Common Stock (Tables)
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12 Months Ended |
Dec. 31, 2023 |
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| Equity [Abstract] |
|
| Summary of Fair Value of Option Awards |
The estimated fair value of stock options granted in the respective periods was determined using the Black-Scholes option pricing model using the following weighted average assumptions:
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|
2023 |
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|
2022 |
|
|
Risk-free interest rates |
|
|
3.60 |
% |
|
|
1.65 |
% |
|
Expected dividend yield |
|
|
0 |
% |
|
|
0 |
% |
|
Expected life |
|
5.75 years |
|
|
5.80 years |
|
|
Expected volatility |
|
|
115.19 |
% |
|
|
122.80 |
% |
|
Forfeiture rate |
|
|
0 |
% |
|
|
0 |
% |
|
|
| Summary of Share-Based Compensation Expense |
The results for the periods set forth below included stock-based compensation expense in the following expense categories of the consolidated statements of loss (in thousands):
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Year ended |
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|
|
December 31, |
|
|
|
2023 |
|
|
2022 |
|
Research and development |
|
$ |
1,122 |
|
|
$ |
1,117 |
|
General and administrative |
|
|
2,317 |
|
|
|
2,153 |
|
Total stock-based compensation |
|
$ |
3,439 |
|
|
$ |
3,270 |
|
|
| Summary of Stock Options Activity |
Stock option transactions and the number of stock options outstanding are summarized below:
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|
Number of |
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Weighted |
|
|
|
Optioned |
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Average |
|
|
|
Common |
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|
Exercise |
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|
|
Shares |
|
|
Price |
|
Balance, January 1, 2023 |
|
|
822,515 |
|
|
$ |
18.57 |
|
Granted |
|
|
639,500 |
|
|
|
5.23 |
|
Expired |
|
|
(35 |
) |
|
|
25,555.20 |
|
Balance, December 31, 2023 |
|
|
1,461,980 |
|
|
$ |
12.12 |
|
|
| Summary of Stock Options Outstanding Regarding Number of Common Shares Issuable upon Exercise of Outstanding Options |
(1) Number of common shares issuable upon exercise of outstanding options:
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Weighted- |
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Average |
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|
|
|
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|
Remaining |
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|
Weighted- |
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|
Contractual |
|
|
|
|
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Average |
|
|
Life |
|
Exercise Prices |
|
Number of Options |
|
|
Exercise Price |
|
|
(in years) |
|
$4.53 - $4.72 |
|
|
25,000 |
|
|
$ |
4.53 |
|
|
|
9.20 |
|
$4.73 - $4.99 |
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|
409,750 |
|
|
|
4.90 |
|
|
|
9.07 |
|
$5.00 - $5.99 |
|
|
156,750 |
|
|
|
5.88 |
|
|
|
9.17 |
|
$6.00 - $7.22 |
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|
122,200 |
|
|
|
6.42 |
|
|
|
8.78 |
|
$7.23 - $7.89 |
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|
45,000 |
|
|
|
7.38 |
|
|
|
7.82 |
|
$7.90 - $8.43 |
|
|
226,250 |
|
|
|
8.26 |
|
|
|
8.01 |
|
$8.44 - $10.78 |
|
|
114,750 |
|
|
|
10.23 |
|
|
|
6.90 |
|
$10.79 - $12.60 |
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|
80,530 |
|
|
|
11.26 |
|
|
|
6.16 |
|
$12.61 - $20.74 |
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|
232,750 |
|
|
|
13.09 |
|
|
|
7.07 |
|
$20.75 - $25,938.00 |
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|
49,000 |
|
|
|
134.00 |
|
|
|
4.70 |
|
|
|
|
1,461,980 |
|
|
$ |
12.12 |
|
|
|
8.06 |
|
|
| Summary of Stock Options Outstanding Regarding Number of Common Shares Issuable upon Exercise of Vested Options |
(2) Number common shares issuable upon exercise of vested options:
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|
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|
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Weighted- |
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|
