v3.24.1.1.u2
Equity-Based Compensation (Tables)
 12 Months Ended
Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]  
Schedule of Equity-Based Compensation Expense Classification in Statement of Operations
Equity-based compensation expense is classified in the statements of operations as follows:
Year Ended December 31,
20232022
Research and development expense$154 $507 
General and administrative expense1,194 862 
$1,348 $1,369 
Schedule of Assumptions Used to Determine Fair Value of Common Stock Option Grants In addition to an assumption on the expected term of the option grants as discussed below, application of the Black-Scholes model requires additional inputs for which we have assumed the values described in the table below:
Year Ended
December 31,
20232022
Expected term
5.8 to 5.8 years
5.3 to 6.1 years
Risk-free interest rate
3.83% to 3.83%; weighted avg. 3.83%
2.86% to 3.56%; weighted avg. 2.90%
Expected volatility
100.9% to 100.9%; weighted avg. 100.9%
95.2% to 95.8%; weighted avg. 95.2%
Forfeiture rate5 %5 %
Expected dividend yield— %— %
The fair value of the underlying common stock and the exercise price for the common stock options granted during the years ended December 31, 2023 and 2022 are summarized in the table below:
Common Stock Options Granted During Period Ended:Fair Value of Underlying Common StockExercise Price of Common Stock Option
Year ended December 31, 2023
$1.58;
weighted avg. $1.58
$1.58;
weighted avg. $1.58
Year ended December 31, 2022
$3.46 to $5.51; weighted avg. $4.56
$3.46 to $5.51; weighted avg. $4.56
Schedule of Common Stock Option Activity
A summary of common stock option activity as of the periods indicated is as follows:
Options
Weighted-Average Exercise Price (1)
Weighted-Average Remaining Contractual Term (years)Aggregate Intrinsic Value (thousands)
Outstanding - December 31, 2021331,420 $61.82 7.0$— 
Granted232,028 4.56 
Settled(124)5.51 
Forfeited(340,491)60.18 
Outstanding - December 31, 2022222,833 $4.74 7.5$— 
Granted10,000 1.58 
Settled— — 
Forfeited(220,718)5.40 
Outstanding - December 31, 202312,115 $4.28 5.4$— 
Exercisable - December 31, 202312,115 $4.26 5.4$— 
Vested and Expected to Vest -
December 31, 2023		12,115 $4.28 5.4$— 
(1)    On March 24, 2022, the Company’s Board of Directors unanimously approved the repricing of all outstanding and unexercised stock options granted under our 2015 Equity Incentive Plan and 2017 Equity Incentive Plan and held by its current employees, executive officers, and directors. Effective April 1, 2022, the exercise price of the eligible stock options was reduced to $5.51, the closing price of our common stock on April 1, 2022. See below section titled “Repricing of Outstanding and Unexercised Options” for more information.
Schedule of Restricted Stock Unit Awards Activity
A summary of restricted stock unit activity of the periods indicated is as follows:
Restricted Stock UnitsWeighted-Average Grant Date Fair Value
Unvested balance - December 31, 202110,109 $50.04 
Granted51,536 3.42 
Vested(5,535)22.04 
Forfeited(35,225)4.75 
Unvested balance - December 31, 202220,885 $12.65 
Granted295,992 1.02 
Vested(309,026)1.91 
Forfeited(4,808)14.58 
Unvested balance - December 31, 20233,043 $10.41 
Schedule of Performance-based Restricted Stock Unit Activity
A summary of performance-based restricted stock unit activity of the periods indicated is as follows:
Restricted Stock UnitsWeighted-Average Grant Date Fair Value
Unvested balance - December 31, 2021— $— 
Granted97,643 3.45 
Unvested balance - December 31, 202297,643 $3.45 
Granted— — 
Settled(97,643)1.91 
Unvested balance - December 31, 2023— $—