Annual report pursuant to Section 13 and 15(d)

Basis of Presentation and Summary of Significant Accounting Policies - Fair Value, Level 3 Rollforward (Details)

v3.8.0.1
Basis of Presentation and Summary of Significant Accounting Policies - Fair Value, Level 3 Rollforward (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Liability Warrants      
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Change in value $ (400) $ (23,600) $ 11,900
Level 1 | Liability Warrants      
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Beginning balance 0 24,076  
Payments of earn-out liability 0 0  
Payments of earn-out liability   0  
Balance, December 31, 2017 0 0  
Transfer-out   (6,235)  
Change in value 0 (17,841)  
Ending balance   0 24,076
Level 2 | Liability Warrants      
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Beginning balance 433 0  
Payments of earn-out liability 0 0  
Payments of earn-out liability   0  
Balance, December 31, 2017 20 6,235  
Transfer-out   0  
Change in value (413) (5,802)  
Ending balance   433 0
Level 3 | Contingently Issuable Shares (Level 3)      
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Beginning balance 4,545 0  
Payments of earn-out liability 0 6,417  
Payments of earn-out liability   0  
Balance, December 31, 2017 1,448 0  
Transfer-out   0  
Change in value (3,097) (1,872)  
Ending balance   4,545 0
Level 3 | Earn-Out Liabilities (Level 3)      
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Beginning balance 1,987 9,652  
Payments of earn-out liability (1,937) 0  
Payments of earn-out liability   4,127  
Balance, December 31, 2017 114 0  
Transfer-out   0  
Change in value 64 (3,538)  
Ending balance $ 100 $ 1,987 $ 9,652