Riverbed Technology 10-Q 1 May 14 2014 Q1 Quarterly report Financial data

Document_And_Entity_Informatio

Document And Entity Information	3 Months Ended
	Mar. 31, 2014	Apr. 29, 2014
Document And Entity Information [Abstract]	'	'
Document Type	'10-Q	'
Amendment Flag	'false	'
Document Period End Date	31-Mar-14	'
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q1	'
Trading Symbol	'rvbd	'
Entity Registrant Name	'Riverbed Technology, Inc.	'
Entity Central Index Key	'0001357326	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Large Accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	160,542,961

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Current assets:	'	'
Cash and cash equivalents	$244,899	$208,022
Short-term investments	229,292	251,339
Trade receivables, net of allowances of $1,709 and $1,996 as of March 31, 2014 and December 31, 2013, respectively	99,096	93,836
Inventory	21,218	25,025
Deferred tax assets	10,434	7,222
Prepaid expenses and other current assets	57,222	49,016
Total current assets	662,161	634,460
Long-term investments	85,461	72,675
Fixed assets, net	68,612	57,810
Goodwill	704,305	704,305
Intangibles, net	382,457	404,467
Other assets	22,324	23,881
Total assets	1,925,320	1,897,598
Current liabilities:	'	'
Accounts payable	42,900	45,518
Accrued compensation and benefits	50,344	51,988
Other accrued liabilities	37,235	36,520
Current maturities of long-term borrowings	15,000	15,000
Deferred revenue	231,430	217,131
Total current liabilities	376,909	366,157
Deferred revenue, non-current	93,386	95,344
Long-term Debt	506,250	'
Borrowings, non-current, net of current maturities	'	510,000
Deferred tax liabilities, non-current	45,881	48,548
Other long-term liabilities	49,755	48,910
Total long-term liabilities	695,272	702,802
Commitments and contingencies	'	'
Stockholders' equity:	'	'
Preferred stock, $0.0001 par value – 30,000 shares authorized, no shares outstanding	0	0
Common stock and additional paid-in capital; $0.0001 par value – 600,000 shares authorized; 160,503 and 159,845 shares issued and outstanding as of March, 31, 2014 and December 31, 2013, respectively	724,319	702,928
Retained earnings	128,583	125,295
Accumulated other comprehensive income	237	416
Total stockholders' equity	853,139	828,639
Total liabilities and stockholders' equity	$1,925,320	$1,897,598

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, except Per Share data, unless otherwise specified
Statement of Financial Position [Abstract]	'	'
Trade receivables, allowances	$1,709	$1,996
Preferred stock, par value (in usd per share)	$0.00	$0.00
Preferred stock, shares authorized	30,000	30,000
Preferred stock, shares outstanding	0	0
Common stock, par value (in usd per share)	$0.00	$0.00
Common stock, shares authorized	600,000	600,000

Condensed_Consolidated_Stateme

Condensed Consolidated Statements Of Operations (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Revenue:	'	'
Product	$150,161	$148,040
Support and services	115,255	98,099
Total revenue	265,416	246,139
Cost of revenue:	'	'
Cost of product	38,281	40,900
Cost of support and services	31,631	28,042
Total cost of revenue	69,912	68,942
Gross profit	195,504	177,197
Operating expenses:	'	'
Sales and marketing	114,745	115,721
Research and development	50,647	48,961
General and administrative	19,125	19,114
Acquisition-related costs	2,668	4,136
Total operating expenses	187,185	187,932
Operating income (loss)	8,319	-10,735
Interest and other expense, net	-2,713	-6,364
Income (loss) before provision for income taxes	5,606	-17,099
Provision (benefit) for income taxes	2,318	-8,989
Net income (loss)	$3,288	($8,110)
Net income (loss) per common share:	'	'
Basic (in usd per shares)	$0.02	($0.05)
Diluted (in usd per shares)	$0.02	($0.05)
Shares used in computing net income (loss) per common share:	'	'
Basic (in shares)	160,190	163,367
Diluted (in shares)	165,313	163,367

