Common Stock (Tables)
|
12 Months Ended |
Dec. 31, 2022 |
|---|
| 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:
|
|
|
2022
|
|
|
2021
|
|
|
|
Risk-free interest rates
|
|
|
1.65
|
%
|
|
|
0.66
|
%
|
|
|
Expected dividend yield
|
|
|
0
|
%
|
|
|
0
|
%
|
|
|
Expected life
|
|
5.80 years
|
|
|
6.00 years
|
|
|
|
Expected volatility
|
|
|
122.80
|
%
|
|
|
110.10
|
%
|
|
|
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):
|
|
|
Year ended
|
|
|
|
|
December 31,
|
|
|
|
|
2022
|
|
|
2021
|
|
|
Research and development
|
|
$
|
1,117
|
|
|
$
|
685
|
|
|
General and administrative
|
|
|
2,153
|
|
|
|
1,502
|
|
|
Total stock-based compensation
|
|
$
|
3,270
|
|
|
$
|
2,187
|
|
|
| Summary of Stock Options Activity |
Stock option transactions and the number of stock options outstanding are summarized below:
|
|
|
Number of
|
|
|
Weighted
|
|
|
|
|
Optioned
|
|
|
Average
|
|
|
|
|
Common
|
|
|
Exercise
|
|
|
|
|
Shares
|
|
|
Price
|
|
|
Balance, January 1, 2022
|
|
|
522,090
|
|
|
$
|
26.11
|
|
|
Granted
|
|
|
300,450
|
|
|
|
7.83
|
|
|
Expired
|
|
|
(25
|
)
|
|
|
28,522.56
|
|
|
Balance, December 31, 2022
|
|
|
822,515
|
|
|
$
|
18.57
|
|
|
| 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:
|
|
|
|
|
|
|
|
|
|
|
Weighted-
|
|
|
|
|
|
|
|
|
|
|
|
|
Average
|
|
|
|
|
|
|
|
|
|
|
|
|
Remaining
|
|
|
|
|
|
|
|
|
Weighted-
|
|
|
Contractual
|
|
|
|
|
|
|
|
|
Average
|
|
|
Life
|
|
|
Exercise Prices
|
|
Number of Options
|
|
|
Exercise Price
|
|
|
(in years)
|
|
|
$5.07 - $7.27
|
|
|
84,200
|
|
|
$
|
6.59
|
|
|
|
9.11
|
|
|
$7.28 - $7.89
|
|
|
35,000
|
|
|
|
7.42
|
|
|
|
8.87
|
|
|
$7.90 - $8.43
|
|
|
226,250
|
|
|
|
8.26
|
|
|
|
9.01
|
|
|
$8.44 - $10.78
|
|
|
114,750
|
|
|
|
10.23
|
|
|
|
7.90
|
|
|
$10.79 - $11.65
|
|
|
74,880
|
|
|
|
11.20
|
|
|
|
7.08
|
|
|
$11.66 - $12.60
|
|
|
5,650
|
|
|
|
12.10
|
|
|
|
8.20
|
|
|
$12.61 - $20.74
|
|
|
232,750
|
|
|
|
13.09
|
|
|
|
8.07
|
|
|
$20.75 - $39.80
|
|
|
14,766
|
|
|
|
28.40
|
|
|
|
6.08
|
|
|
$39.81 - $59.30
|
|
|
18,747
|
|
|
|
51.20
|
|
|
|
5.72
|
|
|
$59.31 - $28,952.00
|
|
|
15,522
|
|
|
|
391.78
|
|
|
|
5.31
|
|
|
|
|
|
822,515
|
|
|
$
|
18.57
|
|
|
|
8.21
|
|
|
| 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:
|
|
|
|
|
|
|
|
|
|
|
Weighted-
|
|
|
|
|
|
|
|
|
|
|
|
|
Average
|
|
|
|
|
|
|
|
|
|
|
|
|
Remaining
|
|
|
|
|
|
|
|
|
Weighted-
|
|
|
Contractual
|
|
|
|
|
|
|
|
|
Average
|
|
|
Life
|
|
|
Exercise Prices
|
|
Number of Options
|
|
|
Exercise Price
|
|
|
(in years)
|
|
|
$5.07 - $7.27
|
|
|
10,295
|
|
|
$
|
7.07
|
|
|
|
8.67
|
|
|
$7.28 - $7.89
|
|
|
6,250
|
|
|
|
7.51
|
|
|
|
8.70
|
|
|
$7.90 - $8.43
|
|
|
—
|
|
|
|
—
|
|
|
|
—
|
|
|
$8.44 - $10.78
|
|
|
65,750
|
|
|
|
10.13
|
|
|
|
7.92
|
|
|
$10.79 - $11.65
