Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Revenue	$ 1,795,000	$ 1,654,000	$ 3,436,000	$ 3,104,000
Cost of revenue	1,501,000	1,489,000	2,822,000	2,557,000
Gross profit	294,000	165,000	614,000	547,000
Operating expenses:
Research and development	1,921,000	2,180,000	4,061,000	4,110,000
Selling, general and administrative	3,393,000	2,930,000	7,046,000	6,511,000
Total operating expenses	5,314,000	5,110,000	11,107,000	10,621,000
Loss from operations	(5,020,000)	(4,945,000)	(10,493,000)	(10,074,000)
Gain on forgiveness of Paycheck Protection Program loan	0	1,358,000	0	1,358,000
Modification of warrants	0	(86,000)	0	(373,000)
Interest expense, net	(284,000)	(245,000)	(554,000)	(479,000)
Other expense, net	(40,000)	(53,000)	(61,000)	(118,000)
Net loss from consolidated companies	(5,344,000)	(3,971,000)	(11,108,000)	(9,686,000)
Impairment loss on investment in unconsolidated limited liability company	(455,000)	0	(455,000)	0
Loss from investment in unconsolidated limited liability company	0	(79,000)	(122,000)	(155,000)
Comprehensive and net loss	(5,799,000)	(4,050,000)	(11,685,000)	(9,841,000)
Series B convertible preferred stock dividends	(1,305,000)	(1,119,000)	(2,571,000)	(2,273,000)
Net loss attributable to common stockholders	$ (7,104,000)	$ (5,169,000)	$ (14,256,000)	$ (12,114,000)
Net loss per share of common stock:
Basic and diluted (in dollars per share)	$ (0.67)	$ (0.49)	$ (1.34)	$ (1.27)
Weighted average shares used in computing net loss per common share:
Basic and diluted (in shares)	10,640,806	10,501,057	10,630,498	9,573,740