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Stock-Based Compensation (Tables) | 9 Months Ended
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Sep. 30, 2025
Share-Based Payment Arrangement [Abstract] |
Stock-Based Compensation Expense | The following stock-based compensation expense was recognized for the periods indicated (in thousands):
| Three Months Ended September 30, |  | Nine Months Ended September 30,
| 2025 |  | 2024 |  | 2025 |  | 2024
Research and development | $ | 2,219 |  |  | $ | 2,940 |  |  | $ | 7,282 |  |  | $ | 9,033 |
Selling, general and administrative | 1,329 |  |  | 3,030 |  |  | 4,343 |  |  | 9,141 |
Total stock-based compensation expense | $ | 3,548 |  |  | $ | 5,970 |  |  | $ | 11,625 |  |  | $ | 18,174 |
Valuation Assumptions Using the Black-Scholes Option-Pricing Model | The fair value of each option award is estimated on the date of grant using the Black-Scholes option-pricing model using the assumptions in the following table for options issued during the period indicated:
| Nine Months Ended September 30,
| 2025 |  | 2024
Expected dividend yield | 0% |  | 0%
Expected volatility | 110.7% - 115.6% |  | 94.9% - 115.7%
Risk-free interest rate | 3.7% - 4.5% |  | 3.5% - 4.7%
Expected term | 6.11 years |  | 6.06 years
Schedule of Stock Options Roll Forward | The following table summarizes stock option activity during the nine months ended September 30, 2025:
| Shares |  | Weighted- Average Exercise Price |  | Weighted-Average Remaining Contractual Term (Years) |  | Aggregate Intrinsic Value (in thousands)
Outstanding, December 31, 2024 | 12,939,517 |  |  | $ | 14.80 |  |  | 6.4 |  |
Granted | 2,874,944 |  |  | 2.19 |  |  |  |  |
Exercised | — |  |  | — |  |  |  |  |
Forfeited | (393,733) |  |  | 9.23 |  |  |  |  |
Expired | (210,693) |  |  | 21.29 |  |  |  |  |
Outstanding, September 30, 2025 | 15,210,035 |  |  | $ | 12.47 |  |  | 6.3 |  | $ | 136 |
As of September 30, 2025: |  |  |  |  |  |  |
Exercisable | 10,698,518 |  |  | $ | 15.18 |  |  | 5.3 |  | $ | 22 |
Vested and expected to vest | 14,880,587 |  |  | $ | 12.59 |  |  | 6.3 |  | $ | 128 |
Schedule of RSU Activity | The following table summarizes RSU activity during the nine months ended September 30, 2025:
| Shares |  | Weighted-Average Grant Date Fair Value
Outstanding, December 31, 2024 | 1,068,994 |  |  | $ | 11.97 |
Granted | 359,420 |  |  | 2.46 |
Vested | (491,146) |  |  | 10.71 |
Forfeited | (100,052) |  |  | 10.35 |
Outstanding, September 30, 2025 | 837,216 |  |  | $ | 8.82 |
Stock Option Additional Information [Table] | The following table summarizes additional information on stock options (in thousands, except per share amounts):
|  |  | Nine Months Ended September 30,
|  |  |  |  | 2025 |  | 2024
Weighted-average fair value per share of stock options granted |  |  |  |  | $ | 1.85 |  |  | $ | 12.79 |
Total intrinsic value of stock options exercised |  |  |  |  | $ | — |  |  | $ | 2,616 |
Total cash received for stock options exercised |  |  |  |  | $ | — |  |  | $ | 3,122 |
Total grant date fair value of stock options vested |  |  |  |  | $ | 12,836 |  |  | $ | 13,533 |

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- Definition Tabular disclosure of the significant assumptions used during the year to estimate the fair value of stock options, including, but not limited to: (a) expected term of share options and similar instruments, (b) expected volatility of the entity's shares, (c) expected dividends, (d) risk-free rate(s), and (e) discount for post-vesting restrictions. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 718 -SubTopic 10 -Subparagraph (f)(2) -Name Accounting Standards Codification -Paragraph 2 -Section 50 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480429/718-10-50-2 + Details
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