|
|
|
54,653
|
|
|
|
11.20
|
|
|
|
7.08
|
|
|
$11.66 - $12.60
|
|
|
3,296
|
|
|
|
12.10
|
|
|
|
8.20
|
|
|
$12.61 - $20.74
|
|
|
111,526
|
|
|
|
13.09
|
|
|
|
8.07
|
|
|
$20.75 - $39.80
|
|
|
14,543
|
|
|
|
28.40
|
|
|
|
6.08
|
|
|
$39.81 - $59.30
|
|
|
18,747
|
|
|
|
51.20
|
|
|
|
5.72
|
|
|
$59.31 - $28,952.00
|
|
|
15,490
|
|
|
|
392.45
|
|
|
|
5.30
|
|
|
|
|
|
300,550
|
|
|
$
|
34.44
|
|
|
|
7.51
|
|
|
| Summary of Restricted Stock Unit Award Activity |
The following table summarizes our restricted stock unit award activity during the year ended December 31, 2022:
|
|
|
|
|
|
|
Weighted
|
|
|
|
|
Number
|
|
|
Average
|
|
|
|
|
of
|
|
|
Grant Date
|
|
|
|
|
Shares
|
|
|
Fair Value
|
|
|
Balance, January 1, 2022
|
|
|
53,250
|
|
|
$
|
13.09
|
|
|
Granted
|
|
|
226,250
|
|
|
|
8.26
|
|
|
Released
|
|
|
(26,625
|
)
|
|
|
13.09
|
|
|
Balance, December 31, 2022
|
|
|
252,875
|
|
|
$
|
8.77
|
|
|
| Summary of Outstanding Warrants |
The following is a summary of outstanding warrants to purchase common stock at December 31, 2022:
|
|
|
Total
|
|
|
|
|
|
|
|
|
|
|
Outstanding
|
|
|
Exercise
|
|
|
|
|
|
|
and
|
|
|
price per
|
|
|
|
|
|
|
Exercisable
|
|
|
Share
|
|
|
Expiration Date
|
|
(1) Warrants issued in September 2017 financing
|
|
|
411
|
|
|
$
|
699.2000
|
|
|
March 2023
|
|
(2) Warrants issued in June 2018 financing
|
|
|
114,100
|
|
|
$
|
80.0000
|
|
|
June 2023
|
|
(3) Warrants issued in October 2018 financing
|
|
|
31,215
|
|
|
$
|
62.8900
|
|
|
October 2023
|
|
(4) Warrants issued in May 2019 financing
|
|
|
60,000
|
|
|
$
|
90.0000
|
|
|
May 2025
|
|
(5) Warrants issued in December 2019 financing
|
|
|
609,258
|
|
|
$
|
2.3100
|
|
|
December 2024
|
|
(6) Warrants issued in April 2020 financing
|
|
|
182,461
|
|
|
$
|
7.2400
|
|
|
April 2025
|
|
(7) Warrants issued in April 2020 financing
|
|
|
24,375
|
|
|
$
|
7.3200
|
|
|
April 2025
|
|
(8) Warrants issued in April 2020 financing
|
|
|
25,270
|
|
|
$
|
7.5900
|
|
|
April 2025
|
|
(9) Pre-Funded Warrants issued in August 2020 financing
|
|
|
142,857
|
|
|
$
|
0.0010
|
|
|
*
|
|
(10) Warrants issued in December 2020 financing
|
|
|
50,000
|
|
|
$
|
8.7500
|
|
|
December 2025
|
|
(11) 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):
|
|
|
Years ended December 31,
|
|
|
|
|
2022
|
|
|
2021
|
|
|
2020
|
|
|
Numerator
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Net loss
|
|
$
|
(42,350
|
)
|
|
$
|
(33,152
|
)
|
|
$
|
(14,730
|
)
|
|
Denominator
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Weighted average number of common shares outstanding
|
|
|
10,593,034
|
|
|
|
8,119,836
|
|
|
|
2,718,909
|
|
|
Basic and diluted net loss per common share
|
|
$
|
(4.00
|
)
|
|
$
|
(4.08
|
)
|
|
$
|
(5.42
|
)
|
|