Condensed_Consolidated_Stateme1

Condensed Consolidated Statements of Comprehensive Income (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Net income (loss)	$3,288	($8,110)
Unrealized gain (loss) on investments, net of tax	'	-159
Foreign currency translation adjustment	'	-633
Derivative instruments gain (loss), net of tax	'	-713
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	-179	-1,505
Comprehensive income (loss)	$3,109	($9,615)

Condensed_Consolidated_Stateme2

Condensed Consolidated Statements Of Cash Flows (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Operating Activities:	'	'
Net income (loss)	$3,288	($8,110)
Adjustments to reconcile net income to net cash provided by operating activities:	'	'
Depreciation and amortization	28,988	31,363
Stock-based compensation	21,749	24,526
Deferred taxes	-5,802	-895
Excess tax benefit from employee stock plans	-1,889	-1,806
Other noncash items	227	0
Changes in operating assets and liabilities:	'	'
Trade receivables	-5,260	12,148
Inventory	3,807	-2,547
Prepaid expenses and other assets	-6,514	-8,668
Accounts payable	-5,094	-12,186
Accrued and other liabilities	-84	-17,265
Income taxes payable	-388	1,713
Deferred revenues	12,341	24,998
Net cash provided by operating activities	45,369	43,271
Investing Activities:	'	'
Capital expenditures	-15,304	-5,354
Purchase of available for sale securities	-94,194	-132,178
Proceeds from maturities of available for sale securities	94,245	90,695
Proceeds from sales of available for sale securities	8,839	14,500
Acquisitions, net of cash and cash equivalents acquired	0	-1,000
Net cash used in investing activities	-6,414	-33,337
Financing Activities:	'	'
Proceeds from issuance of common stock under employee stock plans	25,030	10,815
Payments for repurchases of common stock	-25,000	-25,030
Payments of borrowings principle	-3,750	-49,319
Excess tax benefit from employee stock plans	1,889	1,806
Net cash used in financing activities	-1,831	-61,728
Effect of exchange rate changes on cash and cash equivalents	-247	-1,368
Net increase (decrease) in cash and cash equivalents	36,877	-53,162
Cash and cash equivalents at beginning of period	208,022	280,509
Cash and cash equivalents at end of period	$244,899	$227,347

Organization_And_Significant_A

Organization And Significant Accounting Policies	3 Months Ended
	Mar. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Use of Estimates, Policy [Policy Text Block]	'
	Use of Estimates
	These accounting principles require us to make certain estimates and judgments that can affect the reported amounts of assets and liabilities as of the date of the condensed consolidated financial statements, as well as the reported amounts of revenue and expenses during the periods presented. Significant estimates and assumptions made by management include the determination of the fair value of stock awards issued, inventory valuation, the accounting for income taxes, including the determination of the valuation allowance related to our deferred tax asset balances, goodwill and other intangible assets, reserves for uncertain tax positions, and the accounting for business combinations. We believe that the estimates and judgments upon which we rely are reasonable based upon information available to us at the time that these estimates and judgments were made. To the extent there are material differences between these estimates and actual results, our condensed consolidated financial statements will be affected.
Organization And Significant Accounting Policies	'
	BASIS OF PRESENTATION
	Basis of Presentation
	The condensed consolidated financial statements include our accounts and the accounts of our wholly-owned subsidiaries. Intercompany transactions and balances have been eliminated. The accompanying condensed consolidated balance sheet as of March 31, 2014, the condensed consolidated statements of operations for the three months ended March 31, 2014 and 2013, the condensed consolidated statements of comprehensive income (loss) for the three months ended March 31, 2014 and 2013, and the condensed consolidated statements of cash flows for the three months ended March 31, 2014 and 2013 are unaudited. The accompanying statements should be read in conjunction with the audited consolidated financial statements and related notes contained in our Annual Report on Form 10-K for the year ended December 31, 2013.
	The accompanying condensed consolidated financial statements have been prepared in accordance with United States generally accepted accounting principles (GAAP) pursuant to the rules and regulations of the Securities and Exchange Commission (SEC). They do not include all of the financial information and footnotes required by GAAP for complete financial statements. We believe the unaudited condensed consolidated financial statements have been prepared on the same basis as the audited financial statements and include all adjustments necessary for the fair presentation of our balance sheet as of March 31, 2014, our results of operations, comprehensive income (loss) and our cash flows for the three months ended March 31, 2014 and 2013. All adjustments are of a normal recurring nature. The results for the three months ended March 31, 2014 are not necessarily indicative of the results to be expected for any subsequent quarter or for the year ending December 31, 2014.
	During the three months ended March 31, 2014, there have been no significant changes in our significant accounting policies that were described in our Annual Report on Form 10-K for the year ended December 31, 2013.
	Use of Estimates
	These accounting principles require us to make certain estimates and judgments that can affect the reported amounts of assets and liabilities as of the date of the condensed consolidated financial statements, as well as the reported amounts of revenue and expenses during the periods presented. Significant estimates and assumptions made by management include the determination of the fair value of stock awards issued, inventory valuation, the accounting for income taxes, including the determination of the valuation allowance related to our deferred tax asset balances, goodwill and other intangible assets, reserves for uncertain tax positions, and the accounting for business combinations. We believe that the estimates and judgments upon which we rely are reasonable based upon information available to us at the time that these estimates and judgments were made. To the extent there are material differences between these estimates and actual results, our condensed consolidated financial statements will be affected.

