6. Debt

Our debt consists of:


	March 31,		December 31,
(In thousands)	2019		2018
Term B Loan	$	13,750	$	13,750
2023 Notes		240,984		240,984
2025 Notes		192,500		192,500
Total debt		447,234		447,234
Unamortized debt discount and issuance costs		(62,490)		(64,379)
Net long-term debt	$	384,744	$	382,855

Prepayments of Senior Secured Term Loans

On February 28 and August 1, 2018, we prepaid the principal balance of the Term B Loan by $120.0 million and $110.0 million, respectively. With the prepayments, we incurred a loss on the extinguishment of debt of $3.1 million and $2.6 million, respectively, representing unamortized debt issuance costs. The loss on the extinguishment of debt is presented as part of other expense, net in our consolidated statements of operations. As of March 31, 2019, the outstanding principal balance of the Term B Loan was $13.8 million.

Convertible Senior Notes Due 2025

In accordance with accounting guidance for debt with conversion and other options, we separately account for the liability and equity components of the 2025 Notes by allocating the proceeds between the liability component and the embedded conversion option (“equity component”) due to our ability to settle the conversion obligation of the 2025 Notes in cash, common stock or a combination of cash and common stock, at our option. The carrying amount of the liability component was calculated by measuring the fair value of a similar liability that does not have an associated convertible feature using the income approach. The allocation was performed in a manner that reflected our non-convertible debt borrowing rate for similar debt. The equity component of the 2025 Notes was recognized as a debt discount and represents the difference between the proceeds from the issuance of the 2025 Notes and the fair value of the liability of the 2025 Notes on the date of issuance. The excess of the principal amount of the liability component over its carrying amount (“debt discount”) is amortized to interest expense using the effective interest method over the term of the 2025 Notes. The equity component is not remeasured as long as it continues to meet the conditions for equity classification.

Our outstanding 2025 Notes balances consisted of the following:


	March 31,		December 31,
(In thousands)	2019		2018
Liability component
Principal	$	192,500	$	192,500
Debt discount and issuance costs, net		(60,032)		(61,766)
Net carrying amount	$	132,468	$	130,734
Equity component, net	$	65,361	$	65,361

The following table sets forth total interest expense recognized related to the 2025 Notes for the three months ended March 31, 2019 and 2018:


	Three Months Ended March 31,
(In thousands)	2019		2018
Contractual interest expense	$	1,203	$	1,190
Amortization of debt issuance costs		133		123
Amortization of debt discount		1,601		1,479
Total interest and amortization expense	$	2,937	$	2,792

Debt Maturities

The aggregate scheduled maturities of our long-term debt as of March 31, 2019, are as follows:


(In thousands)
Years ending December 31:
2019 to 2021	$	—
2022		13,750
2023		240,984
Thereafter		192,500
Total	$	447,234