Convertible Senior Notes (Tables)

12 Months Ended

Dec. 31, 2019

0.125% Convertible Senior Notes Due 2024

Schedule of Components of Convertible Senior Notes

The 2024 Notes consist of the following (in thousands):

	As of December 31, 2019
Liability component:
Principal	$	450,000
Less: debt discount, net of amortization		(98,942	)
Net carrying amount	$	351,058
Equity component (1)		86,133

^{(1) Recorded in the consolidated balance sheet within additional paid-in capital, net of $2.6 million transaction costs in equity and net of $0.9 million for taxes.}

Summary of Total Interest Expense Recognized Related To Convertible Senior Notes

The following table sets forth total interest expense recognized related to the 2024 Notes (in thousands):

	Year Ended December 31, 2019
0.125% coupon	$	27
Amortization of debt discount and transaction costs		827
	$	854

Summary of Fair Value and Carrying Value of Convertible Senior Notes

As of December 31, 2019, the fair value of the 2024 Notes, which was determined based on inputs that are observable in the market or that could be derived from, or corroborated with, observable market data, quoted price of the 2024 Notes in an over-the-counter market (Level 2), and carrying value of debt instruments (carrying value excludes the equity component of the Company’s 2024 Notes classified in equity) were as follows (in thousands):

	As of December 31, 2019
	Fair Value		Carrying Value
2024 Notes	$	450,414	$	351,058

1.50% Convertible Senior Notes Due 2022

Schedule of Components of Convertible Senior Notes

The 2022 Notes consist of the following (in thousands):

	As of December 31,
	2019			2018
Liability component:
Principal	$	92,000		$	115,000
Less: debt discount, net of amortization		(12,776	)		(20,903	)
Net carrying amount	$	79,224		$	94,097
Equity component (1)		(14,555	)		22,094

⁽¹⁾ Recorded in the consolidated balance sheet within additional paid-in capital, net of $0.8 million transaction costs in equity. December 31, 2019 also includes $36.7 million market premium representing the excess of the total consideration delivered over the fair value of the liability recognized related to the $23.0 million principal balance repurchase of the 2022 Notes.  

Summary of Total Interest Expense Recognized Related To Convertible Senior Notes

The following table sets forth total interest expense recognized related to the 2022 Notes (in thousands):

	Year Ended December 31,
	2019		2018
1.50% coupon	$	1,709	$	1,725
Amortization of debt discount and transaction costs		4,884		4,616
	$	6,593	$	6,341

Summary of Fair Value and Carrying Value of Convertible Senior Notes

As of December 31, 2019 and 2018, the fair value of the 2022 Notes, which was determined based on inputs that are observable in the market or that could be derived from, or corroborated with, observable market data, quoted price of the 2022 Notes in an over-the-counter market (Level 2), and carrying value of debt instruments (carrying value excludes the equity component of the Company’s convertible notes classified in equity) were as follows (in thousands):

	As of December 31,
	2019				2018
	Fair Value		Carrying Value		Fair Value		Carrying Value
2022 Notes	$	215,801	$	79,224	$	189,802	$	94,097

Summary of Debt Obligations

The following table summarizes the Company’s debt obligations at December 31, 2019 (in thousands):

	Less than 1 Year		1 to 3 Years		3 to 5 Years		More than 5 Years		Total
Debt obligations	$	—	$	92,000	$	450,000	$	—	$	542,000