CDLX

SEC source: 0000899243-20-001907 · doc4.xml · nonDerivative · entry 19

Youngren Bryce · CIK 0001489625 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 1,483

F1 · kind: The sale of these shares were effected pursuant to Rule 10b5-1 trading plans adopted by each of Polaris Venture Partners V, L.P. ("PVP V"), Polaris Venture Partners Entrepreneurs' Fund V, L.P. ("PVPE V"), Polaris Venture Partners Founders' Fund V, L.P. ("PVPFF V") and Polaris Venture Partners Special Founders' Fund V, L.P. ("PVPSFF V") on December 16, 2019.

F2 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $82.52 to $82.62, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (2) to this Form 4.

F11 · ownership.nature: The reportable securities are owned directly by PVPSFF V. PVM V is the general partner of PVPSFF V. The Reporting Person, a member of the Issuer's Board of Directors, is a member of PVM V. Each of Flint and McGuire are the managing members of PVM V. Each of Flint, McGuire and the Reporting Person, in their respective capacities with respect to PVM V, may be deemed to have shared voting and dispositive power over the shares held by PVPSFF V. Each of PVM V, Flint, McGuire and the Reporting Person disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein.

SEC source: 0000899243-20-001907 · doc4.xml · nonDerivative · entry 18

Youngren Bryce · CIK 0001489625 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 791

F1 · kind: The sale of these shares were effected pursuant to Rule 10b5-1 trading plans adopted by each of Polaris Venture Partners V, L.P. ("PVP V"), Polaris Venture Partners Entrepreneurs' Fund V, L.P. ("PVPE V"), Polaris Venture Partners Founders' Fund V, L.P. ("PVPFF V") and Polaris Venture Partners Special Founders' Fund V, L.P. ("PVPSFF V") on December 16, 2019.

F8 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $88.46 to $89.10, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (8) to this Form 4.

F10 · ownership.nature: The reportable securities are owned directly by PVPFF V. PVM V is the general partner of PVPFF V. The Reporting Person, a member of the Issuer's Board of Directors, is a member of PVM V. Each of Flint and McGuire are the managing members of PVM V. Each of Flint, McGuire and the Reporting Person, in their respective capacities with respect to PVM V, may be deemed to have shared voting and dispositive power over the shares held by PVPFF V. Each of PVM V, Flint, McGuire and the Reporting Person disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein.

SEC source: 0000899243-20-001907 · doc4.xml · nonDerivative · entry 17

Youngren Bryce · CIK 0001489625 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 803

F1 · kind: The sale of these shares were effected pursuant to Rule 10b5-1 trading plans adopted by each of Polaris Venture Partners V, L.P. ("PVP V"), Polaris Venture Partners Entrepreneurs' Fund V, L.P. ("PVPE V"), Polaris Venture Partners Founders' Fund V, L.P. ("PVPFF V") and Polaris Venture Partners Special Founders' Fund V, L.P. ("PVPSFF V") on December 16, 2019.

F7 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $87.43 to $88.39, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (7) to this Form 4.

F10 · ownership.nature: The reportable securities are owned directly by PVPFF V. PVM V is the general partner of PVPFF V. The Reporting Person, a member of the Issuer's Board of Directors, is a member of PVM V. Each of Flint and McGuire are the managing members of PVM V. Each of Flint, McGuire and the Reporting Person, in their respective capacities with respect to PVM V, may be deemed to have shared voting and dispositive power over the shares held by PVPFF V. Each of PVM V, Flint, McGuire and the Reporting Person disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein.

SEC source: 0000899243-20-001907 · doc4.xml · nonDerivative · entry 16

Youngren Bryce · CIK 0001489625 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 887

F1 · kind: The sale of these shares were effected pursuant to Rule 10b5-1 trading plans adopted by each of Polaris Venture Partners V, L.P. ("PVP V"), Polaris Venture Partners Entrepreneurs' Fund V, L.P. ("PVPE V"), Polaris Venture Partners Founders' Fund V, L.P. ("PVPFF V") and Polaris Venture Partners Special Founders' Fund V, L.P. ("PVPSFF V") on December 16, 2019.

F6 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $86.43 to $87.42, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (6) to this Form 4.

F10 · ownership.nature: The reportable securities are owned directly by PVPFF V. PVM V is the general partner of PVPFF V. The Reporting Person, a member of the Issuer's Board of Directors, is a member of PVM V. Each of Flint and McGuire are the managing members of PVM V. Each of Flint, McGuire and the Reporting Person, in their respective capacities with respect to PVM V, may be deemed to have shared voting and dispositive power over the shares held by PVPFF V. Each of PVM V, Flint, McGuire and the Reporting Person disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein.

SEC source: 0000899243-20-001907 · doc4.xml · nonDerivative · entry 15

Youngren Bryce · CIK 0001489625 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 924

F1 · kind: The sale of these shares were effected pursuant to Rule 10b5-1 trading plans adopted by each of Polaris Venture Partners V, L.P. ("PVP V"), Polaris Venture Partners Entrepreneurs' Fund V, L.P. ("PVPE V"), Polaris Venture Partners Founders' Fund V, L.P. ("PVPFF V") and Polaris Venture Partners Special Founders' Fund V, L.P. ("PVPSFF V") on December 16, 2019.

F5 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $85.42 to $86.28, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (5) to this Form 4.

F10 · ownership.nature: The reportable securities are owned directly by PVPFF V. PVM V is the general partner of PVPFF V. The Reporting Person, a member of the Issuer's Board of Directors, is a member of PVM V. Each of Flint and McGuire are the managing members of PVM V. Each of Flint, McGuire and the Reporting Person, in their respective capacities with respect to PVM V, may be deemed to have shared voting and dispositive power over the shares held by PVPFF V. Each of PVM V, Flint, McGuire and the Reporting Person disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein.

SEC source: 0000899243-20-001907 · doc4.xml · nonDerivative · entry 14

Youngren Bryce · CIK 0001489625 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 982

F1 · kind: The sale of these shares were effected pursuant to Rule 10b5-1 trading plans adopted by each of Polaris Venture Partners V, L.P. ("PVP V"), Polaris Venture Partners Entrepreneurs' Fund V, L.P. ("PVPE V"), Polaris Venture Partners Founders' Fund V, L.P. ("PVPFF V") and Polaris Venture Partners Special Founders' Fund V, L.P. ("PVPSFF V") on December 16, 2019.

F4 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $84.41 to $85.40, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (4) to this Form 4.

F10 · ownership.nature: The reportable securities are owned directly by PVPFF V. PVM V is the general partner of PVPFF V. The Reporting Person, a member of the Issuer's Board of Directors, is a member of PVM V. Each of Flint and McGuire are the managing members of PVM V. Each of Flint, McGuire and the Reporting Person, in their respective capacities with respect to PVM V, may be deemed to have shared voting and dispositive power over the shares held by PVPFF V. Each of PVM V, Flint, McGuire and the Reporting Person disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein.

