Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($)	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Operating activities
Net loss	$ (22,840,000)	$ (3,797,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	2,083,000	107,000
Depreciation expense	230,000	0
Other non-cash expense		310,000
Amortization of premiums and accretion of discounts on available-for-sale securities, net	226,000
Prepaid expenses and other current assets	3,217,000	(1,203,000)
Changes in operating assets and liabilities:
Unbilled grant receivables	(1,289,000)
Accounts payable and accrued expenses	3,318,000	546,000
Operating lease liability	433,000
Net cash used in operating activities	(14,622,000)	(4,037,000)
Investing activities
Purchases of available-for-sale securities	(173,563,000)
Maturities of available-for-sale securities	152,740,000
Proceeds from sales of available-for-sale securities	9,988,000
Purchases of property and equipment	(418,000)
Principal payments received on stockholder note receivable		3,000
Net cash (used in) provided by investing activities	(11,253,000)	3,000
Financing activities
Proceeds from exercise of common stock options	189,000	238,000
Proceeds from issuance of convertible preferred stock and common stock warrants, net of issuance costs		85,396,000
Proceeds from exercise of common stock warrants		55,000
Proceeds from follow-on public offering, net of issuance costs	96,762,000
Proceeds from issuance of convertible notes, including derivative, net of issuance costs		1,664,000
Payments of deferred offering costs		209,000
Net cash provided by financing activities	96,951,000	87,144,000
Net increase (decrease) in cash and cash equivalents	71,076,000	83,110,000
Cash and cash equivalents, beginning of period	60,625,000	2,056,000
Cash and cash equivalents, end of period	131,701,000	85,166,000
Supplemental disclosures of cash flow information:
Deferred offering costs included in accounts payable and accrued liabilities		206,000
Issuance costs for convertible preferred stock included in accounts payable and accrued liabilities		3,470,000
Allocation of proceeds to common stock warrants issued in Series B convertible preferred stock financing		10,591,000
Issuance of Series B-1 preferred stock upon conversion of promissory notes		4,515,000
Recognition of warrant liability in connection with Series B convertible preferred stock financing		364,000
Recognition of derivative liability upon issuance of convertible notes		$ 774,000
Right-of-use asset obtained in exchange for new operating lease liability	$ 680,000