STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Cash flows used in operating activities:
Net loss	$ (115,438)	$ (111,694)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	1,324	915
Noncash lease expense	1,718	1,328
Stock-based compensation	25,144	20,931
Amortization of premium and discount on marketable securities, net	2,591	1,364
Changes in operating assets and liabilities:
Prepaid expenses and other current and long-term assets	(3,843)	(1,382)
Accounts payable	(347)	3,903
Accrued expenses and other liabilities	6,833	2,463
Operating lease liabilities	(1,711)	(1,359)
Net cash used in operating activities	(83,729)	(83,531)
Cash flows provided by (used in) investing activities:
Purchases of marketable securities	(119,223)	(261,480)
Proceeds from maturities of marketable securities	203,933
Purchases of property and equipment	(3,019)	(2,323)
Net cash provided by (used in) investing activities	81,691	(263,803)
Cash flows provided by financing activities:
Proceeds from the sale of common stock, net of offering costs		161,424
Payment of offering costs		(303)
Proceeds from issuance of common stock in connection with the exercise of stock options	389	3,504
Proceeds from the issuance of common stock under ESPP	426	272
Net cash provided by financing activities	815	164,897
Net (decrease) increase in cash and cash equivalents	(1,223)	(182,437)
Cash, cash equivalents and restricted cash at beginning of year	35,872	218,309
Cash, cash equivalents and restricted cash at end of year	34,649	35,872
Supplemental disclosures:
Operating lease right-of-use assets obtained in exchange for operating lease liabilities	1,803	567
Property and equipment in accounts payable	90	806
Unrealized loss on marketable securities	$ (981)	$ (711)