STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Cash flows used in operating activities:
Net loss	$ (86,797)	$ (78,852)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	962	625
Noncash lease expense	1,281	928
Stock-based compensation	19,299	15,156
Amortization of premium and discount on marketable securities, net	2,770	356
Changes in operating assets and liabilities:
Prepaid expenses and other current and long-term assets	(3,591)	(2,532)
Accounts payable	2,893	7,834
Accrued expenses and other liabilities	3,661	(393)
Operating lease liabilities	(1,280)	(951)
Net cash used in operating activities	(60,802)	(57,829)
Cash flows provided by (used in) investing activities:
Purchases of marketable securities	(85,972)	(259,973)
Proceeds from maturities of marketable securities	168,934
Purchases of property and equipment	(2,626)	(2,026)
Net cash provided by (used in) investing activities	80,336	(261,999)
Cash flows provided by financing activities:
Proceeds from the sale of common stock, net of offering costs		161,424
Proceeds from the issuance of common stock under ESPP	300
Proceeds from the issuance of common stock in connection with the exercise of stock options	360	1,519
Net cash provided by financing activities	660	162,943
Net increase in cash and cash equivalents	20,194	(156,885)
Cash, cash equivalents, and restricted cash at beginning of period	35,872	218,309
Cash, cash equivalents, and restricted cash at end of period	56,066	61,424
Supplemental disclosures:
Operating lease right-of-use assets obtained in exchange for operating lease liabilities	928	567
Property and equipment in accounts payable	323	97
Unrealized loss on marketable securities	$ (1,652)	$ (176)