Convertible Notes (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Convertible notes, long-term	$ 117,949	$ 115,089
1.125% Convertible Senior Notes due 2018
Debt Instrument [Line Items]
Principal amount of convertible notes	138,000
Convertible Senior Notes
Debt Instrument [Line Items]
Total convertible notes	117,949	115,089
Convertible notes, short-term	0	0
Convertible notes, long-term	$ 117,949	$ 115,089
Convertible Senior Notes \| 5% Convertible Senior Notes due 2014
Debt Instrument [Line Items]
Convertible notes stated interest rate (as a percent)	5.00%	5.00%
Convertible Senior Notes \| 1.125% Convertible Senior Notes due 2018
Debt Instrument [Line Items]
Convertible notes stated interest rate (as a percent)	1.125%	1.125%
Principal amount of convertible notes	$ 138,000	$ 138,000
Unamortized discount	(20,051)	(22,911)
Total convertible notes	$ 117,949	$ 115,089

Carrying value as of the balance sheet date of long-term debt (with maturities initially due after one year or beyond the operating cycle if longer) identified as Convertible Notes Payable, excluding current portion. Convertible Notes Payable is a written promise to pay a note which can be exchanged for a specified amount of another, related security, at the option of the issuer and the holder.

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- Definition

Including the current and noncurrent portions, carrying value as of the balance sheet date of a written promise to pay a note, initially due after one year or beyond the operating cycle if longer, which can be exchanged for a specified amount of one or more securities (typically common stock), at the option of the issuer or the holder.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

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Carrying value as of the balance sheet date of the portion of long-term debt due within one year or the operating cycle if longer identified as Convertible Notes Payable. Convertible Notes Payable is a written promise to pay a note which can be exchanged for a specified amount of another, related security, at the option of the issuer and the holder.

+ References

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Face (par) amount of debt instrument at time of issuance.

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- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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- Definition

The amount of debt discount that was originally recognized at the issuance of the instrument that has yet to be amortized.

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