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Stock-Based Compensation (Tables)
 12 Months Ended
Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]  
Share-Based Payment Arrangement, Expensed and Capitalized, Amount The Company recorded stock-based compensation expense in the following expense categories in its accompanying consolidated statements of operations (in thousands):
Year Ended
December 31,
20232022
Research and development$897 $732 
General and administrative521 520 
Total expense$1,418 $1,252 
Share-Based Payment Arrangement, Option, Activity
The following table summarizes the option activity under the stock option plans:
Number
of
shares		Weighted
average
exercise price
per share		Weighted
average
remaining
contractual
term
(years)
Outstanding at December 31, 2022468,632 $13.23 7.37
Assumption of options in connection with the reverse merger215,207 $77.20 2.50
Granted183,391 $18.91 
Exercised(20,348)$8.24 
Expired/Forfeited(23,049)$20.34 
Outstanding at December 31, 2023823,833 $31.43 5.89
Exercisable at December 31, 2023527,053 $38.42 4.73
Share-Based Payment Arrangement, Option, Exercise Price Range
The following table summarizes information about the outstanding and exercisable options at December 31, 2023 (in thousands, except share and per share amounts):

Options OutstandingOptions Exercisable
Exercise Price RangeNumber OutstandingWeighted Average Remaining ContractualWeighted Average Exercise PriceIntrinsic ValueNumber ExercisableWeighted Average Remaining ContractualWeighted average Exercise PriceIntrinsic Value
$5.19 - $9.99
108,6005.12$5.86 $1,469 108,3155.12$5.86 $1,465 
$10.00 - $19.99
365,1126.95$15.06 $1,596 184,8715.37$13.42 $1,120 
$20.00 - $29.99
196,7237.14$22.43 $— 80,8177.41$22.88 $— 
$30.00 - $274.80
153,3982.27$100.05 $— 153,0502.26$99.86 $— 
Schedule of Share-Based Payment Award, Stock Options, Valuation Assumptions
The fair value of each option was estimated on the date of grant using the weighted average assumptions in the table below:
Year Ended
December 31,
20232022
Expected volatility
82.96%-83.70%
71.71%-74.01%
Risk-free interest rate
3.45%-4.46%
1.47%-4.22%
Expected life (in years)
3.58-6.08
5.87-6.09
Expected dividend yield- - 
Fair value of common stock$18.39 $20.24 
Share-Based Payment Arrangement, Restricted Stock and Restricted Stock Unit, Activity
The following table summarizes restricted Class A common stock activity:
Number of
shares		Weighted-
average
grant date fair
value
Unvested balance at December 31, 20226,691 $5.82 
Vested(6,691)$5.82 
Unvested balance at December 31, 2023— $—