Common Stock (Tables)
|
12 Months Ended |
Dec. 31, 2020 |
|---|
| 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:
|
|
|
2020
|
|
|
2019
|
|
|
|
Risk-free interest rates
|
|
|
0.94
|
%
|
|
|
2.52
|
%
|
|
|
Expected dividend yield
|
|
|
0
|
%
|
|
|
0
|
%
|
|
|
Expected life
|
|
6.00 years
|
|
|
5.97 years
|
|
|
|
Expected volatility
|
|
|
108.78
|
%
|
|
|
94.25
|
%
|
|
|
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,
|
|
|
|
|
2020
|
|
|
2019
|
|
|
Research and development
|
|
$
|
403
|
|
|
$
|
364
|
|
|
General and administrative
|
|
|
883
|
|
|
|
837
|
|
|
Total stock-based compensation
|
|
$
|
1,286
|
|
|
$
|
1,201
|
|
|
| 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, 2020
|
|
|
50,498
|
|
|
$
|
190.46
|
|
|
Granted
|
|
|
178,380
|
|
|
|
10.66
|
|
|
Expired
|
|
|
(30
|
)
|
|
|
34,874.40
|
|
|
Forfeited
|
|
|
(1,406
|
)
|
|
|
227.61
|
|
|
Balance, December 31, 2020
|
|
|
227,442
|
|
|
$
|
44.64
|
|
|
| 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)
|
|
|
$8.60 -$9.48
|
|
|
5,500
|
|
|
$
|
8.60
|
|
|
|
9.36
|
|
|
$9.49 - $10.78
|
|
|
98,000
|
|
|
|
10.36
|
|
|
|
9.88
|
|
|
$10.79 - $19.80
|
|
|
74,880
|
|
|
|
11.20
|
|
|
|
9.08
|
|
|
$19.81 - $39.80
|
|
|
14,766
|
|
|
|
28.40
|
|
|
|
8.08
|
|
|
$39.81 - $59.30
|
|
|
18,747
|
|
|
|
51.20
|
|
|
|
7.72
|
|
|
$59.31 - $67.50
|
|
|
8,087
|
|
|
|
67.40
|
|
|
|
7.57
|
|
|
$67.51 - $329.20
|
|
|
2,162
|
|
|
|
77.96
|
|
|
|
8.35
|
|
|
$329.21 - $1,389.00
|
|
|
5,069
|
|
|
|
578.00
|
|
|
|
6.58
|
|
|
$1,389.01 - $6,424.00
|
|
|
109
|
|
|
|
3,845.36
|
|
|
|
4.53
|
|
|
$6,424.01 - $39,204.00
|
|
|
122
|
|
|
|
23,032.56
|
|
|
|
2.58
|
|
|
|
|
|
227,442
|
|
|
$
|
44.64
|
|
|
|
9.13
|
|
|
| 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)
|
|
|
$8.60 -$9.48
|
|
|
—
|
|
|
$
|
—
|
|
|
|
—
|
|
|
$9.49 - $10.78
|
|
|
—
|
|
|
|
—
|
|
|
|
—
|
|
|
$10.79 - $19.80
|
|
|
—
|
|
|
|
—
|
|
|
|
—
|
|
|
$19.81 - $39.80
|
|
|
8,459
|
|
|
|
28.40
|
|
|
|
8.08
|
|
|
$39.81 - $59.30
|
|
|
11,951
|
|
|
|
51.20
|
|
|
|
7.72
|
|
|
$59.31 - $67.50
|
|
|
4,930
|
|
|
|
67.40
|
|
|
|
7.57
|
|
|
$67.51 - $329.20
|
|
|
1,926
|
|
|
|
79.23
|
|
|
|
8.36
|
|
|
$329.21 - $1,389.00
|
|
|
4,317
|
|
|
|
578.00
|
|
|
|
6.58
|
|
|
$1,389.01 - $6,424.00
|
|
|
109
|
|
|
|
3,845.36
|
|
|
|
4.53
|
|
|
$6,424.01 - $39,204.00
|
|
|
122
|
|
|
|
23,032.56
|
|
|
|
2.58
|
|
|
|
|
|
31,814
|
|
|
$
|
221.96
|
|
|
|
7.65
|
|
|
| Summary of Restricted Stock Unit Award Activity |
The following table summarizes our restricted stock unit award activity during the year ended December 31, 2020:
|
|
|
|
|
|
|
Weighted
|
|
|
|
|
Number
|
|
|
Average
|
|
|
|
|
of
|
|
|
Grant Date
|
|
|
|
|
Shares
|
|
|
Fair Value
|
|
|
Balance, January 1, 2020
|
|
|
500
|
|
|
$
|
579.85
|
|
|
Released
|
|
|
(236
|
)
|
|
|
579.96
|
|
|
Forfeited or expired
|
|
|
(33
|
)
|
|
|
578.00
|
|
|
Balance, December 31, 2020
|
|
|
231
|
|
|
$
|
580.00
|
|
|
| Summary of Outstanding Warrants |
The following is a summary of outstanding warrants to purchase common stock at December 31, 2020:
|
|
|
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
|
|
|
660,050
|
|
|
$
|
6.6000
|
|
|
December 2024
|
|
(6) Warrants issued in April 2020 financing
|
|
|
182,461
|
|
|
$
|
7.2400
|
|
|
April 2025
|
|
(7) Warrants issued in April 2020 financing
|
|
|
28,125
|
|
|
$
|
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
|
|
| 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,
|
|
|
|
|
2020
|
|
|
2019
|
|
|
2018
|
|
|
Numerator
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Net loss
|
|
$
|
(14,730
|
)
|
|
$
|
(16,395
|
)
|
|
$
|
(12,687
|
)
|
|
Denominator
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Weighted average number of common shares outstanding
|
|
|
2,718,909
|
|
|
|
412,320
|
|
|
|
175,511
|
|
|
Basic and diluted net loss per common share
|
|
$
|
(5.42
|
)
|
|
$
|
(39.76
|
)
|
|
$
|
(72.29
|
)
|
|