Unsecured Convertible Senior Notes (Tables)

6 Months Ended

Jun. 30, 2022

Debt Instrument [Line Items]

Summary of unsecured convertible senior notes outstanding

	Balance as of June 30, 2022
	2023 Notes		2026 Notes		Total
	(In thousands)
Principal amount	$	95,000	$	225,030	$	320,030
Unamortized debt issuance costs		(956)		(4,716)		(5,672)
Total unsecured convertible senior notes, net	$	94,044	$	220,314	$	314,358
Fair value of outstanding unsecured convertible senior notes (1)	$	85,263	$	132,064

	Balance as of December 31, 2021
	2023 Notes		2026 Notes		Total
	(In thousands)
Principal amount	$	95,000	$	225,030	$	320,030
Unamortized discount		(1,282)		(5,290)		(6,572)
Total unsecured convertible senior notes, net	$	93,718	$	219,740	$	313,458
Fair value of outstanding unsecured convertible senior notes (1)	$	87,163	$	171,867

(1) The fair value is classified as Level 3 due to the limited trading activity for the unsecured convertible senior notes.

Schedule of future minimum payments of debt

	(In thousands)
2023	$	95,000
2024		—
2025		—
2026		225,030
2027		—
Total future minimum principal payments under the 2023 Notes and 2026 Notes	$	320,030

2023 Unsecured Convertible Senior Notes

Debt Instrument [Line Items]

Schedule of total interest expense recognized

	Three Months Ended June 30,				Six Months Ended June 30,
	2022		2021		2022		2021
	(In thousands)				(In thousands)
Contractual interest expense	$	1,484	$	1,484	$	2,969	$	2,969
Amortization of debt issuance costs		164		153		325		303
Total	$	1,648	$	1,637	$	3,294	$	3,272

2026 Unsecured Convertible Senior Notes

Debt Instrument [Line Items]

Schedule of total interest expense recognized

	Three Months Ended June 30,				Six Months Ended June 30,
	2022		2021		2022		2021
	(In thousands)				(In thousands)
Contractual interest expense	$	2,954	$	2,954	$	5,907	$	5,907
Amortization of debt issuance costs		290		273		575		519
Total	$	3,244	$	3,227	$	6,482	$	6,426