Note 11 - Stock Option Plans (Details) - Stock-Based Compensation Expense (USD $) In Thousands, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Benefit for income taxes (1)	$ 0	[1]	$ 0	[1]	$ 0	[1]	$ 0	[1]
Net compensation expense	744		1,802		2,203		2,985
General and Administrative Expense [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Compensation Expense	730		1,546		2,081		2,557
Other Research and Development Expense [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Compensation Expense	14		256		122		428
Stock-based Compensation Expense [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Compensation Expense	$ 744		$ 1,802		$ 2,203		$ 2,985

[1] The stock-based compensation expense has not been tax-effected due to the recording of a full valuation allowance against net deferred tax assets.