Convertible Notes (Tables)

9 Months Ended

Sep. 30, 2021

Debt Disclosure [Abstract]

Convertible Notes

The Notes at September 30, 2021 and December 31, 2020 consisted of the following (in thousands):

	September 30,		December 31,
	2021		2020
Outstanding principal	$	125,500	$	171,500
Unamortized debt discount	(14,524)		(28,524)
Unamortized debt issuance	(898)		(1,765)
Net carrying amount of the liability component	$	110,078	$	141,211

Schedule of Interest Expense

Interest expense for the three and nine months ended September 30, 2021 and 2020 were as follows (in thousands):

	Three Months Ended September 30,				Nine Months Ended September 30,
	2021		2020		2021		2020
Contractual coupon interest	$	1,024	$	1,072	$	3,168	$	3,216
Amortization of the debt discount	2,987		2,666		8,711		7,775
Amortization of debt issuance costs	185		165		539		481
Total interest expense on convertible notes	$	4,196	$	3,903	$	12,418	$	11,472