In August 2019, we issued $345.0 million aggregate principal amount of 1.125% convertible senior notes due 2026 in a private placement to qualified institutional buyers pursuant to Rule 144A under the Securities Act of 1933, as amended, including the exercise in full by the initial purchasers of their option to purchase an additional $45.0 million principal amount (the “Notes”). The Notes were issued pursuant to an indenture and are senior, unsecured obligations of the Company. The Notes bear interest at a fixed rate of 1.125% per annum, payable semi-annually in arrears on February 15 and August 15 of each year, commencing on February 15, 2020. Proceeds from the issuance of the Notes totaled $335.9 million, net of initial purchaser discounts and issuance costs.

The initial conversion rate is 12.4756 shares of our common stock per $1,000 principal amount of Notes, which is equivalent to an initial conversion price of approximately $80.16 per share, subject to adjustment upon the occurrence of specified events.

Holders of the Notes may convert all or a portion of their Notes prior to the close of business on May 15, 2026, in multiples of $1,000 principal amount, only under the following circumstances:

•during any calendar quarter commencing after the calendar quarter ending on September 30, 2019 (and only during such calendar quarter), if the last reported sale price of our Class A common stock, par value $0.001 per share (which we refer to in this offering memorandum as our “Class A common stock”), for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter is greater than or equal to 130% of the conversion price on each applicable trading day;

•during the five consecutive business day period immediately following any ten consecutive trading day period (the “measurement period”) in which the trading price (as defined below) per $1,000 principal amount of Notes for each trading day of the measurement period was less than 98% of the product of the last reported sale price of our Class A common stock and the conversion rate on each such trading day;

•if we call any or all of the Notes for redemption, at any time prior to the close of business on the scheduled trading day immediately preceding the redemption date; or

On or after May 16, 2026, holders of the Notes may convert their Notes at any time until the close of business on the second scheduled trading day immediately preceding the maturity date of the Notes.

Upon conversion, we will pay or deliver, as the case may be, cash, shares of our Class A common stock or a combination of cash and shares of our Class A common stock, at our election, in the manner and subject to the terms and conditions provided in the indenture. It is our current intent to settle conversions through a combination settlement of cash and shares of our Class A common stock with a specified dollar amount per $1,000 principal amount of Notes of $1,000.

If we undergo a fundamental change (as defined in the indenture), holders may require us to repurchase for cash all or any portion of their Notes at a fundamental change repurchase price equal to 100% of the principal amount of the Notes to be repurchased, plus accrued and unpaid interest to, but excluding, the fundamental change repurchase date. In addition, following certain corporate events that occur prior to the maturity date or if we deliver a notice of redemption, we will increase, in certain circumstances, the conversion rate for a holder who elects to convert its Notes in connection with such corporate event or notice of redemption, as the case may be.

The Company may redeem for cash all or any portion of the Notes, at its option, on or after August 21, 2023, if the last reported sale price of the Company’s common stock has been at least 130% of the conversion price then in effect for at least 20 trading days (whether or not consecutive) during any 30 consecutive trading day period (including the last trading day of such period) ending on, and including, the trading day immediately preceding the date on which the Company provides notice of redemption at a redemption price equal to 100% of the principal amount of the Notes to be redeemed, plus any accrued and unpaid interest to, but excluding, the redemption date.

In accounting for the issuance of the Notes, we separated the Notes into liability and equity components. The carrying amount of the liability component was calculated by measuring the fair value of similar debt instruments that do not have an associated convertible feature. The carrying amount of the equity component, representing the conversion option, was determined by deducting the fair value of the liability components from the par value of the Notes. The difference represents the debt discount that is amortized to interest expense at an effective interest rate of 4.3% over the term of the Notes. The carrying amount of the equity component was $60.1 million and is recorded in additional paid-in-capital. The equity component is not remeasured as long as it continues to meet the conditions for equity classification.

In accounting for the issuance costs related to the Notes, we allocated the total amount incurred to the liability and equity components of the Notes based on the proportion of the proceeds allocated to the debt and equity components. Issuance costs attributable to the liability component were $7.5 million. The issuance costs allocated to the liability component are amortized to interest expense under the effective interest rate method over the contractual term of the Notes. Issuance costs attributable to the equity component of the Notes were $1.6 million and are netted against the equity components representing the conversion option in additional paid-in capital.

During the third and fourth quarters of 2021 one of the conversion conditions was met and the Notes are convertible at the option of the holders through March 31, 2022. Specifically, the last reported sale price of our Class A common stock exceeded 130% of the conversion price of the Notes for more than 20 trading days during the 30 consecutive trading days ended September 30, 2021 and December 31, 2021. As a result, the Notes are classified as current liabilities on the condensed consolidated balance sheet as of December 31, 2021. As of December 31, 2021, and through the date of this filing, we have not received any conversion requests for the Notes.


	As of December 31,
	2021		2020
Liability component:
Principal	$	345,000	$	345,000
Unamortized discount	(41,193)		(49,346)
Unamortized issuance costs	(5,146)		(6,164)
Net carrying amount	$	298,661	$	289,490

Equity component, net of purchase discounts and issuance costs	$	58,560	$	58,560


	Year ended December 31,
	2021		2020		2019
Contractual interest expense	$	3,881	$	3,880	$	1,444
Amortization of debt discount	8,153		7,901		2,900
Amortization of issuance costs	1,018		988		362
Total interest expense	$	13,052	$	12,769	$	4,706