Debt - Interest Expense (Details) - USD ($) $ in Thousands |
3 Months Ended | 9 Months Ended | |
|---|---|---|---|
Jan. 31, 2016 |
Jan. 31, 2016 |
Jan. 25, 2015 |
|
| Debt Instrument | |||
| Amortization of the debt discount | $ 7,156 | $ 6,819 | |
| Convertible Debt | 0.5% Convertible Senior Notes Due 2033 | |||
| Debt Instrument | |||
| Contractual interest expense | $ 324 | 972 | |
| Amortization of the debt discount | 2,411 | 7,156 | |
| Amortization of issuance costs | 154 | 462 | |
| Total interest cost | $ 2,889 | $ 8,590 | |
| Effective interest rate on the liability component | 4.87% | 4.87% | |