Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Cash flows from operating activities
Net loss	$ (18,120)	$ (13,178)
Adjustments to reconcile net loss to net cash used in operations:
Depreciation	414	923
Amortization of intangible assets	132	158
Impairment of intangible assets	40	277
Non-cash share-based compensation expense	713	1,606
(Gain) loss on warrant exchange	4,967	(1,900)
Inventory write-downs	42	303
Other non-cash adjustments	(91)	(66)
Change in:
Accounts receivable, net	(645)	1,091
Inventory	(109)	145
Other current and non-current assets	(155)	884
Accounts payable	(25)	(1,486)
Accrued liabilities	335	(1,387)
Deferred revenue	0	(609)
Billings on uncompleted contracts in excess of related costs	(450)	582
Net cash used in operating activities	(12,952)	(12,657)
Cash flows from investing activities
Proceeds on sale of property and equipment	34	35
Purchases of property and equipment	(207)	(375)
Net cash used in investing activities	(173)	(340)
Cash flows from financing activities
Principal payments under capital leases and long-term debt	(15)	(120)
Net proceeds from issuance of common stock and warrants	16,114	11,642
Net cash provided by financing activities	16,099	11,522
Net increase (decrease) in cash and cash equivalents	2,974	(1,475)
Cash and cash equivalents, at beginning of period	5,375	6,850
Cash and cash equivalents, at end of period	8,349	5,375
Supplemental disclosure of cash flow information
Cash paid for interest	3	12
Supplemental schedule of non-cash investing and financing activities
Non-cash additions to property and equipment	101	407
Issuance of common stock for exchange of warrants	$ 9,869	$ 536