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Document and Entity Information - shares	3 Months Ended
Document and Entity Information - shares	Mar. 31, 2014	May 06, 2014
Document and Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2014
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	Q1
Entity Registrant Name	AKAMAI TECHNOLOGIES INC
Entity Central Index Key	0001086222
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		178,001,071

Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 248,726	$ 333,891
Marketable securities	449,404	340,005
Accounts receivable, net of reserves of $6,933 and $3,703 at March 31, 2014 and December 31, 2013, respectively	301,954	271,988
Prepaid expenses and other current assets	89,198	62,096
Deferred income tax assets	38,018	21,734
Total current assets	1,127,300	1,029,714
Property and equipment, net	503,601	450,287
Marketable securities	721,271	573,026
Goodwill	1,050,780	757,368
Acquired intangible assets, net	157,621	77,429
Deferred income tax assets	2,476	2,325
Other assets	88,443	67,536
Total assets	3,651,492	2,957,685
Current liabilities:
Accounts payable	61,707	73,710
Accrued expenses	130,447	150,385
Deferred revenue	48,359	36,952
Other current liabilities	3,673	2,119
Total current liabilities	244,186	263,166
Deferred revenue	4,181	3,199
Deferred income tax liabilities	28,445	4,737
Convertible senior notes	590,714	0
Other liabilities	71,821	57,152
Total liabilities	939,347	328,254
Commitments and contingencies
Stockholders’ equity:
Preferred stock, $0.01 par value; 5,000,000 shares authorized; 700,000 shares designated as Series A Junior Participating Preferred Stock; no shares issued or outstanding	0	0
Common stock, $0.01 par value; 700,000,000 shares authorized; 180,494,143 shares issued and 178,517,946 shares outstanding at March 31, 2014 and 178,580,696 shares issued and outstanding at December 31, 2013	1,832	1,808
Additional paid-in capital	4,687,512	4,561,929
Accumulated other comprehensive loss	(1,637)	(2,091)
Treasury stock, at cost, 1,976,197 shares at March 31, 2014 and no shares at December 31, 2013	(116,147)	0
Accumulated deficit	(1,859,415)	(1,932,215)
Total stockholders’ equity	2,712,145	2,629,431
Total liabilities and stockholders’ equity	$ 3,651,492	$ 2,957,685

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2014	Dec. 31, 2013
Statement of Financial Position [Abstract]
Accounts receivable reserve (in dollars)	$ 6,933	$ 3,703
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares designated as Series A Junior Participating Preferred Stock	700,000	700,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	700,000,000	700,000,000
Common stock, shares issued	180,494,143	178,580,696
Common stock, shares outstanding	178,517,946	178,580,696
Treasury stock, shares	1,976,197	0

Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Income Statement [Abstract]
Revenue	$ 453,502	$ 368,046
Costs and operating expenses:
Cost of revenue	139,612	120,392
Research and development	28,234	21,905
Sales and marketing	81,065	62,690
General and administrative	76,161	55,380
Amortization of acquired intangible assets	6,848	6,060
Restructuring charges	735	431
Total costs and operating expenses	332,655	266,858
Income from operations	120,847	101,188
Interest income	1,639	1,608
Interest expense	(1,941)	0
Other expense, net	(881)	(132)
Income before provision for income taxes	119,664	102,664
Provision for income taxes	46,864	31,177
Net income	$ 72,800	$ 71,487
Net income per share:
Basic (in dollars per share)	$ 0.41	$ 0.40
Diluted (in dollars per share)	$ 0.40	$ 0.39
Shares used in per share calculations:
Basic (in shares)	178,705	177,899
Diluted (in shares)	182,038	181,562

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Statement of Comprehensive Income [Abstract]
Net income	$ 72,800	$ 71,487
Other comprehensive income (loss):
Foreign currency translation adjustments	1,367	(4,014)
Change in unrealized (loss) gain on investments, net of income tax benefit (provision) of $123 and $(10) for the three months ended March 31, 2014 and 2013, respectively	(913)	71
Other comprehensive income (loss)	454	(3,943)
Comprehensive income	$ 73,254	$ 67,544

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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+ Details

Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Statement of Comprehensive Income [Abstract]
Tax on change in unrealized gain on investments, net	$ 123	$ (10)

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Cash flows from operating activities:
Net income	$ 72,800	$ 71,487
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	53,516	42,375
Stock-based compensation	25,114	22,931
Provision for doubtful accounts	87	320
Excess tax benefits from stock-based compensation	(15,178)	(4,119)
Provision for deferred income taxes	1,660	0
Amortization of debt discount and issuance costs	1,941	0
Loss (gain) from disposal of property and equipment	215	(71)
Gain from divestiture of a business	0	(1,188)
Changes in operating assets and liabilities, net of effects of acquisitions and divestitures:
Accounts receivable	(18,137)	(28,355)
Prepaid expenses and other current assets	(20,961)	(11,447)
Accounts payable and accrued expenses	(22,511)	(4,528)
Deferred revenue	5,159	8,225
Other current liabilities	1,287	(111)
Other non-current assets and liabilities	4,031	(2,295)
Net cash provided by operating activities	89,023	93,224
Cash flows from investing activities:
Cash paid for acquired businesses, net of cash acquired	(386,647)	0
Purchases of property and equipment	(52,011)	(43,831)
Capitalization of internal-use software development costs	(31,995)	(16,998)
Purchases of short- and long-term marketable securities	(658,943)	(145,350)
Proceeds from sales of short- and long-term marketable securities	297,059	55,509
Proceeds from maturities of short- and long-term marketable securities	102,911	66,171
Proceeds from the sale of property and equipment	166	260
Other non-currents assets and liabilities	(998)	0
Net cash used in investing activities	(730,458)	(84,239)
Cash flows from financing activities:
Proceeds from the issuance of convertible senior notes, net of issuance costs	679,603	0
Proceeds from the issuance of warrants related to convertible senior notes	77,970	0
Purchase of note hedge related to convertible senior notes	(101,292)	0
Payment of acquired debt and capital leases	(17,862)	0
Proceeds related to the issuance of common stock under stock plans	44,329	10,364
Excess tax benefits from stock-based compensation	15,178	4,119
Employee taxes paid related to net share settlement of stock-based awards	(26,271)	(17,315)
Repurchases of common stock	(116,147)	(40,278)
Net cash provided by (used in) financing activities	555,508	(43,110)
Effects of exchange rate changes on cash and cash equivalents	762	(2,589)
Net decrease in cash and cash equivalents	(85,165)	(36,714)
Cash and cash equivalents at beginning of period	333,891	201,989
Cash and cash equivalents at end of period	248,726	165,275
Supplemental disclosure of cash flow information:
Cash paid for income taxes	54,479	16,097
Non-cash financing and investing activities:
Purchases of property and equipment and capitalization of internal-use software development costs included in accrued expenses	20,093	18,136
Capitalization of stock-based compensation	3,784	2,938
Convertible note receivable received for divestiture of a business	$ 0	$ 18,882

Nature of Business and Basis of Presentation

3 Months Ended

Mar. 31, 2014

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Nature of Business and Basis of Presentation

Akamai Technologies, Inc. (the “Company”) provides cloud services for delivering, optimizing and securing online content and business applications. The Company's globally distributed platform comprises more than 145,000 servers in approximately 1,200 networks in over 90 countries. The Company was incorporated in Delaware in 1998 and is headquartered in Cambridge, Massachusetts. The Company currently operates in one industry segment: providing services for accelerating and improving the delivery of content and applications over the Internet.

The accompanying interim consolidated financial statements are unaudited and have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) for interim financial information. These financial statements include the accounts of the Company and its wholly-owned subsidiaries. All intercompany transactions and balances have been eliminated in the accompanying financial statements.

Certain information and footnote disclosures normally included in the Company’s annual audited consolidated financial statements and accompanying notes have been condensed or omitted in these interim financial statements. Accordingly, the unaudited consolidated financial statements included herein should be read in conjunction with the audited consolidated financial statements and accompanying notes included in the Company’s annual report on Form 10-K for the year ended December 31, 2013, filed with the Securities and Exchange Commission on March 3, 2014.

The results of operations presented in this quarterly report on Form 10-Q are not necessarily indicative of the results of operations that may be expected for any future periods. In the opinion of management, these unaudited consolidated financial statements include all adjustments, consisting only of normal recurring adjustments, that are necessary for a fair statement of the results of all interim periods reported herein.

