Consolidated Statements of Cash Flows - USD ($)	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Operating activities:
Net loss	$ (10,486,000)	$ (9,338,000)
Adjustments required to reconcile net loss to net cash used in operating activities:
Change in fair value of derivative liabilities	(1,997,000)	(2,403,000)
Impairment charges	5,800,000
Stock-based compensation	568,000	1,698,000
Deferred taxes	(1,302,000)
Charge for common stock issuance (Note 6)	519,000
Warrants and other allocable expenses		431,000
Depreciation	255,000	245,000
Amortization of patents	23,000	23,000
Other non-cash adjustments, net	22,000
Changes in operating assets and liabilities:
Accounts receivable, net	12,000	101,000
Accounts payable, accrued expenses, deferred revenue and other	(845,000)	216,000
Accrued compensation	250,000	(32,000)
Prepaid expenses and other current assets	358,000	(49,000)
Net cash used in operating activities	(6,823,000)	(9,108,000)
Investing activities:
Purchases of property and equipment	(40,000)	(266,000)
Net cash used in investing activities	(40,000)	(266,000)
Financing activities:
Costs of Series B redeemable convertible preferred stock conversion to common stock		(173,000)
Dividend payments		(80,000)
Proceeds from sale of common stock and related warrants, net of offering costs	9,353,000	4,224,000
Proceeds from exercises of warrants	31,000
Proceeds from stock issuance under employee stock purchase plan	3,000
Principal payments on note payable	(510,000)
Net cash provided by financing activities	8,877,000	3,971,000
Net increase (decrease) in cash and cash equivalents	2,014,000	(5,403,000)
Cash and cash equivalents, beginning of period	5,711,000	9,370,000
Cash and cash equivalents, end of period	$ 7,725,000	3,967,000
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