Note 8 - Income Taxes (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Internal Revenue Service (IRS) [Member]
Operating Loss Carryforwards	$ 640,297,000
State and Local Jurisdiction [Member]
Operating Loss Carryforwards	255,346,000
Current Income Tax Expense (Benefit)	0	$ 0	$ 0
Deferred Income Tax Expense (Benefit)	0	$ 0	$ 0
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Share-based Compensation Cost	25,149,000
Operating Loss Carryforwards, Excess Tax Benefits Related to Stock-based Compensation not Recorded as DeferredTax Asset	$ 9,021,000