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Note 6 - Secured Notes to Related Parties (Details Textual)				1 Months Ended	3 Months Ended		9 Months Ended
	Aug. 05, 2016 USD ($) shares	Aug. 02, 2016 USD ($)	Jul. 29, 2011 shares	Apr. 30, 2011 USD ($) shares	Sep. 30, 2016 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2015 USD ($)	Dec. 31, 2015 USD ($)
Convertible Debt Securities [Member] \| Common Stock [Member]
Debt Instrument Conversion Ratio Shares \| shares				1,250
Convertible Debt Securities [Member] \| In Case of Debt Conversion [Member]
Debt Instrument, Face Amount					$ 5,900,000		$ 5,900,000
Debt Instrument, Convertible, Number of Equity Instruments							7,400,000
Convertible Debt Securities [Member]
Debt Instrument, Interest Rate, Stated Percentage				6.00%
Debt Instrument Conversion Ratio Multiple of Principal				$ 1,000
Beneficial Ownership after Conversion				9.99%
Notice Period Associated with Beneficial Ownership Percentage Limitation Convertible Notes				61 days
Paid-in-Kind Interest							$ 300,000
Debt Instrument, Increase (Decrease), Other, Net							300,000
Debt Instrument, Face Amount					5,900,000		5,900,000
Debt Instrument, Unamortized Discount					3,200,000		3,200,000
Term Loan [Member] \| Tang Capital [Member]
Debt Instrument, Interest Rate, Stated Percentage		8.00%
Debt Agreement, Maximum Borrowing Capacity		$ 100,000,000
Debt Instrument, Term		2 years
Proceeds from Issuance of Long-term Debt	$ 50,000,000
Proceeds from Issuance of Long-term Debt, Subject to Achievement of Corporate Milestone		$ 50,000,000
Debt Instrument, Fee Amount	$ 0
Debt Instrument, Number of Warrants \| shares	0
Debt Instrument, Convertible, Beneficial Conversion Feature	$ 0
Interest Expense					600,000		600,000
Notes Payable, Related Parties, Noncurrent					50,000,000		50,000,000
Convertible Debt Issuable in Connection with Private Placement				$ 4,500,000
Proceeds from Convertible Debt				$ 4,300,000
Common Shares Registered for Resale in Connection with Convertible Notes \| shares			3,500,000
Interest Expense, Debt, Excluding Amortization					100,000	$ 100,000	300,000	$ 200,000
Amortization of Debt Discount (Premium)					200,000	$ 200,000	510,000	$ 463,000
Convertible Notes Payable, Related Parties, Current					2,732,000		2,732,000		$ 2,222,000
Notes Payable, Related Parties, Noncurrent					$ 50,000,000		$ 50,000,000