Note 5 - Marketable Securities (Detail) - Fair Value and Gross Unrealized Losses of the Available for Sale Securities (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Less than 12 months fair value	$ 86,221
Less than 12 month gross unrealized losses	(228)
Fair value	86,221
Gross unrealized losses	(228)
US Treasury Securities [Member]
Less than 12 months fair value	64,129	15,186
Less than 12 month gross unrealized losses	(7)	(3)
Fair value	64,129	15,186
Gross unrealized losses	(7)	(3)
Securities (Assets) [Member]
Less than 12 months fair value	3,631
Less than 12 month gross unrealized losses	(208)
Fair value	3,631
Gross unrealized losses	(208)
Corporate Debt Securities [Member]
Less than 12 months fair value	18,461
Less than 12 month gross unrealized losses	(13)
Fair value	18,461
Gross unrealized losses	$ (13)