Debt (Tables)

12 Months Ended

Dec. 31, 2020

Schedule of Liability and Equity Components of Convertible Debt

The following table presents details of the Notes (number of shares in millions):


	Initial Conversion Price per $1,000 Principal	Initial Conversion Price		Initial Number of Shares
2023 Notes	24.0460	$	41.59	5.5
2025 Notes	16.3875	$	61.02	3.8

The net carrying amount of the liability components of the 2023 Notes and the 2025 Notes were as follows (in thousands):


	As of December 31, 2020						As of December 31, 2019
	2023 Notes		2025 Notes		Total		2023 Notes
Principal	$	230,000	$	230,000	$	460,000	$	230,000
Unamortized debt discount	(30,425)		(42,930)		(73,355)		(40,768)
Unamortized issuance costs	(3,009)		(5,050)		(8,059)		(4,032)
Net carrying amount	$	196,566	$	182,020	$	378,586	$	185,200

The net carrying amount of the equity component as of December 31, 2020 and 2019 (for the 2023 Notes only) was as follows (in thousands):


	2023 Notes		2025 Notes		Total
Debt discount for conversion option	$	53,820	$	48,346	$	102,166
Issuance costs	(1,626)		(1,514)		(3,140)
Net carrying amount	$	52,194	$	46,832	$	99,026

Interest expense related to the 2023 Notes and the 2025 Notes was as follows (in thousands):


	Year Ended December 31, 2020						Year Ended December 31, 2019
	2023 Notes		2025 Notes		Total		2023 Notes		2025 Notes		Total
Contractual interest expense	$	2,875	$	3,450	$	6,325	$	2,875	$	—	$	2,875
Amortization of debt discount	10,342		5,417		15,759		9,567		—		9,567
Amortization of issuance costs	1,023		637		1,660		946		—		946
Total interest expense	$	14,240	$	9,504	$	23,744	$	13,388	$	—	$	13,388

The net impact to our stockholders' equity, included in additional paid-in capital, of the above components of the 2023 Notes and the 2025 Notes was as follows (in thousands):


	2023 Notes		2025 Notes
Conversion option	$	53,820	$	48,346
Purchase of capped calls	(26,910)		(27,255)
Issuance costs	(1,626)		(1,514)
Total	$	25,284	$	19,577

Schedule of Interest Payments on Debt Instruments

The future payments of the principal and contractual interest related to the Notes as of December 31, 2020 are as follows (in thousands):


	Principal		Interest		Total
2021	$	—	$	8,050	$	8,050
2022	—		8,050		8,050
2023	230,000		8,050		238,050
2024	—		5,175		5,175
2025	230,000		2,588		232,588
Total	$	460,000	$	31,913	$	491,913