| Schedule of Senior Notes |
The Notes, net consisted of the following (in thousands): | | | | | | | | | | | | | | | | | | April 30, 2017 | | January 31, 2017 | | 2018 Notes | | 2020 Notes | | 2018 Notes | | 2020 Notes | Principal amounts: | | | | | | | | Principal | $ | 350,000 |
| | $ | 250,000 |
| | $ | 350,000 |
| | $ | 250,000 |
| Unamortized debt discount(1) | (20,336 | ) | | (34,414 | ) | | (24,380 | ) | | (36,820 | ) | Net carrying amount before unamortized debt issuance costs | 329,664 |
| | 215,586 |
| | 325,620 |
| | 213,180 |
| Unamortized debt issuance costs(1) | (1,698 | ) | | (2,159 | ) | | (2,050 | ) | | (2,327 | ) | Net carrying amount | $ | 327,966 |
| | $ | 213,427 |
| | $ | 323,570 |
| | $ | 210,853 |
| Carrying amount of the equity component(2) | $ | 74,892 |
| | $ | 66,007 |
| | $ | 74,892 |
| | $ | 66,007 |
|
| | (1) | Included in the condensed consolidated balance sheets within Convertible senior notes, net and amortized over the remaining lives of the Notes on a straight-line basis as it approximates the effective interest rate method. |
| | (2) | Included in the condensed consolidated balance sheets within Additional paid-in capital, net of $2 million and $2 million for the 2018 Notes and 2020 Notes, respectively, in equity issuance costs. |
|
| Schedule of Interest Expense Recognized Related to Convertible Senior Notes |
The following table sets forth total interest expense recognized related to the Notes (in thousands): | | | | | | | | | | | | | | | | | | Three Months Ended April 30, | | 2017 | | 2016 | | 2018
Notes | | 2020
Notes | | 2018
Notes | | 2020
Notes | Contractual interest expense | $ | 656 |
| | $ | 938 |
| | $ | 656 |
| | $ | 938 |
| Interest cost related to amortization of debt issuance costs | 352 |
| | 168 |
| | 352 |
| | 167 |
| Interest cost related to amortization of the debt discount | 4,044 |
| | 2,406 |
| | 3,819 |
| | 2,261 |
|
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