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Stock Based Compensation (Details) - USD ($)
$ in Thousands
3 Months Ended
Mar. 31, 2022
Mar. 31, 2021
Share-based Compensation [Abstract]    
Vesting period 4 years  
Stock-based compensation expense $ 778 $ 879
General and Administrative Expense [Member]    
Share-based Compensation [Abstract]    
Stock-based compensation expense 466 383
Research and Development Expense [Member]    
Share-based Compensation [Abstract]    
Stock-based compensation expense 312 $ 496
Stock Options [Member]    
Share-based Compensation [Abstract]    
Unrecognized stock-based compensation expense expected to be recognized related to unvested stock options $ 4,865  
Weighted average amortization period 2 years 8 months 15 days  
Restricted Stock Units (RSUs) [Member]    
Share-based Compensation [Abstract]    
Unrecognized stock-based compensation expense expected to be recognized related to unvested RSUs $ 1,858  
Weighted average amortization period 2 years 1 month 17 days  
2013 Plan [Member]    
Share-based Compensation [Abstract]    
Shares available for grant (in shares) 2,240,296  
2013 Plan [Member] | Stock Options [Member]    
Share-based Compensation [Abstract]    
Vesting period 4 years  
Term of award 10 years  
2013 Plan [Member] | Incentive Stock Options [Member] | Minimum [Member]    
Share-based Compensation [Abstract]    
Exercise price of option granted as percentage of fair market value of shares at date of grant 100.00%  
2013 Plan [Member] | Incentive Stock Options [Member] | Named Executive Officers [Member] | Minimum [Member]    
Share-based Compensation [Abstract]    
Exercise price of option granted as percentage of fair market value of shares at date of grant 100.00%  
2013 Plan [Member] | Incentive Stock Options [Member] | 10% Shareholder [Member] | Minimum [Member]    
Share-based Compensation [Abstract]    
Exercise price of option granted as percentage of fair market value of shares at date of grant 110.00%  
2013 Plan [Member] | Nonqualified Stock Options [Member] | Minimum [Member]    
Share-based Compensation [Abstract]    
Exercise price of option granted as percentage of fair market value of shares at date of grant 85.00%  
2013 Plan [Member] | Nonqualified Stock Options [Member] | Named Executive Officers [Member] | Minimum [Member]    
Share-based Compensation [Abstract]    
Exercise price of option granted as percentage of fair market value of shares at date of grant 100.00%  
2013 Plan [Member] | Restricted Stock Units (RSUs) [Member]    
Share-based Compensation [Abstract]    
Vesting period 4 years