Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Cash flows from operating activities
Net loss	$ (10,244)	$ (14,774)
Adjustments to reconcile net loss to net cash provided by (used in) operations:
Depreciation	297	331
Amortization of intangible assets	96	99
Non-cash share-based compensation expense	718	717
Realized loss on warrant exchange	0	4,967
Inventory write-downs	287	42
Non-cash adjustments	(46)	(76)
Change in:
Accounts receivable, net	95	(553)
Inventory	(440)	(72)
Other current and non-current assets	(43)	(118)
Accounts payable	(53)	110
Accrued liabilities	(6)	(5)
Deferred revenue	7,403	0
Billings in excess of costs and estimated earnings on uncompleted contracts	(225)	(577)
Net cash used in operating activities	(2,161)	(9,909)
Cash flows from investing activities
Proceeds on sale of property and equipment	0	34
Purchases of property and equipment	(1,011)	(173)
Net cash used in investing activities	(1,011)	(139)
Cash flows from financing activities
Principal payments under capital leases and long-term debt	0	(15)
Net proceeds from issuance of common stock and warrants	5,983	15,584
Net cash provided by financing activities	5,983	15,569
Change in cash and cash equivalents	2,811	5,521
Cash and cash equivalents, at beginning of period	8,349	5,375
Cash and cash equivalents, at end of period	11,160	10,896
Supplemental disclosure of cash flow information
Cash paid for interest	1	2
Supplemental schedule of non-cash investing and financing activities
Non-cash additions to property and equipment	155	0
Issuance of common stock for exchange of warrants	$ 0	$ 9,869