Convertible Notes (Tables)

9 Months Ended

Sep. 30, 2020

Debt Disclosure [Abstract]

Convertible Notes

The Notes at September 30, 2020 and December 31, 2019 consisted of the following (in thousands):

	September 30,		December 31,
	2020		2019
Outstanding principal	$	171,500	$	171,500
Unamortized debt discount	(31,267)		(39,042)
Unamortized debt issuance	(1,934)		(2,415)
Net carrying amount of the liability component	$	138,299	$	130,043

Schedule of Interest Expense

Interest expense for the three and nine months ended September 30, 2020 and 2019 were as follows (in thousands):

	Three Months Ended September 30,				Nine Months Ended September 30,
	2020		2019		2020		2019
Contractual coupon interest	$	1,072	$	1,072	$	3,216	$	3,216
Amortization of the debt discount	2,666		2,379		7,775		6,940
Amortization of debt issuance costs	165		147		481		429
Total interest expense on convertible notes	$	3,903	$	3,598	$	11,472	$	10,585