CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS (Unaudited) - USD ($) shares in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Income Statement [Abstract]
Net sales	$ 2,812,000	$ 2,958,000
Cost of sales	1,801,000	2,156,000
Gross profit	1,011,000	802,000
Costs and expenses:
Research and development	6,968,000	6,024,000
Sales, general and administrative	10,105,000	10,673,000
Total costs and expenses	17,073,000	16,697,000
Loss from operations	(16,062,000)	(15,895,000)
Other (expense) income:
Interest expense	(418,000)	(917,000)
Interest expense related-party	(1,013,000)	0
Gain on extinguishment of debt	0	3,366,000
Foreign currency exchange loss	233,000	9,000
Interest income	420,000	22,000
Other income (expense), net	45,000	(50,000)
Total other (expense) income, net	(733,000)	2,430,000
Net loss before income taxes	(16,795,000)	(13,465,000)
Provision for income taxes	0	0
Net loss	$ (16,795,000)	$ (13,465,000)
Basic net loss per share (in usd per share)	$ (0.17)	$ (0.20)
Diluted net loss per share (in usd per share)	$ (0.17)	$ (0.20)
Weighted average shares outstanding, basic (in shares)	98,301	67,755
Weighted average shares outstanding, diluted (in shares)	98,301	67,755
Other comprehensive loss:
Net loss	$ (16,795,000)	$ (13,465,000)
Net unrealized gain (loss) on debt securities available-for-sale	24,000	(93,000)
Foreign currency translation adjustment	(255,000)	(79,000)
Comprehensive loss	$ (17,026,000)	$ (13,637,000)