Revision of Prior Period Amounts

During the third quarter of 2013, the Company identified immaterial classification errors in its historical consolidated statements of cash flows. The errors relate to the timing of cash payments for property and equipment, cash receipts from employees for common stock related to the Company's employee stock purchase plan and cash payments for lease deposits. The cash flows for these items were improperly reflected as changes in operating assets and liabilities rather than as investing or financing activities. There was no impact to the net change in cash and cash equivalents. The Company concluded these errors are immaterial to all annual and quarterly periods previously presented and has reflected the corrections as a revision to the consolidated statements of cash flows previously filed.

The effect of the revisions to the consolidated statements of cash flows for the three months ended March 31, 2013, is as follows (in thousands):



	As Previously Reported		Adjustment		As Revised
Cash flows from operating activities:
Changes in operating assets and liabilities, net of effects from acquisitions:
Prepaid expenses and other current assets	(14,035	)	2,588		(11,447	)
Accounts payable and accrued expenses	7,838		(12,366	)	(4,528	)
Other non-current assets and liabilities	(2,257	)	(38	)	(2,295	)
Net cash provided by operating activities	103,040		(9,816	)	93,224
Cash flows from investing activities:
Purchases of property and equipment	(46,478	)	2,647		(43,831	)
Net cash used in investing activities	(86,886	)	2,647		(84,239	)
Cash flows from financing activities:
Proceeds related to the issuance of common stock under stock plans	3,195		7,169		10,364
Net cash used in financing activities	(50,279	)	7,169		(43,110	)
Net decrease in cash and cash equivalents	(36,714	)	—		(36,714	)

- Definition

The entire disclosure for organization, consolidation and basis of presentation of financial statements disclosure.

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+ Details

Fair Value Measurements

3 Months Ended

Mar. 31, 2014

Marketable Securities [Abstract]

Fair Value Measurements

The following is a summary of available-for-sale marketable securities held as of March 31, 2014 and December 31, 2013 (in thousands):



			Gross Unrealized							Classification Balance Sheet
	Amortized Cost		Gains		Losses			Aggregate Fair Value		Short-Term Marketable Securities		Long-Term Marketable Securities
As of March 31, 2014
Certificates of deposit	$	225	$	—	$	—		$	225	$	172	$	53
Commercial paper	24,986		—		(12		)	24,974		24,974		—
Corporate bonds	874,265		1,087		(1,161		)	874,191		358,887		515,304
U.S. government agency obligations	271,705		14		(434		)	271,285		65,371		205,914
	$	1,171,181	$	1,101	$	(1,607	)	$	1,170,675	$	449,404	$	721,271

As of December 31, 2013
Certificates of deposit	$	222	$	—	$	—		$	222	$	173	$	49
Corporate bonds	736,945		1,197		(281		)	737,861		278,318		459,543
U.S. government agency obligations	174,982		51		(85		)	174,948		61,514		113,434
	$	912,149	$	1,248	$	(366	)	$	913,031	$	340,005	$	573,026

Unrealized gains and unrealized temporary losses on investments classified as available-for-sale are included within accumulated other comprehensive loss in the consolidated balance sheets. Upon realization, those amounts are reclassified from accumulated other comprehensive loss to interest income in the statements of operations. As of March 31, 2014, the Company did not hold any investment-related assets that had been in a continuous loss position for more than 12 months.

The following table details the fair value measurements within the fair value hierarchy of the Company’s financial assets and liability at March 31, 2014 and December 31, 2013 (in thousands):



	Total Fair Value			Fair Value Measurements at Reporting Date Using
	Total Fair Value			Level 1		Level 2		Level 3
As of March 31, 2014
Cash Equivalents and Marketable Securities:
Money market funds	$	21,401		$	21,401	$	—	$	—
Certificates of deposit	225			225		—		—
Commercial paper	48,471			—		48,471		—
Corporate bonds	876,199			—		876,199		—
U.S. government agency obligations	271,285			—		271,285		—
	$	1,217,581		$	21,626	$	1,195,955	$	—
Other Assets:
Note receivable	$	23,245		$	—	$	—	$	23,245

Other Liabilities:
Contingent consideration obligation related to Velocius acquisition	$	(2,600	)	$	—	$	—	$	(2,600	)

As of December 31, 2013
Cash Equivalents and Marketable Securities:
Money market funds	$	40,482		$	40,482	$	—	$	—
Certificates of deposit	3,418			3,418		—		—
Commercial paper	29,999			—		29,999		—
Corporate bonds	737,861			—		737,861		—
U.S. government agency obligations	174,948			—		174,948		—
	$	986,708		$	43,900	$	942,808	$	—
Other Assets:
Note receivable	$	22,879		$	—	$	—	22,879

Other Liabilities:
Contingent consideration obligation related to Velocius acquisition	$	(2,600	)	$	—	$	—	$	(2,600	)

As of March 31, 2014 and December 31, 2013, the Company grouped money market funds and certificates of deposit using a Level 1 valuation because market prices for such investments are readily available in active markets. As of March 31, 2014 and December 31, 2013, the Company grouped commercial paper, U.S. government agency obligations and corporate bonds using a Level 2 valuation because quoted prices for identical or similar assets are available in markets that are inactive.

When developing fair value estimates, the Company maximizes the use of observable inputs and minimizes the use of unobservable inputs. When available, the Company uses quoted market prices to measure fair value. The valuation technique used to measure fair value for the Company's Level 1 and Level 2 assets is a market approach, using prices and other relevant information generated by market transactions involving identical or comparable assets. If market prices are not available, the fair value measurement is based on models that use primarily market-based parameters including yield curves, volatilities, credit ratings and currency rates. In certain cases where market rate assumptions are not available, the Company is required to make judgments about assumptions market participants would use to estimate the fair value of a financial instrument.

The valuation technique used to measure fair value for the Company's Level 3 asset, which consists of a $25.0 million face value convertible note receivable that is due and payable on July 24, 2014, is primarily an income approach, where the expected weighted average future cash flows are discounted back to present value. The significant unobservable inputs used in the fair value measurement of the convertible note receivable are the probability of conversion to equity and the fair value of equity in which the note is convertible to.

The valuation technique used to measure fair value of the Company's Level 3 liability, which consists of contingent consideration related to the acquisition of Velocius Networks, Inc. ("Velocius") (Note 5), is primarily an income approach. The significant unobservable input used in the fair value measurement of the Velocius contingent consideration is the likelihood of achieving development milestones to integrate the acquired technology into the Company's technology.

Significant increases or decreases in the underlying assumptions used to value the Company's Level 3 asset and liability held at March 31, 2014 and December 31, 2013, could significantly increase or decrease the fair value estimates recorded in the consolidated balance sheets.

Contractual maturities of the Company’s available-for-sale marketable securities held at March 31, 2014 and December 31, 2013 were as follows (in thousands):



	March 31, 2014		December 31, 2013
Due in 1 year or less	$	449,404	$	340,005
Due after 1 year through 5 years	721,271		573,026
	$	1,170,675	$	913,031

The following table reflects the activity for the Company’s major classes of assets and liabilities measured at fair value using Level 3 inputs for the three months ended March 31, 2014 (in thousands):



	Other Assets: Note Receivable		Other Liabilities: Contingent Consideration Obligation
Balance as of January 1, 2014	$	22,879	$	(2,600	)
Unrealized gain on convertible note receivable included in other comprehensive income	366		—
Balance as of March 31, 2014	$	23,245	$	(2,600	)

- Definition

The entire disclosure for investments in certain debt and equity securities.

+ References + Details

Accounts Receivable

3 Months Ended

Mar. 31, 2014

Accounts, Notes, Loans and Financing Receivable, Gross, Allowance, and Net [Abstract]

Accounts Receivable

Net accounts receivable consisted of the following as of March 31, 2014 and December 31, 2013 (in thousands):



	March 31, 2014			December 31, 2013
Trade accounts receivable	$	218,310		$	175,391
Unbilled accounts receivable	90,577			100,300
Gross accounts receivable	308,887			275,691
Allowance for doubtful accounts	(754		)	(708		)
Reserve for cash-basis customers	(6,179		)	(2,995		)
Total accounts receivable reserves	(6,933		)	(3,703		)
Accounts receivable, net	$	301,954		$	271,988

- Definition

The entire disclosure for claims held for amounts due a entity, excluding financing receivables. Examples include, but are not limited to, trade accounts receivables, notes receivables, loans receivables. Includes disclosure for allowance for credit losses.

