Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Operating activities
Net loss	$ (48,562)	$ (59,998)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation expense	1,133	1,212
Stock-based compensation expense	7,616	6,726
Net (accretion of discounts) amortization of premiums on marketable securities	(3,078)	641
Changes in operating assets and liabilities:
Accounts receivable	0	2,143
Unbilled accounts receivable	427	394
Prepaid expenses and other current assets	(242)	25
Operating lease assets and liabilities	337	(42)
Other assets	(110)	(1,563)
Accounts payable	251	471
Accrued expenses and other liabilities	(1,428)	3,448
Deferred revenue	(421)	(2,929)
Net cash used in operating activities	(44,901)	(49,472)
Investing activities
Purchases of marketable securities	(143,832)	(15,166)
Maturities of marketable securities	70,132	67,784
Purchases of property and equipment	(366)	(1,564)
Net cash (used in) provided by investing activities	(74,066)	51,054
Financing activities
Proceeds from issuance of common stock in connection with follow-on offering, net of issuance costs	117,345	0
Proceeds from issuance of common stock under benefit plans, net	490	3,159
Net cash provided by financing activities	117,835	3,159
Net (decrease) increase in cash, cash equivalents and restricted cash	(1,132)	4,741
Cash, cash equivalents, and restricted cash, beginning of period	36,190	36,504
Cash, cash equivalents, and restricted cash, end of period	35,058	41,245
Supplemental cash flow information
Cash paid for operating lease liabilities	1,646	1,400
Non-cash investing and financing activities:
Property and equipment purchases unpaid at end of period	47	151
Cash and cash equivalents	33,966	40,153
Restricted cash	$ 1,092	$ 1,092