Annual report pursuant to Section 13 and 15(d)

Fair Value Measurement - Schedule of Fair Value Hierarchies for Financial Assets and Liabilities on Recurring Basis (Details)

v3.20.4
Fair Value Measurement - Schedule of Fair Value Hierarchies for Financial Assets and Liabilities on Recurring Basis (Details) - USD ($)
$ in Thousands
Dec. 31, 2020
Dec. 31, 2019
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Warrant liabilities $ 6,037 $ 4,307
Recurring    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Warrant liabilities 6,037 4,307
Contingent success fee liability   6
Level 1 | Recurring    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Warrant liabilities 0 0
Contingent success fee liability   0
Level 2 | Recurring    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Warrant liabilities 0 0
Contingent success fee liability   0
Level 3 | Recurring    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Warrant liabilities $ 6,037 4,307
Contingent success fee liability   $ 6