+ References + Details

Goodwill and Acquired Intangible Assets

3 Months Ended

Mar. 31, 2014

Goodwill and Intangible Assets Disclosure [Abstract]

Goodwill and Acquired Intangible Assets

The change in the carrying amount of goodwill for the three months ended March 31, 2014 was as follows (in thousands):



Balance as of January 1, 2014	$	757,368
Acquisition of Prolexic Technologies, Inc.	293,412
Balance as of March 31, 2014	$	1,050,780

The Company tests goodwill for impairment at least annually. Through the date the consolidated financial statements were issued, no triggering events had occurred that would indicate a potential impairment exists.

Acquired intangible assets that are subject to amortization consist of the following as of March 31, 2014 and December 31, 2013 (in thousands):



	March 31, 2014							December 31, 2013
	Gross Carrying Amount		Accumulated Amortization			Net Carrying Amount		Gross Carrying Amount		Accumulated Amortization			Net Carrying Amount
Completed technology	$	92,431	$	(38,631	)	$	53,800	$	65,631	$	(35,476	)	$	30,155
Customer-related intangible assets	173,600		(78,708		)	94,892		115,100		(75,563		)	39,537
Non-compete agreements	8,890		(3,060		)	5,830		7,950		(2,623		)	5,327
Trademarks and trade names	4,200		(1,101		)	3,099		3,400		(990		)	2,410
Acquired license rights	490		(490		)	—		490		(490		)	—
Total	$	279,611	$	(121,990	)	$	157,621	$	192,571	$	(115,142	)	$	77,429

Aggregate expense related to amortization of acquired intangible assets for the three months ended March 31, 2014 and 2013 was $6.8 million and $6.1 million, respectively. Based on the Company’s acquired intangible assets as of March 31, 2014, aggregate expense related to amortization of acquired intangible assets is expected to be $25.2 million for the remainder of 2014, and $26.8 million, $25.2 million, $23.1 million and $16.2 million for 2015, 2016, 2017 and 2018, respectively.

- Definition

The entire disclosure for the aggregate amount of goodwill and a description of intangible assets, which may include (a) for amortizable intangible assets (also referred to as finite-lived intangible assets), the carrying amount, the amount of any significant residual value, and the weighted-average amortization period, (b) for intangible assets not subject to amortization (also referred to as indefinite-lived intangible assets), the carrying amount, and (c) the amount of research and development assets acquired and written off in the period, including the line item in the income statement in which the amounts written off are aggregated, if not readily apparent from the income statement. Also discloses (a) for amortizable intangibles assets in total and by major class, the gross carrying amount and accumulated amortization, the total amortization expense for the period, and the estimated aggregate amortization expense for each of the five succeeding fiscal years, (b) for intangible assets not subject to amortization the carrying amount in total and by major class, and (c) for goodwill, in total and for each reportable segment, the changes in the carrying amount of goodwill during the period (including the aggregate amount of goodwill acquired, the aggregate amount of impairment losses recognized, and the amount of goodwill included in the gain (loss) on disposal of a reporting unit). If any part of goodwill has not been allocated to a reportable segment, discloses the unallocated amount and the reasons for not allocating. For each impairment loss recognized related to an intangible asset (excluding goodwill), discloses: (a) a description of the impaired intangible asset and the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method for determining fair value, (c) the caption in the income statement or the statement of activities in which the impairment loss is aggregated, and (d) the segment in which the impaired intangible asset is reported. For each goodwill impairment loss recognized, discloses: (a) a description of the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method of determining the fair value of the associated reporting unit, and (c) if a recognized impairment loss is an estimate not finalized and the reasons why the estimate is not final. May also disclose the nature and amount of any significant adjustments made to a previous estimate of an impairment loss.

+ References + Details

Business Acquisitions

3 Months Ended

Mar. 31, 2014

Business Combinations [Abstract]

Business Acquisitions

Prolexic Acquisition

On February 18, 2014, the Company acquired all of the outstanding preferred and common stock of Prolexic Technologies, Inc. ("Prolexic") in exchange for $392.2 million in cash and the assumption of unvested stock options, subject to post-closing adjustments. The goal of acquiring Prolexic is to provide customers with a comprehensive portfolio of security solutions designed to defend an enterprise’s Web and IP infrastructure against application-layer, network-layer and data center attacks delivered via the Internet. The consolidated financial statements include the operating results of Prolexic from the date of acquisition. The revenue and earnings included in the Company's consolidated financial statements since the acquisition date are not material. Pro forma results of the operations have not been presented because the effects are not material to the consolidated financial statements. Acquisition-related costs were $3.9 million for the three months ended March 31, 2014.

The Company is in the process of gathering the facts and circumstances existing as of the acquisition date in order to finalize the allocation of the purchase price to the fair value of assets acquired and liabilities assumed and establish the related tax basis. As a result, the purchase price allocation is preliminary.

The following table presents the preliminary allocation of the purchase price for Prolexic (in thousands):



Total purchase consideration	$	392,219

Allocation of the purchase consideration:
Cash	$	33,072
Accounts receivable	11,306
Property and equipment	12,169
Identifiable intangible assets	87,040
Goodwill	293,412
Deferred tax assets	16,000
Other current and long-term assets	5,883
Total assets acquired	458,882
Other current liabilities	(7,501		)
Current deferred revenue	(5,812		)
Deferred tax liabilities	(33,723		)
Debt, capital leases and other long-term liabilities	(19,627		)
Total liabilities assumed	(66,663		)
Net assets acquired	$	392,219

The value of the goodwill can be attributed to a number of business factors, including a trained technical and sales workforce; and the fair value of expected cost synergies to be realized. The total amount of goodwill related to the acquisition of Prolexic expected to be deducted for tax purposes is $62.4 million.

The following were the identified intangible assets acquired and their respective weighted average useful lives, as determined based on preliminary valuations (in thousands, except for years):



	Gross Carrying Amount		Weighted Average Useful Life (in years)
Completed technologies	$	26,800	6.9
Customer-related intangible assets	58,500		10.4
Non-compete agreements	940		3.0
Trademark	800		4.9
Total	$	87,040

Velocius Acquisition

On November 8, 2013, the Company acquired Velocius in exchange for $4.3 million in cash. In addition, the Company recorded a liability of $2.6 million for contingent consideration related to expected achievement of post-closing milestones. The Company acquired Velocius with a goal of complementing its hybrid cloud optimization strategy for optimizing IP application traffic across the Internet for remote and branch-end users. The Company allocated $5.4 million of the cost of the acquisition to goodwill and $2.5 million to acquired intangible assets. The allocation of the purchase price was finalized in the first quarter of 2014. The total weighted average useful life of the intangible assets acquired from Velocius is 7.9 years. The value of the goodwill from the acquisition can be attributed to a number of business factors including a trained technical workforce and cost synergies. The total amount of goodwill related to the acquisition of Velocius expected to be deducted for tax purposes is $0.5 million.

Strategic Network Transaction

On November 30, 2012, the Company entered into a strategic alliance with AT&T Services, Inc. ("AT&T"). Under the agreement, AT&T became a reseller of the Company's services and the Company acquired certain assets and contracted to purchase bandwidth, co-location and related services from AT&T. The total consideration is $55.0 million, of which $27.5 million was paid during the third quarter of 2013 and $27.5 million was paid during the first quarter of 2014.

- Definition

The entire disclosure for a business combination (or series of individually immaterial business combinations) completed during the period, including background, timing, and recognized assets and liabilities. The disclosure may include leverage buyout transactions (as applicable).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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+ Details

Convertible Senior Notes

3 Months Ended

Mar. 31, 2014

Debt Disclosure [Abstract]

Convertible Senior Notes

In February 2014, the Company issued $690.0 million par value of convertible senior notes due 2019 (the "Notes"). The Notes are senior unsecured obligations of the Company, do not bear regular interest and mature on February 15, 2019, unless repurchased or converted prior to maturity.

At their option, holders may convert their Notes prior to the close of business on the business day immediately preceding August 15, 2018 only under the following circumstances:

•

during any calendar quarter commencing after the calendar quarter ending June 30, 2014 (and only during such calendar quarter), if the last reported sale price of the Company's common stock for at least 20 trading days (whether or not consecutive) during the period of 30 consecutive trading days ending on the last trading day of the immediately preceding calendar quarter is greater than or equal to 130% of the conversion price on each applicable trading day;


•	during the five business day period after any five consecutive trading day period in which the trading price per $1,000 principal amount of Notes for each trading day of the measurement period was less than 98% of the product of the last reported sale price of the Company's common stock and the conversion rate on each such trading day; or


•	upon the occurrence of specified corporate events.

