Note 2 - Stock-Based Compensation (Tables)

6 Months Ended

Jun. 30, 2013

Note 2 - Stock-Based Compensation (Tables) [Line Items]

Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table Text Block]

	Three months ended June 30,				Six months ended June 30,
	2013		2012		2013		2012
Non-employee	$	-	$	6	$	-	$	11
Employee stock purchase plan		139		179		331		390
Restricted stock		4,772		2,881		8,906		5,061
Stock options		279		763		613		1,682
	$	5,190	$	3,829	$	9,850	$	7,144

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

	RSU's			Weighted Average Grant Date Fair Value Per Share		PSUs			Weighted Average Grant Date Fair Value Per Share		Total			Weighted Average Grant Date Fair Value Per Share		Weighted Average Remaining Recognition Period (Years)
Outstanding at January 1, 2013		1,098,563		$	16.96		531,185		$	18.49		1,629,748		$	17.46		2.18
Awards granted		250,388			23.72		311,540			24.35		561,928			24.07
Performance awards adjustment (1)		-			-		173,265			18.05		173,265			18.05
Awards released		(281,080	)		17.18		(206,409	)		18.90		(487,489	)		17.91
Awards forfeited		(72,505	)		16.59		(28,888	)		17.99		(101,393	)		16.99
Outstanding at June 30, 2013		995,366		$	18.63		780,693		$	20.64		1,776,059		$	19.51		2.09

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

	Three months ended June 30,						Six months ended June 30,
	2013			2012			2013			2012
Expected term (years)		4.1			3.8			4.0			4.1
Expected volatility		50.0	%		53.4	%		51.0	%		53.4	%
Risk-free interest rate		0.7	%		0.6	%		0.7	%		0.6	%
Dividend yield		-			-			-			-

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

Available shares as of January 1, 2013	4,217,960
Additions to plan	713,466
Purchases	(65,247	)
Available shares as of June 30, 2013	4,866,179

Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Method Used

	Six months ended June 30,
	2013			2012
Expected term (years)		0.5			0.5
Expected volatility		28.5	%		50.7	%
Risk-free interest rate		0.1	%		0.1	%
Dividend yield		-			-

Unit Activity [Member]

Note 2 - Stock-Based Compensation (Tables) [Line Items]

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

Available for grant as of January 1, 2013	4,957,244
Additions to plan	1,783,664
Grants	(561,928	)
Performance awards adjustment (1)	(173,265	)
Cancellations	108,274
Available for grant as of June 30, 2013	6,113,989

Plan Status [Member]

Note 2 - Stock-Based Compensation (Tables) [Line Items]

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

	Stock Options			Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (Years)		Aggregate Intrinsic Value
Outstanding at January 1, 2013 (3,603,762 options exercisable at a weighted-average exercise price of $15.59 per share)		3,813,361		$	15.62		2.56	$	25,379,573
Options granted		-			-
Options exercised		(1,110,102	)		14.58
Options forfeited and expired		(6,881	)		19.31
Outstanding at June 30, 2013		2,696,378		$	16.04		2.14	$	21,804,890
Options exercisable at June 30, 2013 and expected to become exercisable		2,690,171		$	16.04		2.13	$	21,741,742
Options vested and exercisable at June 30, 2013		2,564,933		$	16.08		2.01	$	20,644,282