| Summary of Net Carrying Amount of Liability and Equity Components of Convertible Notes |
The net carrying amount of the Notes was as follows as of the dates indicated (in thousands):
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | As of July 31, 2024 | | As of January 31, 2024 | | 2025 Notes | | 2028 Notes | | Total | | 2025 Notes | | 2028 Notes | | Total | | Principal | $ | 57,500 | | | $ | 402,500 | | | $ | 460,000 | | | $ | 57,500 | | | $ | 402,500 | | | $ | 460,000 | | | Less: unamortized issuance costs | (259) | | | (10,402) | | | (10,661) | | | (597) | | | (11,373) | | | (11,970) | | | Net carrying amount | $ | 57,241 | | | $ | 392,098 | | | $ | 449,339 | | | $ | 56,903 | | | $ | 391,127 | | | $ | 448,030 | |
Interest expense recognized related to the Notes was as follows for the periods indicated (in thousands):
| | | | | | | | | | | | | | | | | | | | | | | | | Three months ended July 31, | | Six months ended July 31, | | 2024 | | 2023 | | 2024 | | 2023 | | Contractual interest expense | $ | 1,691 | | | $ | 918 | | | $ | 3,232 | | | $ | 1,797 | | | Amortization of debt issuance costs | 672 | | | 478 | | | 1,279 | | | 933 | | | Total interest expense related to the Notes | $ | 2,363 | | | $ | 1,396 | | | $ | 4,511 | | | $ | 2,730 | |
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