Note 8 - Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2013

Fair Value, by Balance Sheet Grouping [Table Text Block]

	Estimated Fair Market Value as of
	March 31, 2013		December 31, 2012
Cash, cash equivalents and investments
Cash in banks	$	73,486	$	59,145
Money market funds		19,801		15,959
Government agencies / treasuries		81,756		85,521
Auction-rate securities backed by student-loan notes		11,715		11,755
Total cash, cash equivalents and investments	$	186,758	$	172,380

Schedule of Other Current Assets [Table Text Block]

Reported as:	March 31, 2013		December 31, 2012
Cash and cash equivalents	$	93,287	$	75,104
Short-term investments		81,756		85,521
Long-term investments		11,715		11,755
Total cash, cash equivalents and investments	$	186,758	$	172,380

Investments Classified by Contractual Maturity Date [Table Text Block]

	March 31, 2013		December 31, 2012
Due in less than 1 year	$	60,794	$	52,880
Due in 1 - 5 years		20,962		32,641
Due in greater than 5 years		11,715		11,755
	$	93,471	$	97,276

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

	Fair Value Measurements at March 31, 2013
			Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs
	Total		Level 1		Level 2		Level 3
Money market funds	$	19,801	$	19,801	$	-	$	-
US treasuries and US government agency bonds		81,756		-		81,756		-
Long-term available-for-sale auction-rate securities		11,715		-		-		11,715
	$	113,272	$	19,801	$	81,756	$	11,715

	Fair Value Measurements at December 31, 2012
			Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs
	Total		Level 1		Level 2		Level 3
Money market funds	$	15,959	$	15,959	$	-	$	-
US treasuries and US government agency bonds		85,521		-		85,521		-
Long-term available-for-sale auction-rate securities		11,755		-		-		11,755
	$	113,235	$	15,959	$	85,521	$	11,755

Unrealized Gain (Loss) on Investments [Table Text Block]

	As of March 31, 2013
	Adjusted Cost		Unrealized Gains		Unrealized Losses			Total Fair Value		Fair Value of Investments in Unrealized Loss Position
Money market funds	$	19,801	$	-	$	-		$	19,801	$	-
US treasuries and US government agency bonds		81,724		38		(6	)		81,756		15,363
Auction-rate securities backed by student-loan notes		12,220		-		(505	)		11,715		11,715
	$	113,745	$	38	$	(511	)	$	113,272	$	27,078

	As of December 31, 2012
	Adjusted Cost		Unrealized Gains		Unrealized Losses			Total Fair Value		Fair Value of Investments in Unrealized Loss Position
Money market funds	$	15,959	$	-	$	-		$	15,959	$	-
US treasuries and US government agency bonds		85,483		45		(7	)		85,521		14,121
Auction-rate securities backed by student-loan notes		12,245		-		(490	)		11,755		11,755
	$	113,687	$	45	$	(497	)	$	113,235	$	25,876

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

	Auction-Rate Securities
Beginning balances at January 1, 2013	$	11,755
Sales and settlement at par		(25	)
Total realized and unrealized gains (losses):
Included in interest income and other, net		-
Included in other comprehensive income		(15	)
Ending balance at March 31, 2013	$	11,715