Convertible Senior Notes - Schedule of Net Carrying Amount of the Equity Component of the Notes (Details) - USD ($) $ in Thousands |
Apr. 30, 2019 |
Jul. 31, 2018 |
|---|---|---|
| Debt Instrument [Line Items] | ||
| Debt discount for conversion option | $ 84,200 | |
| Convertible Debt | ||
| Debt Instrument [Line Items] | ||
| Issuance costs | (8,800) | |
| Convertible Senior Notes, Equity Component | Convertible Debt | ||
| Debt Instrument [Line Items] | ||
| Debt discount for conversion option | $ 84,168 | |
| Issuance costs | (2,485) | $ (2,500) |
| Net carrying amount | $ 81,683 |