Long-Term Debt - Extinguishment of Debt (Details) - USD ($)		1 Months Ended	3 Months Ended
	Sep. 12, 2016	Jul. 31, 2017	Sep. 30, 2018	Sep. 30, 2017
Line of Credit Facility [Line Items]
Debt extinguishment costs			$ 5,300,000
Senior Secured Credit Facility | Line of Credit
Line of Credit Facility [Line Items]
Aggregate principal amount	$ 100,000,000
Early payment transaction fee on retirement of Term Loan Facility		$ 51,600,000
Senior Secured Credit Facility, Initial Term Loan | Line of Credit
Line of Credit Facility [Line Items]
Amount outstanding	50,000,000
Senior Secured Credit Facility, Delayed Draw Term Loans | Line of Credit
Line of Credit Facility [Line Items]
Amount outstanding	$ 50,000,000
Monthly fee	2.75%
Loan servicing fee	$ 15,000
2019 Convertible Notes
Line of Credit Facility [Line Items]
Early payment transaction fee on retirement of Term Loan Facility		34,400,000
Write-off of debt discount and issuance costs on retirement		35,000,000		$ 35,000,000
Convertible Notes Hedges
Line of Credit Facility [Line Items]
Settlement of derivative, amounts received (paid)		600,000
Convertible Notes Warrants
Line of Credit Facility [Line Items]
Settlement of derivative, amounts received (paid)		(500,000)
Settlement of derivative		$ 2,200,000
LIBOR | Senior Secured Credit Facility | Line of Credit
Line of Credit Facility [Line Items]
Basis spread on variable rate	7.50%