SEC source: 0000899243-20-001907 · doc4.xml · nonDerivative · entry 13

Youngren Bryce · CIK 0001489625 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 1,010

F1 · kind: The sale of these shares were effected pursuant to Rule 10b5-1 trading plans adopted by each of Polaris Venture Partners V, L.P. ("PVP V"), Polaris Venture Partners Entrepreneurs' Fund V, L.P. ("PVPE V"), Polaris Venture Partners Founders' Fund V, L.P. ("PVPFF V") and Polaris Venture Partners Special Founders' Fund V, L.P. ("PVPSFF V") on December 16, 2019.

F2 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $82.52 to $82.62, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (2) to this Form 4.

F10 · ownership.nature: The reportable securities are owned directly by PVPFF V. PVM V is the general partner of PVPFF V. The Reporting Person, a member of the Issuer's Board of Directors, is a member of PVM V. Each of Flint and McGuire are the managing members of PVM V. Each of Flint, McGuire and the Reporting Person, in their respective capacities with respect to PVM V, may be deemed to have shared voting and dispositive power over the shares held by PVPFF V. Each of PVM V, Flint, McGuire and the Reporting Person disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein.

SEC source: 0000899243-20-001907 · doc4.xml · nonDerivative · entry 12

Youngren Bryce · CIK 0001489625 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 2,261

F1 · kind: The sale of these shares were effected pursuant to Rule 10b5-1 trading plans adopted by each of Polaris Venture Partners V, L.P. ("PVP V"), Polaris Venture Partners Entrepreneurs' Fund V, L.P. ("PVPE V"), Polaris Venture Partners Founders' Fund V, L.P. ("PVPFF V") and Polaris Venture Partners Special Founders' Fund V, L.P. ("PVPSFF V") on December 16, 2019.

F8 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $88.46 to $89.10, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (8) to this Form 4.

F9 · ownership.nature: The reportable securities are owned directly by PVPE V. PVM V is the general partner of PVPE V. The Reporting Person, a member of the Issuer's Board of Directors, is a member of PVM V. Each of Flint and McGuire are the managing members of PVM V. Each of Flint, McGuire and the Reporting Person, in their respective capacities with respect to PVM V, may be deemed to have shared voting and dispositive power over the shares held by PVPE V. Each of PVM V, Flint, McGuire and the Reporting Person disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein.

SEC source: 0000899243-20-001907 · doc4.xml · nonDerivative · entry 11

Youngren Bryce · CIK 0001489625 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 2,294

F1 · kind: The sale of these shares were effected pursuant to Rule 10b5-1 trading plans adopted by each of Polaris Venture Partners V, L.P. ("PVP V"), Polaris Venture Partners Entrepreneurs' Fund V, L.P. ("PVPE V"), Polaris Venture Partners Founders' Fund V, L.P. ("PVPFF V") and Polaris Venture Partners Special Founders' Fund V, L.P. ("PVPSFF V") on December 16, 2019.

F7 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $87.43 to $88.39, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (7) to this Form 4.

F9 · ownership.nature: The reportable securities are owned directly by PVPE V. PVM V is the general partner of PVPE V. The Reporting Person, a member of the Issuer's Board of Directors, is a member of PVM V. Each of Flint and McGuire are the managing members of PVM V. Each of Flint, McGuire and the Reporting Person, in their respective capacities with respect to PVM V, may be deemed to have shared voting and dispositive power over the shares held by PVPE V. Each of PVM V, Flint, McGuire and the Reporting Person disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein.

SEC source: 0000899243-20-001907 · doc4.xml · nonDerivative · entry 10

Youngren Bryce · CIK 0001489625 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 2,534

F1 · kind: The sale of these shares were effected pursuant to Rule 10b5-1 trading plans adopted by each of Polaris Venture Partners V, L.P. ("PVP V"), Polaris Venture Partners Entrepreneurs' Fund V, L.P. ("PVPE V"), Polaris Venture Partners Founders' Fund V, L.P. ("PVPFF V") and Polaris Venture Partners Special Founders' Fund V, L.P. ("PVPSFF V") on December 16, 2019.

F6 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $86.43 to $87.42, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (6) to this Form 4.

F9 · ownership.nature: The reportable securities are owned directly by PVPE V. PVM V is the general partner of PVPE V. The Reporting Person, a member of the Issuer's Board of Directors, is a member of PVM V. Each of Flint and McGuire are the managing members of PVM V. Each of Flint, McGuire and the Reporting Person, in their respective capacities with respect to PVM V, may be deemed to have shared voting and dispositive power over the shares held by PVPE V. Each of PVM V, Flint, McGuire and the Reporting Person disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein.

SEC source: 0000899243-20-001907 · doc4.xml · nonDerivative · entry 9

Youngren Bryce · CIK 0001489625 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 2,639

F1 · kind: The sale of these shares were effected pursuant to Rule 10b5-1 trading plans adopted by each of Polaris Venture Partners V, L.P. ("PVP V"), Polaris Venture Partners Entrepreneurs' Fund V, L.P. ("PVPE V"), Polaris Venture Partners Founders' Fund V, L.P. ("PVPFF V") and Polaris Venture Partners Special Founders' Fund V, L.P. ("PVPSFF V") on December 16, 2019.

F5 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $85.42 to $86.28, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (5) to this Form 4.

F9 · ownership.nature: The reportable securities are owned directly by PVPE V. PVM V is the general partner of PVPE V. The Reporting Person, a member of the Issuer's Board of Directors, is a member of PVM V. Each of Flint and McGuire are the managing members of PVM V. Each of Flint, McGuire and the Reporting Person, in their respective capacities with respect to PVM V, may be deemed to have shared voting and dispositive power over the shares held by PVPE V. Each of PVM V, Flint, McGuire and the Reporting Person disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein.

SEC source: 0000899243-20-001907 · doc4.xml · nonDerivative · entry 8

Youngren Bryce · CIK 0001489625 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 2,806

F1 · kind: The sale of these shares were effected pursuant to Rule 10b5-1 trading plans adopted by each of Polaris Venture Partners V, L.P. ("PVP V"), Polaris Venture Partners Entrepreneurs' Fund V, L.P. ("PVPE V"), Polaris Venture Partners Founders' Fund V, L.P. ("PVPFF V") and Polaris Venture Partners Special Founders' Fund V, L.P. ("PVPSFF V") on December 16, 2019.

F4 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $84.41 to $85.40, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (4) to this Form 4.

