Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Operating activities
Net loss	$ (95,639,000)	$ (54,853,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	10,606,000	4,623,000
Depreciation expense	845,000	479,000
Non-cash lease expense	203,000	155,000
Amortization of premiums and accretion of discounts on available-for-sale securities, net	(422,000)	493,000
Changes in operating assets and liabilities:
Unbilled grant receivable	1,109,000	(1,036,000)
Prepaid expenses and other current assets	(1,257,000)	1,650,000
Accounts payable and accrued liabilities	2,101,000	5,150,000
Accrued legal settlement	10,000,000
Operating lease liability	(15,000)	241,000
Net cash used in operating activities	(72,469,000)	(43,098,000)
Investing activities
Purchases of available-for-sale securities	(95,288,000)	(299,197,000)
Maturities of available-for-sale securities	154,093,000	278,639,000
Proceeds from sales of available-for-sale securities		18,052,000
Purchases of property and equipment	(1,141,000)	(1,573,000)
Net cash provided by (used in) investing activities	57,664,000	(4,079,000)
Financing activities
Proceeds from exercise of common stock options	654,000	327,000
Proceeds from public offering, net of issuance costs		96,762,000
Net cash provided by financing activities	654,000	97,089,000
Net (decrease) increase in cash, cash equivalents and restricted cash	(14,151,000)	49,912,000
Cash, cash equivalents and restricted cash, beginning of period	110,537,000	60,625,000
Cash, cash equivalents and restricted cash, end of period	$ 96,386,000	110,537,000
Supplemental disclosures of cash flow information:
Right-of-use asset obtained in exchange for new operating lease liability		$ 680,000