Stockholders' Equity (Tables)
|
12 Months Ended |
Dec. 31, 2022 |
|---|
| Stockholders' Equity |
|
| Summary of restricted stock award activity |
Certain employees, directors and consultants have been awarded restricted stock. The restricted stock vesting consists of milestone and time-based vesting. The following table summarizes restricted stock award activity for the year ended December 31, 2022 and 2021:
|
|
|
|
|
|
|
|
|
|
Weighted Average |
|
|
|
|
Grant Date Fair |
|
|
Number of Shares |
|
Value |
Nonvested at December 31, 2020 |
|
386,982 |
|
$ |
36.09 |
Granted |
|
122,900 |
|
|
28.61 |
Forfeited |
|
(1,566) |
|
|
22.43 |
Vested |
|
(57,050) |
|
|
41.02 |
Nonvested at December 31, 2021 |
|
451,266 |
|
$ |
33.48 |
Granted |
|
159,416 |
|
|
20.00 |
Forfeited |
|
(15,850) |
|
|
30.19 |
Vested |
|
(215,935) |
|
|
36.63 |
Non-vested at December 31, 2022 |
|
378,897 |
|
$ |
26.15 |
|
| Summary of restricted stock units activity |
Certain employees have been awarded restricted stock units. The following table summarizes restricted stock units activity for the year ended December 31, 2022:
|
|
|
|
|
|
|
|
|
|
Weighted Average |
|
|
Number of |
|
Grant Date Fair |
|
|
Shares |
|
Value |
Non-vested at December 31, 2020 |
|
— |
|
$ |
— |
Non-vested at December 31, 2021 |
|
— |
|
|
— |
Granted |
|
85,000 |
|
|
10.50 |
Non-vested at December 31, 2022 |
|
85,000 |
|
$ |
10.50 |
|
| Summary of stock option award activity |
The following table summarizes stock option award activity for the year ended December 31, 2022 and 2021:
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Weighted Average |
|
|
|
|
|
|
|
Remaining |
|
|
|
|
Weighted Average |
|
Contractual Life |
|
|
Stock Options |
|
Exercise Price |
|
(in years) |
Outstanding as of December 31, 2020 |
|
22,000 |
|
$ |
32.00 |
|
8.04 |
Granted |
|
5,000 |
|
|
28.50 |
|
|
Outstanding as of December 31, 2021 |
|
27,000 |
|
$ |
31.35 |
|
7.44 |
Granted |
|
4,000 |
|
|
14.20 |
|
|
Forfeited |
|
(4,000) |
|
|
14.20 |
|
|
Outstanding as of December 31, 2022 |
|
27,000 |
|
$ |
31.35 |
|
6.44 |
Vested and exercisable as of December 31, 2022 |
|
15,500 |
|
$ |
23.06 |
|
6.89 |
|
| Summary of stock options assumptions used |
The Company used the Black-Scholes Model for determining the estimated fair value of stock-based compensation related to stock options. The table below summarizes the assumptions used:
|
|
|
|
|
|
|
|
For the Years Ended December 31, |
|
|
|
2022 |
|
2021 |
|
Risk-free interest rate |
|
2.85 |
% |
1.04% - 1.50 |
% |
Expected dividend yield |
|
— |
|
— |
|
Expected term in years |
|
10.0 |
|
10.0 |
|
Expected volatility |
|
73.07 |
% |
100.65% - 102.71 |
% |
|
| Summary of warrant activities |
A summary of warrant activities for year ended December 31, 2022 and 2021 is presented below:
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Weighted Average |
|
|
|
|
|
|
|
Remaining |
|
|
|
|
Weighted Average |
|
Contractual Life |
|
|
Warrants |
|
Exercise Price |
|
(in years) |
Outstanding as of December 31, 2020 |
|
5,751 |
|
$ |
53.80 |
|
1.22 |
Exercised |
|
(70) |
|
|
— |
|
|
Expired |
|
(4,432) |
|
|
70.00 |
|
|
Outstanding as of December 31, 2021 |
|
1,249 |
|
$ |
— |
|
3.83 |
Granted |
|
4,356,361 |
|
|
3.37 |
|
|
Fractional share adjustment |
|
(13) |
|
|
— |
|
|
Outstanding as of December 31, 2022 |
|
4,357,597 |
|
$ |
3.37 |
|
3.26 |
|
| Summary of stock-based compensation expense |
The following table summarizes stock-based compensation expense for the years ended December 31, 2022 and 2021 (in thousands).
|
|
|
|
|
|
|
|
|
For the year ended December 31, |
|
|
2022 |
|
2021 |
Research and development |
|
$ |
888 |
|
$ |
684 |
General and administrative |
|
|
2,036 |
|
|
2,453 |
Total stock-based compensation expense |
|
$ |
2,924 |
|
$ |
3,137 |
|