Consolidated Statements of Cash Flows - USD ($)	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Operating activities:
Net loss	$ (11,689,000)	$ (9,788,000)
Adjustments required to reconcile net loss to net cash used in operating activities:
Depreciation	578,000	575,000
Stock-based compensation	1,749,000	1,950,000
Non-cash interest expense	62,000	300,000
Payment of accreted interest for deferred consideration for asset acquisition	(586,000)
Changes in operating assets and liabilities:
Award receivable	(607,000)
Accounts payable and accrued liabilities	100,000	234,000
Accrued compensation	652,000	(357,000)
Operating lease right-of-use asset and liability, net	97,000	153,000
Prepaid expenses and other current assets	(369,000)	(1,155,000)
Net cash used in operating activities	(10,013,000)	(8,088,000)
Investing activities:
Purchases of property and equipment	(494,000)	(377,000)
Net cash used in investing activities	(494,000)	(377,000)
Financing activities:
Principal payment of deferred consideration for asset acquisition	(1,414,000)	(1,000,000)
Proceeds from Paycheck Protection Program Loan		718,000
Proceeds from sale of common stock, net of offering costs	19,363,000	22,919,000
Proceeds from exercise of warrants and stock options	445,000	81,000
Net cash provided by financing activities	18,394,000	22,718,000
Net increase in cash, cash equivalents and restricted cash	7,887,000	14,253,000
Cash, cash equivalents and restricted cash, beginning of period	10,849,000	6,733,000
Cash, cash equivalents and restricted cash, end of period	18,736,000	20,986,000
Supplemental schedule of non-cash investing and financing activities:
Unpaid offering costs		91,000
Property and equipment included in accounts payable	$ 162,000	$ 7,000