Note 7 - Income Taxes (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount	$ 7,121,000	$ 8,566,000
Unrecognized Tax Benefits	2,800,000
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	0
Deferred Tax Assets, Net	0
Domestic Tax Authority [Member] | Internal Revenue Service (IRS) [Member]
Operating Loss Carryforwards	$ 252,100,000
Open Tax Period	3 years
Domestic Tax Authority [Member] | Internal Revenue Service (IRS) [Member] | Earliest Tax Year [Member]
Open Tax Year	2013
Domestic Tax Authority [Member] | Internal Revenue Service (IRS) [Member] | Latest Tax Year [Member]
Open Tax Year	2016
State and Local Jurisdiction [Member] | California Franchise Tax Board [Member]
Operating Loss Carryforwards	$ 140,900,000
Open Tax Period	4 years
State and Local Jurisdiction [Member] | California Franchise Tax Board [Member] | Earliest Tax Year [Member]
Open Tax Year	2012
State and Local Jurisdiction [Member] | California Franchise Tax Board [Member] | Latest Tax Year [Member]
Open Tax Year	2016