Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended			54 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2021
Cash flows from operating activities:
Net loss	$ (151,078)	$ (88,444)	$ (16,117)	$ (263,000)
Adjustments to reconcile net loss to cash used in operating activities:
Depreciation and amortization	1,977	839	356
Net amortization/accretion on marketable securities	3,997	326	(4)
Change in accrued interest on marketable securities	485	265	45
Change in fair value of convertible notes payable	0	27,408	0
Debt issuance costs on convertible notes payable	0	3,889	0
Acquired in-process research and development	0	3,565	0
Stock-based compensation expense	26,211	3,753	113
Noncash lease expense	2,104	4,027	249
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(975)	(5,226)	(607)
Other long-term assets	54	261	(153)
Accounts payable	(3,195)	2,807	716
Accrued expenses	4,786	3,229	620
Other liabilities	(2,309)	4,704	(48)
Right-of-use operating assets and liabilities, net	19	685	(252)
Net cash used in operating activities	(117,924)	(37,912)	(15,082)
Cash flows from investing activities:
Purchase of property and equipment	(4,260)	(9,568)	(2,948)
Purchase of marketable securities	(177,734)	(229,328)	(64,633)
Maturities of marketable securities	226,245	78,661	0
Sale of marketable securities	19,473	0	0
Net cash provided by (used in) investing activities	63,724	(160,235)	(67,581)
Cash flows from financing activities:
Proceeds from initial public offering, net of commission and issuance costs	0	263,725	0
Proceeds from issuance of convertible notes, net of issuance costs	0	151,275	0
Principal payments on finance lease	(5)	(32)	(30)
Proceeds from issuance of common stock upon exercise or vesting of stock options	3,127	645	115
Proceeds from issuance of common stock under the employee stock purchase plan	1,338	0	0
Proceeds from issuance of preferred stock, net of financing fees	0	0	104,922
Net cash provided by financing activities	4,460	415,613	105,007
Net increase (decrease) in cash and cash equivalents	(49,740)	217,466	22,344
Cash, cash equivalents and restricted cash at beginning of period	250,036	32,570	10,226
Cash, cash equivalents and restricted cash at end of period	200,296	250,036	32,570	200,296
Supplemental disclosures of non-cash activities:
Common stock issued on conversion of convertible preferred stock	0	122,907	0
Common stock issued on conversion of convertible notes payable	0	186,137	0
Property and equipment additions included in accounts payable and accrued expenses	226	1,280	116
Reduction of right-of-use asset due to modification	(1,741)	0	0
Right-of-use asset obtained in exchange for operating lease liability	3,764	28,839	4
Cash and cash equivalents	198,270	248,009	32,570	198,270
Restricted cash	2,026	2,027	0	2,026
Cash, cash equivalents and restricted cash at end of period	$ 200,296	$ 250,036	$ 32,570	$ 200,296