Total stock-based compensation related to option issuances was as follows: | | | | | | | | | | | | | | | Three Months Ended June 30, | | Six Months Ended June 30, | (in thousands) | | 2026 | | 2025 | | 2026 | | 2025 | Research and development | | $ | 637 | | $ | 666 | | $ | 1,131 | | $ | 1,273 | Selling, general and administrative | | | 411 | | | 692 | | | 783 | | | 1,331 | Total stock-based compensation | | $ | 1,048 | | $ | 1,358 | | $ | 1,914 | | $ | 2,604 |
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) | | 2026 | | 2025 | | 2026 | | 2025 | Research and development | | $ | 490 | | $ | 528 | | $ | 1,126 | | $ | 993 | Selling, general and administrative | | | 967 | | | 1,036 | | | 2,245 | | | 1,986 | Total stock-based compensation | | $ | 1,457 | | $ | 1,564 | | $ | 3,371 | | $ | 2,979 |
Total stock-based compensation related to warrants was as follows: | | | | | | | | | | | | | | | Three Months Ended June 30, | | Six Months Ended June 30, | (in thousands) | | 2026 | | 2025 | | 2026 | | 2025 | Research and development | | $ | — | | $ | 121 | | $ | 32 | | $ | 241 | Selling, general and administrative | | | — | | | 207 | | | 39 | | | 391 | Total stock-based compensation | | $ | — | | $ | 328 | | $ | 71 | | $ | 632 |
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