CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Cash flows from operating activities:
Net loss	$ (6,674)	$ (21,671)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation expense	541	390
Stock‑based compensation expense	2,755	1,794
Amortization of premiums and discounts on marketable securities, net	(237)	142
Changes in operating assets and liabilities:
Collaboration receivable	(6,297)	0
Prepaid expenses and other current assets	4,339	(1,670)
Right-of-use assets, operating leases	3,332	1,582
Other non-current assets	(8,633)	(562)
Accounts payable	534	2,061
Accrued expenses and other current liabilities	4,107	(1,526)
Operating lease liabilities	(1,950)	(1,531)
Deferred revenue	211,582	0
Net cash provided by (used in) operating activities	203,399	(20,991)
Cash flows from investing activities:
Purchases of property and equipment	(1,668)	(594)
Purchases of marketable securities	(101,776)	(182,653)
Maturities of marketable securities	63,000	1,714
Net cash used in investing activities	(40,444)	(181,533)
Cash flows from financing activities:
Proceeds from issuance of common stock in connection with the Vertex Agreement	19,407	0
Proceeds from exercise of stock options	129	50
Net cash provided by financing activities	19,536	50
Net increase (decrease) in cash, cash equivalents, and restricted cash	182,491	(202,474)
Cash, cash equivalents, and restricted cash at beginning of period	49,107	291,064
Cash, cash equivalents, and restricted cash at end of period	231,598	88,590
Supplemental cash flow disclosures:
Purchases of property and equipment included in accounts payable and accrued expenses	57	391
Right-of-use assets surrendered as part of lease modification	7,761	0
Recognition of right-of use asset upon adoption of ACS 842	0	32,991
Transfer of deposits for equipment from operating to investing cash flows	617	495
Vesting of options early exercised subject to repurchase	$ 26	$ 35