Annual report pursuant to Section 13 and 15(d)

Derivative Contracts - Fair Value and Presentation (Details)

v3.8.0.1
Derivative Contracts - Fair Value and Presentation (Details) - Not Designated as Hedging Instrument - USD ($)
$ in Thousands
Dec. 31, 2017
Dec. 31, 2016
Common stock options/warrants | Investments, net    
Derivatives, Fair Value [Line Items]    
Derivative asset, fair value $ 3,333 $ 4,017
Embedded conversion option | 2033 Senior Notes, net of discount    
Derivatives, Fair Value [Line Items]    
Derivative liability, fair value 0 16,736
Forward contracts | Unrealized gains on forward contracts are recorded in Other current assets and prepaid expenses. Unrealized (losses) on forward contracts are recorded in Accrued expenses.    
Derivatives, Fair Value [Line Items]    
Derivative liability, fair value $ (317) $ 39