Note 7 - Stockholder's Equity (Tables)
|
9 Months Ended |
Sep. 30, 2024 |
|---|
| Notes Tables |
|
| Fair Value Measurement Inputs and Valuation Techniques [Table Text Block] |
| |
|
September 30, |
|
|
December 31, |
|
| |
|
2024 |
|
|
2023 |
|
| Stock price |
|
$ |
2.49 |
|
|
$ |
12.00 |
|
| Risk-free interest rate |
|
|
3.58 |
% |
|
|
3.84 |
% |
| Expected dividend yield |
|
|
— |
|
|
|
— |
|
| Expected term in years |
|
|
3.0 |
|
|
|
3.8 |
|
| Expected volatility |
|
|
164 |
% |
|
|
148 |
% |
|
| Schedule of Unvested Restricted Stock Units Roll Forward [Table Text Block] |
| |
Number of |
|
|
Weighted |
|
| |
Units and |
|
|
Average Grant |
|
| |
Awards |
|
|
Date Fair Value |
|
| Unvested balance at December 31, 2023 |
|
1,311 |
|
|
$ |
196.21 |
|
| Granted |
|
— |
|
|
|
— |
|
| Forfeited |
|
— |
|
|
|
— |
|
| Vested |
|
(283 |
) |
|
|
85.50 |
|
| Unvested balance at March 31, 2024 |
|
1,028 |
|
|
$ |
226.69 |
|
| Unvested balance at June 30, 2024 |
|
1,028 |
|
|
$ |
226.69 |
|
| Granted |
|
235,000 |
|
|
|
2.46 |
|
| Forfeited |
|
— |
|
|
|
— |
|
| Vested |
|
— |
|
|
|
— |
|
| Unvested balance at September 30, 2024 |
|
236,028 |
|
|
$ |
3.44 |
|
|
| Share-Based Payment Arrangement, Option, Activity [Table Text Block] |
| |
|
|
|
|
|
|
|
|
|
Weighted |
|
|
|
|
|
| |
|
|
|
|
|
|
|
|
|
Average |
|
|
|
|
|
| |
|
|
|
|
Weighted |
|
|
Remaining |
|
|
Aggregate |
|
| |
|
Number |
|
|
Average |
|
|
Contractual |
|
|
Intrinsic Value |
|
| |
|
of Options |
|
|
Exercise Price |
|
|
Term (years) |
|
|
(in thousands) |
|
| Outstanding at December 31, 2023 |
|
|
22,474 |
|
|
$ |
85.50 |
|
|
|
9.5 |
|
|
$ |
— |
|
| Granted |
|
|
234,000 |
|
|
$ |
2.46 |
|
|
|
|
|
|
$ |
— |
|
| Exercised |
|
|
— |
|
|
$ |
— |
|
|
|
|
|
|
$ |
— |
|
| Cancelled/forfeited |
|
|
— |
|
|
$ |
— |
|
|
|
|
|
|
$ |
— |
|
| Expired |
|
|
— |
|
|
$ |
— |
|
|
|
|
|
|
$ |
— |
|
| Outstanding at Balance at September 30, 2024 |
|
|
256,474 |
|
|
$ |
9.74 |
|
|
|
9.9 |
|
|
$ |
— |
|
| Expected to vest |
|
|
246,802 |
|
|
$ |
6.77 |
|
|
|
9.9 |
|
|
$ |
— |
|
| Exercisable |
|
|
9,672 |
|
|
$ |
85.50 |
|
|
|
8.7 |
|
|
$ |
— |
|
|
| Schedule of Share-Based Payment Award, Stock Options, Valuation Assumptions [Table Text Block] |
| |
|
For the Nine Months Ended |
| |
|
September 30, |
| |
|
2024 |
|
2023 |
| Volatility |
|
135% |
|
124.9 - 125.7% |
| Expected term (in years) |
|
5.64 |
|
5.8 - 5.9 |
| Risk-free rate |
