Note 2 - Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2015

Accounting Policies [Abstract]

Schedule of Weighted Average Number of Shares [Table Text Block]

	Year ended December 31,
	2014		2015
Net income	$	10,494	$	5,591
Weighted average basic shares outstanding:
Common stock		38,656		41,111
Weighted average diluted shares outstanding:
Common stock		38,656		41,111
Dilutive securities (1)		2,576		1,933
Totals		41,232		43,044

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

	2013					2014					2015
Volatility		48.37	–	49.10	%		48.59	–	49.27	%			48.59	%
Expected life (years)			6.00					6.00					6.00
Risk-free interest rate		0.97	–	1.73	%		1.81	–	2.08	%			2.01	%
Dividend yield			—					—					—
Fair value	$	6.63	–	12.61		$	14.71	–	17.26		$	19.30	–	19.37

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

	Number of options			Weighted average exercise price		Weighted average remaining contractual life (years)		Aggregate intrinsic value (in thousands)
Outstanding at December 31, 2012		9,463,657		$	11.76
Options granted		621,100			18.16
Options forfeited		(520,139	)		15.38
Options exercised		(2,229,873	)		10.85
Outstanding at December 31, 2013		7,334,745		$	12.33
Options granted		629,775			32.72
Options forfeited		(204,348	)		20.42
Options exercised		(2,794,225	)		15.20
Outstanding at December 31, 2014		4,965,947		$	12.96
Options granted		35,000			40.20
Options forfeited		(63,749	)		22.75
Options exercised		(1,170,330	)		12.19
Outstanding at December 31, 2015		3,766,868		$	13.28		5.6	$	53,865
Exercisable at December 31, 2015		3,328,227		$	10.89		5.2	$	53,368
Expected to vest after December 31, 2015		368,458		$	31.45		7.4	$	418

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

	Number of awards			Weighted average grant date fair value
Non-vested awards at December 31, 2012		189,412		$	13.68
Awards granted		668,885			15.78
Awards vested		(77,513	)		13.30
Awards forfeited		(26,570	)		14.06
Non-vested awards at December 31, 2013		754,214		$	15.57
Awards granted		573,818			34.08
Awards vested		(376,753	)		17.39
Awards forfeited		(70,846	)		33.00
Non-vested awards at December 31, 2014		880,433		$	25.46
Awards granted		994,410			37.66
Awards vested		(524,569	)		25.77
Awards forfeited		(34,752	)		35.11
Non-vested awards at December 31, 2015		1,315,522		$	34.30

Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]

	Level 1		Level 2			Level 3			Total
As of December 31, 2014
Financial instruments:
Contingent consideration	$	—	$	—		$	(6,587	)	$	(6,587	)
Foreign currency derivative asset		—		272			—			272
As of December 31, 2015
Financial instruments:
Foreign currency derivative asset	$	—	$	848		$	—		$	848
Foreign currency derivative liability		—		(1,215	)		—			(1,215	)

Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]

	Foreign Currency Translation			Net investment hedge - foreign exchange contract			Total
Balance at December 31, 2013	$	(6,420	)	$	483		$	(5,937	)
Change during 2014:
Before-tax amount		(16,923	)		4,900			(12,023	)
Tax (expense) benefit		5,522			(1,938	)		3,584
Total activity in 2014		(11,401	)		2,962			(8,439	)
Balance at December 31, 2014	$	(17,821	)	$	3,445		$	(14,376	)
Change during 2015:
Before-tax amount		(22,127	)		7,060			(15,067	)
Tax (expense) benefit		6,232			(2,792	)		3,440
Total activity in 2015		(15,895	)		4,268			(11,627	)
Balance at December 31, 2015	$	(33,716	)	$	7,713		$	(26,003	)