Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 2013

Equity [Abstract]

Schedule of Share Based Compensation Expense

The following presents the impact of share based compensation expense on our consolidated statements of income (in thousands):

	Year Ended December 31,
	2013		2012		2011
Marketing and selling	$	3,780	$	3,068	$	2,966
Research and development		1,910		1,589		1,612
General and administrative		2,519		2,261		2,396
Total share based compensation	$	8,209	$	6,918	$	6,974

Summary of Stock Option Activity

Stock option activity for all plans for the year ended December 31, 2013 is presented below:

	Number of Shares			Weighted- Average Price per Share		Aggregate Intrinsic Value (1) (in thousands)		Weighted- Average Remaining Contractual Life (in Years)
Outstanding at December 31, 2012		4,032,433		$	10.00
Granted		497,580		$	22.35
Exercised		(1,788,274	)	$	9.01
Expired		(187	)	$	11.48
Forfeited		(37,921	)	$	16.16
Outstanding at December 31, 2013		2,703,631		$	12.84	$	51,421		6.4
Exercisable at December 31, 2013		1,695,968		$	10.02	$	37,044		5.2
Vested and expected to vest at December 31, 2013 (2)		2,636,118		$	12.72	$	50,458

(1) The aggregate intrinsic value is calculated as the positive difference between the exercise price of the underlying options and the quoted price of our shares of common stock on December 31, 2013.

(2) Represents the number of vested options as of December 31, 2013, plus the number of unvested options at December 31, 2013 that are ultimately expected to vest based on our estimated forfeiture rate.

Unvested Share Activity

Unvested share activity for the year ended December 31, 2013 is presented below:

	Shares			Weighted- Average Fair Value Per Share
Unvested shares outstanding at December 31, 2012		571,679		$	12.82
Granted		276,279		$	22.54
Vested		(266,115	)	$	12.44
Forfeited		(13,729	)	$	16.40
Unvested shares outstanding at December 31, 2013		568,114		$	17.64