Note 6 - Stockholders' Equity and Stock-based Compensation (Tables)
|
3 Months Ended |
Mar. 31, 2025 |
|---|
| Notes Tables |
|
| Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block] |
| | | Three Months Ended March 31, | |
| | | 2025 | | | 2024 | |
| Research and development | | $ | 2,762 | | | $ | 949 | |
| General and administrative | | | 2,919 | | | | 810 | |
| Total stock-based compensation expense | | $ | 5,681 | | | $ | 1,759 | |
| | | Three Months Ended March 31, | |
| | | 2025 | | | 2024 | |
| Time-based options | | $ | 4,107 | | | $ | 1,163 | |
| Performance-based options | | | — | | | | 8 | |
| Market-based options | | | 1,469 | | | | 507 | |
| ESPP | | | 105 | | | | 81 | |
| Total stock-based compensation expense | | $ | 5,681 | | | $ | 1,759 | |
|
| Performance-based and Market-based Options [Member] |
|
| Notes Tables |
|
| Share-Based Payment Arrangement, Option, Activity [Table Text Block] |
| | | Stock Options Outstanding | |
| | | Number of shares | | | Weighted average exercise price | | | Weighted average remaining life (in years) | |
| Balances — December 31, 2024 | | | — | | | $ | — | | | | — | |
| Options granted | | | 1,200,000 | | | | 18.74 | | | | | |
| Options exercised | | | — | | | | — | | | | | |
| Options canceled | | | — | | | | — | | | | | |
| Options expired | | | — | | | | — | | | | | |
| Balances — March 31, 2025 | | | 1,200,000 | | | $ | 18.74 | | | | 9.79 | |
| Exercisable — March 31, 2025 | | | — | | | | — | | | | — | |
|
| Market-based Options [Member] |
|
| Notes Tables |
|
| Share-Based Payment Arrangement, Option, Activity [Table Text Block] |
| | | Stock Options Outstanding | |
| | | Number of shares | | | Weighted average exercise price | | | Weighted average remaining life (in years) | |
| Balances — December 31, 2024 | | | 2,461,389 | | | $ | 6.95 | | | | 8.43 | |
| Options granted | | | 232,500 | | | | 19.44 | | | | | |
| Options exercised | | | — | | | | — | | | | | |
| Options canceled | | | — | | | | — | | | | | |
| Options expired | | | — | | | | — | | | | | |
| Balances — March 31, 2025 | | | 2,693,889 | | | $ | 8.03 | | | | 8.33 | |
| Exercisable — March 31, 2025 | | | — | | | | — | | | | — | |
|
| Share-Based Payment Arrangement, Option [Member] |
|
| Notes Tables |
|
| Schedule of Share-Based Payment Award, Stock Options, Valuation Assumptions [Table Text Block] |
| | | Three Months Ended March 31, | |
| | | 2025 | | | 2024 | |
| Expected term in years | | | 5.0 - 6.9 | | | | 5.3 - 6.3 | |
| Expected volatility | | | 93% - 100% | | | | 91% - 95% | |
| Risk-free interest rate | | | 4.1% - 4.6% | | | | 4.0% - 4.5% | |
| Dividend yield | | | — | | | | — | |
| | | Three Months Ended March 31, | |
| | | 2025 | | | 2024 | |
| Expected term in years | | | 5.5 - 7.0 | | | | 5.5 - 5.8 | |
| Expected volatility | | | 90% | | | | 90% | |
| Risk-free interest rate | | | 4.5% - 4.6% | | | | 4.2% | |
| Dividend yield | | | — | | | | — | |
| | | Three Months Ended March 31, | |
| | | 2025 | | | 2024 | |
| Expected term in years | | | 6.1 - 8.9 | | | | — | |
| Expected volatility | | | 90% | | | | — | |
| Risk-free interest rate | | | 4.4% - 4.6% | | | | — | |
| Dividend yield | | | — | | | | — | |
|
| Performance Options [Member] |
|
| Notes Tables |
|
| Share-Based Payment Arrangement, Option, Activity [Table Text Block] |
| | | Stock Options Outstanding | |
| | | Number of shares | | | Weighted average exercise price | | | Weighted average remaining life (in years) | |
| Balances — December 31, 2024 | | | 442,678 | | | $ | 7.71 | | | | 6.79 | |
| Options granted | | | — | | | | — | | | | | |
| Options exercised | | | — | | | | — | | | | | |
| Options canceled | | | — | | | | — | | | | | |
| Options expired | | | — | | | | — | | | | | |
| Balances — March 31, 2025 | | | 442,678 | | | $ | 7.71 | | | | 6.54 | |
| Exercisable — March 31, 2025 | | | 437,678 | | | $ | 7.70 | | | | 6.52 | |
|
| Time-based Options [Member] |
|
| Notes Tables |
|
| Share-Based Payment Arrangement, Option, Activity [Table Text Block] |
| | | Stock Options Outstanding | |
| | | Number of shares | | | Weighted average exercise price | | | Weighted average remaining life (in years) | |
| Balances — December 31, 2024 | | | 8,075,265 | | | $ | 10.49 | | | | 6.72 | |
| Options granted | | | 1,172,600 | | | | 19.04 | | | | | |
| Options exercised | | | (51,000 | ) | | | 7.45 | | | | | |
| Options canceled | | | (40,000 | ) | | | 15.10 | | | | | |
| Options expired | | | — | | | | — | | | | | |
| Balances — March 31, 2025 | | | 9,156,865 | | | $ | 11.58 | | | | 6.97 | |
| Exercisable — March 31, 2025 | | | 4,309,452 | | | $ | 13.27 | | | | 4.82 | |
|
| The 2017 Employee Stock Purchase Plan [Member] |
|
| Notes Tables |
|
| Schedule of Share-Based Payment Award, Stock Options, Valuation Assumptions [Table Text Block] |
| | | Three Months Ended March 31, | |
| | | 2025 | | | 2024 | |
| Expected term in years | | | 0.5 - 1.0 | | | | 0.5 - 1.0 | |
| Expected volatility | | | 98% | | | | 98% | |
| Risk-free interest rate | | | 4.1% - 4.3% | | | | 4.9% - 5.3% | |
| Dividend yield | | | — | | | | — | |
|
| The 2015 Plan, 2017 Plan and Inducement Plan [Member] |
|
| Notes Tables |
|
| Share-Based Payment Arrangement, Option, Activity [Table Text Block] |
| | | Stock Options Outstanding | |
| | | Number of shares | | | Weighted average exercise price | | | Weighted average remaining life (in years) | |
| Balances — December 31, 2024 | | | 10,979,332 | | | $ | 9.59 | | | | 7.11 | |
| Options granted | | | 2,605,100 | | | | 18.94 | | | | | |
| Options exercised | | | (51,000 | ) | | | 7.45 | | | | | |
| Options canceled | | | (40,000 | ) | | | 15.10 | | | | | |
| Options expired | | | — | | | | — | | | | | |
| Balances — March 31, 2025 | | | 13,493,432 | | | $ | 11.38 | | | | 7.47 | |
| Exercisable — March 31, 2025 | | | 4,747,130 | | | $ | 12.75 | | | | 4.98 | |
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