Condensed Consolidated Statements of Cash Flows (Unaudited) $ in Thousands	9 Months Ended
	Sep. 30, 2024 USD ($)	Sep. 30, 2023 USD ($)
Operating activities:
Net loss	$ (184,968)	$ (127,195)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	30,087	11,189
Non-cash operating lease expense	2,436	2,469
Depreciation and amortization	474	502
Net accretion of investments in marketable securities	(4,638)	(3,068)
Other noncash expenses	21	54
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	15,306	(3,274)
Accounts payable	5,770	1,331
Accrued liabilities	5,401	8,646
Operating lease liabilities	(2,485)	(2,490)
Net cash used in operating activities	(132,596)	(111,836)
Investing activities:
Purchases of marketable securities	(205,324)	(89,000)
Proceeds from maturities of marketable securities	234,341	139,783
Cash paid for acquisition of assets	(775)
Purchases of property and equipment		(73)
Net cash provided by investing activities	28,242	50,710
Financing activities:
Proceeds from issuance of common stock upon initial public offering, net of underwriting discounts and commissions		232,565
Proceeds from exercise of stock options	6,255	2,517
Proceeds from issuance of common stock		810
Repurchase of unvested early exercised shares		(491)
Payments for offering costs in connection with at-the-market offering and initial public offering	(225)	(2,984)
Net cash provided by financing activities	6,030	232,417
Net change in cash and cash equivalents and restricted cash	(98,324)	171,291
Cash and cash equivalents and restricted cash at beginning of year	375,251	242,206
Cash and cash equivalents and restricted cash at end of period	276,927	413,497
Components of cash and restricted cash:
Cash and cash equivalents	275,714	412,284
Restricted Cash	1,213	1,213
Total cash and cash equivalents and restricted cash	276,927	413,497
Supplemental disclosure of cash flow information:
Cash paid for income taxes	473
Offering costs in connection with at-the-market offering included in accrued liabilities	$ 321
Conversion of preferred stock into common stock upon completion of initial public offering		843,687
Offering costs related to initial public offering included in accounts payable and accrued liabilities		$ 2,963