Note 10 - Fair Value Measurement (Tables)

3 Months Ended

Mar. 31, 2015

Fair Value Disclosures [Abstract]

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

	Fair Value Measurement at March 31, 2015
			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	$	46,965	$	46,965	$	-	$	-
Certificates of deposit		23,050		-		23,050		-
U.S. treasuries and government agency bonds		114,741		-		114,741		-
Auction-rate securities backed by student-loan notes		5,394		-		-		5,394
Mutual funds under deferred compensation plan		4,490		4,490		-		-
Total	$	194,640	$	51,455	$	137,791	$	5,394
Liabilities:
Contingent consideration	$	2,507	$	-	$	-	$	2,507
Total	$	2,507	$	-	$	-	$	2,507

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

Balance at January 1, 2015	$	5,389
Change in unrealized loss included in other comprehensive income		5
Ending balance at March 31, 2015	$	5,394

Schedule of Defined Benefit Plans Disclosures [Table Text Block]

	March 31,		December 31,
	2015		2014
Time-to-liquidity (months)		24		24
Expected return		2.5%		2.9%
Discount rate		3.6% - 6.6%		4.0% - 7.0%