Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements - Summary of Financial Instruments Measured on a Recurring Basis (Details)

v3.10.0.1
Fair Value Measurements - Summary of Financial Instruments Measured on a Recurring Basis (Details) - Fair Value, Measurements, Recurring - USD ($)
$ in Thousands
Sep. 30, 2018
Dec. 31, 2017
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Fair value of financial assets $ 16,408 $ 11,469
Fair value of financial liabilities 5,242 3,872
Warrant liability    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Fair value of financial liabilities 5,242 3,872
Quoted Prices in Active Markets for Identical Assets (Level 1)    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Fair value of financial assets 16,408 11,469
Fair value of financial liabilities 0 0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Warrant liability    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Fair value of financial liabilities 0 0
Significant Other Observable Inputs (Level 2)    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Fair value of financial assets 0 0
Fair value of financial liabilities 0 0
Significant Other Observable Inputs (Level 2) | Warrant liability    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Fair value of financial liabilities 0 0
Significant Unobservable Inputs (Level 3)    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Fair value of financial assets 0 0
Fair value of financial liabilities 5,242 3,872
Significant Unobservable Inputs (Level 3) | Warrant liability    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Fair value of financial liabilities 5,242 3,872
Cash on deposit    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Fair value of financial assets   1,316
Cash on deposit | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Fair value of financial assets   1,316
Cash on deposit | Significant Other Observable Inputs (Level 2)    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Fair value of financial assets   0
Cash on deposit | Significant Unobservable Inputs (Level 3)    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Fair value of financial assets   0
Money market funds    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Fair value of financial assets 15,983 10,153
Money market funds | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Fair value of financial assets 15,983 10,153
Money market funds | Significant Other Observable Inputs (Level 2)    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Fair value of financial assets 0 0
Money market funds | Significant Unobservable Inputs (Level 3)    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Fair value of financial assets 0 $ 0
Cash    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Fair value of financial assets 97  
Cash | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Fair value of financial assets 97  
Cash | Significant Other Observable Inputs (Level 2)    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Fair value of financial assets 0  
Cash | Significant Unobservable Inputs (Level 3)    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Fair value of financial assets 0  
Restricted cash    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Fair value of financial assets 328  
Restricted cash | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Fair value of financial assets 328  
Restricted cash | Significant Other Observable Inputs (Level 2)    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Fair value of financial assets 0  
Restricted cash | Significant Unobservable Inputs (Level 3)    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Fair value of financial assets $ 0