Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Cash flows from operating activities:
Net loss	$ (5,014)	$ (3,467)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation of property and equipment	504	576
Redeemable warrants valuation adjustment	(923)
Amortization and abandonment of patent and trademark rights	17	70
Equity-based compensation	101	238
Realized gain(loss) on sale of marketable securities	(6)	87
Change in assets and liabilities:
Escrow account for litigation settlement		(1,750)
Accounts receivable	(98)
Prepaid expenses and other current assets	(298)	(43)
Accounts payable	85	178
Accrued expenses	331	1,819
Net cash used in operating activities	5,301	(2,292)
Cash flows from investing activities:
Sale of marketable securities	1,500	1,918
Purchase of property, equipment and construction in progress	(3)	(160)
Lease deposit refund		2
Additions to patent and trademark rights	(14)	(207)
Net cash provided by investing activities	1,483	1,553
Cash flows from financing activities:
Payments on capital leases		(1)
Debt issuance costs	(89)
Proceeds from note payable	606
Proceeds from sale of stock, net of issuance costs	2,115	163
Net cash provided by financing activities	2,632	162
Net decrease in cash and cash equivalents	(1,186)	(577)
Cash and cash equivalents at beginning of period	2,408	2,115
Cash and cash equivalents at end of period	1,222	1,538
Supplemental disclosures of non-cash investing and financing cash flow information:
Unrealized gain on marketable securities	29	184
Insurance proceeds from legal settlement		3,536
Stock issued for accrued expenses	106
Fair value of redeemable warrants granted	$ 1,990