Note 12 - Share-based Compensation (Tables)
|
12 Months Ended |
Dec. 31, 2021 |
|---|
| Notes Tables |
|
| Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block] |
| |
|
December 31, 2021 |
|
|
December 31, 2020 |
|
| Research and development |
|
$ |
463 |
|
|
$ |
534 |
|
| General and administrative |
|
|
1,095 |
|
|
|
1,309 |
|
| Total share-based compensation |
|
$ |
1,558 |
|
|
$ |
1,843 |
|
|
| Share-based Payment Arrangement, Option, Activity [Table Text Block] |
| |
|
Shares Underlying Options |
|
|
Weighted Average Exercise Price Per Share |
|
|
Aggregate Intrinsic Value |
|
| Balances at December 31, 2019 |
|
|
1,220,359 |
|
|
$ |
5.33 |
|
|
$ |
678 |
|
| Granted |
|
|
302,332 |
|
|
|
4.73 |
|
|
|
|
|
| Exercised |
|
|
(14,283 |
) |
|
|
3.21 |
|
|
|
|
|
| Expired/cancelled |
|
|
(78,147 |
) |
|
|
5.29 |
|
|
|
|
|
| Forfeited |
|
|
(40,697 |
) |
|
|
4.86 |
|
|
|
|
|
| Balances at December 31, 2020 |
|
|
1,389,564 |
|
|
$ |
5.24 |
|
|
$ |
7,109 |
|
| Granted |
|
|
638,008 |
|
|
|
5.18 |
|
|
|
|
|
| Exercised |
|
|
(40,000 |
) |
|
|
6.10 |
|
|
|
|
|
| Expired/cancelled |
|
|
(20,972 |
) |
|
|
12.65 |
|
|
|
|
|
| Forfeited |
|
|
(70,000 |
) |
|
|
4.24 |
|
|
|
|
|
| Balances at December 31, 2021 |
|
|
1,896,600 |
|
|
$ |
5.25 |
|
|
$ |
169 |
|
|
| Schedule of Nonvested Share Activity [Table Text Block] |
| |
|
Shares Underlying Options |
|
|
Weighted Grant Date Fair Value Per Share |
|
| Unvested at December 31, 2020 |
|
|
390,826 |
|
|
$ |
3.49 |
|
| Granted |
|
|
638,008 |
|
|
|
3.16 |
|
| Vested |
|
|
(347,110 |
) |
|
|
3.26 |
|
| Forfeited |
|
|
(70,000 |
) |
|
|
3.70 |
|
| Unvested at December 31, 2021 |
|
|
611,724 |
|
|
$ |
3.21 |
|
|
| Share-based Payment Arrangement, Option, Exercise Price Range [Table Text Block] |
| |
|
|
|
Outstanding, Vested and Expected to Vest |
|
|
Options Vested and Exercisable |
|
| Per Share Exercise Price |
|
Shares |
|
|
Weighted Average Remaining Contractual Life (Years) |
|
|
Weighted Average Exercise Price |
|
|
Options Exercisable |
|
|
Weighted Average Remaining Contractual Life (Years) |
|
| $2.00 |
- |
$2.99 |
|
|
120,500 |
|
|
|
4.0 |
|
|
$ |
2.39 |
|
|
|
120,500 |
|
|
|
4.0 |
|
| $3.00 |
- |
$3.99 |
|
|
170,508 |
|
|
|
8.2 |
|
|
|
3.75 |
|
|
|
49,325 |
|
|
|
6.4 |
|
| $4.00 |
- |
$4.99 |
|
|
953,567 |
|
|
|
7.5 |
|
|
|
4.50 |
|
|
|
823,025 |
|
|
|
7.3 |
|
| $5.00 |
- |
$10.00 |
|
|
594,525 |
|
|
|
8.2 |
|
|
|
6.38 |
|
|
|
249,526 |
|
|
|
6.4 |
|
| $10.01 |
- |
$34.00 |
|
|
57,500 |
|
|
|
4.0 |
|
|
|
16.18 |
|
|
|
42,500 |
|
|
|
2.2 |
|
| |
|
|
|
|
1,896,600 |
|
|
|
7.4 |
|
|
$ |
5.25 |
|
|
|
1,284,876 |
|
|
|
6.6 |
|
|
| Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block] |
| |
|
2021 |
|
|
2020 |
|
| Common share fair value |
|
$3.64 |
– |
$10.04 |
|
|
$4.08 |
– |
$6.91 |
|
| Risk-free interest rate |
|
0.5 |
– |
1.3% |
|
|
0.3 |
– |
1.3% |
|
| Expected dividend yield |
|
|
0% |
|
|
|
|
0% |
|
|
| Expected option life (years) |
|
5.0 |
– |
5.5 |
|
|
5.0 |
– |
5.2 |
|
| Expected stock price volatility |
|
94.7 |
– |
106.1% |
|
|
94.4 |
– |
102.2% |
|
|