v3.26.1
Note 3 - Fair Value Measurements (Tables)
12 Months Ended
Dec. 31, 2025
Notes Tables  
Fair Value, Assets Measured on Recurring Basis [Table Text Block]
           

Fair Value Measurements Using

 
           

Quoted

                 
           

Prices in

                 
           

Active

                 
           

Markets

   

Significant

         
           

for

   

Other

   

Significant

 
   

As of

   

Identical

   

Observable

   

Unobservable

 
   

December

   

Items

   

Inputs

   

Inputs

 
   

31, 2025

   

(Level 1)

   

(Level 2)

   

(Level 3)

 

Assets

                               

Restricted cash held as a certificate of deposit

  $ 267     $ 267     $     $  
                                 

Liabilities

                               

Warrant liability

  $ 30,432     $     $ 30,432     $  
           

Fair Value Measurements Using

 
           

Quoted

                 
           

Prices in

                 
           

Active

                 
           

Markets

   

Significant

         
           

for

   

Other

   

Significant

 
   

As of

   

Identical

   

Observable

   

Unobservable

 
   

December

   

Items

   

Inputs

   

Inputs

 
   

31, 2024

   

(Level 1)

   

(Level 2)

   

(Level 3)

 

Assets

                               

Restricted cash held as a certificate of deposit

  $ 477     $ 477     $     $  
Fair Value Measurement Inputs and Valuation Techniques [Table Text Block]
   

December

2023

Warrants

 

Measurement event

 

Stockholder Approval

 
         

Date

 

May 28, 2024

 

Total Value (in millions)

  $ 0.2  

Gain (Loss) (in thousands)

  $ (51 )
         

Assumptions:

       

Exercise price

  $ 43.75  

Market price

  $ 24.70  

Volatility

    83.9 %

Risk-free rate

    4.56 %

Dividend yield

    0.0 %

Term (years)

    5.1  
   

March

   

March

 
   

2024

   

2024

 
   

Warrant

   

Warrant

 

Measurement event

 

Reporting Date

   

Stockholder Approval

 

Date

 

March 31, 2024

   

May 28, 2024

 

Total Value (in millions)

  $ 0.1     $ 0.1  

Gain (Loss) (in thousands)

  $ 21     $ 28  
                 

Assumptions:

               

Exercise price

  $ 24.50     $ 24.50  

Market price

  $ 18.30     $ 24.70  

Volatility

    86.9 %     83.9 %

Risk-free rate

    4.21 %     4.56 %

Dividend yield

    0.0 %     0.0 %

Term (years)

    5.5       5.3  
   

September 2022, November 2022,

and May 2023 Warrants

 

Measurement event

 

Prior to amendment

   

After amendment

 

Date

 

June 14, 2024

   

June 14, 2024

 

Total Value (in thousands)

 

$66

   

$100

 

Loss (in thousands)

 

not applicable

   

$70

 
                 

Assumptions:

               

Exercise price

 

$

43.75

- 262.50    

$

12.50

 

Market price

 

$

12.55

   

$

12.55

 

Volatility

   

89.3

%

   

89.3

%

Risk-free rate

   

4.27

-

5.08

%

   

4.27

-

5.08

%

Dividend yield

   

0.0

%

   

0.0

%

Term (years)

   

1.0

-

4.4

     

1.0

-

4.4

%

   

Series F-1

 

Measurement event

 

Prior to adjustment

   

After adjustment

 
                 

Date

 

September 27, 2024

   

September 27, 2024

 

Total value (in millions)

  $ 1.7     $ 1.9  

Deemed dividend (in millions)

 

not applicable

    $ 0.2  
                 

Assumptions:

               

Exercise price

  $ 5.50     $ 3.30  

Market price

  $ 3.55     $ 3.55  

Volatility

    97.1 %     97.1 %

Risk-free rate

    3.55 %     3.55 %

Dividend yield

    0.0 %     0.0 %

Term (in years)

    4.84       4.84  
   

Series F-2

 

Measurement event

 

Prior to adjustment

   

After adjustment

 
                 

Date

 

September 27, 2024

   

September 27, 2024

 

Total value (in millions)

  $ 0.2     $ 0.6  

Deemed dividend (in millions)

 

not applicable

    $ 0.4  
                 

Assumptions:

               

Exercise price

  $ 5.50     $ 3.30  

Market price

  $ 3.55     $ 3.55  

Volatility

    97.1 %     97.1 %

Risk-free rate

    4.64 %     4.64 %

Dividend yield

    0.0 %     0.0 %

Term (in years)

    0.34       0.34  
   

Series F-3

 

Measurement event

 

Prior to adjustment

   

After adjustment

 
                 

Date

 

September 27, 2024

   

September 27, 2024

 

Total value (in millions)

  $ 0.6     $ 1.0  

Deemed dividend (in millions)

 

not applicable

      0.4  
                 

Assumptions:

               

Exercise price

  $ 5.50     $ 3.30  

Market price

  $ 3.55     $ 3.55  

Volatility

    97.1 %     97.1 %

Risk-free rate

    4.10 %     4.10 %

Dividend yield

    0.0 %     0.0 %

Term (in years)

    0.84       0.84  
   

Series C Preferred Stock

 

Measurement event

 

Prior to ratchet

   

After ratchet

 

Date

 

March 24, 2024

   

March 24, 2024

 

Total value (a) (in millions)

  $ 0.5     $ 0.9  

Deemed dividend (in millions)

 

not applicable

    $ 0.4  
                 

Assumptions:

               

Exercise price

  $ 43.75     $ 24.50  

Market price

  $ 23.85     $ 23.85  

Volatility

    79.9 %     79.9 %

Risk-free rate

    5.51 %     5.51 %

Dividend yield

    0.0 %     0.0 %

Term (in years)

    0.1       0.1  
   

Unsecured

Convertible

Notes

derivative

   

Unsecured

Convertible

Notes

derivative

 

Measurement event

 

Issuance

   

Shareholder Approval

 

Date

 

March 25, 2024

   

May 28, 2024

 

Total value (in millions)

  $ 0.2     $ 0.2  

Gain (Loss) (in thousands)

 

not applicable

    $ (82 )
                 

Assumptions:

               

Exercise price

  $ 24.50     $ 24.50  

Market price

  $ 22.55     $ 24.70  

Volatility

    86.9 %     83.9 %

Risk-free rate

    4.54 %     4.94 %

Dividend yield

    0.0 %     0.0 %

Term (years)

    2.0       1.8