Total stock-based compensation related to option issuances was as follows: | | | | | | | | | | | | | | | Three Months Ended June 30, | | Six Months Ended June 30, | (in thousands) | | 2025 | | 2024 | | 2025 | | 2024 | Research and development | | $ | 666 | | $ | 308 | | $ | 1,273 | | $ | 817 | Selling, general and administrative | | | 692 | | | 710 | | | 1,331 | | | 1,191 | Total stock-based compensation | | $ | 1,358 | | $ | 1,018 | | $ | 2,604 | | $ | 2,008 |
Total stock-based compensation related to restricted stock awards and restricted stock units was as follows: | | | | | | | | | | | | | | | Three Months Ended June 30, | | Six Months Ended June 30, | (in thousands) | | 2025 | | 2024 | | 2025 | | 2024 | Research and development | | $ | 528 | | $ | 392 | | $ | 993 | | $ | 739 | Selling, general and administrative | | | 1,036 | | | 1,086 | | | 1,986 | | | 2,073 | Total stock-based compensation | | $ | 1,564 | | $ | 1,478 | | $ | 2,979 | | $ | 2,812 |
Total stock-based compensation related to warrants was as follows: | | | | | | | | | | | | | | | Three Months Ended June 30, | | Six Months Ended June 30, | (in thousands) | | 2025 | | 2024 | | 2025 | | 2024 | Research and development | | $ | 121 | | $ | 121 | | $ | 241 | | $ | 241 | Selling, general and administrative | | | 207 | | | 144 | | | 391 | | | 288 | Total stock-based compensation | | $ | 328 | | $ | 265 | | $ | 632 | | $ | 529 |
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