F9 · ownership.nature: The reportable securities are owned directly by PVPE V. PVM V is the general partner of PVPE V. The Reporting Person, a member of the Issuer's Board of Directors, is a member of PVM V. Each of Flint and McGuire are the managing members of PVM V. Each of Flint, McGuire and the Reporting Person, in their respective capacities with respect to PVM V, may be deemed to have shared voting and dispositive power over the shares held by PVPE V. Each of PVM V, Flint, McGuire and the Reporting Person disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein.

SEC source: 0000899243-20-001907 · doc4.xml · nonDerivative · entry 7

Youngren Bryce · CIK 0001489625 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 2,887

F1 · kind: The sale of these shares were effected pursuant to Rule 10b5-1 trading plans adopted by each of Polaris Venture Partners V, L.P. ("PVP V"), Polaris Venture Partners Entrepreneurs' Fund V, L.P. ("PVPE V"), Polaris Venture Partners Founders' Fund V, L.P. ("PVPFF V") and Polaris Venture Partners Special Founders' Fund V, L.P. ("PVPSFF V") on December 16, 2019.

F2 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $82.52 to $82.62, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (2) to this Form 4.

F9 · ownership.nature: The reportable securities are owned directly by PVPE V. PVM V is the general partner of PVPE V. The Reporting Person, a member of the Issuer's Board of Directors, is a member of PVM V. Each of Flint and McGuire are the managing members of PVM V. Each of Flint, McGuire and the Reporting Person, in their respective capacities with respect to PVM V, may be deemed to have shared voting and dispositive power over the shares held by PVPE V. Each of PVM V, Flint, McGuire and the Reporting Person disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein.

SEC source: 0000899243-20-001907 · doc4.xml · nonDerivative · entry 6

Youngren Bryce · CIK 0001489625 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 115,865

F1 · kind: The sale of these shares were effected pursuant to Rule 10b5-1 trading plans adopted by each of Polaris Venture Partners V, L.P. ("PVP V"), Polaris Venture Partners Entrepreneurs' Fund V, L.P. ("PVPE V"), Polaris Venture Partners Founders' Fund V, L.P. ("PVPFF V") and Polaris Venture Partners Special Founders' Fund V, L.P. ("PVPSFF V") on December 16, 2019.

F8 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $88.46 to $89.10, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (8) to this Form 4.

F3 · ownership.nature: The reportable securities are owned directly by PVP V. Polaris Venture Management Co. V, L.L.C. ("PVM V") is the general partner of PVP V. The Reporting Person, a member of the Issuer's Board of Directors, is a member of PVM V. Each of Jonathan A. Flint ("Flint") and Terrance G. McGuire ("McGuire") are the managing members of PVM V. Each of Flint, McGuire and the Reporting Person, in their respective capacities with respect to PVM V, may be deemed to have shared voting and dispositive power over the shares held by PVP V. Each of PVM V, Flint, McGuire and the Reporting Person disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein.

SEC source: 0000899243-20-001907 · doc4.xml · nonDerivative · entry 5

Youngren Bryce · CIK 0001489625 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 117,559

F1 · kind: The sale of these shares were effected pursuant to Rule 10b5-1 trading plans adopted by each of Polaris Venture Partners V, L.P. ("PVP V"), Polaris Venture Partners Entrepreneurs' Fund V, L.P. ("PVPE V"), Polaris Venture Partners Founders' Fund V, L.P. ("PVPFF V") and Polaris Venture Partners Special Founders' Fund V, L.P. ("PVPSFF V") on December 16, 2019.

F7 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $87.43 to $88.39, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (7) to this Form 4.

F3 · ownership.nature: The reportable securities are owned directly by PVP V. Polaris Venture Management Co. V, L.L.C. ("PVM V") is the general partner of PVP V. The Reporting Person, a member of the Issuer's Board of Directors, is a member of PVM V. Each of Jonathan A. Flint ("Flint") and Terrance G. McGuire ("McGuire") are the managing members of PVM V. Each of Flint, McGuire and the Reporting Person, in their respective capacities with respect to PVM V, may be deemed to have shared voting and dispositive power over the shares held by PVP V. Each of PVM V, Flint, McGuire and the Reporting Person disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein.

SEC source: 0000899243-20-001907 · doc4.xml · nonDerivative · entry 4

Youngren Bryce · CIK 0001489625 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 129,881

F1 · kind: The sale of these shares were effected pursuant to Rule 10b5-1 trading plans adopted by each of Polaris Venture Partners V, L.P. ("PVP V"), Polaris Venture Partners Entrepreneurs' Fund V, L.P. ("PVPE V"), Polaris Venture Partners Founders' Fund V, L.P. ("PVPFF V") and Polaris Venture Partners Special Founders' Fund V, L.P. ("PVPSFF V") on December 16, 2019.

F6 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $86.43 to $87.42, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (6) to this Form 4.

F3 · ownership.nature: The reportable securities are owned directly by PVP V. Polaris Venture Management Co. V, L.L.C. ("PVM V") is the general partner of PVP V. The Reporting Person, a member of the Issuer's Board of Directors, is a member of PVM V. Each of Jonathan A. Flint ("Flint") and Terrance G. McGuire ("McGuire") are the managing members of PVM V. Each of Flint, McGuire and the Reporting Person, in their respective capacities with respect to PVM V, may be deemed to have shared voting and dispositive power over the shares held by PVP V. Each of PVM V, Flint, McGuire and the Reporting Person disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein.

SEC source: 0000899243-20-001907 · doc4.xml · nonDerivative · entry 3

Youngren Bryce · CIK 0001489625 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 135,281

F1 · kind: The sale of these shares were effected pursuant to Rule 10b5-1 trading plans adopted by each of Polaris Venture Partners V, L.P. ("PVP V"), Polaris Venture Partners Entrepreneurs' Fund V, L.P. ("PVPE V"), Polaris Venture Partners Founders' Fund V, L.P. ("PVPFF V") and Polaris Venture Partners Special Founders' Fund V, L.P. ("PVPSFF V") on December 16, 2019.

F5 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $85.42 to $86.28, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (5) to this Form 4.

F3 · ownership.nature: The reportable securities are owned directly by PVP V. Polaris Venture Management Co. V, L.L.C. ("PVM V") is the general partner of PVP V. The Reporting Person, a member of the Issuer's Board of Directors, is a member of PVM V. Each of Jonathan A. Flint ("Flint") and Terrance G. McGuire ("McGuire") are the managing members of PVM V. Each of Flint, McGuire and the Reporting Person, in their respective capacities with respect to PVM V, may be deemed to have shared voting and dispositive power over the shares held by PVP V. Each of PVM V, Flint, McGuire and the Reporting Person disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein.

