Security	Date	Code	Shares	Price	A/D	Owned after	D/I	Nature of ownership
Common Stock^F2	Sep 5, 2017	J	1,368,013	$0.00	D	2,736,032	I	see footnote
Common Stock^F4	Sep 5, 2017	J	8,110	$0.00	D	16,224	I	see footnote
Common Stock^F6	Sep 5, 2017	J	814,599	$0.00	D	1,629,204	I	see footnote
Common Stock^F8	Sep 5, 2017	J	23,899	$0.00	D	47,801	I	see footnote
Common Stock^F10	Sep 5, 2017	J	61,993	$0.00	D	123,994	I	see footnote
Common Stock^F12	Sep 5, 2017	J	26,491	$0.00	D	52,987	I	see footnote
Common Stock^F14	Sep 5, 2017	J	292,529	$0.00	A	292,529	I	see footnote
Common Stock^F14	Sep 5, 2017	J	292,529	$0.00	D	0	I	see footnote
Common Stock^F17	Sep 5, 2017	J	17,283	$0.00	A	17,283	I	see footnote
Common Stock^F17	Sep 5, 2017	J	17,283	$0.00	D	0	I	see footnote
Common Stock^F20	Sep 5, 2017	J	1,240	$0.00	A	1,240	I	see footnote
Common Stock^F20	Sep 5, 2017	J	1,240	$0.00	D	0	I	see footnote

Table II — derivative securities

No Table II lines on this filing.

Explanation of responses

F1Represents a pro-rata in-kind distribution of Common Stock of the Issuer by Versant Venture Capital IV, L.P. ("VVC IV") without consideration to its partners.
F10These securities are held of record by VVC CAN. Versant Ventures V GP-GP (Canada), 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 respective pecuniary interests therein.
F11Represents a pro-rata in-kind distribution of Common Stock of the Issuer by Versant Ophthalmic Affiliates Fund I, L.P. ("VOA") without consideration to its partners.
F12These securities are held of record by 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 interest therein.
F13Represents a change in the form of ownership of VV IV by virtue of the receipt of shares in the pro-rata in-kind distribution of Common Stock of the Issuer for no consideration by VVC IV and VSF IV.
F14The shares are held VV IV.
F15Represents a pro-rata in-kind distribution of Common Stock of the Issuer by VV IV without consideration to its members.
F16Represents a change in the form of ownership of VV V by virtue of the receipt of shares in the pro-rata in-kind distribution of Common Stock of the Issuer for no consideration by VVC V, VAF V and VOA.
F17The shares are held VV V.
F18. Represents a pro-rata in-kind distribution of Common Stock of the Issuer by VV V without consideration to its members.
F19Represents a change in the form of ownership of VV V CAN by virtue of the receipt of shares in the pro-rata in-kind distribution of Common Stock of the Issuer for no consideration by VVC CAN.
F2These securities are held of record by 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 interest therein.
F20The shares are held VV V CAN.
F21Represents a pro-rata in-kind distribution of Common Stock of the Issuer by VV V CAN without consideration to its partners.
F3Represents a pro-rata in-kind distribution of Common Stock of the Issuer by Versant Side Fund IV, L.P. ("VSF IV") without consideration to its partners.
F4These securities are held of record by 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 interest therein.
F5Represents a pro-rata in-kind distribution of Common Stock of the Issuer by Versant Venture Capital V, L.P. ("VVC V") without consideration to its partners.
F6These securities are held of record by 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 interest therein.
F7Represents a pro-rata in-kind distribution of Common Stock of the Issuer by Versant Affiliates Fund V, L.P. ("VAF V") without consideration to its partners.
F8These securities are held of record by 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 interest therein.
F9Represents a pro-rata in-kind distribution of Common Stock of the Issuer by Versant Venture Capital V (Canada) LP ("VVC CAN") without consideration to its partners.