Note 3 - Financial Instruments (Details) - Available-for-sale Securities (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
Mar. 31, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 69,741	$ 14,761
Unrealized Gains	5
Unrealized Losses	(5)	(6)
Fair Value	69,741us-gaap_AvailableForSaleSecurities	14,755us-gaap_AvailableForSaleSecurities
US Government Agencies Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	64,452	6,510
Unrealized Gains	4
Unrealized Losses	(4)	(2)
Fair Value	64,452	6,508
Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	5,289	8,251
Unrealized Gains	1
Unrealized Losses	(1)	(4)
Fair Value	$ 5,289	$ 8,247

This item represents the cost of debt securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

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