Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Cash flows from operating activities
Net loss	$ (6,731)	$ (11,419)
Adjustments to reconcile net loss to net cash provided by (used in) operations:
Depreciation	180	250
Amortization of intangible assets	64	66
Non-cash share-based compensation expense	424	506
Realized loss on warrant exchange		4,967
Inventory write-downs	287	25
Non-cash adjustments	(31)	(59)
Change in:
Accounts receivable, net	(651)	(30)
Inventory	(519)	(7)
Other current and non-current assets	(30)	(194)
Accounts payable	248	19
Accrued liabilities	508	(230)
Deferred revenue	7,937	0
Billings in excess of costs and estimated earnings on uncompleted contracts	(225)	(560)
Net cash provided by (used in) operating activities	1,461	(6,666)
Cash flows from investing activities
Proceeds on sale of property and equipment	0	28
Purchases of property and equipment	(719)	(109)
Net cash used in investing activities	(719)	(81)
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	5,994	13,851
Net cash provided by financing activities	5,994	13,836
Change in cash and cash equivalents	6,736	7,089
Cash and cash equivalents, at beginning of period	8,349	5,375
Cash and cash equivalents, at end of period	15,085	12,464
Supplemental disclosure of cash flow information
Cash paid for interest	1	1
Supplemental schedule of non-cash investing and financing activities
Non-cash additions to property and equipment	187	29
Issuance of common stock for exchange of warrants	$ 0	$ 9,869