Convertible 3.75% Senior Notes (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Debt issuance costs	$ 3,200	$ 4,000
Convertible Notes Payable
Debt Instrument [Line Items]
Face amount of the Notes	143,750	143,750
Unamortized discount	29,160	36,759
Debt issuance costs	3,199	4,027
Carrying amount of the Notes	$ 111,391	$ 102,964

Including the current and noncurrent portions, carrying amount of debt identified as being convertible into another form of financial instrument (typically the entity's common stock) as of the balance sheet date, which originally required full repayment more than twelve months after issuance or greater than the normal operating cycle of the company.

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-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 210
-Section S99
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-Subparagraph (SX 210.9-03(16))
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