Note 2 - Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2015

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Schedule of Compensation Cost for Share-based Payment Arrangements, Allocation of Share-based Compensation Costs by Plan [Table Text Block]

	Three Months Ended September 30,				Nine Months Ended September 30,
	2015		2014		2015		2014
Cost of revenue	$	303	$	246	$	829	$	669
Research and development		2,932		2,388		8,055		6,638
Selling, general and administrative		7,240		6,225		20,307		17,565
Total	$	10,475	$	8,859	$	29,191	$	24,872

Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity [Table Text Block]

		Time-Based RSUs			Weighted-Average Grant Date Fair Value Per Share			PSUs			Weighted-Average Grant Date Fair Value Per Share			MSUs		Weighted-Average Grant Date Fair Value Per Share			Total			Weighted-Average Grant Date Fair Value Per Share
	(in thousands)						(in thousands)						(in thousands)					(in thousands)
Outstanding at January 1, 2015			589		$	28.48			1,659		$	28.11			1,800	$	23.57			4,048		$	26.14
Granted (1)			263		$	49.59			659		$	48.53			-	$	-			922		$	48.83
Performance adjustment (2)			-		$	-			(70	)	$	41.83			-	$	-			(70	)	$	41.83
Released			(257	)	$	25.58			(555	)	$	23.56			-	$	-			(812	)	$	24.20
Forfeited			(40	)	$	35.12			(24	)	$	28.27			-	$	-			(64	)	$	32.54
Outstanding at September 30, 2015			555		$	39.38			1,669		$	37.11			1,800	$	23.57			4,024		$	31.37

Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block]

	Shares			Weighted-Average Exercise Price		Weighted-Average Remaining Contractual Term		Aggregate Intrinsic Value
	(in thousands)					(in years)		(in thousands)
Outstanding at January 1, 2015		590		$	15.80		1.2	$	20,039
Exercised		(438	)	$	15.69
Forfeited and expired		(1	)	$	15.95
Outstanding at September 30, 2015		151		$	16.13		1.3	$	5,294
Options exercisable at September 30, 2015 and expected to vest		151		$	16.13		1.3	$	5,294
Options exercisable at September 30, 2015		149		$	16.19		1.2	$	5,213

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]

	Three Months Ended September 30,						Nine Months Ended September 30,
	2015			2014			2015			2014
Expected term (years)		0.5			0.5			0.5			0.5
Expected volatility		24.8	%		25.1	%		30.3	%		29.5	%
Risk-free interest rate		0.2	%		0.1	%		0.2	%		0.1	%
Dividend yield		1.6	%		1.4	%		1.4	%		0.7	%