SEC source: 0000899243-20-001907 · doc4.xml · nonDerivative · entry 2

Youngren Bryce · CIK 0001489625 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 143,847

F1 · kind: The sale of these shares were effected pursuant to Rule 10b5-1 trading plans adopted by each of Polaris Venture Partners V, L.P. ("PVP V"), Polaris Venture Partners Entrepreneurs' Fund V, L.P. ("PVPE V"), Polaris Venture Partners Founders' Fund V, L.P. ("PVPFF V") and Polaris Venture Partners Special Founders' Fund V, L.P. ("PVPSFF V") on December 16, 2019.

F4 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $84.41 to $85.40, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (4) to this Form 4.

F3 · ownership.nature: The reportable securities are owned directly by PVP V. Polaris Venture Management Co. V, L.L.C. ("PVM V") is the general partner of PVP V. The Reporting Person, a member of the Issuer's Board of Directors, is a member of PVM V. Each of Jonathan A. Flint ("Flint") and Terrance G. McGuire ("McGuire") are the managing members of PVM V. Each of Flint, McGuire and the Reporting Person, in their respective capacities with respect to PVM V, may be deemed to have shared voting and dispositive power over the shares held by PVP V. Each of PVM V, Flint, McGuire and the Reporting Person disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein.

SEC source: 0000899243-20-001907 · doc4.xml · nonDerivative · entry 1

Youngren Bryce · CIK 0001489625 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 147,975

F1 · kind: The sale of these shares were effected pursuant to Rule 10b5-1 trading plans adopted by each of Polaris Venture Partners V, L.P. ("PVP V"), Polaris Venture Partners Entrepreneurs' Fund V, L.P. ("PVPE V"), Polaris Venture Partners Founders' Fund V, L.P. ("PVPFF V") and Polaris Venture Partners Special Founders' Fund V, L.P. ("PVPSFF V") on December 16, 2019.

F2 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $82.52 to $82.62, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (2) to this Form 4.

F3 · ownership.nature: The reportable securities are owned directly by PVP V. Polaris Venture Management Co. V, L.L.C. ("PVM V") is the general partner of PVP V. The Reporting Person, a member of the Issuer's Board of Directors, is a member of PVM V. Each of Jonathan A. Flint ("Flint") and Terrance G. McGuire ("McGuire") are the managing members of PVM V. Each of Flint, McGuire and the Reporting Person, in their respective capacities with respect to PVM V, may be deemed to have shared voting and dispositive power over the shares held by PVP V. Each of PVM V, Flint, McGuire and the Reporting Person disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein.

SEC source: 0001666071-20-000011 · wf-form4_157930764628835.xml · derivative · entry 5

SOMERS KIRK · CIK 0001204015 · Chief Legal & Privacy Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 13,886

Underlying: Common Stock · 778 shares

Expires 2026-08-02

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · kind: These transactions were effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on December 17, 2019.

F5 · derivative.exercise_date: This option became exercisable with respect to one quarter (1/4) of the shares of stock subject to this option on June 15, 2017 (the "Initial Vesting Date"). The option becomes exercisable in respect of the remaining shares in thirty-six (36) equal monthly installments commencing one (1) month after the Initial Vesting Date, provided the Reporting Person continuously provides service to the Issuer through each vesting period.

SEC source: 0001666071-20-000011 · wf-form4_157930764628835.xml · nonDerivative · entry 4

SOMERS KIRK · CIK 0001204015 · Chief Legal & Privacy Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 76,893

F1 · kind: These transactions were effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on December 17, 2019.

F4 · price: The price reported is a weighted average sales price. These shares were sold in multiple transactions at prices ranging from $84.86 to $84.99, inclusive.

SEC source: 0001666071-20-000011 · wf-form4_157930764628835.xml · nonDerivative · entry 3

SOMERS KIRK · CIK 0001204015 · Chief Legal & Privacy Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 77,812

F1 · kind: These transactions were effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on December 17, 2019.

F3 · price: The price reported is a weighted average sales price. These shares were sold in multiple transactions at prices ranging from $83.86 to $84.21, inclusive.

SEC source: 0001666071-20-000011 · wf-form4_157930764628835.xml · nonDerivative · entry 2

SOMERS KIRK · CIK 0001204015 · Chief Legal & Privacy Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 78,262

F1 · kind: These transactions were effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on December 17, 2019.

F2 · price: The price reported is a weighted average sales price. These shares were sold in multiple transactions at prices ranging from $82.83 to $83.65, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in footnotes (2), (3) and (4) to this Form 4.

SEC source: 0001666071-20-000011 · wf-form4_157930764628835.xml · nonDerivative · entry 1

SOMERS KIRK · CIK 0001204015 · Chief Legal & Privacy Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 83,671

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · kind: These transactions were effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on December 17, 2019.

SEC source: 0000899243-20-001528 · doc4.xml · nonDerivative · entry 24

Youngren Bryce · CIK 0001489625 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 1,484

F1 · kind: The sale of these shares were effected pursuant to Rule 10b5-1 trading plans adopted by each of Polaris Venture Partners V, L.P. ("PVP V"), Polaris Venture Partners Entrepreneurs' Fund V, L.P. ("PVPE V"), Polaris Venture Partners Founders' Fund V, L.P. ("PVPFF V") and Polaris Venture Partners Special Founders' Fund V, L.P. ("PVPSFF V") on December 16, 2019.

F8 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $83.84 to $84.53, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (8) to this Form 4.

F11 · ownership.nature: The reportable securities are owned directly by PVPSFF V. PVM V is the general partner of PVPSFF V. The Reporting Person, a member of the Issuer's Board of Directors, is a member of PVM V. Each of Flint and McGuire are the managing members of PVM V. Each of Flint, McGuire and the Reporting Person, in their respective capacities with respect to PVM V, may be deemed to have shared voting and dispositive power over the shares held by PVPSFF V. Each of PVM V, Flint, McGuire and the Reporting Person disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein.

SEC source: 0000899243-20-001528 · doc4.xml · nonDerivative · entry 23

Youngren Bryce · CIK 0001489625 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 1,578

F1 · kind: The sale of these shares were effected pursuant to Rule 10b5-1 trading plans adopted by each of Polaris Venture Partners V, L.P. ("PVP V"), Polaris Venture Partners Entrepreneurs' Fund V, L.P. ("PVPE V"), Polaris Venture Partners Founders' Fund V, L.P. ("PVPFF V") and Polaris Venture Partners Special Founders' Fund V, L.P. ("PVPSFF V") on December 16, 2019.

F7 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $82.81 to $83.79, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (7) to this Form 4.

F11 · ownership.nature: The reportable securities are owned directly by PVPSFF V. PVM V is the general partner of PVPSFF V. The Reporting Person, a member of the Issuer's Board of Directors, is a member of PVM V. Each of Flint and McGuire are the managing members of PVM V. Each of Flint, McGuire and the Reporting Person, in their respective capacities with respect to PVM V, may be deemed to have shared voting and dispositive power over the shares held by PVPSFF V. Each of PVM V, Flint, McGuire and the Reporting Person disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein.

