Transactions Table

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Explanation of Responses:

Id	Content
F1	Represents the number of shares sold by the Reporting Person to cover tax withholding obligations in connection with the vesting of restricted stock units. This sale is mandated by the Issuer's election under its equity incentive plans to require the satisfaction of tax withholding obligations to be funded by a "sell to cover" transaction and does not represent a discretionary trade by the Reporting Person.
F2	The price reported in Column 4 is a weighted average price calculated by the broker. These shares were sold as part of a block trade in multiple transactions at prices ranging from $249.70 to $254.53, 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 range set forth in this footnote (2) with regard to the block trade.
F3	Includes 89 shares of Class A Common Stock acquired under a Section 423 Employee Stock Purchase Plan.
F4	Each Restricted Stock Unit ("RSU") represents the right to receive one share of the Issuer's Class A Common Stock.
F5	25% of the shares underlying the RSU vested on March 15, 2019, and the remaining shares underlying the RSU shall vest in 12 equal quarterly installments thereafter, subject to the Reporting Person's continuous employment with the Issuer on each such date.
F6	25% of the shares underlying the RSU vested on March 15, 2020, and the remaining shares underlying the RSU shall vest in 12 equal quarterly installments thereafter, subject to the Reporting Person's continuous employment with the Issuer on each such date.
F7	25% of the shares underlying the RSU vested on March 15, 2021, and the remaining shares underlying the RSU shall vest in 12 equal quarterly installments thereafter, subject to the Reporting Person's continuous employment with the Issuer on each such date.
F8	The shares subject to the option are fully vested and exercisable by the Reporting Person.
F9	25% of the shares subject to the option vested on February 1, 2019 and the remaining shares subject to the option shall vest in 36 equal monthly installments thereafter, subject to the Reporting Person's continuous employment with the Issuer on each such date.
F10	25% of the shares subject to the option vested on February 1, 2020 and the remaining shares subject to the option shall vest in 36 equal monthly installments thereafter, subject to the Reporting Person's continuous employment with the Issuer on each such date.
F11	25% of the shares subject to the option vested on February 1, 2021 and the remaining shares subject to the option shall vest in 36 equal monthly installments thereafter, subject to the Reporting Person's continuous employment with the Issuer on each such date.
F12	25% of the shares subject to the option shall vest on February 1, 2022 and the remaining shares subject to the option shall vest in 36 equal monthly installments thereafter, subject to the Reporting Person's continuous employment with the Issuer on each such date.
F13	25% of the shares underlying the RSU shall vest on March 15, 2022, and the remaining shares underlying the RSU shall vest in 12 equal quarterly installments thereafter, subject to the Reporting Person's continuous employment with the Issuer on each such date.