Consolidated Statements of Cash Flows - USD ($)	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Cash flows from operating activities
Net loss	$ (6,963,000)	$ (3,724,000)
Adjustments required to reconcile net loss to net cash used in operating activities:
Change in fair value of warrant liability	(1,371,000)	(1,566,000)
Warrants issued	431,000	213,000
Amortization of patents	15,000	15,000
Depreciation	158,000	117,000
Stock-based compensation	1,364,000	105,000
Changes in operating assets and liabilities:
Accounts receivable	107,000	100,000
Accounts payable, accrued expenses, deferred revenue and other	573,000	181,000
Accrued severance	(236,000)	(234,000)
Prepaid expenses and other current assets	(55,000)	(174,000)
Net cash used in operating activities	(5,977,000)	(4,967,000)
Investing activities:
Purchases of property and equipment	(237,000)	(44,000)
Net cash used in investing activities	(237,000)	(44,000)
Financing activities:
Proceeds from warrant exercises		397,000
Costs of Series B conversion to common stock	(173,000)
Dividend payments	(63,000)
Proceeds from issuance of common stock, net	4,224,000	12,384,000
Net cash provided by financing activities	3,988,000	12,781,000
Net (decrease) increase in cash and cash equivalents	(2,226,000)	7,770,000
Cash and cash equivalents, beginning of period	9,370,000	6,581,000
Cash and cash equivalents, end of period	7,144,000	14,351,000
Supplemental schedule of non-cash financing activities:
Accretion of Series B redeemable convertible preferred stock	1,858,000	2,166,000
Fair value of warrant liability upon issuance	$ 1,816,000	$ 4,210,000