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	$ (3,467)	$ (8,290)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation of property and equipment	576	458
Amortization and abandonment of patent and trademark rights	70	79
Equity-based compensation	238	111
Realized loss on sale of marketable securities	87
Change in assets and liabilities:
Escrow account for litigation settlement	(1,750)
Inventories		(1,009)
Prepaid expenses and other current assets	(43)	61
Accounts payable	178	189
Accrued expenses	1,819	(836)
Net cash used in operating activities	(2,292)	(9,237)
Cash flows from investing activities:
Purchase of property, equipment and construction in progress	(160)	(240)
Additions to patent, trademark and licensing rights	(207)	(169)
Deposits on capital leases refunded	2
Sales and maturities of short-term and long-term marketable securities	1,918	54
Net cash provided by (used in) investing activities	1,553	(355)
Cash flows from financing activities:
Payments on capital leases	(1)	(15)
Proceeds from sale of stock, net of issuance costs	163	9,293
Net cash provided by financing activities	162	9,278
Net decrease in cash and cash equivalents	(577)	(314)
Cash and cash equivalents at beginning of period	2,115	2,156
Cash and cash equivalents at end of period	1,538	1,842
Supplemental disclosures of non-cash investing and financing cash flow information:
Issuance of common stock for accounts payable		672
Unrealized (loss) gain on marketable securities	184	(26)
Supplemental disclosure of cash flow information:
Cash paid for interest expense		(2)
Insurance proceeds from legal settlement	$ 3,536