CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Cash flows from operating activities:
Net loss	$ (19,839)	$ (22,906)	$ (67,653)	$ (61,732)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization expense	800	700	2,281	1,842
Net amortization of premiums and accretion of discounts on marketable securities			291	1,389
Amortization of operating lease right-of-use assets			783	879
Stock-based compensation expense			7,884	6,944
Loss on disposal of property and equipment			200	73
Changes in operating assets and liabilities:
Prepaid expenses and other current assets			(1,454)	(2,219)
Accounts payable			(718)	172
Other assets			(28)	35
Operating lease liabilities			6,394	70
Accrued expenses and other current liabilities			(6,116)	4,751
Net cash used in operating activities			(58,136)	(47,796)
Cash flows from investing activities:
Purchases of property and equipment			(11,642)	(8,114)
Purchases of marketable securities			(94,201)	(151,370)
Proceeds from sales or maturities of marketable securities			110,000	254,001
Net cash provided by investing activities			4,157	94,517
Cash flows from financing activities:
Proceeds from at the market equity offering, net of issuance costs			7,189
Payments of finance lease obligations				(189)
Proceeds from exercise of stock options			297	393
Payments of offering costs				(100)
Net cash provided by financing activities			7,486	104
Net increase (decrease) in cash, cash equivalents and restricted cash			(46,493)	46,825
Cash, cash equivalents and restricted cash at beginning of period			124,355	70,249
Cash, cash equivalents and restricted cash at end of period	77,862	117,074	77,862	117,074
Supplemental cash flow information:
Cash paid for interest				1
Supplemental disclosure of non-cash investing and financing information:
Purchases of property and equipment included in accounts payable and accrued expenses			17
Deferred offering costs included in accounts payable and accrued expenses				253
Operating lease liabilities arising from obtaining right-of-use assets				9,946
Vesting of common stock subject to repurchase			11	31
Remeasurement of operating lease right-of-use asset for lease modification				5,592
Reconciliation of cash, cash equivalents and restricted cash:
Cash and cash equivalents	75,413	114,626	75,413	114,626
Restricted cash	2,449	2,448	2,449	2,448
Total cash, cash equivalents and restricted cash shown in the statement of cash flows	$ 77,862	$ 117,074	$ 77,862	$ 117,074