BALANCE SHEET COMPONENTS (Tables)

3 Months Ended

Mar. 31, 2023

Organization, Consolidation and Presentation of Financial Statements [Abstract]

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

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

	March 31, 2023		December 31, 2022
Accounts receivable	$	50	$	119
Allowance for uncollectible accounts	(4)		(6)
Accounts receivable, net	$	46	$	113

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

	Three Months Ended March 31,
	2023		2022
Balance as of beginning of period	$	6	$	—
Increase in provision	—		—
Amounts written off, less recoveries	(2)		—
Balance as of end of period	$	4	$	—

Schedule of inventory, net and activity in reserve for obsolescence

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

	March 31, 2023		December 31, 2022
Raw materials	$	771	$	772
Work in progress	6		—
Finished goods	56		99
Total inventory	833		871
Less: reserve for obsolescence	(18)		(18)
Inventory, net	$	815	$	853

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

	Three Months Ended March 31,
	2023		2022
Balance as of beginning of period	$	18	$	29
Increase in reserve	—		—
Amounts relieved	—		(3)
Balance as of end of period	$	18	$	26

Schedule of prepaid expenses

Prepaid expenses consist of the following (in thousands):

	March 31, 2023		December 31, 2022
Software licenses	$	113	$	157
Marketing programs and conferences	10		74
Insurance	93		61
Patents	24		39
Professional services	198		41
Other	12		6
Total prepaid expenses	$	450	$	378

Schedule of property and equipment, net

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

	March 31, 2023		December 31, 2022
Research and development equipment	$	1,563	$	1,558
Office and computer equipment	801		800
Autos	54		54
Furniture and fixtures	41		41
Leasehold improvements	119		119
Total in service	2,578		2,572
Accumulated depreciation and amortization	(2,319)		(2,283)
Total in service, net	259		289
Construction in progress	—		5
Property and equipment, net	$	259	$	294

Schedule of accrued expenses

Accrued expenses consist of the following (in thousands):

	March 31, 2023		December 31, 2022
Compensation, severance and related benefits	$	416	$	497
Legal services	150		36
Product warranty	18		18
Personal property and franchise tax	—		6
Other	—		3
Total accrued expenses	$	584	$	560