Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Cash flows from operating activities:
Net loss	$ (12,093)	$ (12,994)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation of property and equipment	663	500
Amortization and abandonment of patent and trademark rights	166	414
Redeemable warrants valuation adjustment	0	(1)
Equity-based compensation	148	260
Change in assets and liabilities:
Inventories	(1,326)	0
Prepaid expenses and other current assets	121	123
Accounts payable	97	1,214
Accrued expenses	(515)	553
Net cash used in operating activities	(12,739)	(9,931)
Cash flows from investing activities:
Purchase of property, equipment and construction in progress	(226)	(386)
Additions to patent and trademark rights	(188)	(187)
Deposits on capital leases refunded	0	2
Sales and maturities of short-term and long-term marketable securities	2,497	1,222
Net cash provided by investing activities	2,083	651
Cash flows from financing activities:
Payments on capital leases	(19)	(24)
Proceeds from sale of stock, net of issuance costs	9,680	9,763
Net cash provided by financing activities	9,661	9,739
Net (decrease) increase in cash and cash equivalents	(995)	459
Cash and cash equivalents at beginning of period	2,156	803
Cash and cash equivalents at end of period	1,161	1,262
Supplemental disclosures of non-cash investing and financing cash flow information:
Issuance of common stock for accounts payable	672	38
Supplemental disclosure of cash flow information:
Cash paid for interest expense	$ (3)	$ (9)