Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (9,229,000)	$ (8,131,000)	$ (9,527,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	820,000	1,015,000	1,885,000
Stock-based compensation expense	87,000	84,000	341,000
Adjustments to fair value of warrant derivatives		(52,000)	(99,000)
Adjustments to warrant exercise price		24,000
Changes in assets and liabilities:
Accounts receivable	(343,000)	151,000	(143,000)
Inventory	(90,000)	(70,000)	(34,000)
Prepaid expenses and other current assets	(16,000)	22,000	26,000
Patents and licenses		14,000	212,000
Other assets	9,000		27,000
Accounts payable, accrued expenses and other liabilities	(41,000)	12,000	(132,000)
Net cash used in operating activities	(8,803,000)	(6,931,000)	(7,444,000)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchase of property and equipment		(189,000)	(152,000)
Net cash used in investing activities		(189,000)	(152,000)
CASH FLOWS FROM FINANCING ACTIVITIES:
Net proceeds from sale of common, prefunded warrants and preferred stock	3,801,000	9,680,000
Net proceeds from exercise of warrants	99,000		200,000
Net cash provided by financing activities	3,900,000	9,680,000	200,000
Net increase (decrease) in cash and cash equivalents	(4,903,000)	2,560,000	(7,396,000)
Cash and cash equivalents at beginning of year	5,616,000	3,056,000	10,452,000
Cash and cash equivalents at end of year	$ 713,000	$ 5,616,000	$ 3,056,000