The net carrying amount of the liability component of the 2024 Convertible Senior Notes is as follows (in thousands):
| | | | | | | | | June 30, 2024 | | | | Principal | $ | 172,500 | | | | | Minus: | | | | | | | | | Unamortized issuance costs | (5,332) | | | | | Net carrying amount | $ | 167,168 | | | |
Interest expense recognized related to the 2024 Convertible Senior Notes is as follows (in thousands): | | | | | | | | | | | | | | | | | Three Months Ended June 30, | | Six Months Ended June 30, | | 2024 | | | | 2024 | | | | Contractual interest expense (due in cash) | $ | 1,812 | | | | | $ | 1,812 | | | | | | | | | | | | | Amortization of debt issuance costs | 277 | | | | | 277 | | | | | Total interest expense related to the 2024 Convertible Senior Notes | $ | 2,089 | | | | | $ | 2,089 | | | | | Effective interest rate | 4.84 | % | | | | 4.84 | % | | |
The net carrying amount of the liability component of the 2020 Convertible Senior Notes is as follows (in thousands):
| | | | | | | | | | | | | June 30, 2024 | | December 31, 2023 | | Principal | $ | 46,070 | | | $ | 230,000 | | | Minus: | | | | | | | | | Unamortized issuance costs | (353) | | | (2,496) | | | Net carrying amount of the liability component | $ | 45,717 | | | $ | 227,504 | |
Interest expense recognized related to the 2020 Convertible Senior Notes is as follows (in thousands): | | | | | | | | | | | | | | | | | | | | | | | | | Three Months Ended June 30, | | Six Months Ended June 30, | | 2024 | | 2023 | | 2024 | | 2023 | | Contractual interest expense (due in cash) | $ | 115 | | | $ | 575 | | | $ | 690 | | | $ | 1,150 | | | | | | | | | | | Amortization of debt issuance costs | 73 | | | 365 | | | 438 | | | 730 | | | Total interest expense related to the 2020 Convertible Senior Notes | $ | 188 | | | $ | 940 | | | $ | 1,128 | | | $ | 1,880 | | | Effective interest rate | 1.64 | % | | 1.64 | % | | 1.64 | % | | 1.64 | % |
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