BALANCE SHEET COMPONENTS (Tables)

3 Months Ended

Mar. 31, 2024

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Schedule of accounts receivable, net and activity in allowance for uncollectible accounts

Accounts receivable, net consisted of the following (in thousands):

	March 31, 2024		December 31, 2023
Accounts receivable	$	165	$	99
Allowance for uncollectible accounts	(4)		(4)
Accounts receivable, net	$	161	$	95

The following was the activity in the allowance for uncollectible accounts (in thousands):

	Three Months Ended March 31,
	2024		2023
Balance as of beginning of period	$	4	$	6
Increase in provision	—		—
Amounts written off, less recoveries	—		(2)
Balance as of end of period	$	4	$	4

Schedule of inventory, net and activity in reserve for obsolescence

Inventory, net consisted of the following (in thousands):

	March 31, 2024		December 31, 2023
Raw materials	$	797	$	747
Work in progress	11		—
Finished goods	71		53
Total inventory	879		800
Less: reserve for obsolescence	(5)		(5)
Inventory, net	$	874	$	795

The following was the activity in the reserve for obsolescence (in thousands):

	Three Months Ended March 31,
	2024		2023
Balance as of beginning of period	$	5	$	18
Increase in reserve	—		—
Amounts relieved	—		—
Balance as of end of period	$	5	$	18

Schedule of prepaid expenses

Prepaid expenses consisted of the following (in thousands):

	March 31, 2024		December 31, 2023
Software licenses	139		152
Professional services	66		30
Insurance	49		64
Deposit on equipment purchase	25		—
Patents	9		14
Prepaid inventory	8		111
Other	50		17
Total prepaid expenses	$	346	$	388

Schedule of property and equipment, net

Property and equipment, net consisted of the following (in thousands):

	March 31, 2024		December 31, 2023
Research and development equipment	$	1,763	$	1,763
Office and computer equipment	808		808
Autos	54		54
Furniture and fixtures	41		41
Leasehold improvements	143		141
Total in service	2,809		2,807
Accumulated depreciation and amortization	(2,456)		(2,419)
Property and equipment, net	$	353	$	388

Schedule of accrued expenses

Accrued expenses consisted of the following (in thousands):

	March 31, 2024		December 31, 2023
Compensation, severance and related benefits	$	285	$	232
Legal and consulting professional services	27		121
Product warranty	12		15
Other	67		—
Total accrued expenses	$	391	$	368

Schedule of maturities of notes payable

As of March 31, 2024, future principal payments were as follows (in thousands):

2024	$	25
2025	36
2026	39
2027	43
2028	38
Total principal payments	181
Less: current portion of notes payable	(34)
Notes payable, less current portion	$	147