Quarterly report pursuant to Section 13 or 15(d)

Stock-based Compensation, Weighted Average Assumptions Used in Black-Scholes Option-pricing Model (Details)

v3.22.1
Stock-based Compensation, Weighted Average Assumptions Used in Black-Scholes Option-pricing Model (Details) - USD ($)
$ / shares in Units, $ in Thousands
3 Months Ended
Mar. 31, 2022
Mar. 31, 2021
2018 Equity Incentive Plan [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Abstract]    
Common stock available for future issuance (in shares) 0  
2020 Plan Evergreen Provision [Member]    
Weighted-average Assumptions Used in Black-Scholes Option-pricing Model [Abstract]    
Expected stock price volatility 99.60% 86.60%
Expected life of options 6 years 5 years 7 months 6 days
Expected dividend yield 0.00% 0.00%
Risk free interest rate 1.70% 0.80%
Share-based Compensation Arrangement by Share-based Payment Award [Abstract]    
Stock options vested (in shares) 62,698 118,217
Weighted average fair value per share of options vesting (in dollars per share) $ 2.90 $ 3.66
Exercise of stock options (in shares) 24,309 7,386
Aggregate intrinsic value $ 59 $ 74
Stock options forfeited (in shares) 8,288 0
Common stock available for future issuance (in shares) 1,280,792  
Unrecognized stock-based compensation cost $ 3,300  
Weighted average period to recognized stock-based compensation 1 year 6 months  
Inducement Plan [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Abstract]    
Common stock available for future issuance (in shares) 1,280,792