|
3.6% |
|
4.1% |
| Expected dividend yield |
|
—% |
|
—% |
|
| Share-Based Payment Arrangement, Cost by Plan [Table Text Block] |
| |
|
For the Three Months Ended |
|
|
For the Nine Months Ended |
|
| |
|
September 30, |
|
|
September 30, |
|
| |
|
2024 |
|
|
2023 |
|
|
2024 |
|
|
2023 |
|
| Research and development |
|
$ |
89 |
|
|
$ |
144 |
|
|
$ |
179 |
|
|
$ |
150 |
|
| General and administrative |
|
|
242 |
|
|
|
417 |
|
|
|
535 |
|
|
|
449 |
|
| Total stock-based compensation expense |
|
$ |
331 |
|
|
$ |
561 |
|
|
$ |
714 |
|
|
$ |
599 |
|
|
| Schedule of Stockholders' Equity Note, Warrants or Rights [Table Text Block] |
| |
|
|
|
|
|
Weighted |
|
|
|
|
|
| |
|
|
|
|
|
Average |
|
|
Aggregate |
|
| |
|
|
|
|
|
Exercise |
|
|
Intrinsic Value |
|
| |
|
Warrants |
|
|
Price |
|
|
(in thousands) |
|
| Outstanding, December 31, 2023 |
|
|
524,601 |
|
|
$ |
32.42 |
|
|
$ |
— |
|
| Granted |
|
|
441,076 |
|
|
|
6.20 |
|
|
|
|
|
| Exercised |
|
|
(220,538 |
) |
|
|
22.55 |
|
|
|
|
|
| Outstanding, March 31, 2024 |
|
|
745,139 |
|
|
$ |
29.50 |
|
|
$ |
— |
|
| Granted |
|
|
1,420,741 |
|
|
|
6.25 |
|
|
|
|
|
| Exercised |
|
|
(689,680 |
) |
|
|
6.20 |
|
|
|
|
|
| Outstanding, June 30, 2024 |
|
|
1,476,200 |
|
|
$ |
8.64 |
|
|
$ |
— |
|
| Outstanding, September 30, 2024 |
|
|
1,476,200 |
|
|
$ |
8.64 |
|
|
$ |
— |
|
|
| Warrant [Member] |
|
| Notes Tables |
|
| Fair Value Measurement Inputs and Valuation Techniques [Table Text Block] |
| |
|
January 2023 |
|
|
New Series A |
|
|
New Series B |
|
| |
|
Warrants |
|
|
Warrants |
|
|
Warrants |
|
| Stock price |
|
$ |
14.25 |
|
|
$ |
14.25 |
|
|
$ |
14.25 |
|
| Risk-free interest rate |
|
|
4.40 |
% |
|
|
4.02 |
% |
|
|
4.40 |
% |
| Expected dividend yield |
|
|
— |
|
|
|
— |
|
|
|
— |
|
| Expected term in years |
|
|
2.1 |
|
|
|
5.0 |
|
|
|
1.5 |
|
| Expected volatility |
|
|
185 |
% |
|
|
138 |
% |
|
|
187 |
% |
| |
|
October 2022 |
|
|
Series C |
|
|
Series D |
|
|
Placement Agent |
|
| |
|
Warrants |
|
|
Warrants |
|
|
Warrants |
|
|
Warrants |
|
| Stock price |
|
$ |
4.76 |
|
|
$ |
4.76 |
|
|
$ |
4.76 |
|
|
$ |
4.76 |
|
| Risk-free interest rate |
|
|
5 |
% |
|
|
4.64 |
% |
|
|
4.96 |
% |
|
|
4.64 |
% |
| Expected dividend yield |
|
|
— |
|
|
|
— |
|
|
|
— |
|
|
|
— |
|
| Expected term in years |
|
|
3.4 |
|
|
|
5.0 |
|
|
|
1.5 |
|
|
|
5.0 |
|
| Expected volatility |
|
|
160 |
% |
|
|
141 |
% |
|
|
132 |
% |
|
|
141 |
% |
|