Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Cash flows from operating activities
Net loss	$ (16,382)	$ (11,102)
Adjustments to reconcile net loss to net cash used in operations:
Depreciation	679	602
Amortization of intangible assets	87	95
Share-based compensation expense	1,027	980
Inventory write-downs	202	187
Other non-cash adjustments	(47)	47
Change in:
Accounts receivable, net	5	(134)
Inventory	(3,222)	(577)
Other current and non-current assets	(2,434)	177
Accounts payable	1,769	(145)
Accrued liabilities	102	(277)
Deferred revenue	(748)	(685)
Billings in excess of costs and estimated earnings on uncompleted contracts	1,285	0
Other currrent liabilities	9,856	(26)
Other long-term liabilities	(26)	0
Net cash used in operating activities	(7,847)	(10,858)
Cash flows from investing activities
Purchases of property and equipment	(2,448)	(282)
Net cash used in investing activities	(2,448)	(282)
Cash flows from financing activities
Net proceeds from issuance of common stock and warrants	20,459	9,055
Net cash provided by financing activities	20,459	9,055
Change in cash and cash equivalents	10,164	(2,085)
Cash and cash equivalents, at beginning of period	15,139	7,888
Cash and cash equivalents, at end of period	25,303	5,803
Supplemental schedule of non-cash investing and financing activities
Non-cash additions to property and equipment	245	276
Issuance of common stock for commitment fee	$ 0	$ 721