Stock Option and Compensation Plans (Tables)

12 Months Ended

Dec. 31, 2015

Stock Option and Compensation Plans

Summary of the stock option activity including weighted average exercise prices, options outstanding and exercisable

	Years ended December 31,
	2015					2014					2013
	Common Stock Options			Weighted Average Exercise Price		Common Stock Options			Weighted Average Exercise Price		Common Stock Options			Weighted Average Exercise Price
Outstanding at beginning of year:		3,680		$	21.03		2,708		$	9.41		1,344		$	1.65
Granted		764		$	47.31		1,744		$	33.92		1,583		$	14.82
Exercised		(1,133	)	$	10.31		(621	)	$	4.75		(151	)	$	0.61
Expired or forfeited		(302	)	$	34.09		(151	)	$	28.50		(68	)	$	1.53
Outstanding at end of year:		3,009		$	30.43		3,680		$	21.03		2,708		$	9.41

	Years ended December 31,
	2015		2014		2013
Options exercisable at end of year		955		993		984
Weighted average grant date fair value (per share) of options granted during the period	$	31.33	$	24.41	$	10.48

Summary of the stock options outstanding and exercisable

			As of December 31, 2015
			Options Outstanding				Options Exercisable
Range of Exercise Prices	Total Options Outstanding		Weighted Average Remaining Life (Years)		Weighted Average Exercise Price		Number Exercisable		Weighted Average Exercise Price
$0.12-$10.03		448		6.6	$	7.70		201	$	5.38
$10.04-$20.00		339		6.7	$	13.45		130	$	13.52
$20.01-$30.00		162		7.8	$	25.61		76	$	25.51
$30.01-$40.00		1,270		8.1	$	33.28		511	$	33.31
$40.01-$55.00		742		9.2	$	45.50		37	$	43.23
$55.01-$70.34		48		9.6	$	70.26		—	$	—
		3,009		8.0	$	30.43		955	$	24.50
Aggregate Intrinsic Value	$	144,758					$	51,594

Schedule of cash proceeds from, and the aggregate intrinsic value of, stock options exercised

	Years ended December 31,
	2015		2014		2013
Cash Proceeds from options exercised	$	11,473	$	2,949	$	94
Aggregate intrinsic value of options exercised	$	49,255	$	21,646	$	4,545

Summary of the Company's outstanding shares of RSU awards

	Restricted Stock Units			Weighted Average Grant-Date Fair Value
Outstanding, December 31, 2014		37		$	34.13
Awarded		336			45.04
Vested		(55	)		41.90
Forfeited		(30	)		42.01
Outstanding, December 31, 2015		288		$	44.54