Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Cash flows from operating activities:
Net loss	$ (6,329)	$ (12,093)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation of property and equipment	854	663
Amortization and abandonment of patent and trademark rights	125	166
Equity-based compensation	344	148
Realized loss on sale of marketable securities	56
Redeemable warrants valuation adjustment	(103)
Change in assets and liabilities:
Inventories		(1,326)
Prepaid expenses and other current assets	(224)	121
Accounts payable	(202)	97
Accrued expenses	201	(515)
Net cash used in operating activities	(5,278)	(12,739)
Cash flows from investing activities:
Purchase of property, equipment and construction in progress	(160)	(226)
Additions to patent, trademark and licensing rights	(282)	(188)
Deposits on capital leases refunded	14
Sales and maturities of short-term and long-term marketable securities	3,371	2,497
Net cash provided by investing activities	2,943	2,083
Cash flows from financing activities:
Payments on capital leases	(1)	(19)
Proceeds from sale of stock, net of issuance costs	4,694	9,680
Net cash provided by financing activities	4,693	9,661
Net increase (decrease) in cash and cash equivalents	2,358	(995)
Cash and cash equivalents at beginning of period	2,115	2,156
Cash and cash equivalents at end of period	4,473	1,161
Supplemental disclosures of non-cash investing and financing cash flow information:
Issuance of common stock for accounts payable		672
Unrealized gain (loss) on marketable securities	112	(241)
Fair Value of redeemable warrants	2,617
Supplemental disclosure of cash flow information:
Cash paid for interest expense		(3)
Insurance proceeds from legal settlement	$ 1,626