Security	Conv. / exercise price	Date	Code	Shares	A/D	Exercisable	Expires	Underlying	Underlying shares	Owned after	D/I
Convertible Promissory Note^F2,F4,F3	$7.00	Oct 11, 2017	J	—	A	—	—	Common Stock	—	—	I
Convertible Promissory Note^F2,F5,F3	$7.00	Oct 11, 2017	J	—	A	—	—	Common Stock	—	—	I
Convertible Promissory Note^F2,F6,F3	$7.00	Oct 11, 2017	J	—	A	—	—	Common Stock	—	—	I

Explanation of responses

F1The securities were originally acquired from the Issuer on September 6, 2017; however, the conversion price was set upon the pricing of the Issuer's Initial Public Offering (the "IPO").
F2The amount reported represents the principal amount of the Reporting Person's Convertible Promissory Note (the "Note") only. Accrued interest of 5% per year based on the actual number of days outstanding through the conversion date will also convert.
F3The outstanding principal and accrued interest of the Note automatically converts into shares of the Issuer's Common Stock at the price per share available to the public as set forth in the final prospectus related to the IPO upon the closing of the IPO; if not so converted, the Note has a maturity date of September 6, 2018, at which time it will automatically convert into shares of the Issuer's capital stock.
F4See additional Form 4 filed by Alloy Ventures 2002, LLC ("Ventures 2002") for additional members of this joint filing. The securities are directly held by Alloy Partners 2002, L.P. ("Alloy Partners 2002"). Ventures 2002, as the sole general partner of Alloy Partners 2002, may be deemed to beneficially own the securities held by Alloy Partners 2002. Craig Taylor, Douglas Kelly, John Shoch, Tony DiBona and Daniel Rubin are managing directors of Ventures 2002, and as such may be deemed to beneficially own the securities held by Alloy Partners 2002. Each Reporting Person disclaims beneficial ownership of such securities except to the extent of any pecuniary interest therein.
F5See additional Form 4 filed by Ventures 2002 for additional members of this joint filing. The securities are directly held by Alloy Ventures 2002, L.P. ("Alloy Ventures 2002"). Ventures 2002, as the sole general partner of Alloy Ventures 2002, may be deemed to beneficially own the securities held by Alloy Ventures 2002. Craig Taylor, Douglas Kelly, John Shoch, Tony DiBona and Daniel Rubin are managing directors of Ventures 2002, and as such may be deemed to beneficially own the securities held by Alloy Ventures 2002. Each Reporting Person disclaims beneficial ownership of such securities except to the extent of any pecuniary interest therein.
F6See additional Form 4 filed by Ventures 2002 for additional members of this joint filing. The securities are directly held by Alloy Ventures 2005, L.P. ("Alloy Ventures 2005"). Alloy Ventures 2005, LLC ("Ventures 2005"), as the sole general partner of Alloy Ventures 2005, may be deemed to beneficially own the securities held by Alloy Ventures 2005. Craig Taylor, Douglas Kelly, John Shoch, Tony DiBona, Daniel Rubin, Michael Hunkapiller and Ammar H. Hanafi are managing directors of Ventures 2005, and as such may be deemed to beneficially own the securities held by Alloy Ventures 2005. Each Reporting Person disclaims beneficial ownership of such securities except to the extent of any pecuniary interest therein.