Convertible Senior Notes (Tables)

9 Months Ended

Sep. 30, 2020

Debt Disclosure [Abstract]

Schedule of Notes

The Notes consist of the following:

(in thousands)	September 30, 2020		December 31, 2019
Liability:
Principal	$	143,750	$	143,750
Unamortized debt discount	(19,087)		(23,880)
Unamortized issuance costs	(2,152)		(2,692)
Net carrying amount	$	122,511	$	117,178
Stockholders’ equity:
Debt discount for conversion option	$	33,350	$	33,350
Issuance costs	(1,136)		(1,136)
Net carrying amount	$	32,214	$	32,214

Schedule of Interest Expense Related to the Notes

Interest expense related to the Notes is as follows:

	Three months ended September 30,				Nine months ended September 30,
(in thousands)	2020		2019		2020		2019
Contractual interest expense	$	539	$	539	$	1,617	$	1,617
Amortization of debt discount	1,644		1,521		4,793		4,414
Amortization of issuance costs	185		172		540		498
Total interest expense	$	2,368	$	2,232	$	6,950	$	6,529

Schedule of Net Impact on Stockholders' Equity of Components of Convertible Debt

The net impact to the Company’s stockholders' equity, included in additional paid-in capital, of the above components of the Notes is as follows:

(in thousands)	September 30, 2020
Conversion option	$	33,350
Purchase of capped calls	(8,907)
Issuance costs	(1,136)
Total	$	23,307