Note 2 - Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2012

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

	Estimated Fair Market Value as of December 31,
	2012		2011
Cash, cash equivalents and investments
Cash in banks	$	59,145	$	43,305
Money market funds		15,959		51,066
Government agencies/ treasuries		85,521		79,827
Auction-rate securities backed by student-loan notes		11,755		13,675
Total cash, cash equivalents and investments	$	172,380	$	187,873

Schedule of Other Current Assets [Table Text Block]

	December 31,
Reported as:	2012		2011
Cash and cash equivalents	$	75,104	$	96,371
Short-term investments		85,521		77,827
Long-term investments		11,755		13,675
Total cash, cash equivalents and investments	$	172,380	$	187,873

Investments Classified by Contractual Maturity Date [Table Text Block]

	December 31,
	2012		2011
Due in less than 1 year	$	52,880	$	45,133
Due in 1 - 5 years		32,641		32,694
Due in greater than 5 years		11,755		13,675
	$	97,276	$	91,502

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

	Fair Value Measurements at December 31, 2012 Using
			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

	Fair Value Measurements at December 31, 2011 Using
			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	$	51,066	$	51,066	$	-	$	-
US treasuries and US government agency bonds		79,827		-		79,827		-
Long-term available-for-sale auction-rate securities		13,675		-		-		13,675
	$	144,568	$	51,066	$	79,827	$	13,675

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

	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

	As of December 31, 2011
	Adjusted Cost		Unrealized Gains		Unrealized Losses			Total Fair Value		Fair Value of Investments in Unrealized Loss Position
Money market funds	$	51,066	$	-	$	-		$	51,066	$	-
US treasuries and US government agency bonds		79,830		14		(17	)		79,827		25,281
Auction-rate securities backed by student-loan notes		14,305		-		(630	)		13,675		13,675
	$	145,201	$	14	$	(647	)	$	144,568	$	38,956

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

	Auction-Rate Securities
Beginning balance at January 1, 2011	$	19,180
Sales and settlement at par		(5,775	)
Unrealized gain		270
Ending balance at December 31, 2011		13,675
Sales and settlement at par		(2,100	)
Total realized and unrealized gains:
Included in interest income and other, net		40
Included in other comprehensive income		140
Ending balance at December 31, 2012	$	11,755