Note 4 - Fair Value Measurement (Tables)

12 Months Ended

Dec. 31, 2014

Fair Value Disclosures [Abstract]

Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]

	Fair Value Measurement at December 31, 2014
			Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs
	Total		Level 1		Level 2		Level 3
Assets:
Money market funds	$	60,078	$	60,078	$	-	$	-
Certificates of deposit		22,778		-		22,778		-
U.S. treasuries and government agency bonds		89,674		-		89,674		-
Auction-rate securities backed by student-loan notes		5,389		-		-		5,389
Mutual funds under deferred compensation plan		2,236		2,236		-		-
Total	$	180,155	$	62,314	$	112,452	$	5,389
Liabilities:
Contingent consideration	$	2,507	$	-	$	-	$	2,507
Total	$	2,507	$	-	$	-	$	2,507

	Fair Value Measurement at December 31, 2013
			Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs
	Total		Level 1		Level 2		Level 3
Assets:
Money market funds	$	35,588	$	35,588	$	-	$	-
U.S. treasuries and government agency bonds		128,126		-		128,126		-
Auction-rate securities backed by student-loan notes		9,860		-		-		9,860
Total	$	173,574	$	35,588	$	128,126	$	9,860

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

Balance at January 1, 2013	$	11,755
Sales and settlement at par		(2,025	)
Change in unrealized loss included in other comprehensive income		130
Ending balance at December 31, 2013		9,860
Sales and settlement at par		(4,650	)
Change in unrealized loss included in other comprehensive income		179
Ending balance at December 31, 2014	$	5,389

Schedule of Defined Benefit Plans Disclosures [Table Text Block]

	As of December 31,
	2014		2013
Time-to-liquidity (months)		24		24
Expected return		2.9%		2.5%
Discount rate		4.0% - 7.0%		3.3% - 8.1%

Schedule of Net Benefit Costs [Table Text Block]

	As of December 31,
	2014
Project revenue in 2016 (in millions)		$2.1 - $3.8
Discount rate		9.0%
Probability of occurrence		20% - 50%