| Three Months Ended March 31, | ||||||||
| 2024 | 2023 | |||||||
| Cash flows from operating activities | ||||||||
| Net loss | $ | (25,148) | $ | (16,133) | ||||
| Adjustments to reconcile net loss to net cash used in operating activities | ||||||||
| Stock-based compensation expense | 5,057 | 529 | ||||||
| Depreciation | 1,273 | 841 | ||||||
| Loss on fixed assets write-off | 4 | — | ||||||
| Non-cash lease expense | 1,126 | 983 | ||||||
| Amortization of premiums and discounts on available-for-sale marketable securities | (1,221) | (2,155) | ||||||
| Amortization of non-cash collaboration revenue | (30) | (78) | ||||||
| Changes in operating assets and liabilities: | ||||||||
| Accounts receivable | 369 | — | ||||||
| Contract assets | — | 1,274 | ||||||
| Prepaid expenses and other assets | (938) | (97) | ||||||
| Accounts payable | 3,159 | 1,205 | ||||||
| Income tax payable | — | 1,937 | ||||||
| Deferred revenue and collaboration advance | (10,360) | (7,790) | ||||||
| Accrued expenses and other current liabilities | (2,962) | (1,304) | ||||||
| Operating lease liabilities | (179) | (467) | ||||||
| Other non-current liabilities | — | 260 | ||||||
| Net cash used in operating activities | (29,850) | (20,995) | ||||||
| Cash flows from investing activities | ||||||||
| Purchases of property and equipment | (915) | (2,668) | ||||||
| Purchases of available-for-sale marketable securities | (174,663) | (119,198) | ||||||
| Maturities of available-for-sale marketable securities | 80,846 | 49,798 | ||||||
| Net cash used in investing activities | (94,732) | (72,068) | ||||||
| Cash flows from financing activities | ||||||||
| Proceeds from issuance of common stock upon initial public offering, net of underwriting discounts and commissions and other offering costs | 86,537 | — | ||||||
| Proceeds from issuance of redeemable convertible preferred stock, net of issuance costs | — | 4,295 | ||||||
| Net cash provided by financing activities | 86,537 | 4,295 | ||||||
| Net decrease in cash, cash equivalents and restricted cash | (38,045) | (88,768) | ||||||
| Cash, cash equivalents and restricted cash at beginning of period | 145,851 | 190,514 | ||||||
| Cash, cash equivalents and restricted cash at end of period | $ | 107,806 | $ | 101,746 | ||||
| Supplemental disclosure of non-cash information | ||||||||
| Conversion of redeemable convertible preferred stock to common stock upon initial public offering | 350,758 | — | ||||||
| Issuance of common stock and restricted common stock in exchange for profits interests upon Reorganization | 9,457 | — | ||||||
| Initial public offering costs included in accounts payable, accrued liabilities and other current liabilities | 2,524 | — | ||||||
| Reclassification of deferred offering costs paid in prior year to stockholders’ equity | 3,283 | |||||||
| Purchases of property and equipment included in accounts payable, accrued expenses and other current liabilities | 418 | 1,425 | ||||||
| Operating lease right-of-use assets obtained in exchange for new lease liabilities | — | 30,608 | ||||||
| Remeasurement of operating right-of use asset and lease liability | 12 | — | ||||||
| Reconciliation of cash, cash equivalents and restricted cash | ||||||||
| Cash and cash equivalents | $ | 102,558 | $ | 95,673 | ||||
| Restricted cash | 5,248 | 6,073 | ||||||
| Cash, cash equivalents and restricted cash at end of period | $ | 107,806 | $ | 101,746 | ||||
