Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Cash flows from operating activities
Net loss	$ (899)	$ (2,724)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	262	253
Non-cash operating lease expense	289	265
Impairment of intangible assets	250	65
Stock-based compensation	644	1,279
Gain on forgiveness of debt	(1,137)
Interest expense on related party note payable	118	105
Change in fair value of warrant liability		(207)
Other non-cash operating activity	(1)
Changes in operating assets and liabilities:
Accounts receivable	(441)	1,112
Inventory, net	(268)	316
Prepaid expenses and other current assets	39	33
Deposits and other assets	24	27
Accounts payable	148	(294)
Accrued liabilities	17	(256)
Operating lease liabilities	(342)	(315)
Net cash used in operating activities	(1,297)	(341)
Cash flows from investing activities
Purchases of property and equipment	(23)	(28)
Payments for patent licenses	(22)	(80)
Net cash used in investing activities	(45)	(108)
Cash flows from financing activities
Proceeds from Paycheck Protection Program loans	474	654
Proceeds from note payable from a related party	350
Net cash provided by financing activities	824	654
Net increase (decrease) in cash	(518)	205
Cash, beginning of period	689	484
Cash, end of period	171	689
Supplemental disclosure of cash flow information:
Cash paid for interest	5	5
Supplemental disclosure of non-cash investing and financing activities:
Gain on forgiveness of debt	1,137
Right-of-use assets obtained in exchange for operating lease liabilities	479	421
Right-of-use assets reduction related to operating lease termination	196
Patent license costs included in accrued liabilities	$ 6	$ 3