Condensed Consolidated Statements of Cash Flows (unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Operating activities:
Net loss	$ (4,338)	$ (4,034)
(Loss) Income from discontinued operations	(21)	45
Loss from continuing operations	(4,317)	(4,079)
Adjustments to reconcile net loss to net cash used in operating activities - continuing operations:
Depreciation	107	109
Share-based compensation expense	0	178
Change in fair value of derivative liabilities and loss on debt extinguishment	(27)	378
Inventory obsolescence	(5)	218
Bad debt expense	29	36
Changes in operating assets and liabilities:
Accounts receivable, net	726	761
Costs in excess of billings on uncompleted contracts		2
Inventory	266	140
Deferred costs on uncompleted contracts	(51)	(87)
Net investment in sales-type leases and other current assets	(80)	(50)
Other non-current assets	17	(273)
Accounts payable	731	(1,152)
Accrued liabilities	(106)	136
Deferred revenue and other current liabilities	142	(330)
Other liabilities	(89)	(17)
Net cash used in operating activities - continuing operations	(2,657)	(4,030)
Net cash provided by (used in) operating activities - discontinued operations	198	(122)
Net cash used in operating activities	(2,459)	(4,152)
Investing activities:
Payments related to POWERHOUSE license	(64)
Purchases of property and equipment	(4)	(252)
Proceeds from sale of property and equipment		2
Net cash used in investing activities	(68)	(250)
Financing activities:
Proceeds from warrant exercises, net of costs	8
Restricted cash released upon conversion of debt		173
Proceeds from the issuance of warrants, net of costs	822
Proceeds from the issuance of common stock, net of costs	830	16,029
Principal payments on revolving line of credit		(663)
Net cash provided by financing activities	1,660	15,539
Net (decrease) increase in cash	(867)	11,137
Cash at beginning of year	1,170	2,940
Cash at end of year	$ 303	14,077
Non-cash items
Convertible notes interest paid with common stock		$ 125