Stock Incentive Plans (Tables)

6 Months Ended

Jun. 30, 2019

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, 2017		4,034,152
Additional awards authorized		1,168,865
Awards granted		(666,913	)
Awards forfeited		124,478
Awards withheld for tax purposes		56,710
Balance at December 31, 2018		4,717,292
Additional options authorized		1,218,402
Awards granted		(532,551	)
Awards forfeited		103,561
Awards withheld for tax purposes		38,148
Balance at June 30, 2019		5,544,852

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)
Balance at December 31, 2017		2,601,181		$	12.24		7.17	$	113,958
Options granted		366,928		$	68.32
Options exercised		(798,424	)	$	7.19
Options forfeited		(75,548	)	$	34.30
Balance at December 31, 2018		2,094,137		$	23.20		7.02	$	97,976
Options granted		20,010		$	82.77
Options exercised		(357,321	)	$	9.12
Options forfeited		(41,437	)	$	54.96
Balances at June 30, 2019		1,715,389		$	26.06		6.57	$	91,452
Options exercisable – June 30, 2019		1,173,390		$	15.74		5.95	$	74,322
Options vested and expected to vest – June 30, 2019		1,687,960		$	25.57		6.54	$	90,783