Convertible Subordinated Notes (Tables)
 6 Months Ended
Jun. 30, 2018
Convertible Subordinated Notes [Abstract]  
Schedule of Liability and Equity Components of Convertible Subordinated Notes
The carrying values of the liability and equity components of the Convertible Notes at December 31, 2017 and June 30, 2018 are reflected in our Consolidated Balance Sheets as follows (in thousands):
 
December 31, 2017
 
June 30, 2018
Long-term liabilities:
 
 
 
Principal amount
$
143,750

 
$
28,764

Unamortized discount of liability component
(17,559
)
 
(3,042
)
Convertible Notes issuance costs, net of accumulated amortization of $1,877 and $429, respectively
(1,750
)
 
(297
)
Carrying value of the liability component
$
124,441

 
$
25,425

 
 
 
 
Carrying value of the equity component
$
17,973

 
$
3,585