Annual report pursuant to Section 13 and 15(d)

Summary of Significant Accounting Policies - Fair Value Measurements (Details)

v3.8.0.1
Summary of Significant Accounting Policies - Fair Value Measurements (Details) - Significant Other Unobservable Inputs (Level 3)
$ in Thousands
12 Months Ended
Dec. 31, 2017
USD ($)
Warrant Liability – Current  
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]  
Beginning balance $ 0
Issuances of warrants 2,453
Reclass of liability from long-term to current 1,846
Change in fair value - net 2,643
Transfer in and out (exercise of warrants) (5,201)
Expiration of warrants (1,238)
Ending balance 503
Warrant Liability – Long-Term  
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]  
Beginning balance 0
Issuances of warrants 1,690
Reclass of liability from long-term to current (1,846)
Change in fair value - net (95)
Transfer in and out (exercise of warrants) 251
Expiration of warrants 0
Ending balance 0
Warrant Liability – Total  
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]  
Beginning balance 0
Issuances of warrants 4,143
Reclass of liability from long-term to current 0
Change in fair value - net 2,548
Transfer in and out (exercise of warrants) (4,950)
Expiration of warrants (1,238)
Ending balance $ 503