Security	Date	Code	Shares	Price	A/D	Owned after	D/I	Nature of ownership
Common Stock^F2	Mar 23, 2018	S	929,881	$27.637	D	2,773,380	I	See footnote
Common Stock^F3	Mar 23, 2018	S	182,639	$27.637	D	544,726	I	See footnote
Common Stock^F4	Mar 23, 2018	S	80,515	$27.637	D	240,139	I	See footnote
Common Stock^F5	holding	—	—		—	25,000	I	See footnote

Table II — derivative securities

No Table II lines on this filing.

Explanation of responses

F1The Reporting Persons sold shares to the underwriters in connection with the closing of the Issuer's follow-on public offering. The reported sale price reflects the price at which the Reporting Person sold shares to the underwriters, which is net of underwriting commissions.
F2The shares are held of record by Accel VIII L.P. ("Accel VIII"). Arthur C. Patterson and James R. Swartz are the managing members of Accel VIII Associates LLC ("Accel Associates"), the general partner of Accel VIII, and share voting and dispositive power over the shares held by Accel VIII. Each of the reporting persons disclaims beneficial ownership of these shares except to the extent of any pecuniary interest therein, and the filing of this report is not an admission that any reporting person is the beneficial owner of these shares for purposes of Section 16 or for any other purpose.
F3The shares are held of record by Accel Internet Fund IV L.P. ("Fund IV"). Messrs. Patterson and Swartz are the managing members of Accel Associates, the general partner of Fund IV, and share voting and dispositive power over the shares held by Fund IV. Each of the reporting persons disclaims beneficial ownership of these shares except to the extent of any pecuniary interest therein, and the filing of this report is not an admission that any reporting person is the beneficial owner of these shares for purposes of Section 16 or for any other purpose.
F4The shares are held of record by Accel Investors 2000 L.L.C. ("Investors 2000"). Messrs. Patterson and Swartz are the managing members of Investors 2000 and share voting and dispositive power over the shares held by Investors 2000. Each of the reporting persons disclaims beneficial ownership of these shares except to the extent of any pecuniary interest therein, and the filing of this report is not an admission that any reporting person is the beneficial owner of these shares for purposes of Section 16 or for any other purpose.
F5The shares are held directly by ACP Family Partnership L.P. Members of Arthur C. Patterson's immediate family are beneficial holders of ACP Family Partnership L.P., and the reporting person may be deemed to exercise voting and investment power over such shares.