Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash flows from operating activities:
Net loss (including noncontrolling interests)	$ (5,495)	$ (5,649)	$ (7,835)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	72	255	1,075
Depreciation and amortization	953	360	187
Loss on disposal of property and equipment		91	28
Changes in operating assets and liabilities:
Accounts receivable	542	(204)	(239)
Projects in process	(1)	158	38
Inventory	(372)	(737)
Prepaid expenses and other current assets	293	(1,316)	(263)
Accounts payable and accrued expenses	(896)	343	871
Deferred revenues	(677)	447	(1,925)
Net cash used in operating activities	(5,581)	(6,252)	(8,063)
Cash flows from investing activities:
Purchase of property and equipment	(656)	(987)	(198)
Investment in joint venture		(3)
Proceeds from sale of property and equipment		5
Net cash used in investing activities	(656)	(985)	(198)
Cash flow from financing activities:
Proceeds from issuance of common stock and warrants, net of offering costs	9,079	7,913	5,422
Contributions from noncontrolling interests			3
Proceeds from note payable	1,713
Payments on note payable	(1,713)
Principal payments on capital lease obligations	(438)	(116)	(57)
Net cash provided by financing activities	8,641	7,797	5,368
Effect of exchange rate changes on cash	(84)	(166)	(154)
Net change in cash	2,320	394	(3,047)
Cash at beginning of year	3,476	3,082	6,129
Cash at end of year	5,796	3,476	3,082
Supplemental disclosure of cash flow information:
Cash paid for interest	73	48	18
Cash paid for income taxes	219	367	93
Supplemental disclosure of non-cash investing and financing activities:
Purchase of equipment with capital lease obligation	$ 1,287	$ 983