On or after August 15, 2018, holders may convert all or any portion of their Notes at any time prior to the close of business on the second scheduled trading day immediately preceding the maturity date, regardless of the foregoing circumstances.

Upon conversion, the Company, at its election, may pay or deliver to holders cash, shares of the Company's common stock or a combination of cash and shares of the Company's common stock. The initial conversion rate is 11.1651 shares of the Company's common stock per $1,000 principal amount, which is equivalent to an initial conversion price of approximately $89.56 per share, subject to adjustments in certain events, and represents a potential conversion into 7.7 million shares.

In accounting for the issuance of the Notes, the Company separated the Notes into liability and equity components. The carrying cost of the liability component was calculated by measuring the fair value of a similar debt obligation that does not have an associated convertible feature. The carrying amount of the equity component representing the conversion option was determined by deducting the fair value of the liability component from the par value of the Notes. The difference between the principal amount of the Notes and the proceeds allocated to the liability component (“debt discount”), is amortized to interest expense using the effective interest method over the term of the Notes. The equity component is recorded in additional paid-in capital in the consolidated balance sheet and will not be remeasured as long as it continues to meet the conditions for equity classification.

In accounting for the transaction costs related to the issuance of the Notes, the Company allocated the total transaction costs incurred to the liability and equity components based on their relative values. Transaction costs attributable to the liability component are being amortized to interest expense over the term of the Notes, and transaction costs attributable to the equity component are netted with the equity component of the Notes in stockholders’ equity.

The Notes consisted of the following components (in thousands):



	March 31, 2014
Liability component:
Principal	$	690,000
Less: debt discount, net of amortization	(99,286		)
Net carrying amount	$	590,714

Equity component:	$	101,276

The estimated fair value of the Company's Notes at March 31, 2014 was $683.7 million. The fair value was determined based on data points other than quoted prices that are observable, either directly or indirectly, and has been classified as Level 2 within the fair value hierarchy. Based on the closing price of the Company's common stock of $58.21 on March 31, 2014, the value of the Notes if converted to common stock was less than the principal amount of $690.0 million.

The Company used $62.0 million of the proceeds from the offering to repurchase shares of its common stock, concurrent with the issuance of the Notes. The repurchase was made in accordance with the stock repurchase plan previously approved by the Board of Directors (Note 7). Additionally, $23.3 million of the proceeds was used for the net cost of the convertible note hedge and warrant transactions. The Company intends to use the remaining net proceeds for working capital and other general corporate purposes, as well as for potential acquisitions and strategic transactions.

Note Hedge

To minimize the impact of potential dilution upon conversion of the Notes, the Company entered into convertible note hedge transactions with respect to its common stock. The Company paid $101.3 million for the note hedge transactions. The note hedge transactions cover approximately 7.7 million shares of the Company’s common stock at a strike price that corresponds to the initial conversion price of the Notes, also subject to adjustment, and are exercisable upon conversion of the Notes. The note hedge transactions are intended to reduce dilution upon potential conversion of the Notes.

Warrants

Separately, the Company entered into warrant transactions, whereby the Company sold warrants to acquire, subject to anti-dilution adjustments, up to 7.7 million shares of the Company’s common stock at a strike price of approximately $104.49 per share. The Company received aggregate proceeds of $78.0 million from the sale of the warrants. The convertible note hedge and warrant transactions will generally have the effect of increasing the conversion price of the Notes to approximately $104.49 per share.

Interest Expense

The Notes do not bear regular interest, but have an effective interest rate of 3.2% attributable to the conversion feature. The following table sets forth total interest expense included in the statement of operations related to the Notes (in thousands):



	For the Three Months Ended March 31, 2014
Amortization of debt discount	$	188
Amortization of debt issuance costs	1,990
Capitalization of interest expense	(237		)
Total interest expense	$	1,941

Stockholders' Equity

3 Months Ended

Mar. 31, 2014

Stockholders' Equity Note [Abstract]

Stockholders' Equity

Stockholders’ Equity

Stock Repurchase Program

In January 2013, the Board of Directors authorized a $150.0 million extension of its share repurchase program, effective for a twelve-month period beginning February 1, 2013. In October 2013, the Board of Directors authorized a new $750.0 million share repurchase program, effective from October 16, 2013 through December 31, 2016. During the three months ended March 31, 2014, the Company repurchased 2.0 million shares of its common stock for $116.1 million. During the three months ended March 31, 2013, the Company repurchased 1.1 million shares of its common stock for $40.3 million.

Stock-Based Compensation

The following table summarizes stock-based compensation included in the Company’s consolidated statements of operations for the three months ended March 31, 2014 and 2013 (in thousands):



	For the Three Months Ended March 31,
	2014			2013
Cost of revenue	$	2,795		$	2,627
Research and development	4,477			4,369
Sales and marketing	10,532			9,431
General and administrative	7,310			6,504
Total stock-based compensation	25,114			22,931
Provision for income taxes	(8,224		)	(6,964		)
Total stock-based compensation, net of income taxes	$	16,890		$	15,967

In addition to the amounts of stock-based compensation reported in the table above, the Company’s consolidated statements of operations for the three months ended March 31, 2014 and 2013 include stock-based compensation reflected as a component of amortization of capitalized internal-use software of $1.9 million, before income taxes.

- Definition

The entire disclosure for shareholders' equity comprised of portions attributable to the parent entity and noncontrolling interest, including other comprehensive income. Includes, but is not limited to, balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings, accumulated balance for each classification of other comprehensive income and amount of comprehensive income.

+ References

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+ Details

Accumulated Other Comprehensive Loss

3 Months Ended

Mar. 31, 2014

Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]

Comprehensive Income

Accumulated Other Comprehensive Loss

The following table summarizes the changes in accumulated other comprehensive loss, which is reported as a component of stockholders' equity, for the three months ended March 31, 2014 (in thousands):



	Foreign Currency Translation Adjustments			Net Unrealized Gain (Loss) on Investments			Total
Balance as of January 1, 2014	$	(6,715	)	$	4,624		$	(2,091	)
Other comprehensive income (loss)	1,367			(913		)	454
Balance as of March 31, 2014	$	(5,348	)	$	3,711		$	(1,637	)

The tax effect on accumulated unrealized gain on investments was insignificant as of March 31, 2014 and December 31, 2013. Amounts reclassified from accumulated other comprehensive loss to net income were insignificant for the three months ended March 31, 2014.

- Definition

The entire disclosure for comprehensive income, which includes, but is not limited to, 1) the amount of income tax expense or benefit allocated to each component of other comprehensive income, including reclassification adjustments, 2) the reclassification adjustments for each classification of other comprehensive income and 3) the ending accumulated balances for each component of comprehensive income.

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+ Details

Income Taxes	3 Months Ended
Income Taxes	Mar. 31, 2014
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company’s effective income tax rate, including discrete items, was 39.2% and 30.4% for the three months ended March 31, 2014 and 2013, respectively. The effective income tax rate is based upon estimated income for the year, the estimated composition of the income in different jurisdictions and discrete adjustments, if any, in the applicable quarterly periods, including retroactive changes in tax legislation, settlements of tax audits or assessments, the resolution or identification of tax position uncertainties and acquisitions of other companies. The discrete items in the first quarter of 2014 include a deferred tax charge, the tax effect of certain stock options and interest and penalties related to uncertain tax positions. For the three months ended March 31, 2014, the effective income tax rate was higher than the federal statutory tax rate mainly due to the effects of accounting for stock-based compensation in accordance with the authoritative guidance for share-based payments and state income tax. For the three months ended March 31, 2013, the effective income tax rate was lower than the federal statutory tax rate mainly due to the composition of income in foreign jurisdictions that is taxed at lower rates compared to the statutory tax rates in the United States, as well as the reinstatement of the federal research and development credit at the beginning of 2013 which was retroactive to 2012.

Net Income per Share

3 Months Ended

Mar. 31, 2014

Earnings Per Share Reconciliation [Abstract]

Net Income per Share

Basic net income per share is computed using the weighted average number of common shares outstanding during the applicable period. Diluted net income per share is computed using the weighted average number of common shares outstanding during the period, plus the dilutive effect of potential common stock. Potential common stock consists of shares issuable pursuant to stock options, restricted stock units (“RSUs”), deferred stock units, convertible senior notes and warrants issued by the Company. The dilutive effect of outstanding awards and convertible securities is reflected in diluted earnings per share by application of the treasury stock method.

