Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Other Income (Expense), Net
Loss before income taxes	$ (23,767)	$ (22,789)
Income tax benefit	29	55
Net loss	$ (23,738)	$ (22,734)
Net loss per share
Net (loss) income per share, basic (in dollars per share)	$ (0.10)	$ (0.10)
Net (loss) income per share, diluted (in dollars per share)	$ (0.10)	$ (0.10)
Weighted average shares outstanding, basic (in shares)	249,220,335	229,770,381
Weighted average shares outstanding, diluted (in shares)	249,220,335	229,770,381
Continuing Operations
Revenues
Total revenues	$ 1,065	$ 1,851
Operating Expenses
Research and development	14,249	12,163
Selling, general and administrative	10,151	11,639
Total operating expenses	25,475	25,329
Operating loss	(24,410)	(23,478)
Other Income (Expense), Net
Interest expense	(2)	(324)
Interest income	608	633
Other income, net	37	380
Total other income, net	643	689
Loss before income taxes	(23,767)	(22,789)
Income tax benefit	29	55
Continuing Operations | Product revenues
Revenues
Total revenues	138	324
Continuing Operations | Service revenues
Revenues
Total revenues	919	1,527
Operating Expenses
Cost of products and services	1,075	1,527
Continuing Operations | Other revenues
Revenues
Total revenues	$ 8	$ 0