Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Cash flows from operating activities:
Net loss	$ (56,284)	$ (51,844)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	5,257	8,125
Depreciation and amortization expense	1,459	1,485
Loss on disposal of property and equipment	0	95
Noncash lease expense	2,158	0
Net amortization of premiums on marketable securities	306	630
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(46)	(1,167)
Accounts payable	(462)	(1,874)
Accrued expenses and other current liabilities	(546)	591
Operating lease liabilities	(2,244)	0
Deferred rent	0	118
Net cash used in operating activities	(50,402)	(43,841)
Cash flows from investing activities:
Purchases of property and equipment	(314)	(1,249)
Purchases of marketable securities	(59,718)	0
Maturities of marketable securities	35,000	55,000
Net cash provided by (used in) investing activities	(25,032)	53,751
Cash flows from financing activities:
Proceeds from private investment	0	86,400
Proceeds from issuance of common stock under the ATM Program, net of commissions	2,904	0
Payments of offering costs	(141)	(303)
Proceeds from exercise of common stock options	0	3,294
Proceeds from issuance of common stock under Employee Stock Purchase Plan	49	86
Net cash provided by financing activities	2,812	89,477
Net increase (decrease) in cash, cash equivalents and restricted cash	(72,622)	99,387
Cash, cash equivalents and restricted cash at beginning of period	133,430	59,932
Cash, cash equivalents and restricted cash at end of period	$ 60,808	$ 159,319