Convertible Senior Notes (Tables)

6 Months Ended

Jun. 30, 2020

Debt Disclosure [Abstract]

Schedule of Notes

The Notes consist of the following:

(in thousands)	June 30, 2020			December 31, 2019
Liability:
Principal	$	143,750		$	143,750
Unamortized debt discount	(20,731		)	(23,880		)
Unamortized issuance costs	(2,337		)	(2,692		)
Net carrying amount	$	120,682		$	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 June 30,				Six months ended June 30,
(in thousands)	2020		2019		2020		2019
Contractual interest expense	$	539	$	539	$	1,078	$	1,078
Amortization of debt discount	1,590		1,471		3,149		2,893
Amortization of issuance costs	179		166		355		326
Total interest expense	$	2,308	$	2,176	$	4,582	$	4,297

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