Note 2 - Stock-based Compensation (Tables)

6 Months Ended

Jun. 30, 2016

Notes Tables

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,
	2016		2015		2016		2015
Cost of revenue	$	380	$	284	$	814	$	526
Research and development		3,318		2,503		7,016		5,123
Selling, general and administrative		8,049		6,710		12,896		13,067
Total	$	11,747	$	9,497	$	20,726	$	18,716

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 and MPSUs			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
Outstanding at January 1, 2016		499		$	40.75		1,933		$	38.99		1,800		$	23.57		4,232		$	32.64
Granted		116		$	61.45		1,253	(1)	$	40.77		-		$	-		1,369		$	42.52
Performance adjustment		-		$	-		(234	) (2)	$	41.14		-		$	-		(234	)	$	41.14
Released		(142	)	$	33.69		(563	)	$	30.07		-		$	-		(705	)	$	30.80
Forfeited		(18	)	$	42.92		(129	)	$	36.82		(180	)	$	23.57		(327	)	$	029.87
Outstanding at June 30, 2016		455		$	48.18		2,260		$	42.10		1,620		$	23.57		4,335		$	35.81

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

	Six Months Ended June 30,
	2016			2015
Expected term (years)		0.5			0.5
Expected volatility		29.7	%		35.7	%
Risk-free interest rate		0.4	%		0.1	%
Dividend yield		1.4	%		1.2	%