The following table sets forth the components used in the computation of basic and diluted net income per share for three months ended March 31, 2014 and 2013 (in thousands, except per share data):



	For the Three Months Ended March 31,
	2014		2013
Numerator:
Net income	$	72,800	$	71,487
Denominator:
Shares used for basic net income per share	178,705		177,899
Effect of dilutive securities:
Stock options	1,382		1,776
RSUs and deferred stock units	1,951		1,887
Convertible senior notes	—		—
Warrants related to issuance of convertible senior notes	—		—
Shares used for diluted net income per share	182,038		181,562
Basic net income per share	$	0.41	$	0.40
Diluted net income per share	$	0.40	$	0.39

For the three months ended March 31, 2014 and 2013, certain potential outstanding shares from stock options, service-based RSUs, convertible notes and warrants were excluded from the computation of diluted net income per share because the effect of including these items would be anti-dilutive. Additionally, certain performance-based RSUs were excluded from the computation of diluted net income per share because the underlying performance conditions for such RSUs had not been met as of these dates. The number of potentially outstanding shares excluded from the computation of diluted net income per share for three months ended March 31, 2014 and 2013 are as follows (in thousands):



	For the Three Months Ended March 31,
	2014	2013
Stock options	651	2,148
Service-based RSUs	514	495
Performance-based RSUs	575	1,148
Convertible senior notes	7,704	—
Warrants related to issuance of convertible senior notes	7,704	—

The calculation of assumed proceeds used to determine the diluted weighted average shares outstanding under the treasury stock method in the periods presented was adjusted by tax windfalls and shortfalls associated with all of the Company’s outstanding stock awards. Such windfalls and shortfalls are computed by comparing the tax deductible amount of outstanding stock awards to their grant date fair values and multiplying the results by the applicable statutory tax rate. A positive result creates a windfall, which increases the assumed proceeds, and a negative result creates a shortfall, which reduces the assumed proceeds.

Nature of Business and Basis of Presentation (Tables)

3 Months Ended

Mar. 31, 2014

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Schedule of Effect of the Revisions to the Consolidated Statements of Cash Flows

The effect of the revisions to the consolidated statements of cash flows for the three months ended March 31, 2013, is as follows (in thousands):



	As Previously Reported		Adjustment		As Revised
Cash flows from operating activities:
Changes in operating assets and liabilities, net of effects from acquisitions:
Prepaid expenses and other current assets	(14,035	)	2,588		(11,447	)
Accounts payable and accrued expenses	7,838		(12,366	)	(4,528	)
Other non-current assets and liabilities	(2,257	)	(38	)	(2,295	)
Net cash provided by operating activities	103,040		(9,816	)	93,224
Cash flows from investing activities:
Purchases of property and equipment	(46,478	)	2,647		(43,831	)
Net cash used in investing activities	(86,886	)	2,647		(84,239	)
Cash flows from financing activities:
Proceeds related to the issuance of common stock under stock plans	3,195		7,169		10,364
Net cash used in financing activities	(50,279	)	7,169		(43,110	)
Net decrease in cash and cash equivalents	(36,714	)	—		(36,714	)

Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2014

Marketable Securities [Abstract]

Schedule of Marketable Securities

The following is a summary of available-for-sale marketable securities held as of March 31, 2014 and December 31, 2013 (in thousands):



			Gross Unrealized							Classification Balance Sheet
	Amortized Cost		Gains		Losses			Aggregate Fair Value		Short-Term Marketable Securities		Long-Term Marketable Securities
As of March 31, 2014
Certificates of deposit	$	225	$	—	$	—		$	225	$	172	$	53
Commercial paper	24,986		—		(12		)	24,974		24,974		—
Corporate bonds	874,265		1,087		(1,161		)	874,191		358,887		515,304
U.S. government agency obligations	271,705		14		(434		)	271,285		65,371		205,914
	$	1,171,181	$	1,101	$	(1,607	)	$	1,170,675	$	449,404	$	721,271

As of December 31, 2013
Certificates of deposit	$	222	$	—	$	—		$	222	$	173	$	49
Corporate bonds	736,945		1,197		(281		)	737,861		278,318		459,543
U.S. government agency obligations	174,982		51		(85		)	174,948		61,514		113,434
	$	912,149	$	1,248	$	(366	)	$	913,031	$	340,005	$	573,026

Schedule of Fair Value Measurement

The following table details the fair value measurements within the fair value hierarchy of the Company’s financial assets and liability at March 31, 2014 and December 31, 2013 (in thousands):



	Total Fair Value			Fair Value Measurements at Reporting Date Using
	Total Fair Value			Level 1		Level 2		Level 3
As of March 31, 2014
Cash Equivalents and Marketable Securities:
Money market funds	$	21,401		$	21,401	$	—	$	—
Certificates of deposit	225			225		—		—
Commercial paper	48,471			—		48,471		—
Corporate bonds	876,199			—		876,199		—
U.S. government agency obligations	271,285			—		271,285		—
	$	1,217,581		$	21,626	$	1,195,955	$	—
Other Assets:
Note receivable	$	23,245		$	—	$	—	$	23,245

Other Liabilities:
Contingent consideration obligation related to Velocius acquisition	$	(2,600	)	$	—	$	—	$	(2,600	)

As of December 31, 2013
Cash Equivalents and Marketable Securities:
Money market funds	$	40,482		$	40,482	$	—	$	—
Certificates of deposit	3,418			3,418		—		—
Commercial paper	29,999			—		29,999		—
Corporate bonds	737,861			—		737,861		—
U.S. government agency obligations	174,948			—		174,948		—
	$	986,708		$	43,900	$	942,808	$	—
Other Assets:
Note receivable	$	22,879		$	—	$	—	22,879

Other Liabilities:
Contingent consideration obligation related to Velocius acquisition	$	(2,600	)	$	—	$	—	$	(2,600	)

Schedule of Contractual Maturities of Marketable Securities and Other Investment Related Assets

Contractual maturities of the Company’s available-for-sale marketable securities held at March 31, 2014 and December 31, 2013 were as follows (in thousands):



	March 31, 2014		December 31, 2013
Due in 1 year or less	$	449,404	$	340,005
Due after 1 year through 5 years	721,271		573,026
	$	1,170,675	$	913,031

Schedule of Fair Value Assets and Liabilities Unobservable Input Reconciliation



	Other Assets: Note Receivable		Other Liabilities: Contingent Consideration Obligation
Balance as of January 1, 2014	$	22,879	$	(2,600	)
Unrealized gain on convertible note receivable included in other comprehensive income	366		—
Balance as of March 31, 2014	$	23,245	$	(2,600	)

- Definition

Tabular disclosure of available-for-sale securities which includes, but is not limited to, changes in the cost basis and fair value, fair value and gross unrealized gain (loss), fair values by type of security, contractual maturity and classification, amortized cost basis, contracts to acquire securities to be accounted for as available-for-sale, debt maturities, transfers to trading, change in net unrealized holding gain (loss) net of tax, continuous unrealized loss position fair value, aggregate losses qualitative disclosures, other than temporary impairment (OTTI) losses or other disclosures related to available for sale securities.

+ References + Details

Accounts Receivable (Tables)

3 Months Ended

Mar. 31, 2014

Accounts, Notes, Loans and Financing Receivable, Gross, Allowance, and Net [Abstract]

Schedule of Accounts Receivable

Net accounts receivable consisted of the following as of March 31, 2014 and December 31, 2013 (in thousands):



	March 31, 2014			December 31, 2013
Trade accounts receivable	$	218,310		$	175,391
Unbilled accounts receivable	90,577			100,300
Gross accounts receivable	308,887			275,691
Allowance for doubtful accounts	(754		)	(708		)
Reserve for cash-basis customers	(6,179		)	(2,995		)
Total accounts receivable reserves	(6,933		)	(3,703		)
Accounts receivable, net	$	301,954		$	271,988

Goodwill and Acquired Intangible Assets (Tables)

3 Months Ended

Mar. 31, 2014

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of Goodwill

The change in the carrying amount of goodwill for the three months ended March 31, 2014 was as follows (in thousands):



Balance as of January 1, 2014	$	757,368
Acquisition of Prolexic Technologies, Inc.	293,412
Balance as of March 31, 2014	$	1,050,780

Schedule of Acquired Intangible Assets

Acquired intangible assets that are subject to amortization consist of the following as of March 31, 2014 and December 31, 2013 (in thousands):



