| Net loss per share | 
 11. Net loss per share 
  
The following table sets forth the computation
of basic and diluted net loss per share (in thousands, except share and per share data): 
  
  
    |   | 
  | 
    Three Months Ended  June 30, | 
  | 
  | 
    Six Months Ended  June 30, | 
  | 
 
  
    |   | 
  | 
    2021 | 
  | 
  | 
    2022 | 
  | 
  | 
    2021 | 
  | 
  | 
    2022 | 
  | 
 
  
    | Numerator: | 
  | 
      | 
  | 
  | 
      | 
  | 
  | 
      | 
  | 
  | 
      | 
  | 
 
  
    | Net loss | 
  | 
    $ | 
(1,100 | 
) | 
  | 
    $ | 
(3,636 | 
) | 
  | 
    $ | 
(2,064 | 
) | 
  | 
    $ | 
(7,173 | 
) | 
 
  
    |   | 
  | 
      | 
  | 
  | 
  | 
      | 
  | 
  | 
  | 
      | 
  | 
  | 
  | 
      | 
  | 
  | 
 
  
    | Denominator: | 
  | 
      | 
  | 
  | 
  | 
      | 
  | 
  | 
  | 
      | 
  | 
  | 
  | 
      | 
  | 
  | 
 
  
    | Weighted-average shares outstanding used in computing net loss per share attributable to common stockholders, basic and diluted | 
  | 
      | 
8,771,290 | 
  | 
  | 
      | 
15,028,689 | 
  | 
  | 
      | 
8,677,497 | 
  | 
  | 
      | 
15,024,581 | 
  | 
 
  
    | Net loss per share attributable to common stockholders, basic and diluted | 
  | 
    $ | 
(0.13 | 
) | 
  | 
    $ | 
(0.24 | 
) | 
  | 
    $ | 
(0.24 | 
) | 
  | 
    $ | 
(0.48 | 
) | 
 
   
  
The following outstanding shares of potentially
dilutive securities were excluded from the computation of diluted net loss per share for the periods presented because including them
would have been antidilutive: 
  
  
    |   | 
  | 
    
 Three Months Ended  June 30, 
 | 
  | 
  | 
    
 Six Months Ended  June 30, 
 | 
  | 
 
  
    |   | 
  | 
    2021 | 
  | 
  | 
    2022 | 
  | 
  | 
    2021 | 
  | 
  | 
    2022 | 
  | 
 
  
    |   | 
  | 
      | 
  | 
  | 
      | 
  | 
  | 
      | 
  | 
  | 
      | 
  | 
 
  
    | Options to purchase common stock | 
  | 
      | 
660,921 | 
  | 
  | 
      | 
1,177,104 | 
  | 
  | 
      | 
660,921 | 
  | 
  | 
      | 
1,177,104 | 
  | 
 
  
    | Warrants to purchase common stock | 
  | 
      | 
-  | 
  | 
  | 
      | 
4,784,193 | 
  | 
  | 
      | 
-  | 
  | 
  | 
      | 
4,784,193 | 
  | 
 
  
    | Total | 
  | 
      | 
660,921 | 
  | 
  | 
      | 
5,961,297 | 
  | 
  | 
      | 
660,921 | 
  | 
  | 
      | 
5,961,297 | 
  | 
 
   
 |