SEC source: 0000899243-20-001528 · doc4.xml · nonDerivative · entry 22

Youngren Bryce · CIK 0001489625 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 1,686

F1 · kind: The sale of these shares were effected pursuant to Rule 10b5-1 trading plans adopted by each of Polaris Venture Partners V, L.P. ("PVP V"), Polaris Venture Partners Entrepreneurs' Fund V, L.P. ("PVPE V"), Polaris Venture Partners Founders' Fund V, L.P. ("PVPFF V") and Polaris Venture Partners Special Founders' Fund V, L.P. ("PVPSFF V") on December 16, 2019.

F6 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $81.81 to $82.80, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (6) to this Form 4.

F11 · ownership.nature: The reportable securities are owned directly by PVPSFF V. PVM V is the general partner of PVPSFF V. The Reporting Person, a member of the Issuer's Board of Directors, is a member of PVM V. Each of Flint and McGuire are the managing members of PVM V. Each of Flint, McGuire and the Reporting Person, in their respective capacities with respect to PVM V, may be deemed to have shared voting and dispositive power over the shares held by PVPSFF V. Each of PVM V, Flint, McGuire and the Reporting Person disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein.

SEC source: 0000899243-20-001528 · doc4.xml · nonDerivative · entry 18

Youngren Bryce · CIK 0001489625 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 1,011

F1 · kind: The sale of these shares were effected pursuant to Rule 10b5-1 trading plans adopted by each of Polaris Venture Partners V, L.P. ("PVP V"), Polaris Venture Partners Entrepreneurs' Fund V, L.P. ("PVPE V"), Polaris Venture Partners Founders' Fund V, L.P. ("PVPFF V") and Polaris Venture Partners Special Founders' Fund V, L.P. ("PVPSFF V") on December 16, 2019.

F8 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $83.84 to $84.53, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (8) to this Form 4.

F10 · ownership.nature: The reportable securities are owned directly by PVPFF V. PVM V is the general partner of PVPFF V. The Reporting Person, a member of the Issuer's Board of Directors, is a member of PVM V. Each of Flint and McGuire are the managing members of PVM V. Each of Flint, McGuire and the Reporting Person, in their respective capacities with respect to PVM V, may be deemed to have shared voting and dispositive power over the shares held by PVPFF V. Each of PVM V, Flint, McGuire and the Reporting Person disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein.

SEC source: 0000899243-20-001528 · doc4.xml · nonDerivative · entry 17

Youngren Bryce · CIK 0001489625 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 1,075

F1 · kind: The sale of these shares were effected pursuant to Rule 10b5-1 trading plans adopted by each of Polaris Venture Partners V, L.P. ("PVP V"), Polaris Venture Partners Entrepreneurs' Fund V, L.P. ("PVPE V"), Polaris Venture Partners Founders' Fund V, L.P. ("PVPFF V") and Polaris Venture Partners Special Founders' Fund V, L.P. ("PVPSFF V") on December 16, 2019.

F7 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $82.81 to $83.79, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (7) to this Form 4.

F10 · ownership.nature: The reportable securities are owned directly by PVPFF V. PVM V is the general partner of PVPFF V. The Reporting Person, a member of the Issuer's Board of Directors, is a member of PVM V. Each of Flint and McGuire are the managing members of PVM V. Each of Flint, McGuire and the Reporting Person, in their respective capacities with respect to PVM V, may be deemed to have shared voting and dispositive power over the shares held by PVPFF V. Each of PVM V, Flint, McGuire and the Reporting Person disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein.

SEC source: 0000899243-20-001528 · doc4.xml · nonDerivative · entry 16

Youngren Bryce · CIK 0001489625 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 1,148

F1 · kind: The sale of these shares were effected pursuant to Rule 10b5-1 trading plans adopted by each of Polaris Venture Partners V, L.P. ("PVP V"), Polaris Venture Partners Entrepreneurs' Fund V, L.P. ("PVPE V"), Polaris Venture Partners Founders' Fund V, L.P. ("PVPFF V") and Polaris Venture Partners Special Founders' Fund V, L.P. ("PVPSFF V") on December 16, 2019.

F6 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $81.81 to $82.80, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (6) to this Form 4.

F10 · ownership.nature: The reportable securities are owned directly by PVPFF V. PVM V is the general partner of PVPFF V. The Reporting Person, a member of the Issuer's Board of Directors, is a member of PVM V. Each of Flint and McGuire are the managing members of PVM V. Each of Flint, McGuire and the Reporting Person, in their respective capacities with respect to PVM V, may be deemed to have shared voting and dispositive power over the shares held by PVPFF V. Each of PVM V, Flint, McGuire and the Reporting Person disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein.

SEC source: 0000899243-20-001528 · doc4.xml · nonDerivative · entry 12

Youngren Bryce · CIK 0001489625 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 2,889

F1 · kind: The sale of these shares were effected pursuant to Rule 10b5-1 trading plans adopted by each of Polaris Venture Partners V, L.P. ("PVP V"), Polaris Venture Partners Entrepreneurs' Fund V, L.P. ("PVPE V"), Polaris Venture Partners Founders' Fund V, L.P. ("PVPFF V") and Polaris Venture Partners Special Founders' Fund V, L.P. ("PVPSFF V") on December 16, 2019.

F8 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $83.84 to $84.53, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (8) to this Form 4.

F9 · ownership.nature: The reportable securities are owned directly by PVPE V. PVM V is the general partner of PVPE V. The Reporting Person, a member of the Issuer's Board of Directors, is a member of PVM V. Each of Flint and McGuire are the managing members of PVM V. Each of Flint, McGuire and the Reporting Person, in their respective capacities with respect to PVM V, may be deemed to have shared voting and dispositive power over the shares held by PVPE V. Each of PVM V, Flint, McGuire and the Reporting Person disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein.

SEC source: 0000899243-20-001528 · doc4.xml · nonDerivative · entry 11

Youngren Bryce · CIK 0001489625 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 3,073

F1 · kind: The sale of these shares were effected pursuant to Rule 10b5-1 trading plans adopted by each of Polaris Venture Partners V, L.P. ("PVP V"), Polaris Venture Partners Entrepreneurs' Fund V, L.P. ("PVPE V"), Polaris Venture Partners Founders' Fund V, L.P. ("PVPFF V") and Polaris Venture Partners Special Founders' Fund V, L.P. ("PVPSFF V") on December 16, 2019.

F7 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $82.81 to $83.79, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (7) to this Form 4.

