Annual report pursuant to Section 13 and 15(d)

Debt - Notes (Details)

v3.8.0.1
Debt - Notes (Details) - USD ($)
$ in Thousands
12 Months Ended
Feb. 01, 2017
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Debt Instrument [Roll Forward]        
Amortization of debt discount, debt issuance cost   $ 224 $ 237 $ 1,212
Change in fair value of derivative instruments   (52) (2,778) 39,083
Embedded conversion option, ending balance $ 13,600      
Senior Notes        
Debt Instrument [Roll Forward]        
Embedded conversion option, beginning balance   16,736 23,737  
Convertible notes, beginning balance   31,850 32,200  
Discount, beginning balance   (4,612) (6,525)  
Debt issuance costs, net beginning balance   (273) (426)  
Total, beginning balance   43,701 48,986  
Amortization of debt discount, discount   2,047 1,913  
Amortization of debt discount, debt issuance cost   148 153  
Amortization of debt discount and debt issuance costs   2,195 2,066  
Change in fair value of derivative instruments   (3,185) (7,001)  
Conversion     0  
2033 Senior Notes, conversion     (350)  
Discount, conversion     0  
Conversion of debt issuance cost     0  
Conversion total     (350)  
Embedded conversion option, conversion   (13,551)    
Embedded conversion option, ending balance   0 16,736 23,737
Convertible notes, ending balance   31,850 31,850 32,200
Discount, ending balance   (2,565) (4,612) (6,525)
Debt issuance costs, net ending balance   (125) (273) (426)
Total, ending balance   $ 29,160 $ 43,701 $ 48,986