Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 2014

Equity [Abstract]

Stock option plan activity

Following is a summary of the Company’s stock option plan activity and related information:

	Shares		Weighted Average Exercise Price		Weighted Average Remaining Contractual Term in Years	Aggregate Intrinsic Value (In  thousands)
Balance at December 31, 2013	1,746,709		$	16.79	7.57	$	62,705
Granted	389,934		72.09
Exercised	(281,515	)	15.71
Forfeited	(49,967	)	16.69
Cancelled	(4,464	)	80.56
Balance at December 31, 2014	1,800,697		28.78		7.25	51,558
Exercisable at December 31, 2014	1,127,667		20.86		6.62	38,395
Options vested and expected to vest as of December 31, 2014	1,800,697		$	28.78	7.25	$	51,558

Stock option plan activity, by exercise price range

Following is a further breakdown of the options outstanding as of December 31, 2014:

Range of exercise prices	Options outstanding	Weighted average remaining  life in years	Weighted average exercise price		Options exercisable	Weighted average exercise price
$8.58 – $10.12	382,047	6.06	$	9.98	365,174	$	9.98
$10.72 – $13.53	52,739	7.30	12.45		49,437	12.47
$14.47 – $14.47	427,504	7.11	14.47		273,781	14.47
$16.14 – $21.92	453,177	6.97	20.79		260,375	20.05
$32.00 – $74.42	485,230	8.58	65.42		178,900	56.34
$8.58 – $74.42	1,800,697	7.25	$	28.78	1,127,667	$	20.86

Restricted stock activity

The following is a summary of the Company’s restricted stock activity and related information:

	Shares		Weighted-Average Grant Date Fair Value
Non-vested at December 31, 2013	115,386		$	21.93
Granted	45,571		70.20
Vested	(74,312	)	25.21
Forfeited	(3,972	)	18.42
Non-vested at December 31, 2014	82,673		$	45.76