0.25% Convertible Senior Notes, Convertible Note Hedge and Warrant (Tables)

3 Months Ended

Mar. 31, 2020

Debt Instrument [Line Items]

Schedule of Interest Expense

Interest expense related to the 2022 Notes is as follows:

	Three Months Ended March 31,
	2020		2019
	(in thousands)
Contractual interest expense	$	250	$	250
Amortization of debt discount		5,307		4,894
Amortization of issuance costs		396		366
Total interest expense	$	5,953	$	5,510

0.25% Convertible Senior Notes Due 2022 as Liability Component [Member]

Debt Instrument [Line Items]

Schedule of Net Carrying Amount of Notes

The net carrying amount of the liability component of the 2022 Notes is as follows:

	As of March 31, 2020			As of December 31, 2019
	(in thousands)
Principal	$	399,990		$	399,992
Unamortized debt discount		(49,992	)		(55,299	)
Unamortized issuance costs		(3,733	)		(4,129	)
Net carrying amount	$	346,265		$	340,564