Debt (Details) - USD ($)			1 Months Ended		3 Months Ended
	Apr. 17, 2014	Aug. 01, 2011	Apr. 30, 2014	Feb. 28, 2013	Sep. 30, 2015	Sep. 30, 2014	Jun. 30, 2015
Debt
Principal amount of the Notes					$ 215,000,000
Carrying amount of the equity conversion component					31,033,000
Unamortized debt discount					(10,227,000)
Net carrying amount					204,773,000
Interest expense related to contractual interest coupon						$ 1,943,000
Interest expense related to amortization of debt discount						1,759,000
Interest expense related to amortization of debt issuance costs					$ 403,000	363,000
Total interest expense recognized						$ 4,065,000
3.75% Convertible Notes
Debt
Aggregate principal amount of debt issued		$ 100,000,000
Interest rate (as a percent)		3.75%			3.75%		3.75%
Principal amount of the Notes					$ 100,000,000
Proceeds from debt, net of costs		$ 96,100,000
Debt issuance costs, amortization period		5 years
Conversion rate, number of shares to be issued per $1000 of principal amount (in shares)					105.5548
Principal amount used for debt instrument conversion ratio					$ 1,000
Conversion price (in dollars per share)					$ 9.47
Number of consecutive trading days during which the closing price of the entity's common stock must exceed the conversion price for at least 20 days in order for the notes to be convertible into common stock					30 days
Number of consecutive business days immediately after any five consecutive trading day period during the note measurement period					5 days
Number of consecutive trading days before five consecutive business days during the note measurement period					5 days
Number of working days preceding maturity date for delivery of shares or payment of cash					33 days
Repurchase price, as percentage of principal amount, if company undergoes change of control					100.00%
Number of consecutive trading days during which the closing price of the entity's common stock must exceed the conversion price for at least 20 days in order for the notes to be redeemable					30 days
Discount rate on liability component (as a percent)		10.00%
Debt issuance costs and discount allocated to equity conversion component		$ 900,000
Carrying amount of the equity conversion component		24,100,000			$ 23,189,000
Unamortized debt discount					(4,866,000)
Net carrying amount		$ 75,900,000			$ 95,134,000
Amortization period		5 years
3.75% Convertible Notes | Minimum
Debt
Number of days within 30 consecutive trading days in which the closing price of the entity's common stock must exceed the conversion price for the notes to be convertible into common stock					20 days
Percentage of the closing sales price of the entity's common stock that the conversion price must exceed in order for the notes to be convertible					130.00%
Percentage of the closing sales price of the entity's common stock that the conversion price must exceed in order for the notes to be redeemable					130.00%
Number of days within 30 consecutive trading days in which the closing price of the entity's common stock must exceed the conversion price for the notes to be redeemable					20 days
3.75% Convertible Notes | Maximum
Debt
Percentage of the trading price to the product of the sale price of the entity's common stock and the conversion rate					98.00%
3.50% Convertible Notes
Debt
Aggregate principal amount of debt issued				$ 115,000,000
Interest rate (as a percent)				3.50%	3.50%		3.50%
Principal amount of the Notes					$ 44,654,000
Proceeds from debt, net of costs				$ 110,500,000
Debt issuance costs, amortization period				5 years
Conversion rate, number of shares to be issued per $1000 of principal amount (in shares)					187.6877
Conversion rate, amount of debt to be issued per $1000 of principal amount	$ 1,000
Principal amount used for debt instrument conversion ratio					$ 1,000
Conversion price (in dollars per share)					$ 5.33
Repurchase price, as percentage of principal amount, if company undergoes change of control					100.00%
Net carrying amount					$ 44,654,000
Aggregate principal amount of debt refinanced			$ 70,300,000
3.50% Series A Convertible Notes
Debt
Aggregate principal amount of debt issued	$ 70,300,000
Interest rate (as a percent)	3.50%				3.50%		3.50%
Principal amount of the Notes					$ 70,346,000
Conversion rate, number of shares to be issued per $1000 of principal amount (in shares)					187.6877
Conversion rate, amount of debt to be issued per $1000 of principal amount					$ 1,000
Conversion price (in dollars per share)					$ 5.33
Number of days within 30 consecutive trading days in which the closing price of the entity's common stock must exceed the conversion price for the notes to be convertible into common stock					20 days
Number of consecutive trading days during which the closing price of the entity's common stock must exceed the conversion price for at least 20 days in order for the notes to be convertible into common stock					30 days
Percentage of the closing sales price of the entity's common stock that the conversion price must exceed in order for the notes to be convertible					130.00%
Number of consecutive business days immediately after any five consecutive trading day period during the note measurement period					5 days
Number of consecutive trading days before five consecutive business days during the note measurement period					5 days
Percentage of the trading price to the product of the sale price of the entity's common stock and the conversion rate					98.00%
Number of working days preceding maturity date for delivery of shares or payment of cash					17 days
Discount rate on liability component (as a percent)					7.00%
Carrying amount of the equity conversion component					$ 7,844,000
Unamortized debt discount					(5,361,000)
Net carrying amount					64,985,000
Interest expense related to contractual interest coupon					1,945,000
Interest expense related to amortization of debt discount					1,920,000
Interest expense related to amortization of debt issuance costs					403,000
Total interest expense recognized					4,268,000
Payment to the convertible note holders to modify the notes	$ (400,000)
Portion of cash amount paid allocated to debt discount					400,000
Portion of cash amount paid allocated to equity component					$ 47,000,000
Repurchase price, as a percentage of the principal amount, in the event of a fundamental change, as defined in Indenture					100.00%