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|
|
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|
Average |
|
|
|
|
|
|
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|
Remaining |
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|
|
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|
Weighted- |
|
|
Contractual |
|
|
|
|
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Average |
|
|
Life |
|
Exercise Prices |
|
Number of Options |
|
|
Exercise Price |
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|
(in years) |
|
$4.53 - $4.72 |
|
|
— |
|
|
|
— |
|
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|
— |
|
$4.73 - $4.99 |
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|
— |
|
|
|
— |
|
|
|
— |
|
$5.00 - $5.99 |
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|
41,064 |
|
|
|
5.85 |
|
|
|
9.14 |
|
$6.00 - $7.22 |
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|
39,263 |
|
|
|
6.88 |
|
|
|
8.14 |
|
$7.23 - $7.89 |
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|
24,270 |
|
|
|
7.38 |
|
|
|
7.80 |
|
$7.90 - $8.43 |
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|
144,549 |
|
|
|
8.26 |
|
|
|
8.01 |
|
$8.44 - $10.78 |
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|
114,750 |
|
|
|
10.23 |
|
|
|
6.90 |
|
$10.79 - $12.60 |
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|
78,507 |
|
|
|
11.26 |
|
|
|
6.15 |
|
$12.61 - $20.74 |
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|
169,715 |
|
|
|
13.09 |
|
|
|
7.07 |
|
$20.75 - $25,938.00 |
|
|
49,000 |
|
|
|
134.00 |
|
|
|
4.70 |
|
|
|
|
661,118 |
|
|
$ |
19.25 |
|
|
|
7.18 |
|
|
| Summary of Restricted Stock Unit Award Activity |
The following table summarizes our restricted stock unit award activity during the year ended December 31, 2023:
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Weighted |
|
|
|
Number |
|
|
Average |
|
|
|
of |
|
|
Grant Date |
|
|
|
Shares |
|
|
Fair Value |
|
Balance, January 1, 2023 |
|
|
252,875 |
|
|
$ |
8.77 |
|
Granted |
|
|
394,750 |
|
|
|
4.90 |
|
Released |
|
|
(139,750 |
) |
|
|
9.18 |
|
Balance, December 31, 2023 |
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|
507,875 |
|
|
$ |
5.65 |
|
|
| Summary of Outstanding Warrants |
The following is a summary of outstanding warrants to purchase common stock at December 31, 2023:
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Total |
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|
Outstanding |
|
|
Exercise |
|
|
|
|
|
and |
|
|
price per |
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|
|
|
|
Exercisable |
|
|
Share |
|
|
Expiration Date |
(1) Warrants issued in May 2019 financing |
|
|
60,000 |
|
|
$ |
90.0000 |
|
|
May 2025 |
(2) Warrants issued in December 2019 financing |
|
|
510,924 |
|
|
$ |
2.3100 |
|
|
December 2024 |
(3) Warrants issued in April 2020 financing |
|
|
182,461 |
|
|
$ |
7.2400 |
|
|
April 2025 |
(4) Warrants issued in April 2020 financing |
|
|
24,375 |
|
|
$ |
7.3200 |
|
|
April 2025 |
(5) Warrants issued in April 2020 financing |
|
|
25,270 |
|
|
$ |
7.5900 |
|
|
April 2025 |
(6) Pre-Funded Warrants issued in August 2020 financing |
|
|
142,857 |
|
|
$ |
0.0010 |
|
|
* |
(7) Warrants issued in December 2020 financing |
|
|
50,000 |
|
|
$ |
8.7500 |
|
|
December 2025 |
(8) Warrants issued in November 2022 financing |
|
|
4,093,141 |
|
|
$ |
4.5000 |
|
|
November 2029 |
|
| Computation of Basic and Diluted Net Loss Attributable to Common Shareholders Per Share |
The following table presents the computation of basic and diluted net loss attributable to common stockholders per share (in thousands, except per share and share amounts):
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|
Years ended December 31, |
|
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|
2023 |
|
|
2022 |
|
|
2021 |
|
Numerator |
|
|
|
|
|
|
|
|
|
Net loss |
|
$ |
(29,815 |
) |
|
$ |
(42,350 |
) |
|
$ |
(33,152 |
) |
Denominator |
|
|
|
|
|
|
|
|
|
Weighted average number of common shares outstanding |
|
|
19,827,354 |
|
|
|
10,593,034 |
|
|
|
8,119,836 |
|
Basic and diluted net loss per common share |
|
$ |
(1.50 |
) |
|
$ |
(4.00 |
) |
|
$ |
(4.08 |
) |
|