Convertible Senior Notes (Tables)

3 Months Ended

Mar. 31, 2020

2025 Notes

Convertible Senior Notes

Summary of the Notes

The 2025 Notes consist of the following (in thousands):

	As of March 31,		As of December 31,
Liability component	2020		2019
Principal	$	287,500	$	287,500
Less: Debt discount, net (1)		(78,131)		(81,207)
Net carrying amount	$	209,369	$	206,293

(1) Included in the accompanying consolidated balance sheets within convertible senior notes and amortized to interest expense over the expected life of the 2025 Notes using the effective interest rate method.

Schedule of total interest expense recognized related to the Notes

The following table sets forth total interest expense recognized related to the 2025 Notes (in thousands):

	Quarters Ended
	March 31,
	2020			2019
Contractual interest expense	$	988		$	975
Amortization of debt discount		3,076			2,836
Total	$	4,064		$	3,811
Effective interest rate of the liability component		7.9	%		7.9	%

2022 Notes

Convertible Senior Notes

Summary of the Notes

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

	As of March 31,		As of December 31,
Liability component	2020		2019
Principal	$	274,970	$	274,995
Less: Debt discount, net (2)		(37,118)		(40,878)
Net carrying amount	$	237,852	$	234,117

(2) Included in the accompanying consolidated balance sheets within convertible senior notes and amortized to interest expense over the expected life of the 2022 Notes using the effective interest rate method.

Schedule of total interest expense recognized related to the Notes

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

	Quarters Ended
		March 31,
	2020			2019
Contractual interest expense	$	2,062		$	2,034
Amortization of debt discount		3,761			3,374
Total	$	5,823		$	5,408
Effective interest rate of the liability component		10.0	%		10.0	%