CONDENSED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
CASH FLOWS FROM OPERATING ACTIVITIES
Net loss	$ (2,364)	$ (2,665)
Adjustments to reconcile net loss to net cash used in operating activities:
Gain on investments		(18)
Bad debts expense		5
Depreciation and amortization	111	117
Stock-based compensation	252	698
Loss on remeasurement of common stock warrant liability	5
(Increase) decrease in current assets:
Accounts receivable	(11)	9
Prepaid expenses	(3)	(75)
Inventory	(74)	(247)
Deposits	1	2
Increase (decrease) in current liabilities:
Accounts payable	99	(22)
Accrued expenses	37	(116)
Deferred rent	(1)	(6)
Net cash used in operating activities	(1,948)	(2,318)
CASH FLOWS FROM INVESTING ACTIVITIES
Proceeds received on sale of securities		798
Purchase of property and equipment	(11)	(3)
Net cash provided by (used in) investing activities	(11)	795
CASH FLOWS FROM FINANCING ACTIVITIES
Repayments of notes payable, net	(32)	(26)
Repayments of notes payable, related parties		(6)
Repayments of capital lease obligations	(19)	(18)
Proceeds from the exercise of warrants	36
Net cash provided by financing activities	(15)	(50)
NET CHANGE IN CASH	(1,974)	(1,573)
CASH AT BEGINNING OF PERIOD	4,920	2,101
CASH AT END OF PERIOD	2,946	528
SUPPLEMENTAL INFORMATION:
Interest paid	13	22
Income taxes paid
NON-CASH INVESTING AND FINANCING ACTIVITIES:
Purchases of equipment under capital lease obligations		10
Common stock issued on accrued bonus	$ 32