F9 · ownership.nature: The reportable securities are owned directly by PVPE V. PVM V is the general partner of PVPE V. The Reporting Person, a member of the Issuer's Board of Directors, is a member of PVM V. Each of Flint and McGuire are the managing members of PVM V. Each of Flint, McGuire and the Reporting Person, in their respective capacities with respect to PVM V, may be deemed to have shared voting and dispositive power over the shares held by PVPE V. Each of PVM V, Flint, McGuire and the Reporting Person disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein.

SEC source: 0000899243-20-001528 · doc4.xml · nonDerivative · entry 10

Youngren Bryce · CIK 0001489625 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 3,283

F1 · kind: The sale of these shares were effected pursuant to Rule 10b5-1 trading plans adopted by each of Polaris Venture Partners V, L.P. ("PVP V"), Polaris Venture Partners Entrepreneurs' Fund V, L.P. ("PVPE V"), Polaris Venture Partners Founders' Fund V, L.P. ("PVPFF V") and Polaris Venture Partners Special Founders' Fund V, L.P. ("PVPSFF V") on December 16, 2019.

F6 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $81.81 to $82.80, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (6) to this Form 4.

F9 · ownership.nature: The reportable securities are owned directly by PVPE V. PVM V is the general partner of PVPE V. The Reporting Person, a member of the Issuer's Board of Directors, is a member of PVM V. Each of Flint and McGuire are the managing members of PVM V. Each of Flint, McGuire and the Reporting Person, in their respective capacities with respect to PVM V, may be deemed to have shared voting and dispositive power over the shares held by PVPE V. Each of PVM V, Flint, McGuire and the Reporting Person disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein.

SEC source: 0000899243-20-001528 · doc4.xml · nonDerivative · entry 6

Youngren Bryce · CIK 0001489625 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 148,071

F1 · kind: The sale of these shares were effected pursuant to Rule 10b5-1 trading plans adopted by each of Polaris Venture Partners V, L.P. ("PVP V"), Polaris Venture Partners Entrepreneurs' Fund V, L.P. ("PVPE V"), Polaris Venture Partners Founders' Fund V, L.P. ("PVPFF V") and Polaris Venture Partners Special Founders' Fund V, L.P. ("PVPSFF V") on December 16, 2019.

F8 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $83.84 to $84.53, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (8) to this Form 4.

F3 · ownership.nature: The reportable securities are owned directly by PVP V. Polaris Venture Management Co. V, L.L.C. ("PVM V") is the general partner of PVP V. The Reporting Person, a member of the Issuer's Board of Directors, is a member of PVM V. Each of Jonathan A. Flint ("Flint") and Terrance G. McGuire ("McGuire") are the managing members of PVM V. Each of Flint, McGuire and the Reporting Person, in their respective capacities with respect to PVM V, may be deemed to have shared voting and dispositive power over the shares held by PVP V. Each of PVM V, Flint, McGuire and the Reporting Person disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein.

SEC source: 0000899243-20-001528 · doc4.xml · nonDerivative · entry 5

Youngren Bryce · CIK 0001489625 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 157,469

F1 · kind: The sale of these shares were effected pursuant to Rule 10b5-1 trading plans adopted by each of Polaris Venture Partners V, L.P. ("PVP V"), Polaris Venture Partners Entrepreneurs' Fund V, L.P. ("PVPE V"), Polaris Venture Partners Founders' Fund V, L.P. ("PVPFF V") and Polaris Venture Partners Special Founders' Fund V, L.P. ("PVPSFF V") on December 16, 2019.

F7 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $82.81 to $83.79, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (7) to this Form 4.

F3 · ownership.nature: The reportable securities are owned directly by PVP V. Polaris Venture Management Co. V, L.L.C. ("PVM V") is the general partner of PVP V. The Reporting Person, a member of the Issuer's Board of Directors, is a member of PVM V. Each of Jonathan A. Flint ("Flint") and Terrance G. McGuire ("McGuire") are the managing members of PVM V. Each of Flint, McGuire and the Reporting Person, in their respective capacities with respect to PVM V, may be deemed to have shared voting and dispositive power over the shares held by PVP V. Each of PVM V, Flint, McGuire and the Reporting Person disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein.

SEC source: 0000899243-20-001528 · doc4.xml · nonDerivative · entry 4

Youngren Bryce · CIK 0001489625 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 168,203

F1 · kind: The sale of these shares were effected pursuant to Rule 10b5-1 trading plans adopted by each of Polaris Venture Partners V, L.P. ("PVP V"), Polaris Venture Partners Entrepreneurs' Fund V, L.P. ("PVPE V"), Polaris Venture Partners Founders' Fund V, L.P. ("PVPFF V") and Polaris Venture Partners Special Founders' Fund V, L.P. ("PVPSFF V") on December 16, 2019.

F6 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $81.81 to $82.80, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (6) to this Form 4.

F3 · ownership.nature: The reportable securities are owned directly by PVP V. Polaris Venture Management Co. V, L.L.C. ("PVM V") is the general partner of PVP V. The Reporting Person, a member of the Issuer's Board of Directors, is a member of PVM V. Each of Jonathan A. Flint ("Flint") and Terrance G. McGuire ("McGuire") are the managing members of PVM V. Each of Flint, McGuire and the Reporting Person, in their respective capacities with respect to PVM V, may be deemed to have shared voting and dispositive power over the shares held by PVP V. Each of PVM V, Flint, McGuire and the Reporting Person disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein.

SEC source: 0000899243-20-001528 · doc4.xml · nonDerivative · entry 21

Youngren Bryce · CIK 0001489625 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 1,707

F1 · kind: The sale of these shares were effected pursuant to Rule 10b5-1 trading plans adopted by each of Polaris Venture Partners V, L.P. ("PVP V"), Polaris Venture Partners Entrepreneurs' Fund V, L.P. ("PVPE V"), Polaris Venture Partners Founders' Fund V, L.P. ("PVPFF V") and Polaris Venture Partners Special Founders' Fund V, L.P. ("PVPSFF V") on December 16, 2019.

F5 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $84.88 to $85.13, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (5) to this Form 4.

F11 · ownership.nature: The reportable securities are owned directly by PVPSFF V. PVM V is the general partner of PVPSFF V. The Reporting Person, a member of the Issuer's Board of Directors, is a member of PVM V. Each of Flint and McGuire are the managing members of PVM V. Each of Flint, McGuire and the Reporting Person, in their respective capacities with respect to PVM V, may be deemed to have shared voting and dispositive power over the shares held by PVPSFF V. Each of PVM V, Flint, McGuire and the Reporting Person disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein.

