Stock Incentive Plans (Tables)

9 Months Ended

Sep. 30, 2018

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Summary of Share-based Awards Available for Grant under 2016 Plan

A summary of share-based awards available for grant under the 2016 Plan is as follows:

	Awards Available for Grant
Balance at December 31, 2016		3,743,037
Additional options authorized		1,106,966
Awards granted		(837,436	)
Awards forfeited		21,585
Balance at December 31, 2017		4,034,152
Additional options authorized		1,168,865
Awards granted		(607,269	)
Awards forfeited		108,060
Awards withheld for tax purposes		25,517
Balance at September 30, 2018		4,729,325

Summary of Stock Option Activity Under 2006 and 2016 Plans

The following table summarizes stock option activity under the 2006 and 2016 Plans:

				Options Outstanding
	Options Outstanding			Weighted- Average Exercise Price Per Share		Weighted- Average Remaining Contractual Life (years)		Aggregate Intrinsic Value (in thousands)
Balances at December 31, 2016		2,977,218		$	6.16		6.93	$	70,979
Options granted		465,271		$	36.76
Options exercised		(827,556	)	$	4.11
Options forfeited		(13,752	)	$	14.43
Balances at December 31, 2017		2,601,181		$	12.24		7.17	$	113,958
Options granted		355,658		$	67.97
Options exercised		(683,534	)	$	7.32
Options forfeited		(68,179	)	$	32.18
Balances at September 30, 2018		2,205,126		$	22.14		7.21	$	159,924
Options exercisable – September 30, 2018		1,296,158		$	9.32		6.29	$	110,608
Options vested and expected to vest – September 30, 2018		2,151,796		$	21.48		7.17	$	157,476