Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Operating activities
Net loss	$ (109,872)	$ (80,847)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation expense	2,414	2,515
Stock-based compensation expense	13,350	11,070
Net amortization of premiums and discounts on marketable securities	152	673
Changes in operating assets and liabilities:
Accounts receivable	2,500	(500)
Unbilled accounts receivable	908	(606)
Prepaid expenses and other current assets	(170)	(134)
Operating lease assets and liabilities	(372)	(438)
Other assets	(1,562)	36
Accounts payable	(1,176)	973
Accrued expenses and other liabilities	555	1,950
Deferred revenue	(3,777)	(13,170)
Net cash used in operating activities	(97,050)	(78,478)
Investing activities
Purchases of marketable securities	(151,153)	(216,234)
Maturities of marketable securities	165,529	88,278
Purchases of property and equipment	(1,963)	(1,713)
Net cash used in investing activities	12,413	(129,669)
Financing activities
Proceeds from issuance of common stock in connection with public offerings, net of issuance costs	80,804	182,857
Principal payments on capital lease obligations		(18)
Proceeds from issuance of common stock under benefit plans, net	3,519	3,668
Net cash provided by financing activities	84,323	186,507
Net decrease in cash, cash equivalents and restricted cash	(314)	(21,640)
Cash, cash equivalents, and restricted cash, beginning of period	36,504	58,144
Cash, cash equivalents, and restricted cash, end of period	36,190	36,504
Supplemental cash flow information
Cash paid for operating lease liabilities	2,219
Non-cash investing and financing activities:
Property and equipment purchases unpaid at end of period	26	37
Cash and cash equivalents	35,098	35,412
Restricted cash	$ 1,092	$ 1,092