Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Operating activities
Net loss	$ (160,805)	$ (123,482)	$ (83,463)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	836	342	51
Non-cash lease costs	1,272	1,124	685
Acquired in-process research and development			4,739
Stock-based compensation	26,273	23,839	13,914
Net amortization of premiums and accretion of discounts on investments	(6,487)	(940)
Accretion of term loan discount and issuance costs	250	44
Changes in operating assets and liabilities
Prepaid expenses and other current assets	(1,291)	(1,476)	(1,662)
Other assets	1,366	750	(9,682)
Accounts payable	458	4,506	3,290
Payable and accrued liabilities due to related party	(1,107)	20	1,419
Accrued expenses and other current liabilities	11,224	7,027	3,306
Other non-current liabilities	(2,353)	(977)	(698)
Net cash used in operating activities	(130,364)	(89,223)	(68,101)
Investing activities
Purchase of investments	(246,629)	(376,789)
Maturities of investments	292,560	142,800
Purchase of property and equipment	(1,274)	(1,427)	(666)
Acquisition of in-process research and development			(4,257)
Net cash provided by (used in) investing activities	44,657	(235,416)	(4,923)
Financing activities
Proceeds from equity offerings, net of underwriter discounts ($3.8 million) and issuance costs ($0.6 million)	58,887
Proceeds from exercise of stock options under equity incentive plan	269	567	2,551
Proceeds from issuance of common stock under employee stock purchase plan	523	336	202
Principal payments on finance leases	(388)	(388)	(281)
Proceeds from issuance of term loan, net		10,000
Payments of debt issuance costs		(655)
Net cash provided by financing activities	59,291	9,860	2,472
Net decrease in cash, cash equivalents and restricted cash	(26,416)	(314,779)	(70,552)
Cash, cash equivalents and restricted cash at beginning of year	48,888	363,667	434,219
Cash, cash equivalents and restricted cash at end of period	22,472	48,888	363,667
Supplemental disclosure
Cash paid for interest	1,177	103	11
Cash paid for taxes			274
Supplemental disclosure of non-cash investing and financing activities
Purchase of property and equipment in accounts payable and accrued expenses	1,407	2,145	237
Acquisition of in-process research and development in accounts payable and accrued expenses			482
Right-of-use asset acquired under operating leases		4,613	1,780
Right-of-use asset acquired under finance leases	2,600		776
Reconciliation of cash and cash equivalents and restricted cash:
Cash and cash equivalents	22,406	48,822	363,667
Restricted cash (included in other assets)	66	66
Total cash and cash equivalents and restricted cash	$ 22,472	$ 48,888	$ 363,667