Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2016

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Schedule of Stock Based Compensation Expense

The following table summarizes the components of total stock-based compensation expense included in the Company’s consolidated statements of income for the years ended December 31, 2016, 2015 and 2014 (in thousands):

	2016			2015			2014
Cost of revenue	$	18,287		$	14,145		$	11,934
Research and development	29,739			23,927			19,341
Sales and marketing	55,407			53,542			47,570
General and administrative	41,073			35,063			33,151
Total stock-based compensation	144,506			126,677			111,996
Provision for income taxes	(49,014		)	(49,033		)	(39,182		)
Total stock-based compensation, net of taxes	$	95,492		$	77,644		$	72,814

Schedule of Stock Options Granted Black Scholes

The grant-date fair values of the Company's stock option awards granted during the year ended December 31, 2014 were estimated using the Black-Scholes option pricing model with the following weighted-average assumptions:

	2014
Expected term (in years)	4.4
Risk-free interest rate	0.8	%
Expected volatility	40.4	%
Dividend yield	—	%

Schedule of Assumptions Used

The grant-date fair values of the Company's RSUs with market-based vesting conditions granted during the year ended December 31, 2016 were estimated using a Monte Carlo simulation model with the following assumptions:

	2016
Expected term (in years)	3.0
Risk-free interest rate	0.8	%
Akamai historical share price volatility	34.3	%
Average volatility of peer-company share price	27.6	%

The grant-date fair values of the Company's ESPP awards granted during the years ended December 31, 2016, 2015 and 2014 were estimated using the Black-Scholes option pricing model with the following weighted-average assumptions:

	2016		2015		2014
Expected term (in years)	0.5		0.5		0.5
Risk-free interest rate	0.5	%	0.2	%	0.1	%
Expected volatility	36.2	%	28.0	%	33.5	%
Dividend yield	—	%	—	%	—	%

Schedule of Summary of Stock Option Activity

The following table summarizes stock option activity during the year ended December 31, 2016:

	Shares (in thousands)		Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value (in thousands)
Outstanding at January 1, 2016	1,524		$	32.39
Exercised	(643	)	28.17
Forfeited	(7	)	29.69
Outstanding at December 31, 2016	874		$	35.51	2.36	$	27,261
Exercisable at December 31, 2016	829		$	35.58	2.24	$	25,781
Vested or expected to vest December 31, 2016	870		$	35.52	2.35	$	27,123

Schedule Of Deferred Stock Units Activity

The following table summarizes the DSU activity for the year ended December 31, 2016:

	Units (in thousands)		Weighted Average Grant Date Fair Value
Outstanding at January 1, 2016	146		$	45.42
Granted	46		50.72
Vested and distributed	(28	)	57.24
Outstanding at December 31, 2016	164		$	44.90

Schedule of Restricted Stock Units by Type

The following table summarizes the different types of restricted stock units ("RSUs") granted by the Company during the year ended December 31, 2016 (in thousands):

	December 31, 2016
RSUs with service-based vesting conditions	3,873
RSUs with market-based vesting conditions	127
RSUs with performance-based vesting conditions	116
Total	4,116

Schedule of Restricted Stock Units Activity

The following table summarizes the RSU activity for the year ended December 31, 2016:

	Units (in thousands)		Weighted Average Grant Date Fair Value
Outstanding at January 1, 2016	4,495		$	62.20
Granted	4,116		56.40
Vested	(2,374	)	59.13
Forfeited	(527	)	59.68
Outstanding at December 31, 2016	5,710		$	59.51