Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities
Net income (loss)	$ 3,266,000	$ (2,515,000)
Adjustments to reconcile net income (loss) to net cash provided by operating activities
Depreciation	338,000	339,000
Stock-based compensation expense	1,519,000	1,270,000
Stock issued for services		107,000
Write off of deferred financing costs		68,000
Amortization of debt discount		156,000
Loss from equity-method investment in SAVSU	672,000	1,005,000
Amortization of deferred rent related to lease incentives	(127,000)	(127,000)
Change in operating assets and liabilities
Accounts receivable, trade	(2,024,000)	172,000
Inventories	(1,662,000)	(89,000)
Prepaid expenses and other current assets	(104,000)	(181,000)
Accounts payable	(11,000)	21,000
Accrued compensation and other current liabilities	497,000	292,000
Accrued interest		152,000
Deferred rent	(16,000)	(65,000)
Net cash provided by operating activities	2,348,000	605,000
Cash flows from investing activities
Investment in SAVSU	(6,000,000)
Purchase of property and equipment	(500,000)	(144,000)
Net cash used in investing activities	(6,500,000)	(144,000)
Cash flows from financing activities
Proceeds from private equity transaction	20,000,000
Proceeds from note payable to related party		1,000,000
Proceeds from exercise of common stock options and warrants	12,900,000	3,978,000
Payments on equipment loan	(12,000)	(13,000)
Payments on capital lease obligation	(13,000)	(11,000)
Payments for redemption of preferred stock	(4,250,000)
Payments related to stock issuance	(43,000)	(9,000)
Payments of preferred stock dividends	(436,000)	(106,000)
Deferred costs paid related to potential stock issuance		(43,000)
Net cash provided by financing activities	28,146,000	4,796,000
Net increase in cash and cash equivalents	23,994,000	5,257,000
Cash and cash equivalents - beginning of year	6,663,000	1,406,000
Cash and cash equivalents - end of year	30,657,000	6,663,000
Non-cash investing and financing activities
Series A preferred stock dividends accrued not yet paid		106,000
Stock issued for services in prior period included in liabilities at prior year-end	36,000	36,000
Receivables converted to equity investment in SAVSU	150,000
Preferred stock issued to convert related party note payable and accrued interest		4,250,000
Capital lease obligations incurred for purchase of equipment		52,000
Purchase of equipment with debt	18,000	39,000
Legal fees for private equity transaction not yet paid	44,000
Purchase of property and equipment not yet paid	$ 54,000	$ 22,000