Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Revenues
Total revenues	$ 1,767	$ 2,911	$ 3,618	$ 8,424
Operating Expenses
Impairment of goodwill			0	482
Impairment of other noncurrent assets			0	638
Other income (Expense), Net
Equity in net loss of affiliates			0	(1)
Loss from continuing operations before income taxes	(20,384)	(26,148)	(43,173)	(50,104)
Income tax benefit	65	89	120	147
Income from discontinued operations, net of income taxes	0	8,424	0	13,071
Net loss	$ (20,319)	$ (17,635)	$ (43,053)	$ (36,886)
Net Loss per Share
Net loss from continuing operations per share, basic (in dollars per share)	$ (0.08)	$ (0.13)	$ (0.18)	$ (0.25)
Net loss from continuing operating per share, diluted (in dollars per share)	(0.08)	(0.13)	(0.18)	(0.25)
Net income (loss) from discontinued operations per share, diluted (in dollars per share)	0	0.04	0	0.07
Net income (loss) from discontinued operations per share, basic (in dollars per share)	0	0.04	0	0.07
Net loss per share, basic (in dollars per share)	(0.08)	(0.09)	(0.18)	(0.18)
Net loss per share, diluted (in dollars per share)	$ (0.08)	$ (0.09)	$ (0.18)	$ (0.18)
Weighted average shares outstanding, basic (in shares)	248,003,322	200,461,441	240,307,403	200,047,629
Weighted average shares outstanding, diluted (in shares)	248,003,322	200,461,441	240,307,403	200,047,629
Continuing Operations
Revenues
Total revenues	$ 1,767	$ 2,911	$ 3,618	$ 8,424
Operating Expenses
Research and development	11,874	11,954	24,037	23,755
Selling, general and administrative	9,316	12,670	20,954	26,359
Impairment of goodwill	0	0	0	482
Impairment of other noncurrent assets	0	638	0	638
Total operating expenses	22,887	27,073	48,215	54,739
Operating loss	(21,120)	(24,162)	(44,597)	(46,315)
Other income (Expense), Net
Interest expense	(136)	(2,063)	(460)	(4,101)
Interest income	828	37	1,460	75
Other income, net	44	40	424	238
Total other income (expense), net	736	(1,986)	1,424	(3,788)
Equity in net loss of affiliates	0	0	0	(1)
Loss from continuing operations before income taxes	(20,384)	(26,148)	(43,173)	(50,104)
Income tax benefit	65	89	120	147
Loss from continuing operations	(20,319)	(26,059)	(43,053)	(49,957)
Continuing Operations | Product revenues
Revenues
Total revenues	324	621	648	1,113
Continuing Operations | Service revenues
Revenues
Total revenues	1,438	2,213	2,965	7,146
Operating Expenses
Cost of products and services	1,697	1,811	3,224	3,505
Continuing Operations | Other revenues
Revenues
Total revenues	$ 5	$ 77	$ 5	$ 165