Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements (Measurement Levels) (Details)

v3.22.1
Fair Value Measurements (Measurement Levels) (Details) - Warrants - Fair value, measurements, recurring - USD ($)
$ in Thousands
Mar. 31, 2022
Dec. 31, 2021
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Derivative liability $ 735 $ 801
Quoted Prices in Active Markets (Level 1)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Derivative liability 0 0
Significant Other Observable Inputs (Level 2)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Derivative liability 0 0
Significant Unobservable Inputs (Level 3)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Derivative liability 735 801
Warrant liability - Hale    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Derivative liability 644 685
Warrant liability - Hale | Quoted Prices in Active Markets (Level 1)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Derivative liability 0 0
Warrant liability - Hale | Significant Other Observable Inputs (Level 2)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Derivative liability 0 0
Warrant liability - Hale | Significant Unobservable Inputs (Level 3)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Derivative liability 644 685
Warrant liability - iStudy    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Derivative liability 91 116
Warrant liability - iStudy | Quoted Prices in Active Markets (Level 1)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Derivative liability 0 0
Warrant liability - iStudy | Significant Other Observable Inputs (Level 2)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Derivative liability 0 0
Warrant liability - iStudy | Significant Unobservable Inputs (Level 3)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Derivative liability $ 91 $ 116