Statements of Cash Flows (Unaudited) - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Cash flows from operating activities
Net income	$ 427,000	$ 3,000
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation	98,000	78,000
Stock-based compensation expense	606,000	373,000
Amortization of operating lease liability	(43,000)
Interest expense – finance type lease	2,000
Amortization of deferred rent related to lease incentives	0	(32,000)
Loss from equity-method investment in SAVSU	232,000	144,000
Change in operating assets and liabilities
Accounts receivable, trade	118,000	(23,000)
Inventories	(551,000)	10,000
Prepaid expenses and other current assets	6,000	12,000
Accounts payable	553,000	(69,000)
Accrued compensation and other current liabilities	(302,000)	(101,000)
Deferred rent		(3,000)
Net cash provided by operating activities	1,146,000	392,000
Cash flows from investing activities
Purchase of property and equipment	(156,000)	(41,000)
Net cash used in investing activities	(156,000)	(41,000)
Cash flows from financing activities
Payments on equipment loan	(4,000)	(3,000)
Payments on capital lease obligation/finance lease	(4,000)	(3,000)
Proceeds from exercise of common stock options and warrants	185,000	73,000
Cash received in advance of issuance of stock on warrant exercises		57,000
Payments of preferred stock dividends		(106,000)
Net cash provided by financing activities	177,000	18,000
Net increase in cash and cash equivalents	1,167,000	369,000
Cash and cash equivalents - beginning of period	30,657,000	6,663,000
Cash and cash equivalents - end of period	31,824,000	7,032,000
Non-cash investing and financing activities
Stock issued for services provided in prior period included in liabilities at year-end		36,000
Purchase of equipment with debt		18,000
Series A preferred stock dividends accrued not yet paid		106,000
Purchase of property & equipment not yet paid	$ 46,000