	March 31, 2014							December 31, 2013
	Gross Carrying Amount		Accumulated Amortization			Net Carrying Amount		Gross Carrying Amount		Accumulated Amortization			Net Carrying Amount
Completed technology	$	92,431	$	(38,631	)	$	53,800	$	65,631	$	(35,476	)	$	30,155
Customer-related intangible assets	173,600		(78,708		)	94,892		115,100		(75,563		)	39,537
Non-compete agreements	8,890		(3,060		)	5,830		7,950		(2,623		)	5,327
Trademarks and trade names	4,200		(1,101		)	3,099		3,400		(990		)	2,410
Acquired license rights	490		(490		)	—		490		(490		)	—
Total	$	279,611	$	(121,990	)	$	157,621	$	192,571	$	(115,142	)	$	77,429

Business Acquisitions (Tables)

3 Months Ended

Mar. 31, 2014

Business Acquisition [Line Items]

Schedule of Acquired Intangible Assets

Acquired intangible assets that are subject to amortization consist of the following as of March 31, 2014 and December 31, 2013 (in thousands):



	March 31, 2014							December 31, 2013
	Gross Carrying Amount		Accumulated Amortization			Net Carrying Amount		Gross Carrying Amount		Accumulated Amortization			Net Carrying Amount
Completed technology	$	92,431	$	(38,631	)	$	53,800	$	65,631	$	(35,476	)	$	30,155
Customer-related intangible assets	173,600		(78,708		)	94,892		115,100		(75,563		)	39,537
Non-compete agreements	8,890		(3,060		)	5,830		7,950		(2,623		)	5,327
Trademarks and trade names	4,200		(1,101		)	3,099		3,400		(990		)	2,410
Acquired license rights	490		(490		)	—		490		(490		)	—
Total	$	279,611	$	(121,990	)	$	157,621	$	192,571	$	(115,142	)	$	77,429

Prolexic Technologies, Inc.

Business Acquisition [Line Items]

Schedule of Preliminary Allocation of the Purchase Price

The following table presents the preliminary allocation of the purchase price for Prolexic (in thousands):



Total purchase consideration	$	392,219

Allocation of the purchase consideration:
Cash	$	33,072
Accounts receivable	11,306
Property and equipment	12,169
Identifiable intangible assets	87,040
Goodwill	293,412
Deferred tax assets	16,000
Other current and long-term assets	5,883
Total assets acquired	458,882
Other current liabilities	(7,501		)
Current deferred revenue	(5,812		)
Deferred tax liabilities	(33,723		)
Debt, capital leases and other long-term liabilities	(19,627		)
Total liabilities assumed	(66,663		)
Net assets acquired	$	392,219

Schedule of Acquired Intangible Assets

The following were the identified intangible assets acquired and their respective weighted average useful lives, as determined based on preliminary valuations (in thousands, except for years):



	Gross Carrying Amount		Weighted Average Useful Life (in years)
Completed technologies	$	26,800	6.9
Customer-related intangible assets	58,500		10.4
Non-compete agreements	940		3.0
Trademark	800		4.9
Total	$	87,040

Convertible Senior Notes (Tables)

3 Months Ended

Mar. 31, 2014

Debt Disclosure [Abstract]

Schedule of Convertible Senior Notes

The Notes consisted of the following components (in thousands):



	March 31, 2014
Liability component:
Principal	$	690,000
Less: debt discount, net of amortization	(99,286		)
Net carrying amount	$	590,714

Equity component:	$	101,276

Schedule of Interest Expense

The following table sets forth total interest expense included in the statement of operations related to the Notes (in thousands):



	For the Three Months Ended March 31, 2014
Amortization of debt discount	$	188
Amortization of debt issuance costs	1,990
Capitalization of interest expense	(237		)
Total interest expense	$	1,941

- Definition

Tabular disclosure of long-debt instruments or arrangements, including identification, terms, features, collateral requirements and other information necessary to a fair presentation. These are debt arrangements that originally required repayment more than twelve months after issuance or greater than the normal operating cycle of the entity, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21475-112644

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6479336&loc=d3e64711-112823

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(e),(f))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=6584090&loc=d3e28878-108400

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21538-112644

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21506-112644

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28541-108399

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21521-112644

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 22
-Article 5

+ Details

Stockholders' Equity (Tables)

3 Months Ended

Mar. 31, 2014

Stockholders' Equity Note [Abstract]

Schedule of Stock-Based Compensation Expense

The following table summarizes stock-based compensation included in the Company’s consolidated statements of operations for the three months ended March 31, 2014 and 2013 (in thousands):



	For the Three Months Ended March 31,
	2014			2013
Cost of revenue	$	2,795		$	2,627
Research and development	4,477			4,369
Sales and marketing	10,532			9,431
General and administrative	7,310			6,504
Total stock-based compensation	25,114			22,931
Provision for income taxes	(8,224		)	(6,964		)
Total stock-based compensation, net of income taxes	$	16,890		$	15,967

Accumulated Other Comprehensive Loss (Tables)

3 Months Ended

Mar. 31, 2014

Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]

Schedule of Accumulated Other Comprehensive Income (Loss)

The following table summarizes the changes in accumulated other comprehensive loss, which is reported as a component of stockholders' equity, for the three months ended March 31, 2014 (in thousands):



	Foreign Currency Translation Adjustments			Net Unrealized Gain (Loss) on Investments			Total
Balance as of January 1, 2014	$	(6,715	)	$	4,624		$	(2,091	)
Other comprehensive income (loss)	1,367			(913		)	454
Balance as of March 31, 2014	$	(5,348	)	$	3,711		$	(1,637	)

Net Income per Share (Tables)

3 Months Ended

Mar. 31, 2014

Earnings Per Share Reconciliation [Abstract]

Schedule of Components Used in Diluted and Basic Income Per Common Share

The following table sets forth the components used in the computation of basic and diluted net income per share for three months ended March 31, 2014 and 2013 (in thousands, except per share data):



	For the Three Months Ended March 31,
	2014		2013
Numerator:
Net income	$	72,800	$	71,487
Denominator:
Shares used for basic net income per share	178,705		177,899
Effect of dilutive securities:
Stock options	1,382		1,776
RSUs and deferred stock units	1,951		1,887
Convertible senior notes	—		—
Warrants related to issuance of convertible senior notes	—		—
Shares used for diluted net income per share	182,038		181,562
Basic net income per share	$	0.41	$	0.40
Diluted net income per share	$	0.40	$	0.39

Schedule of Shares Excluded from Computation of Diluted Earnings Per Share

The number of potentially outstanding shares excluded from the computation of diluted net income per share for three months ended March 31, 2014 and 2013 are as follows (in thousands):



	For the Three Months Ended March 31,
	2014	2013
Stock options	651	2,148
Service-based RSUs	514	495
Performance-based RSUs	575	1,148
Convertible senior notes	7,704	—
Warrants related to issuance of convertible senior notes	7,704	—

Nature of Business and Basis of Presentation - Narrative (Details) server in Thousands	3 Months Ended
	Mar. 31, 2014 countries network segment server
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of servers \| server	145
Number of networks \| network	1,200
Number of countries servers are in \| countries	90
Number of industry segments \| segment	1

Nature of Business and Basis of Presentation - Revision of Prior Period Amounts (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Changes in operating assets and liabilities, net of effects from acquisitions:
Prepaid expenses and other current assets	$ (20,961)	$ (11,447)
Accounts payable and accrued expenses	(22,511)	(4,528)
Other non-current assets and liabilities	4,031	(2,295)
Net cash provided by operating activities	89,023	93,224
Purchases of property and equipment	(52,011)	(43,831)
Net cash used in investing activities	(730,458)	(84,239)
Proceeds related to the issuance of common stock under stock plans	44,329	10,364
Net cash used in financing activities	555,508	(43,110)
Net decrease in cash and cash equivalents	$ (85,165)	(36,714)
As previously reported [Member]
Changes in operating assets and liabilities, net of effects from acquisitions:
Prepaid expenses and other current assets		(14,035)
Accounts payable and accrued expenses		7,838
Other non-current assets and liabilities		(2,257)
Net cash provided by operating activities		103,040
Purchases of property and equipment		(46,478)
Net cash used in investing activities		(86,886)
Proceeds related to the issuance of common stock under stock plans		3,195
Net cash used in financing activities		(50,279)
Net decrease in cash and cash equivalents		(36,714)
Adjustment [Member]
Changes in operating assets and liabilities, net of effects from acquisitions:
Prepaid expenses and other current assets		2,588
Accounts payable and accrued expenses		(12,366)
Other non-current assets and liabilities		(38)
Net cash provided by operating activities		(9,816)
Purchases of property and equipment		2,647
Net cash used in investing activities		2,647
Proceeds related to the issuance of common stock under stock plans		7,169
Net cash used in financing activities		7,169
Net decrease in cash and cash equivalents		$ 0

