CONDENSED STATEMENT OF CASH FLOWS (Unaudited)	9 Months Ended
	Sep. 30, 2023 USD ($)	Sep. 30, 2022 USD ($)
Cash flows from operating activities
Net loss	$ (89,747,000)	$ (81,255,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Share-based compensation expense	13,687,000	12,399,000
Depreciation and amortization	3,618,000	1,908,000
Accretion and amortization of premiums and discounts on investments, net	(6,915,000)	763,000
Realized gain on investments	(34,000)	0
Impairment of right-of-use assets	4,100,000
Non-cash lease expense	1,653,000	3,269,000
Changes in operating assets and liabilities:
Prepaid expenses and other assets	1,093,000	(1,575,000)
Operating lease liabilities	6,112,000	11,446,000
Accounts payable and accrued and other liabilities	3,627,000	3,376,000
Net cash used in operating activities	(62,806,000)	(49,669,000)
Cash flows from investing activities
Purchases of property and equipment	(21,340,000)	(12,073,000)
Purchases of investments	(196,877,000)	(310,313,000)
Maturities of investments	281,395,000	132,950,000
Net cash provided by (used in) investing activities	63,178,000	(189,436,000)
Cash flows from financing activities
Proceeds from stock option exercises	22,000	1,365,000
Proceeds from ESPP purchases	374,000
Proceeds from ATM offering, net of issuance costs		1,612,000
Proceeds from secondary offering, net of issuance costs		215,611,000
Net cash provided by financing activities	396,000	218,588,000
Net (decrease) increase in cash and cash equivalents	768,000	(20,517,000)
Cash, cash equivalents, and restricted cash beginning of period	40,237,000	62,914,000
Cash, cash equivalents, and restricted cash end of period	41,005,000	42,397,000
Reconciliation of cash, cash equivalents and restricted cash to the balance sheet:
Cash and cash equivalents	38,262,000	39,654,000
Restricted cash	2,743,000	2,743,000
Total cash, cash equivalents and restricted cash	41,005,000	42,397,000
Supplemental disclosures of non-cash investing activities:
Acquisitions of property and equipment in accounts payable and accrued and other current liabilities	$ 1,842,000	$ 7,228,000