Stock-based Compensation (Tables)

9 Months Ended

Sep. 30, 2019

Stock-based Compensation

Summary of stock option activity

				Remaining	Aggregate
		Exercise		Contractual Term	Intrinsic Value
	Shares	Price		(in years)	(in thousands)(1)
Balance at December 31, 2018	2,620,295	$	20.40	1.49	$	25,697
Granted	—	$	—	—	$	—
Exercised	(1,603,139)	$	20.00	—	$	29,909
Forfeited/canceled	—	$	—	—	$	—
Balance at September 30, 2019	1,017,156	$	21.04	0.80	$	21,138
Vested and exercisable as of September 30, 2019	1,017,156	$	21.04	0.80	$	21,138

(1) The aggregate intrinsic value is calculated as the difference between the exercise price of the underlying awards and the closing stock price of our Class A common stock as of the respective date.

Summary of additional information regarding exercisable and vested stock options

	Stock Options Exercisable
	and Vested
		Weighted-
		Average
	Number of	Remaining Life
Range of exercise prices	Shares	(in years)
$20.00	897,156	0.69
$28.80	120,000	1.57
$20.00 - $28.80	1,017,156	0.80

Summary of activities for unvested RSUs

	Unvested Restricted Stock Units
		Weighted-Average
	Number of	Grant-Date
	Shares	Fair Value
Unvested at December 31, 2018	1,055,325	$	41.66
Granted	670,279	$	39.64
Vested	(271,037)	$	34.58
Forfeited/canceled	(202,621)	$	32.40
Unvested at September 30, 2019	1,251,946	$	43.62
Expected to vest after September 30, 2019	1,341,575	$	43.45