Security	Date	Code	Shares	Price	A/D	Owned after	D/I	Nature of ownership
Class A Common Stock^F1,F2	Dec 7, 2018	C	3,985,708	$0.00	A	3,985,708	I	By Madrona Venture Fund III, L.P.
Class A Common Stock^F2	Dec 7, 2018	J	3,985,708	$0.00	D	0	I	By Madrona Venture Fund III, L.P.
Class A Common Stock^F1,F2	Dec 7, 2018	C	159,224	$0.00	A	159,224	I	By Madrona Venture Fund III-A, L.P.
Class A Common Stock^F2	Dec 7, 2018	J	159,224	$0.00	D	0	I	By Madrona Venture Fund III-A, L.P.
Class A Common Stock^F1,F4	Dec 7, 2018	C	833,818	$0.00	A	833,818	I	By Madrona Venture Fund IV, L.P.
Class A Common Stock^F4	Dec 7, 2018	J	833,818	$0.00	D	0	I	By Madrona Venture Fund IV, L.P.
Class A Common Stock^F1,F4	Dec 7, 2018	C	21,251	$0.00	A	21,251	I	By Madrona Venture Fund IV-A, L.P.
Class A Common Stock^F4	Dec 7, 2018	J	21,251	$0.00	D	0	I	By Madrona Venture Fund IV-A, L.P.

Table II — derivative securities

Security	Conv. / exercise price	Date	Code	Shares	A/D	Exercisable	Expires	Underlying	Underlying shares	Owned after	D/I
Class B Common Stock^F5,F2	—	Dec 7, 2018	C	3,985,708	D	—	—	Class A Common Stock	3,985,708	16,235,797	I
Class B Common Stock^F5,F2	—	Dec 7, 2018	C	159,224	D	—	—	Class A Common Stock	159,224	648,592	I
Class B Common Stock^F5,F4	—	Dec 7, 2018	C	833,818	D	—	—	Class A Common Stock	833,818	3,396,564	I
Class B Common Stock^F5,F4	—	Dec 7, 2018	C	21,251	D	—	—	Class A Common Stock	21,251	86,563	I

Explanation of responses

F1Represents the number of shares that were acquired upon conversion of Class B Common Stock to Class A Common Stock in connection with the exercise of the options listed in Table II.
F2These securities are held of record by Madrona Venture Fund III, L.P ("Madrona III") and Madrona Venture Fund III-A, L.P. ("Madrona III-A"), as applicable. Madrona Investment Partners III, L.P. ("Madrona Partners III") is the general partner of Madrona III and Madrona III-A, and Madrona III General Partner, LLC ("Madrona III LLC") is the general partner of Madrona Partners III. Matthew McIlwain, a member of the issuer's board of directors, together with Tom Alberg, Paul Goodrich, Scott Jacobson, Len Jordon, and Tim Porter, are the managing members of Madrona III LLC, and each may be deemed to share voting and investment power over the securities held by Madrona III and Madrona III-A. Each of such individuals disclaims beneficial ownership over such securities except to the extent of his pecuniary interest therein, and the securities' inclusion herein shall not be deemed an admission of beneficial ownership of the reported securities for purposes of Section 16 or any other purposes.
F3The shares reported on this form represent pro rata distributions, and not sales, of securities by the reporting holder to its partners or members of the funds for which it acts as nominee without consideration.
F4These securities are held of record by Madrona Venture Fund IV, L.P. ("Madrona IV") and Madrona Venture Fund IV-A, L.P. ("Madrona IV-A"), as applicable. Madrona Investment Partners IV, L.P.("Madrona Partners IV") is the general partner of Madrona IV and Madrona IV-A, and Madrona IV General Partner, LLC ("Madrona IV LLC") is the general partner of Madrona Partners IV. Matthew McIlwain, a member of the issuer's board of directors, together with Tom Alberg, Paul Goodrich, Scott Jacobson, Len Jordon, and Tim Porter, are the managing members of Madrona IV LLC, and each may be deemed to share voting and investment power over the securities held by Madrona Fund IV and Madrona Fund IV-A. Each of such individuals disclaims beneficial ownership over such securities except to the extent of his pecuniary interest therein, and the securities' inclusion herein shall not be deemed an admission of beneficial ownership of the reported securities for purposes of Section 16 or any other purposes.
F5The Class B Common Stock is convertible into the issuer's Class A Common Stock on a 1-for-1 basis (a) at the option of the holder or (b) automatically upon (i) any transfer, except for certain permitted transfers, or (ii) the date that is the earliest of (x) the date specified by a vote of the holders of not less than a majority of the outstanding shares of Class B Common Stock, (y) April 26, 2025 and (z) the date that the total number of shares of outstanding Class B Common Stock ceases to represent at least 15% of all outstanding shares of the issuer's common stock, and has no expiration date.