Table:
|  | December 31, 2019 | December 31, 2018 |
| --- | --- | --- |
| Principal amount | $300,000 | $300,000 |
| Unamortized debt discount | (2,691) | (4,348) |
| Net carrying amount before unamortized debt issuance costs | 297,309 | 295,652 |
| Unamortized debt issuance costs | (4,135) | (6,685) |
| Net carrying value | $293,174 | $288,967 |
Paragraphs:
9. DEBT AND OTHER FINANCING ARRANGEMENTS
2021 Senior Convertible Notes
In 2017, the Company issued $300.0 million principal amount of 5.75% senior convertible notes (the “2021 Notes”) for a purchase price equal to 98% of the principal amount. The Company received net proceeds of $284.9 million, net of a discount of $6.0 million and issuance costs of $9.1 million. The debt discount is being accreted to interest expense over the term of the 2021 Notes using the interest method. The issuance costs were deferred and are being amortized to interest expense over the same term.
The 2021 Notes are governed by an Indenture, dated December 8, 2017 between the Company and US Bank National Association, as trustee (the “2017 Indenture”). The 2021 Notes mature on July 1, 2021, unless earlier repurchased or converted. Interest is payable semi-annually in arrears on January 1 and July 1, commencing January 1, 2018.
The 2021 Notes are convertible at an initial conversion rate of 23.8095 shares of the Company’s common stock per $1,000 principal amount of the 2021 Notes, which represents an initial conversion price of $42.00 per share, subject to adjustment for anti-dilutive issuances, voluntary increases in the conversion rate, and make-whole adjustments upon a fundamental change. A fundamental change includes a change in control, delisting of the Company’s common stock, and a liquidation of the Company. Upon conversion, the Company will deliver the applicable number of the Company’s common stock and cash in lieu of any fractional shares. Holders of the 2021 Notes may convert their 2021 Notes at any time prior to the close of business on the scheduled trading day immediately preceding the maturity date.
The holders of the 2021 Notes may require the Company to repurchase all or a portion of their 2021 Notes at a cash repurchase price equal to 100% of the principal amount of the 2021 Notes being repurchased, plus the remaining scheduled interest through and including the maturity date, upon a fundamental change and events of default, including non-payment of interest or principal and other obligations under the 2017 Indenture.
The net carrying amounts of the liability components of the 2021 Notes consist of the following (in thousands):
The effective interest rate of the liability component is 6.4% for the 2021 Notes.
Question:
What is the change in net carrying value between 2018 and 2019?