VVC V, except to the extent of its pecuniary interests therein.
F5These securities are held of record by Versant Affiliates Fund V, L.P. ("VAF V"). VV V is the sole general partner of VAF V and may be deemed to have voting and investment power over the securities held by VAF V and as a result may be deemed to have beneficial ownership over such securities, however, VV V disclaims beneficial ownership of the securities held by VAF V, except to the extent of its pecuniary interests therein.
F6These securities are held of record by Versant Venture Capital V (Canada) LP ("VVC CAN"). Versant Ventures V (Canada) GP-GP, Inc. ("VV V CAN GP") is the sole general partner of Versant Ventures V (Canada), L.P. ("VV V CAN") and VV V CAN is the sole general partner of VVC CAN. VV V CAN GP and VV V CAN may be deemed to have voting and investment power over the securities held by VVC CAN and as a result may be deemed to have beneficial ownership over such securities, however, each disclaim beneficial ownership of the securities held by VVC CAN, except to the extent of their pecuniary interests therein.
F7These securities are held of record by Versant Ophthalmic Affiliates Fund I, L.P. ("VOA"). VV V is the sole general partner of VOA and may be deemed to have voting and investment power over the securities held by VOA and as a result may be deemed to have beneficial ownership over such securities, however, VV V disclaims beneficial ownership of the securities held by VOA, except to the extent of its pecuniary interests therein.

Remarks

This amendment is being filed solely to report the conversion of preferred stock into common stock that occurred upon the closing of the Issuer's initial public offering (the "IPO") on October 24, 2016, which conversion was inadvertently omitted from the original Form 4 filed on October 26, 2016, and to correct the transaction code for the purchases in the IPO, which was previously reported as "A," and not to report any other transactions in securities of the Issuer.