Convertible Senior Notes (Tables)

12 Months Ended

Dec. 31, 2020

Debt Disclosure [Abstract]

Summary of Convertible Notes

The 2023 Notes consist of the following:

	As of December 31,
	2020		2019
Liability component:
Principal	$	48,035	$	229,999
Unamortized debt discount	(4,915)		(33,376)
Unamortized debt issuance costs	(501)		(3,486)
Net carrying amount	42,619		193,137
Equity component
Net carrying amount	$	7,784	$	48,919

The 2026 Notes consist of the following:

	As of December 31,
	2020		2019
Liability component:
Principal	$	316,250	$	316,250
Unamortized debt discount	(67,977)		(78,672)
Unamortized debt issuance costs	(5,114)		(5,931)
Net carrying amount	243,159		231,647
Equity component:
Net carrying amount	$	81,550	$	81,550

The 2025 Notes consist of the following:

	As of December 31, 2020
Liability component:
Principal	$	350,000
Unamortized debt discount	(73,075)
Unamortized debt issuance costs	(5,235)
Net carrying amount	271,690
Equity component:
Net allocation of proceeds	74,556
Net issuance costs	(1,459)
Net carrying amount	$	73,097

Summary of Interest Expense

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

	As of December 31,
	2020		2019
Contractual interest expense	$	1,566	$	1,725
Amortization of debt issuance costs	999		1,001
Amortization of debt discount	9,080		9,414
Total	$	11,645	$	12,140

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

	As of December 31,
	2020		2019
Contractual interest expense	$	2,365	$	593
Amortization of debt issuance costs	821		466
Amortization of debt discount	10,696		5,740
Total	$	13,882	$	6,799

The following table sets forth total interest expense recognized related to the 2025 Notes:

	As of December 31, 2020
Contractual interest expense	$	51
Amortization of debt issuance costs	157
Amortization of debt discount	1,541
Total	$	1,749