SEC source: 0000899243-20-001528 · doc4.xml · nonDerivative · entry 20

Youngren Bryce · CIK 0001489625 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 1,717

F1 · kind: The sale of these shares were effected pursuant to Rule 10b5-1 trading plans adopted by each of Polaris Venture Partners V, L.P. ("PVP V"), Polaris Venture Partners Entrepreneurs' Fund V, L.P. ("PVPE V"), Polaris Venture Partners Founders' Fund V, L.P. ("PVPFF V") and Polaris Venture Partners Special Founders' Fund V, L.P. ("PVPSFF V") on December 16, 2019.

F4 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $83.87 to $84.815, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (4) to this Form 4.

F11 · ownership.nature: The reportable securities are owned directly by PVPSFF V. PVM V is the general partner of PVPSFF V. The Reporting Person, a member of the Issuer's Board of Directors, is a member of PVM V. Each of Flint and McGuire are the managing members of PVM V. Each of Flint, McGuire and the Reporting Person, in their respective capacities with respect to PVM V, may be deemed to have shared voting and dispositive power over the shares held by PVPSFF V. Each of PVM V, Flint, McGuire and the Reporting Person disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein.

SEC source: 0000899243-20-001528 · doc4.xml · nonDerivative · entry 19

Youngren Bryce · CIK 0001489625 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 1,856

F1 · kind: The sale of these shares were effected pursuant to Rule 10b5-1 trading plans adopted by each of Polaris Venture Partners V, L.P. ("PVP V"), Polaris Venture Partners Entrepreneurs' Fund V, L.P. ("PVPE V"), Polaris Venture Partners Founders' Fund V, L.P. ("PVPFF V") and Polaris Venture Partners Special Founders' Fund V, L.P. ("PVPSFF V") on December 16, 2019.

F2 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $82.87 to $83.86, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (2) to this Form 4.

F11 · ownership.nature: The reportable securities are owned directly by PVPSFF V. PVM V is the general partner of PVPSFF V. The Reporting Person, a member of the Issuer's Board of Directors, is a member of PVM V. Each of Flint and McGuire are the managing members of PVM V. Each of Flint, McGuire and the Reporting Person, in their respective capacities with respect to PVM V, may be deemed to have shared voting and dispositive power over the shares held by PVPSFF V. Each of PVM V, Flint, McGuire and the Reporting Person disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein.

SEC source: 0000899243-20-001528 · doc4.xml · nonDerivative · entry 15

Youngren Bryce · CIK 0001489625 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 1,163

F1 · kind: The sale of these shares were effected pursuant to Rule 10b5-1 trading plans adopted by each of Polaris Venture Partners V, L.P. ("PVP V"), Polaris Venture Partners Entrepreneurs' Fund V, L.P. ("PVPE V"), Polaris Venture Partners Founders' Fund V, L.P. ("PVPFF V") and Polaris Venture Partners Special Founders' Fund V, L.P. ("PVPSFF V") on December 16, 2019.

F5 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $84.88 to $85.13, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (5) to this Form 4.

F10 · ownership.nature: The reportable securities are owned directly by PVPFF V. PVM V is the general partner of PVPFF V. The Reporting Person, a member of the Issuer's Board of Directors, is a member of PVM V. Each of Flint and McGuire are the managing members of PVM V. Each of Flint, McGuire and the Reporting Person, in their respective capacities with respect to PVM V, may be deemed to have shared voting and dispositive power over the shares held by PVPFF V. Each of PVM V, Flint, McGuire and the Reporting Person disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein.

SEC source: 0000899243-20-001528 · doc4.xml · nonDerivative · entry 14

Youngren Bryce · CIK 0001489625 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 1,171

F1 · kind: The sale of these shares were effected pursuant to Rule 10b5-1 trading plans adopted by each of Polaris Venture Partners V, L.P. ("PVP V"), Polaris Venture Partners Entrepreneurs' Fund V, L.P. ("PVPE V"), Polaris Venture Partners Founders' Fund V, L.P. ("PVPFF V") and Polaris Venture Partners Special Founders' Fund V, L.P. ("PVPSFF V") on December 16, 2019.

F4 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $83.87 to $84.815, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (4) to this Form 4.

F10 · ownership.nature: The reportable securities are owned directly by PVPFF V. PVM V is the general partner of PVPFF V. The Reporting Person, a member of the Issuer's Board of Directors, is a member of PVM V. Each of Flint and McGuire are the managing members of PVM V. Each of Flint, McGuire and the Reporting Person, in their respective capacities with respect to PVM V, may be deemed to have shared voting and dispositive power over the shares held by PVPFF V. Each of PVM V, Flint, McGuire and the Reporting Person disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein.

SEC source: 0000899243-20-001528 · doc4.xml · nonDerivative · entry 13

Youngren Bryce · CIK 0001489625 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 1,265

F1 · kind: The sale of these shares were effected pursuant to Rule 10b5-1 trading plans adopted by each of Polaris Venture Partners V, L.P. ("PVP V"), Polaris Venture Partners Entrepreneurs' Fund V, L.P. ("PVPE V"), Polaris Venture Partners Founders' Fund V, L.P. ("PVPFF V") and Polaris Venture Partners Special Founders' Fund V, L.P. ("PVPSFF V") on December 16, 2019.

F2 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $82.87 to $83.86, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (2) to this Form 4.

F10 · ownership.nature: The reportable securities are owned directly by PVPFF V. PVM V is the general partner of PVPFF V. The Reporting Person, a member of the Issuer's Board of Directors, is a member of PVM V. Each of Flint and McGuire are the managing members of PVM V. Each of Flint, McGuire and the Reporting Person, in their respective capacities with respect to PVM V, may be deemed to have shared voting and dispositive power over the shares held by PVPFF V. Each of PVM V, Flint, McGuire and the Reporting Person disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein.

SEC source: 0000899243-20-001528 · doc4.xml · nonDerivative · entry 9

Youngren Bryce · CIK 0001489625 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 3,323

F1 · kind: The sale of these shares were effected pursuant to Rule 10b5-1 trading plans adopted by each of Polaris Venture Partners V, L.P. ("PVP V"), Polaris Venture Partners Entrepreneurs' Fund V, L.P. ("PVPE V"), Polaris Venture Partners Founders' Fund V, L.P. ("PVPFF V") and Polaris Venture Partners Special Founders' Fund V, L.P. ("PVPSFF V") on December 16, 2019.

F5 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $84.88 to $85.13, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (5) to this Form 4.

F9 · ownership.nature: The reportable securities are owned directly by PVPE V. PVM V is the general partner of PVPE V. The Reporting Person, a member of the Issuer's Board of Directors, is a member of PVM V. Each of Flint and McGuire are the managing members of PVM V. Each of Flint, McGuire and the Reporting Person, in their respective capacities with respect to PVM V, may be deemed to have shared voting and dispositive power over the shares held by PVPE V. Each of PVM V, Flint, McGuire and the Reporting Person disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein.

