Convertible Senior Notes - Additional Information (Details)
|
2 Months Ended |
3 Months Ended |
|
|
Jul. 31, 2018
USD ($)
day
$ / shares
|
Apr. 30, 2019
USD ($)
day
$ / shares
|
Jun. 30, 2018
USD ($)
|
| Debt Instrument [Line Items] |
|
|
|
| Proceeds from borrowings on convertible senior notes, net of issuance costs |
$ 291,100,000
|
|
|
| Convertible debt, conversion ratio |
14.6738
|
|
|
| Convertible debt, conversion ratio denominator |
$ 1,000
|
|
|
| Initial conversion price (in dollars per share) | $ / shares |
$ 68.15
|
$ 68.15
|
|
| Consecutive threshold trading days | day |
30
|
30
|
|
| Threshold percentage of stock price trigger |
130.00%
|
130.00%
|
|
| Carrying amount of convertible debt equity component |
$ 84,200,000
|
|
|
| Fair value of convertible debt |
|
$ 630,800,000
|
|
| Minimum |
|
|
|
| Debt Instrument [Line Items] |
|
|
|
| Threshold trading days | day |
20
|
20
|
|
| Redemption Period 1 |
|
|
|
| Debt Instrument [Line Items] |
|
|
|
| Consecutive threshold trading days | day |
30
|
|
|
| Threshold percentage of stock price trigger |
130.00%
|
|
|
| Redemption Period 1 | Minimum |
|
|
|
| Debt Instrument [Line Items] |
|
|
|
| Threshold trading days | day |
20
|
|
|
| Redemption Period 2 |
|
|
|
| Debt Instrument [Line Items] |
|
|
|
| Convertible debt, conversion ratio denominator |
$ 1,000
|
|
|
| Threshold trading days | day |
5
|
|
|
| Consecutive threshold trading days | day |
5
|
|
|
| Redemption Period 2 | Maximum |
|
|
|
| Debt Instrument [Line Items] |
|
|
|
| Trading price as a percentage of stock price and debt conversion rate |
98.00%
|
|
|
| Convertible Debt |
|
|
|
| Debt Instrument [Line Items] |
|
|
|
| Face amount of debt |
$ 50,000,000
|
|
$ 250,000,000
|
| Interest rate |
0.75%
|
|
0.75%
|
| Convertible debt, conversion ratio denominator |
|
$ 100
|
|
| Percentage of principal amount redeemed |
100.00%
|
|
|
| Debt issuance costs |
$ 8,800,000
|
|
|
| Effective interest rate |
7.03%
|
|
|
| Convertible Debt | Convertible Senior Notes, Liability Component |
|
|
|
| Debt Instrument [Line Items] |
|
|
|
| Debt issuance costs |
$ 6,300,000
|
5,743,000
|
|
| Convertible Debt | Convertible Senior Notes, Equity Component |
|
|
|
| Debt Instrument [Line Items] |
|
|
|
| Carrying amount of convertible debt equity component |
|
84,168,000
|
|
| Debt issuance costs |
$ 2,500,000
|
$ 2,485,000
|
|