Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Operating activities
Net loss	$ (83,736)	$ (57,363)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation expense	1,823	1,894
Stock-based compensation expense	10,079	7,277
Net amortization of premiums on marketable securities	753	287
Changes in operating assets and liabilities:
Accounts receivable	2,487	2,000
Unbilled accounts receivable	347	(637)
Prepaid expenses and other current assets	(936)	(570)
Operating lease assets and liabilities	(207)	(359)
Other assets	(1,556)	59
Accounts payable	(2,079)	(203)
Accrued expenses and other liabilities	(1,007)	2,745
Deferred revenue	(3,322)	(11,750)
Net cash used in operating activities	(77,354)	(56,620)
Investing activities
Purchases of marketable securities	(67,864)	(181,349)
Maturities of marketable securities	118,486	61,968
Purchases of property and equipment	(1,847)	(1,194)
Net cash provided by (used in) investing activities	48,775	(120,575)
Financing activities
Proceeds from issuance of common stock in connection with follow-on offering, net of issuance costs	80,853	182,934
Principal payments on capital lease obligations	0	(17)
Proceeds from issuance of common stock under benefit plans, net	3,252	2,699
Net cash provided by financing activities	84,105	185,616
Net increase (decrease) in cash, cash equivalents and restricted cash	55,526	8,421
Cash, cash equivalents, and restricted cash, beginning of period	36,504	58,144
Cash, cash equivalents, and restricted cash, end of period	92,030	66,565
Supplemental cash flow information
Cash paid for operating lease liabilities	2,219	0
Non-cash investing and financing activities:
Offering costs unpaid at end of period	49	76
Property and equipment purchases unpaid at end of period	20	314
Cash and cash equivalents	90,938	65,473
Restricted cash	$ 1,092	$ 1,092