CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
REVENUE:
Total revenue	$ 1,464,000	$ 3,647,000
Cost of revenue	15,319,000	8,732,000
Gross loss	(13,855,000)	(5,085,000)
OPERATING EXPENSES:
Research and development	26,171,000	37,644,000
Sales and marketing	12,528,000	19,317,000
General and administrative	25,234,000	36,762,000
Impairment of long-lived assets	9,988,000	0
Total operating expenses	73,921,000	93,723,000
LOSS FROM OPERATIONS	(87,776,000)	(98,808,000)
OTHER INCOME (EXPENSE):
Change in fair value of convertible note and warrant liabilities	(858,000)	(14,000)
Interest income and other	1,317,000	1,545,000
Interest expense and other	248,000	(1,379,000)
Total other income (expense), net	707,000	152,000
Provision for income tax expense	57,000	58,000
Net loss	(87,126,000)	(98,714,000)
Change in net unrealized gain (loss) on available-for-sale securities, net of tax	1,264,000	(940,000)
Change in fair value due to instrument-specific credit risk, net of tax	(21,000)	(25,000)
Net losses reclassified into income during the period, net of tax	46,000	77,000
Comprehensive loss	$ (85,837,000)	$ (99,602,000)
PER SHARE DATA
Net loss per common share (basic) (in dollars per share)	$ (14.95)	$ (18.82)
Net loss per common share (diluted) (in dollars per share)	$ (14.95)	$ (18.82)
Weighted average common shares outstanding (basic) (in shares)	5,827,721	5,245,624
Weighted average common shares outstanding (diluted) (in shares)	5,827,721	5,245,624
Prototype sales
REVENUE:
Total revenue	$ 477,000	$ 1,743,000
Development contracts
REVENUE:
Total revenue	$ 987,000	$ 1,904,000