Fair Value Measurements - Narrative (Details)	Mar. 31, 2014 USD ($)
Fair Value Disclosures [Abstract]
Face value of note receivable	$ 25,000,000

Fair Value Measurements - Marketable Securities (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 1,171,181	$ 912,149
Gross Unrealized Gains	1,101	1,248
Gross Unrealized Losses	(1,607)	(366)
Aggregate Fair Value	1,170,675	913,031
Short-Term Marketable Securities	449,404	340,005
Long-Term Marketable Securities	721,271	573,026
Certificates of deposit
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	225	222
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Aggregate Fair Value	225	222
Short-Term Marketable Securities	172	173
Long-Term Marketable Securities	53	49
Commercial paper
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	24,986
Gross Unrealized Gains	0
Gross Unrealized Losses	(12)
Aggregate Fair Value	24,974
Short-Term Marketable Securities	24,974
Long-Term Marketable Securities	0
Corporate bonds
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	874,265	736,945
Gross Unrealized Gains	1,087	1,197
Gross Unrealized Losses	(1,161)	(281)
Aggregate Fair Value	874,191	737,861
Short-Term Marketable Securities	358,887	278,318
Long-Term Marketable Securities	515,304	459,543
U.S. government agency obligations
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	271,705	174,982
Gross Unrealized Gains	14	51
Gross Unrealized Losses	(434)	(85)
Aggregate Fair Value	271,285	174,948
Short-Term Marketable Securities	65,371	61,514
Long-Term Marketable Securities	$ 205,914	$ 113,434

Fair Value Measurements - Schedule of Fair Value Measurement (Details) - USD ($) $ in Thousands	Mar. 31, 2014	Dec. 31, 2013
Cash Equivalents and Marketable Securities:
Aggregate Fair Value	$ 1,170,675	$ 913,031
Certificates of deposit
Cash Equivalents and Marketable Securities:
Aggregate Fair Value	225	222
Commercial paper
Cash Equivalents and Marketable Securities:
Aggregate Fair Value	24,974
Corporate bonds
Cash Equivalents and Marketable Securities:
Aggregate Fair Value	874,191	737,861
U.S. government agency obligations
Cash Equivalents and Marketable Securities:
Aggregate Fair Value	271,285	174,948
Total Fair Value
Cash Equivalents and Marketable Securities:
Cash equivalents and marketable securities	1,217,581	986,708
Other Assets:
Note receivable	23,245	22,879
Other Liabilities:
Contingent consideration obligation related to Velocius acquisition	(2,600)	(2,600)
Total Fair Value \| Money market funds
Cash Equivalents and Marketable Securities:
Money market funds	21,401	40,482
Total Fair Value \| Certificates of deposit
Cash Equivalents and Marketable Securities:
Aggregate Fair Value	225	3,418
Total Fair Value \| Commercial paper
Cash Equivalents and Marketable Securities:
Aggregate Fair Value	48,471	29,999
Total Fair Value \| Corporate bonds
Cash Equivalents and Marketable Securities:
Aggregate Fair Value	876,199	737,861
Total Fair Value \| U.S. government agency obligations
Cash Equivalents and Marketable Securities:
Aggregate Fair Value	271,285	174,948
Level 1
Cash Equivalents and Marketable Securities:
Cash equivalents and marketable securities	21,626	43,900
Other Assets:
Note receivable	0	0
Other Liabilities:
Contingent consideration obligation related to Velocius acquisition	0	0
Level 1 \| Money market funds
Cash Equivalents and Marketable Securities:
Money market funds	21,401	40,482
Level 1 \| Certificates of deposit
Cash Equivalents and Marketable Securities:
Aggregate Fair Value	225	3,418
Level 1 \| Commercial paper
Cash Equivalents and Marketable Securities:
Aggregate Fair Value	0	0
Level 1 \| Corporate bonds
Cash Equivalents and Marketable Securities:
Aggregate Fair Value	0	0
Level 1 \| U.S. government agency obligations
Cash Equivalents and Marketable Securities:
Aggregate Fair Value	0	0
Level 2
Cash Equivalents and Marketable Securities:
Cash equivalents and marketable securities	1,195,955	942,808
Other Assets:
Note receivable	0	0
Other Liabilities:
Contingent consideration obligation related to Velocius acquisition	0	0
Level 2 \| Money market funds
Cash Equivalents and Marketable Securities:
Money market funds	0	0
Level 2 \| Certificates of deposit
Cash Equivalents and Marketable Securities:
Aggregate Fair Value	0	0
Level 2 \| Commercial paper
Cash Equivalents and Marketable Securities:
Aggregate Fair Value	48,471	29,999
Level 2 \| Corporate bonds
Cash Equivalents and Marketable Securities:
Aggregate Fair Value	876,199	737,861
Level 2 \| U.S. government agency obligations
Cash Equivalents and Marketable Securities:
Aggregate Fair Value	271,285	174,948
Level 3
Cash Equivalents and Marketable Securities:
Cash equivalents and marketable securities	0	0
Other Assets:
Note receivable	23,245	22,879
Other Liabilities:
Contingent consideration obligation related to Velocius acquisition	(2,600)	(2,600)
Level 3 \| Money market funds
Cash Equivalents and Marketable Securities:
Money market funds	0	0
Level 3 \| Certificates of deposit
Cash Equivalents and Marketable Securities:
Aggregate Fair Value	0	0
Level 3 \| Commercial paper
Cash Equivalents and Marketable Securities:
Aggregate Fair Value	0	0
Level 3 \| Corporate bonds
Cash Equivalents and Marketable Securities:
Aggregate Fair Value	0	0
Level 3 \| U.S. government agency obligations
Cash Equivalents and Marketable Securities:
Aggregate Fair Value	$ 0	$ 0

Fair Value Measurements - Contractual Maturities (Details) - USD ($) $ in Thousands	Mar. 31, 2014	Dec. 31, 2013
Fair Value Disclosures [Abstract]
Due in 1 year or less	$ 449,404	$ 340,005
Due after 1 year through 5 years	721,271	573,026
Aggregate fair value	$ 1,170,675	$ 913,031

Fair Value Measurements - Schedule of Activity of Major Classes of Assets Measured at Fair Value Using Level 3 Inputs (Details) - Level 3 $ in Thousands	3 Months Ended
	Mar. 31, 2014 USD ($)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance as of January 1, 2014, other assets	$ 22,879
Balance as of January 1, 2014, other liabilities	(2,600)
Unrealized gain on convertible note receivable included in other comprehensive income	366
Balance as of March 31, 2014, other assets	23,245
Balance as of March 31, 2014, other liabilities	$ (2,600)

Accounts Receivable - Schedule of Accounts Receivable (Details) - USD ($) $ in Thousands	Mar. 31, 2014	Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross accounts receivable	$ 308,887	$ 275,691
Allowance for doubtful accounts	(754)	(708)
Reserve for cash-basis customers	(6,179)	(2,995)
Total accounts receivable reserves	(6,933)	(3,703)
Accounts receivable, net	301,954	271,988
Trade accounts receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross accounts receivable	218,310	175,391
Unbilled accounts receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross accounts receivable	$ 90,577	$ 100,300

Goodwill and Acquired Intangible Assets - Schedule of Goodwill (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2014 USD ($)
Schedule of Goodwill
Balance as of January 1, 2014	$ 757,368
Acquisition of Prolexic Technologies, Inc.	293,412
Balance as of March 31, 2014	$ 1,050,780

Goodwill and Acquired Intangible Assets - Schedule of Acquired Intangible Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2014	Dec. 31, 2013
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 279,611	$ 192,571
Accumulated Amortization	(121,990)	(115,142)
Net Carrying Amount	157,621	77,429
Completed technology
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	92,431	65,631
Accumulated Amortization	(38,631)	(35,476)
Net Carrying Amount	53,800	30,155
Customer-related intangible assets
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	173,600	115,100
Accumulated Amortization	(78,708)	(75,563)
Net Carrying Amount	94,892	39,537
Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	8,890	7,950
Accumulated Amortization	(3,060)	(2,623)
Net Carrying Amount	5,830	5,327
Trademarks and trade names
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	4,200	3,400
Accumulated Amortization	(1,101)	(990)
Net Carrying Amount	3,099	2,410
Acquired license rights
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	490	490
Accumulated Amortization	(490)	(490)
Net Carrying Amount	$ 0	$ 0

