Consolidated Statements of Cash Flows - USD ($)	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Operating activities:
Net loss	$ (9,707,000)	$ (6,963,000)
Adjustments required to reconcile net loss to net cash used in operating activities:
Change in fair value of derivative liabilities	(2,034,000)	(1,371,000)
Impairment charges	5,800,000
Stock-based compensation	470,000	1,364,000
Deferred taxes	(1,302,000)
Warrants and other allocable expenses		431,000
Depreciation	170,000	158,000
Amortization of patents	15,000	15,000
Other non-cash adjustments	18,000
Changes in operating assets and liabilities:
Accounts receivable, net	12,000	107,000
Accounts payable, accrued expenses, deferred revenue and other	(189,000)	509,000
Accrued compensation	177,000	(172,000)
Prepaid expenses and other current assets	340,000	(55,000)
Net cash used in operating activities	(6,230,000)	(5,977,000)
Investing activities:
Purchases of property and equipment	(7,000)	(237,000)
Net cash used in investing activities	(7,000)	(237,000)
Financing activities:
Costs of Series B redeemable convertible preferred stock conversion to common stock		(173,000)
Dividend payments		(63,000)
Proceeds from sale of common stock and related warrants, net of offering costs	9,690,000	4,224,000
Proceeds from stock issuance under employee stock purchase plan	3,000
Principal payment on note payable	(205,000)
Net cash used in financing activities	9,488,000	3,988,000
Net increase (decrease) in cash and cash equivalents	3,251,000	(2,226,000)
Cash and cash equivalents, beginning of period	5,711,000	9,370,000
Cash and cash equivalents, end of period	8,962,000	7,144,000
Supplemental schedule of non-cash financing activities:
Accretion of Series B redeemable convertible preferred stock		1,858,000
Fair value of warrant liability upon issuance		$ 1,816,000
Offering costs included in accounts payable	$ 339,000