Note 3 - Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2014

Fair Value Disclosures [Abstract]

Fair Value, Assets Measured on Recurring Basis [Table Text Block]

	As of December 31, 2014
	Quoted Prices in Active Markets (Level 1)		Significant Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
Financial assets
Cash equivalents	$	68,830	$	-	$	-	$	68,830
Government securities		6,508		-		-		6,508
Corporate bonds		-		8,247		-		8,247
Total	$	75,338	$	8,247	$	-	$	83,585

	As of December 31, 2013
	Quoted Prices in Active Markets (Level 1)		Significant Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
Financial assets
Cash equivalents	$	2,781	$	-	$	-	$	2,781
Government securities		2,359		-		-		2,359
Total	$	5,140	$	-	$	-	$	5,140
Financial liabilities
Derivative liability	$	-	$	-	$	1,443	$	1,443
Total	$	-	$	-	$	1,443	$	1,443

Available-for-sale Securities [Table Text Block]

	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
December 31, 2014
Government securities
(Due within 1 year)	$	6,510	$	-	$	(2	)	$	6,508
Corporate bonds
(Due within 1 year)		8,251		-		(4	)		8,247
	$	14,761	$	-	$	(6	)	$	14,755
December 31, 2013
Government securities
(Due within 1 year)	$	2,359	$	-	$	-		$	2,359
	$	2,359	$	-	$	-		$	2,359