Goodwill and Acquired Intangible Assets - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization of acquired intangible assets	$ 6,848	$ 6,060
Future amortization expense to be recognized in remainder of 2014	25,200
Future amortization expense 2015	26,800
Future amortization expense 2016	25,200
Future amortization expense 2017	23,100
Future amortization expense 2018	$ 16,200

Business Acquisitions - Narrative (Details) - USD ($)				3 Months Ended
Business Acquisitions - Narrative (Details) - USD ($)	Feb. 18, 2014	Nov. 08, 2013	Nov. 30, 2012	Mar. 31, 2014	Sep. 30, 2013	Dec. 31, 2013
Business Acquisition [Line Items]
Allocated to goodwill				$ 1,050,780,000		$ 757,368,000
Prolexic Technologies, Inc.
Business Acquisition [Line Items]
Total purchase consideration	$ 392,219,000
Acquisition-related costs	3,900,000
Allocated to goodwill	293,412,000
Allocated to intangible assets	87,040,000
Goodwill, expected tax deductible amount	$ 62,400,000
Velocius
Business Acquisition [Line Items]
Total purchase consideration		$ 4,300,000
Contingent consideration liability		2,600,000
Allocated to goodwill		5,400,000
Allocated to intangible assets		$ 2,500,000
Weighted Average Useful Life (in years)		7 years 10 months 24 days
Goodwill, expected tax deductible amount		$ 500,000
Strategic Network Acquisition
Business Acquisition [Line Items]
Total purchase consideration			$ 55,000,000.0
Consideration paid				$ 27,500,000	$ 27,500,000

Business Acquisitions - Schedule of Preliminary Allocation of the Purchase Price (Details) - USD ($) $ in Thousands	Feb. 18, 2014	Mar. 31, 2014	Dec. 31, 2013
Allocation of the purchase consideration:
Goodwill		$ 1,050,780	$ 757,368
Prolexic Technologies, Inc.
Business Acquisition [Line Items]
Total purchase consideration	$ 392,219
Allocation of the purchase consideration:
Cash	33,072
Accounts receivable	11,306
Property and equipment	12,169
Identifiable intangible assets	87,040
Goodwill	293,412
Deferred tax assets	16,000
Other current and long-term assets	5,883
Total assets acquired	458,882
Other current liabilities	(7,501)
Current deferred revenue	(5,812)
Deferred tax liabilities	(33,723)
Debt, capital leases and other long-term liabilities	(19,627)
Total liabilities assumed	(66,663)
Net assets acquired	$ 392,219

Business Acquisitions - Schedule of Acquired Intangible Assets (Details) - Prolexic Technologies, Inc. $ in Thousands	Feb. 18, 2014 USD ($)
Business Acquisition [Line Items]
Gross Carrying Amount	$ 87,040
Completed technology
Business Acquisition [Line Items]
Gross Carrying Amount	$ 26,800
Weighted Average Useful Life (in years)	6 years 10 months 24 days
Customer-related intangible assets
Business Acquisition [Line Items]
Gross Carrying Amount	$ 58,500
Weighted Average Useful Life (in years)	10 years 4 months 18 days
Non-compete agreements
Business Acquisition [Line Items]
Gross Carrying Amount	$ 940
Weighted Average Useful Life (in years)	3 years
Trademarks and trade names
Business Acquisition [Line Items]
Gross Carrying Amount	$ 800
Weighted Average Useful Life (in years)	4 years 10 months 24 days

Convertible Senior Notes - Narrative (Details) $ / shares in Units, shares in Millions	1 Months Ended	3 Months Ended
	Feb. 28, 2014 USD ($) d $ / shares $ / unit shares	Mar. 31, 2014 USD ($) $ / shares	Mar. 31, 2013 USD ($)
Debt Instrument [Line Items]
Debt issued	$ 690,000,000	$ 690,000,000
Conversion rate (in shares)	11.1651
Principal amount per conversion	$ 1,000
Conversion price (in dollars per share) \| $ / shares	$ 89.56
Potential shares to be converted (in shares) \| shares	7.7
Threshold trading days exceeding price \| d	20
Threshold consecutive trading days exceeding price	30 days
Threshold greater than percentage of stock price trigger	130.00%
Threshold trading days not exceeding price \| d	5
Threshold consecutive trading days not exceeding price	5 days
Threshold less than percentage of stock price trigger	98.00%
Fair value of note receivable		$ 683,700,000
Closing price of common stock (in dollars per share) \| $ / shares		$ 58.21
Repurchases of common stock	$ 62,000,000	$ 116,147,000	$ 40,278,000
Payments for purchase of convertible note hedge and warrant transactions	23,300,000
Payments for note hedge transactions	$ 101,300,000	101,292,000	0
Warrant strike price (in dollars per share) \| $ / unit	104.49
Proceeds from sale of warrants	$ 78,000,000	$ 77,970,000	$ 0
Effective interest rate	3.20%

Convertible Senior Notes - Schedule of Convertible Senior Notes (Details) - USD ($)	Mar. 31, 2014	Feb. 28, 2014	Dec. 31, 2013
Liability component:
Principal	$ 690,000,000	$ 690,000,000
Less: debt discount, net of amortization	(99,286,000)
Net carrying amount	590,714,000		$ 0
Convertible senior notes
Liability component:
Equity component	$ 101,276,000

Convertible Senior Notes - Schedule of Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Debt Disclosure [Abstract]
Amortization of debt discount	$ 188
Amortization of debt issuance costs	1,990
Capitalization of interest expense	(237)
Interest expense	$ 1,941	$ 0

Stockholders' Equity - Narrative (Details) - USD ($) shares in Millions	1 Months Ended		3 Months Ended
	Oct. 31, 2013	Jan. 31, 2013	Mar. 31, 2014	Mar. 31, 2013
Stockholders' Equity Note [Abstract]
Stock repurchase program, authorized amount	$ 750,000,000	$ 150,000,000
Shares repurchased during period (in shares)			2.0	1.1
Value of shares repurchased during period			$ 116,100,000	$ 40,300,000
Amortization expense from capitalized stock-based compensation			$ 1,900,000

Stockholders' Equity - Schedule of Stock Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	$ 25,114	$ 22,931
Provision for income taxes	(8,224)	(6,964)
Total stock-based compensation, net of income taxes	16,890	15,967
Cost of revenues
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	2,795	2,627
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	4,477	4,369
Sales and marketing
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	10,532	9,431
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	$ 7,310	$ 6,504

Accumulated Other Comprehensive Loss - Schedule of Accumulated Other Comprehensive Income Loss (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Accumulated Other Comprehensive Loss [Roll Forward]
Balance as of January 1, 2014	$ (2,091)
Other comprehensive income (loss)	454	$ (3,943)
Balance as of March 31, 2014	(1,637)
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Loss [Roll Forward]
Balance as of January 1, 2014	(6,715)
Other comprehensive income (loss)	1,367
Balance as of March 31, 2014	(5,348)
Net Unrealized Gain (Loss) on Investments
Accumulated Other Comprehensive Loss [Roll Forward]
Balance as of January 1, 2014	4,624
Other comprehensive income (loss)	(913)
Balance as of March 31, 2014	$ 3,711

- Definition

Accumulated change in equity from transactions and other events and circumstances from non-owner sources, net of tax effect, at period end. Excludes Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge.

+ References + Details

Income Taxes - Narrative (Details)	3 Months Ended
Income Taxes - Narrative (Details)	Mar. 31, 2014	Mar. 31, 2013
Income Tax Disclosure [Abstract]
Effective income tax rate	39.20%	30.40%

Net Income per Share - Schedule of Components Used in Diluted and Basic Income Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Numerator [Abstract]
Net income	$ 72,800	$ 71,487
Denominator [Abstract]
Shares used for basic net income per share (in shares)	178,705	177,899
Effect of dilutive securities:
Convertible senior notes	0	0
Warrants related to issuance of convertible senior notes	0	0
Shares used for diluted net income per share (in shares)	182,038	181,562
Basic net income per share (in dollars per share)	$ 0.41	$ 0.40
Diluted net income per share (in dollars per share)	$ 0.40	$ 0.39
Stock options
Effect of dilutive securities:
Dilutive securities	1,382	1,776
RSUs and deferred stock units
Effect of dilutive securities:
Dilutive securities	1,951	1,887

Net Income per Share - Schedule of Shares Excluded from Computation of Diluted EPS (Details) - shares shares in Thousands	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities	651	2,148
Service-based RSUs
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities	514	495
Performance-based RSUs
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities	575	1,148
Convertible senior notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities	7,704	0
Warrants related to issuance of convertible senior notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities	7,704	0