Note 2 - Stock-Based Compensation (Tables)

6 Months Ended

Jun. 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 June 30,				Six Months Ended June 30,
	2015		2014		2015		2014
Cost of revenue	$	284	$	219	$	526	$	424
Research and development		2,503		2,245		5,123		4,250
Selling, general and administrative		6,710		5,951		13,067		11,339
Total	$	9,497	$	8,415	$	18,716	$	16,013

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)		252		$	49.63		659		$	48.53		-	$	-		911		$	48.83
Performance adjustment (2)		-		$	-		(130	)	$	43.45		-	$	-		(130	)	$	43.45
Released		(199	)	$	24.52		(481	)	$	23.77		-	$	-		(680	)	$	23.99
Forfeited		(38	)	$	34.91		(25	)	$	28.27		-	$	-		(63	)	$	32.32
Outstanding at June 30, 2015		604		$	38.24		1,682		$	36.17		1,800	$	23.57		4,086		$	30.92

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		(425	)	$	15.71
Forfeited and expired		(1	)	$	15.96
Outstanding at June 30, 2015		165		$	16.05		1.5	$	5,683
Options exercisable at June 30, 2015 and expected to vest		164		$	16.05		1.5	$	5,681
Options exercisable at June 30, 2015		159		$	16.18		1.5	$	5,481

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

	Six Months Ended June 30,
	2015			2014
Expected term (years)		0.5			0.5
Expected volatility		35.7	%		33.9	%
Risk-free interest rate		0.1	%		0.1	%
Dividend yield		1.2	%		-