Condensed Consolidated Statements of Cash Flows (unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Cash flows from operating activities:
Net loss	$ (9,499)	$ (15,281)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	1,125	1,044
Warrant revaluation (income) expense	(7,511)	1,061
Depreciation and amortization	391	346
Provision for (recovery of) doubtful accounts	(12)	(1)
Inventory reserve	151	0
Intangible asset impairment	3,905	0
Loss on disposal or impairment of property and equipment	65	0
Decrease (increase) in operating assets:
Accounts receivable	12	2
Inventory	222	87
Prepaid expenses and other current assets	728	549
Other assets	(64)	0
Increase (decrease) in operating liabilities:
Accounts payable	(3)	1,061
Related party payable	(9,796)	(338)
Accrued expenses and deferred rent	(518)	599
Deferred revenue	(49)	84
Net cash used in operating activities	(20,853)	(10,787)
Cash flows from investing activities:
Purchase of property and equipment	(143)	(111)
Net cash used in investing activities	(143)	(111)
Cash flows from financing activities:
Payment of deferred offering costs	(109)	0
Proceeds from the exercise of stock options	0	255
Principle payments on capital lease obligations	(2)	(2)
Net cash (used in) provided by financing activities	(111)	253
Net decrease in cash and cash equivalents	(21,107)	(10,645)
Cash and cash equivalents, beginning of period	29,268	37,495
Cash and cash equivalents, end of period	8,161	26,850
Supplemental Cash Flow Disclosures:
Property and equipment in accounts payable	46	0
Deferred offering costs in accounts payable	$ 11	$ 0