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Convertible Senior Notes (Tables) | 9 Months Ended
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Sep. 30, 2019
Debt Disclosure [Abstract] |
Convertible Debt | ​
​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | September 30, | ​ | December 31,
​ |  | 2019 |  | 2018
​ | ​ | (In thousands)
Principal amount | ​ | $ | 210,000 | ​ | $ | 210,000
Unamortized discount | ​ |  | (49,907) | ​ |  | (56,156)
Unamortized issuance costs attributable to principal amount | ​ |  | (4,322) | ​ |  | (4,863)
Total Convertible Notes, net | ​ | $ | 155,771 | ​ | $ | 148,981
​

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- Definition Tabular disclosure of borrowings which can be exchanged for a specified number of another security at the option of the issuer or the holder. Disclosures include, but are not limited to, principal amount, amortized premium or discount, and amount of liability and equity components. + References No definition available. + Details
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- References No definition available. + Details
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