Debt (Tables)

6 Months Ended

Jun. 30, 2021

Debt Disclosure [Abstract]

Convertible Debt

The table below summarizes the net carrying amount of the Convertible Notes, including the unamortized debt discount and debt issuance costs.

	June 30, 2021		December 31, 2020
	(Thousands)
Principal	$	500,000	$	500,000
Less: Unamortized debt discount	119,105		129,103
Less: Unamortized debt issuance costs	10,562		11,263
Net carrying value of Convertible Notes	$	370,333	$	359,634

The table below summarizes the components of interest expense related to the Convertible Notes.

	Three Months Ended June 30,				Six Months Ended June 30,
	2021		2020		2021		2020
	(Thousands)
Contractual interest expense	$	2,187	$	1,507	$	4,375	$	1,507
Amortization of debt discount	5,046		3,231		9,998		3,231
Amortization of issuance costs	358		209		701		209
Total Convertible Notes interest expense	$	7,591	$	4,947	$	15,074	$	4,947