Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Cash flows from operating activities:
Net loss	$ (2,821)	$ (1,642)
Adjustments to reconcile net loss to net cash used in operating activities:
Other income	(30)	0
Gain on forgiveness of PPP loan	0	(801)
Depreciation	44	47
Stock-based compensation	44	140
Provision for doubtful accounts receivable	(9)	6
Provision for slow-moving and obsolete inventories	129	89
Provision for warranties	(30)	12
Amortization of loan discounts and origination fees	69	38
Changes in operating assets and liabilities (sources / (uses) of cash):
Accounts receivable	(83)	532
Inventories	370	(1,963)
Short-term deposits	12	12
Prepaid and other assets	20	4
Accounts payable	61	951
Accrued and other liabilities	(211)	(209)
Deferred revenue	(268)	1
Total adjustments	118	(1,141)
Net cash used in operating activities	(2,703)	(2,783)
Cash flows from investing activities:
Acquisitions of property and equipment	(35)	(109)
Net cash used in investing activities	(35)	(109)
Cash flows from financing activities (sources / (uses) of cash):
Proceeds from the exercise of warrants	0
Principal payments under finance lease obligations	(1)	(1)
Common stock withheld in lieu of income tax withholding on vesting of restricted stock units	0	(2)
Payments on the 2021 Streeterville note	(615)	0
Net proceeds from the credit line borrowings - Credit Facilities	897	1,080
Net cash provided by financing activities	281	1,604
Net decrease in cash and restricted cash	(2,457)	(1,288)
Cash and restricted cash, beginning of period	2,682	2,178
Cash and restricted cash, end of period	225	890
Classification of cash and restricted cash:
Cash	225	548
Restricted cash held in other assets	0	342
Cash and restricted cash	$ 225	$ 890