Consolidated Statements of Operations - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Income Statement [Abstract]
Services revenue	$ 912,000	$ 964,000	$ 1,778,000	$ 3,008,000
Grant revenue	482,000	1,428,000	1,553,000	2,923,000
Total revenue	1,394,000	2,392,000	3,331,000	5,931,000
Cost of revenue:
Cost of services revenue (including depreciation)	1,060,000	1,386,000	2,001,000	3,978,000
Cost of grant revenue	442,000	1,428,000	1,513,000	2,923,000
Provision for contract losses	20,000	0	390,000	33,737,000
Total cost of revenue	1,522,000	2,814,000	3,904,000	40,638,000
Gross loss	(128,000)	(422,000)	(573,000)	(34,707,000)
Operating expenses:
Selling, general and administrative	17,652,000	22,403,000	21,817,000	42,465,000
Research and development	4,946,000	5,905,000	10,206,000	15,280,000
Impairment charges	0	0	1,008,000	0
Total operating expenses	22,598,000	28,308,000	33,031,000	57,745,000
Operating loss	(22,726,000)	(28,730,000)	(33,604,000)	(92,452,000)
Interest income, net	270,000	213,000	553,000	407,000
Gain (loss) on warrant remeasurement	(52,000)	8,284,000	252,000	12,310,000
Other income (expense), net	827,000	(109,000)	574,000	(185,000)
Net loss before taxes	(21,681,000)	(20,342,000)	(32,225,000)	(79,920,000)
(Provision) benefit for income taxes	(2,000)	125,000	(2,000)	735,000
Net loss	$ (21,683,000)	$ (20,217,000)	$ (32,227,000)	$ (79,185,000)
Loss per share:
Loss per share – Basic (in dollars per share)	$ (0.11)	$ (0.11)	$ (0.16)	$ (0.42)
Loss per share – Diluted (in dollars per share)	$ (0.11)	$ (0.11)	$ (0.16)	$ (0.42)
Weighted average number of shares outstanding – Basic (in shares)	200,616,841	190,182,474	198,768,335	187,123,737
Weighted average number of shares outstanding – Diluted (in shares)	200,616,841	190,182,474	198,768,335	187,123,737