Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Cash flows from operating activities
Net income (loss)	$ 4,119	$ (6,836)
Adjustments to reconcile net loss to net cash and cash equivalents used in operating activities:
Bad debt expense	78	24
Depreciation and amortization	613	722
Loss on sale of property and equipment	47
Gain resulting from termination of lease	(38)
Provision for product warranties	530	296
Gain on bargain purchase		(588)
Stock-based compensation	415	386
Impairment of intangible assets	88
Changes in operating assets (decrease (increase)):
Accounts receivable	(8,432)	10,250
Inventories	2,735	(1,430)
Prepaid and other current assets	(557)	(199)
Changes in operating liabilities (increase (decrease)):
Accounts payable and accrued expenses	962	(2,303)
Deferred revenue	(637)	(460)
Product warranties	(209)	(296)
Total adjustments	(4,405)	6,402
Net cash used in operating activities	(286)	(434)
Cash flows from investing activities
Acquisition of property and equipment	(128)	(359)
Proceeds from the sale of property and equipment	257
Investments matured		7,389
Net cash provided by investing activities	129	7,030
Cash flows from financing activities
Loan proceeds		267
Principal repayment of loan payable	(216)
Withholding taxes on stock compensation	(15)	(57)
Exercise of warrants		1
Net cash provided by (used in) financing activities	(231)	211
Net increase (decrease) in cash and cash equivalents	(388)	6,807
Cash and cash equivalents, beginning of year	14,907	8,100
Cash and cash equivalents, end of year	14,519	14,907
Supplemental disclosure of cash flow information:
Interest paid	2	12
Supplemental schedule of noncash investing and financing transactions
Transfer of property and equipment to inventory	66
PPP loan (forgiveness portion)		758
Decrease in operating lease right-of-use assets and operating lease liabilities resulting from early termination of lease	$ 655