Debt - Convertible Senior Notes - Liability and Equity Components (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Liability component
Principal	$ 447,234	$ 677,234
Debt discount and issuance costs, net	(66,232)	(77,872)
Convertible senior notes \| 2025 Notes
Liability component
Principal	192,500	$ 192,500
Debt discount and issuance costs, net	(63,460)
Net carrying amount	129,040
Equity component, net	$ 65,361

n/a

No definition available.

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- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

+ References

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-Publisher FASB
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- Definition

The carrying amount of the equity component of convertible debt which may be settled in cash upon conversion.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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- Definition

Amount of unamortized debt discount (premium) and debt issuance costs.

+ References

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- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
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-Subparagraph (b)(3)
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