CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS (Unaudited) - USD ($) shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Income Statement [Abstract]
Net sales	$ 3,122,000	$ 3,588,000	$ 8,439,000	$ 8,056,000
Cost of sales	2,136,000	2,287,000	5,502,000	4,745,000
Gross profit	986,000	1,301,000	2,937,000	3,311,000
Costs and expenses:
Research and development	4,712,000	5,001,000	17,341,000	16,191,000
Sales, general and administrative	10,806,000	11,465,000	37,744,000	35,738,000
Total costs and expenses	15,518,000	16,466,000	55,085,000	51,929,000
Loss from operations	(14,532,000)	(15,165,000)	(52,148,000)	(48,618,000)
Other income (expense):
Interest expense	(4,211,000)	(3,955,000)	(12,477,000)	(11,540,000)
Gain on extinguishment of debt	9,840,000	0	9,840,000	0
Foreign currency exchange (loss) gain	(78,000)	229,000	(238,000)	191,000
Interest income	0	149,000	55,000	753,000
Other (expense) income, net	(5,000)	(15,000)	69,000	(82,000)
Total other income (expense), net	5,546,000	(3,592,000)	(2,751,000)	(10,678,000)
Net loss before income taxes	(8,986,000)	(18,757,000)	(54,899,000)	(59,296,000)
Provision for income taxes	0	0	0	0
Net loss	$ (8,986,000)	$ (18,757,000)	$ (54,899,000)	$ (59,296,000)
Basic net loss per share (usd per share)	$ (0.15)	$ (0.33)	$ (0.91)	$ (1.07)
Diluted net loss per share (usd per share)	$ (0.15)	$ (0.33)	$ (0.91)	$ (1.07)
Weighted average shares outstanding basic (shares)	61,146	56,560	60,250	55,617
Weighted average shares outstanding diluted (shares)	61,146	56,560	60,250	55,617
Other comprehensive loss:
Net loss	$ (8,986,000)	$ (18,757,000)	$ (54,899,000)	$ (59,296,000)
Net unrealized (loss) gain on debt securities available-for-sale	(3,000)	(117,000)	(21,000)	62,000
Foreign currency translation adjustment	(27,000)	71,000	(87,000)	90,000
Comprehensive loss	$ (9,016,000)	$ (18,803,000)	$ (55,007,000)	$ (59,144,000)