Stock Based Awards and Other Equity Instruments (Tables)

3 Months Ended

Mar. 31, 2017

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Amount of Stock-Based Compensation Expense Related to Stock-Based Awards, Primarily Stock Options and Restricted Stock Units (RSUs)

The following table presents the amount of stock-based compensation expense related to stock-based awards, primarily stock options and restricted stock units (“RSUs”), on our unaudited condensed consolidated statements of operations during the periods presented:

	Three months ended
	March 31,
	2017			2016
	(in millions)
Selling and marketing	$	5		$	4
Technology and content		7			9
General and administrative		7			6
Total stock-based compensation		19			19
Income tax benefit from stock-based compensation		(7	)		(7	)
Total stock-based compensation, net of tax effect	$	12		$	12

Summary of Stock Option

A summary of the status and activity for stock option awards relating to our common stock for the three months ended March 31, 2017, is presented below:

				Weighted		Weighted
				Average		Average
				Exercise		Remaining		Aggregate
	Options			Price Per		Contractual		Intrinsic
	Outstanding			Share		Life		Value
	(in thousands)					(in years)		(in millions)
Options outstanding at December 31, 2016		5,818		$	57.60
Granted		1,486			42.89
Exercised (1)		(374	)		29.10
Cancelled or expired		(170	)		85.55
Options outstanding at March 31, 2017		6,760		$	55.24		6.4	$	13
Exercisable as of March 31, 2017		2,885		$	47.97		4.9	$	12
Vested and expected to vest after March 31, 2017 (2)		6,760		$	55.24		6.4	$	13

(1) Inclusive of 219,451 of options which were not converted into shares due to net share settlement in order to cover the aggregate exercise price and the required amount of employee withholding taxes. Potential shares that had been convertible under stock options that were withheld under net share settlement remain in the authorized but unissued pool under the 2011 Incentive Plan and can be reissued by the Company. Total payments for the employees’ tax obligations to the taxing authorities due to net share settlements are reflected as a financing activity within the unaudited condensed consolidated statements of cash flows.

(2) The Company accounts for forfeitures as they occur, rather than estimate expected forfeitures as allowed under GAAP and   therefore do not include a forfeiture rate in our vested and expected to vest calculation unless necessary for a performance condition award.

Weighted-Average Assumptions of Estimated Fair Value of Stock Option Grants

The fair value of stock option grants under the 2011 Incentive Plan has been estimated at the date of grant using the Black–Scholes option pricing model with the following weighted average assumptions for the periods presented:

	Three months ended
	March 31,
	2017			2016
Risk free interest rate		1.91	%		1.28	%
Expected term (in years)		5.35			5.18
Expected volatility		41.53	%		41.64	%
Expected dividend yield	—  %			—  %

Summary of RSU Activity

The following table presents a summary of our RSU activity during the three months ended March 31, 2017:

				Weighted
				Average
				Grant-		Aggregate
	RSUs			Date Fair		Intrinsic
	Outstanding			Value Per Share		Value
	(in thousands)					(in millions)
Unvested RSUs outstanding as of December 31, 2016		2,856		$	69.35
Granted		3,732			42.90
Vested and released (1)		(692	)		67.30
Cancelled		(104	)		63.40
Unvested RSUs outstanding as of March 31, 2017		5,792		$	52.65	$	250
Expected to vest after March 31, 2017 (2)		5,792		$	52.65	$	250

(1) Inclusive of 212,894 RSUs withheld due to net share settlement to satisfy required employee tax withholding requirements. Potential shares which had been convertible under RSUs that were withheld under net share settlement remain in the authorized but unissued pool under the 2011 Incentive Plan and can be reissued by the Company. Total payments for the employees’ tax obligations to the taxing authorities due to net share settlements are reflected as a financing activity within the unaudited condensed consolidated statements of cash flows.

(2) The Company accounts for forfeitures as they occur, rather than estimate expected forfeitures as allowed under GAAP and   therefore do not include a forfeiture rate in our expected to vest calculation unless necessary for a performance condition award.

Summary of Unrecognized Stock-Based Compensation Expense and Weighted Average Period Remaining

A summary of our remaining unrecognized stock-based compensation expense and the weighted average remaining amortization period at March 31, 2017 related to our non-vested stock options and RSU awards is presented below (in millions, except in years information):

	Stock
	Options		RSUs
Unrecognized compensation expense	$	64	$	283
Weighted average period remaining (in years)		2.9		3.4