Long-term Debt (Tables)

6 Months Ended

Jun. 30, 2023

Debt Disclosure [Abstract]

Schedule of long-term debt instruments

The 2025 Notes and 2026 Notes consisted of the following (in millions):

	June 30, 2023 (unaudited)
Long-term debt:	2026 Notes		2025 Notes
Principal	$	380.0	$	23.3
Less: Unamortized debt issuance costs	(7.3)		(0.3)
Net carrying amount	$	372.7	$	23.0

	December 31, 2022
Long-term debt:	2026 Notes		2025 Notes
Principal	$	380.0	$	23.3
Less: Unamortized debt issuance costs	(8.3)		(0.4)
Net carrying amount	$	371.7	$	22.9

Interest expense for the three and six months ended June 30, 2023 and 2022 related to the 2026 Notes and 2025 Notes consisted of the following (in millions):

2026 Notes

	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2023		2022		2023		2022
Coupon interest	$	0.1	$	0.1	$	0.2	$	0.2
Amortization of debt issuance costs	0.6		0.6		$	1.0	$	1.1
Total interest expense recognized	$	0.7	$	0.7	$	1.2	$	1.3

2025 Notes

	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2023		2022		2023		2022
Coupon interest	$	0.1	$	0.1	$	0.1	$	0.1
Amortization of debt issuance costs	—		—		$	0.1	$	0.1
Total interest expense recognized	$	0.1	$	0.1	$	0.2	$	0.2