Stock-Based Compensation (Tables)
12 Months Ended
Dec. 31, 2021
Schedule of expenses relating to employee and non-employee stock-based awards

The Company’s results of operations include expenses relating to stock-based awards as follows (in thousands):

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Year Ended December 31, 

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2021

    

2020

    

2019

Research and development

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$

2,161

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$

2,791

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$

3,103

General and administrative

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2,071

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2,956

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4,245

Total

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$

4,232

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$

5,747

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$

7,348

Employee stock options  
Schedule of fair value of share-based awards to employees was estimated using Black Scholes model

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Year Ended December 31, 

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2021

    

2020

    

2019

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Risk-free interest rate

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0.9

%  

0.5

%  

1.9

%

Expected volatility

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86.7

%  

82.7

%  

82.1

%

Expected term (in years)

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6.0

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6.0

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6.0

 

Expected dividend yield

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0

%  

0

%  

0

%