SEC source: 0000899243-20-001528 · doc4.xml · nonDerivative · entry 8

Youngren Bryce · CIK 0001489625 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 3,344

F1 · kind: The sale of these shares were effected pursuant to Rule 10b5-1 trading plans adopted by each of Polaris Venture Partners V, L.P. ("PVP V"), Polaris Venture Partners Entrepreneurs' Fund V, L.P. ("PVPE V"), Polaris Venture Partners Founders' Fund V, L.P. ("PVPFF V") and Polaris Venture Partners Special Founders' Fund V, L.P. ("PVPSFF V") on December 16, 2019.

F4 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $83.87 to $84.815, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (4) to this Form 4.

F9 · ownership.nature: The reportable securities are owned directly by PVPE V. PVM V is the general partner of PVPE V. The Reporting Person, a member of the Issuer's Board of Directors, is a member of PVM V. Each of Flint and McGuire are the managing members of PVM V. Each of Flint, McGuire and the Reporting Person, in their respective capacities with respect to PVM V, may be deemed to have shared voting and dispositive power over the shares held by PVPE V. Each of PVM V, Flint, McGuire and the Reporting Person disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein.

SEC source: 0000899243-20-001528 · doc4.xml · nonDerivative · entry 7

Youngren Bryce · CIK 0001489625 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 3,614

F1 · kind: The sale of these shares were effected pursuant to Rule 10b5-1 trading plans adopted by each of Polaris Venture Partners V, L.P. ("PVP V"), Polaris Venture Partners Entrepreneurs' Fund V, L.P. ("PVPE V"), Polaris Venture Partners Founders' Fund V, L.P. ("PVPFF V") and Polaris Venture Partners Special Founders' Fund V, L.P. ("PVPSFF V") on December 16, 2019.

F2 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $82.87 to $83.86, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (2) to this Form 4.

F9 · ownership.nature: The reportable securities are owned directly by PVPE V. PVM V is the general partner of PVPE V. The Reporting Person, a member of the Issuer's Board of Directors, is a member of PVM V. Each of Flint and McGuire are the managing members of PVM V. Each of Flint, McGuire and the Reporting Person, in their respective capacities with respect to PVM V, may be deemed to have shared voting and dispositive power over the shares held by PVPE V. Each of PVM V, Flint, McGuire and the Reporting Person disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein.

SEC source: 0000899243-20-001528 · doc4.xml · nonDerivative · entry 3

Youngren Bryce · CIK 0001489625 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 170,303

F1 · kind: The sale of these shares were effected pursuant to Rule 10b5-1 trading plans adopted by each of Polaris Venture Partners V, L.P. ("PVP V"), Polaris Venture Partners Entrepreneurs' Fund V, L.P. ("PVPE V"), Polaris Venture Partners Founders' Fund V, L.P. ("PVPFF V") and Polaris Venture Partners Special Founders' Fund V, L.P. ("PVPSFF V") on December 16, 2019.

F5 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $84.88 to $85.13, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (5) to this Form 4.

F3 · ownership.nature: The reportable securities are owned directly by PVP V. Polaris Venture Management Co. V, L.L.C. ("PVM V") is the general partner of PVP V. The Reporting Person, a member of the Issuer's Board of Directors, is a member of PVM V. Each of Jonathan A. Flint ("Flint") and Terrance G. McGuire ("McGuire") are the managing members of PVM V. Each of Flint, McGuire and the Reporting Person, in their respective capacities with respect to PVM V, may be deemed to have shared voting and dispositive power over the shares held by PVP V. Each of PVM V, Flint, McGuire and the Reporting Person disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein.

SEC source: 0000899243-20-001528 · doc4.xml · nonDerivative · entry 2

Youngren Bryce · CIK 0001489625 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 171,364

F1 · kind: The sale of these shares were effected pursuant to Rule 10b5-1 trading plans adopted by each of Polaris Venture Partners V, L.P. ("PVP V"), Polaris Venture Partners Entrepreneurs' Fund V, L.P. ("PVPE V"), Polaris Venture Partners Founders' Fund V, L.P. ("PVPFF V") and Polaris Venture Partners Special Founders' Fund V, L.P. ("PVPSFF V") on December 16, 2019.

F4 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $83.87 to $84.815, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (4) to this Form 4.

F3 · ownership.nature: The reportable securities are owned directly by PVP V. Polaris Venture Management Co. V, L.L.C. ("PVM V") is the general partner of PVP V. The Reporting Person, a member of the Issuer's Board of Directors, is a member of PVM V. Each of Jonathan A. Flint ("Flint") and Terrance G. McGuire ("McGuire") are the managing members of PVM V. Each of Flint, McGuire and the Reporting Person, in their respective capacities with respect to PVM V, may be deemed to have shared voting and dispositive power over the shares held by PVP V. Each of PVM V, Flint, McGuire and the Reporting Person disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein.

SEC source: 0000899243-20-001528 · doc4.xml · nonDerivative · entry 1

Youngren Bryce · CIK 0001489625 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 185,185

F1 · kind: The sale of these shares were effected pursuant to Rule 10b5-1 trading plans adopted by each of Polaris Venture Partners V, L.P. ("PVP V"), Polaris Venture Partners Entrepreneurs' Fund V, L.P. ("PVPE V"), Polaris Venture Partners Founders' Fund V, L.P. ("PVPFF V") and Polaris Venture Partners Special Founders' Fund V, L.P. ("PVPSFF V") on December 16, 2019.

F2 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $82.87 to $83.86, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (2) to this Form 4.

F3 · ownership.nature: The reportable securities are owned directly by PVP V. Polaris Venture Management Co. V, L.L.C. ("PVM V") is the general partner of PVP V. The Reporting Person, a member of the Issuer's Board of Directors, is a member of PVM V. Each of Jonathan A. Flint ("Flint") and Terrance G. McGuire ("McGuire") are the managing members of PVM V. Each of Flint, McGuire and the Reporting Person, in their respective capacities with respect to PVM V, may be deemed to have shared voting and dispositive power over the shares held by PVP V. Each of PVM V, Flint, McGuire and the Reporting Person disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein.

SEC source: 0001666071-20-000009 · wf-form4_157913252579532.xml · nonDerivative · entry 1

Evans David Thomas · CIK 0001730451 · Chief Financial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 22,236

F1 · kind: This transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 23, 2019.

SEC source: 0001666071-20-000005 · wf-form4_157851970093830.xml · nonDerivative · entry 1

Grimes Scott D. · CIK 0001617486 · Director · Chief Executive Officer

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 142,112

F1 · kind: These sales were effected pursuant to a Rule 10b5-1 trading plan adopted by the trustees of the 2013 Scott Grimes GRAT UAD (the "GRAT") on November 15, 2019.

F2 · ownership.nature: The reportable securities are held by the GRAT.