| Balance Sheets | 2026-03-31 | 2025-12-31 | 2025-09-30 | 2025-06-30 |
|---|---|---|---|---|
| Cash and cash equivalents | 56,129 | 40,265 | 48,616 | 31,194 |
| Collaboration receivable, current - related party | 0 | 25,359 | 868 | 24,453 |
| Other receivables | 44 | 28 | 1,591 | 2,460 |
| Prepaid expenses and other current assets | 1,439 | 1,634 | 1,248 | 1,295 |
| Total current assets | 57,612 | 67,286 | 52,323 | 59,402 |
| Operating lease right of use assets | 1,256 | 1,480 | 1,694 | 2,564 |
| Other assets | 153 | 153 | 153 | 153 |
| Total assets | 59,021 | 68,919 | 54,170 | 62,119 |
| Deferred revenue, current | NaN | 0 | 0 | 0 |
| Accounts payable | 217 | 693 | 1,395 | 780 |
| Accrued expenses and other current liabilities | 3,142 | 5,578 | 7,809 | 6,727 |
| Operating lease liabilities | 1,967 | 1,956 | 1,899 | 1,844 |
| Income taxes payable | 163 | 383 | 163 | 163 |
| Deferred revenue, current - related party | 0 | 258 | 2,383 | 5,431 |
| Total current liabilities | 5,489 | 8,868 | 13,649 | 14,945 |
| Non-current operating lease liabilities | 507 | 939 | 1,452 | 1,771 |
| Deferred revenue, non-current | NaN | 0 | 12,575 | 12,575 |
| Deferred revenue, non-current - related party | NaN | 0 | 0 | 0 |
| Other long-term liabilities | 91 | 91 | NaN | NaN |
| Total liabilities | 6,087 | 9,898 | 27,676 | 29,291 |
| Common stock, 0.001 par value 120,000,000 shares authorized as of march 31, 2026 and december 31, 2025 57,891,493 shares issued and outstanding as of march 31, 2026 and 56,414,657 shares issued and outstanding as of december 31, 2025 | 58 | 56 | 56 | 56 |
| Additional paid-in capital | 511,145 | 510,031 | 509,024 | 507,976 |
| Accumulated deficit | -458,269 | -451,066 | -482,586 | -475,204 |
| Total stockholders' equity | 52,934 | 59,021 | 26,494 | 32,828 |
| Total liabilities and stockholders' equity | 59,021 | 68,919 | 54,170 | 62,119 |
Spero Therapeutics, Inc. (SPRO)
Spero Therapeutics, Inc. (SPRO)