Note 7 - Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 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]

	Year Ended December 31,
	2015		2014		2013
Cost of revenue	$	1,166	$	903	$	631
Research and development		11,156		9,019		6,219
Selling, general and administrative		29,241		23,532		13,851
Total	$	41,563	$	33,454	$	20,701

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
	(in thousands)					(in thousands)					(in thousands)				(in thousands)
Outstanding at January 1, 2013		1,099		$	16.96		531		$	18.49		-	$	-		1,630		$	17.46
Granted		299		$	24.25		875	(1)	$	24.43		1,800	$	23.57		2,974		$	23.89
Performance adjustment		-		$	-		(124	)(2)	$	21.98		-	$	-		(124	)	$	21.98
Released		(519	)	$	17.57		(206	)	$	18.90		-	$	-		(725	)	$	17.95
Forfeited		(125	)	$	17.06		(48	)	$	19.06		-	$	-		(173	)	$	17.61
Outstanding at December 31, 2013		754		$	19.41		1,028		$	23.02		1,800	$	23.57		3,582		$	22.53
Granted		335		$	36.71		1,091	(1)	$	34.23		-	$	-		1,426		$	34.82
Performance adjustment		-		$	-		(139	)(2)	$	31.40		-	$	-		(139	)	$	31.40
Released		(468	)	$	20.36		(304	)	$	18.12		-	$	-		(772	)	$	19.48
Forfeited		(32	)	$	19.75		(17	)	$	19.79		-	$	-		(49	)	$	19.77
Outstanding at December 31, 2014		589		$	28.48		1,659		$	28.11		1,800	$	23.57		4,048		$	26.14
Granted		271		$	49.82		1,291	(1)	$	45.24		-	$	-		1,562		$	46.03
Performance adjustment		-		$	-		(364	)(2)	$	39.20		-	$	-		(364	)	$	39.20
Released		(319	)	$	26.56		(629	)	$	23.40		-	$	-		(948	)	$	24.47
Forfeited		(42	)	$	35.60		(24	)	$	28.68		-	$	-		(66	)	$	33.06
Outstanding at December 31, 2015		499		$	40.75		1,933		$	38.99		1,800	$	23.57		4,232		$	32.64

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, 2013		3,813		$	15.62		2.6	$	25,380
Exercised		(2,446	)	$	15.49
Forfeited and expired		(11	)	$	15.27
Outstanding at December 31, 2013		1,356		$	15.86		1.9	$	25,506
Exercised		(742	)	$	16.09
Forfeited and expired		(24	)	$	10.07
Outstanding at December 31, 2014		590		$	15.80		1.2	$	20,039
Exercised		(498	)	$	15.55
Forfeited and expired		(2	)	$	6.10
Outstanding at December 31, 2015		90		$	17.50		1.3	$	4,134
Options exercisable at December 31, 2015 and expected to vest		90		$	17.50		1.3	$	4,134
Options exercisable at December 31, 2015		89		$	17.50		1.3	$	4,126

Schedule of Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range [Table Text Block]

			Options Outstanding						Options Exercisable
Range of Exercises Prices			Shares		Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term		Shares		Weighted- Average Exercise Price
			(in thousands)				(in years)		(in thousands)
$11.09	-	$19.29		69	$	16.25		1.5		69	$	16.25
$19.56	-	$23.02		21	$	21.76		0.7		20	$	21.76
				90	$	17.50		1.3		89	$	17.50

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

	Year Ended December 31,
	2015			2014			2013
Expected term (years)		0.5			0.5			0.5
Expected volatility		30.3	%		29.4	%		28.0	%
Risk-free interest rate		0.2	%		0.1	%		0.1	%
Dividend yield		1.4	%		0.7	%		-