Convertible Senior Notes (Tables)

3 Months Ended

Mar. 31, 2020

Debt Disclosure [Abstract]

Summary of Convertible Notes

The 2026 Notes consist of the following:

	As of March 31, 2020			As of December 31, 2019
Liability component:
Principal	$	316,250		$	316,250
Unamortized debt discount	(76,073		)	(78,672		)
Unamortized debt issuance costs	(5,732		)	(5,931		)
Net carrying amount	234,445			231,647
Equity component:
Net carrying amount	$	81,550		$	81,550

The 2023 Notes consist of the following:

	As of March 31, 2020			As of December 31, 2019
Liability component:
Principal	$	229,997		$	229,999
Unamortized debt discount	(30,942		)	(33,376		)
Unamortized debt issuance costs	(3,228		)	(3,486		)
Net carrying amount	195,827			193,137
Equity component:
Net carrying amount	$	48,919		$	48,919

Summary of Interest Expense

The following table sets forth total interest expense recognized related to the 2023 Notes:

	Three months ended March 31,
	2020		2019
Contractual interest expense	$	431	$	437
Amortization of debt issuance costs	259		250
Amortization of debt discount	2,434		2,298
Total	$	3,124	$	2,985

The following table sets forth total interest expense recognized related to the 2026 Notes:

	Three months ended
	March 31, 2020
Contractual interest expense	$	586
Amortization of debt issuance costs	200
Amortization of debt discount	2,597
Total	$	3,383