Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Cash flows from operating activities
Net loss	$ (11,102)	$ (10,244)
Adjustments to reconcile net loss to net cash provided by (used in) operations:
Depreciation	602	297
Amortization of intangible assets	95	96
Share-based compensation expense	980	718
Inventory write-downs	187	287
Other non-cash adjustments	47	(46)
Change in:
Accounts receivable, net	(134)	95
Inventory	(577)	(440)
Other current and non-current assets	177	(43)
Accounts payable	(145)	(53)
Accrued liabilities	(303)	(6)
Deferred revenue	(685)	7,403
Billings on uncompleted contracts in excess of related costs	0	(225)
Net cash used in operating activities	(10,858)	(2,161)
Cash flows from investing activities
Purchases of property and equipment	(282)	(1,011)
Net cash used in investing activities	(282)	(1,011)
Cash flows from financing activities
Net proceeds from issuance of common stock and warrants	9,055	5,983
Net cash provided by financing activities	9,055	5,983
Change in cash and cash equivalents	(2,085)	2,811
Cash and cash equivalents at beginning of period	7,888	8,349
Cash and cash equivalents at end of period	5,803	11,160
Supplemental schedule of non-cash investing and financing activities
Non-cash additions to property and equipment	276	155
Issuance of common stock for commitment fee	$ 721	$ 0