Recent_Accounting_Pronouncemen

Recent Accounting Pronouncements (Notes)	3 Months Ended
	Mar. 31, 2014
Recent accounting pronouncements [Abstract]	'
New Accounting Pronouncements	'
	2	RECENT ACCOUNTING PRONOUNCEMENTS
	In July 2013, the Financial Accounting Standards Board (FASB) released Accounting Standards Update (ASU) No. 2013-11, Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists. The new standard requires that an unrecognized tax benefit should be presented as a reduction of a deferred tax asset for a net operating loss carryforward or other tax credit carryforward when settlement in this manner is available under the tax law. We are required to adopt this standard starting fiscal year 2015 and are currently in the process of determining the impact, if any, on its financial position.
	In February 2013, the FASB issued ASU No. 2013-04, Liabilities (Topic 405): Obligations Resulting from Joint and Several Liability Arrangements for which the Total Amount of the Obligation Is Fixed at the Reporting Date (ASU No. 2013-04), which addresses the recognition, measurement, and disclosure of certain obligations resulting from joint and several arrangements including debt arrangements, other contractual obligations, and settled litigation and judicial rulings. ASU No. 2013-04 will be effective for us in fiscal 2014. The adoption of this guidance did not have a significant impact to our condensed consolidated financial statements.
	In March 2013, the FASB issued ASU No. 2013-05, Foreign Currency Matters (Topic 830): Parent’s Accounting for the Cumulative Translation Adjustment upon Derecognition of Certain Subsidiaries or Groups of Assets within a Foreign Entity or of an Investment in a Foreign Entity (ASU No. 2013-05), which addresses the accounting for the cumulative translation adjustment when a parent either sells a part or all of its investment in a foreign entity or no longer holds a controlling financial interest in a subsidiary or group of assets that is a nonprofit activity or a business within a foreign entity. ASU No. 2013-05 shall be effective prospectively beginning with fiscal 2014. The adoption of this guidance did not have a significant impact to our condensed consolidated financial statements.
	In July 2012, the FASB issued ASU No. 2012-02, Intangibles-Goodwill and Other (Topic 350)-Testing Indefinite-Lived Intangible Assets for Impairment (ASU No. 2012-02), to allow entities to use a qualitative approach to test indefinite-lived intangible assets for impairment. ASU No. 2012-02 permits an entity to first perform a qualitative assessment to determine whether it is more likely than not that the fair value of an indefinite-lived intangible asset is less than its carrying value. If it is concluded that this is the case, it is necessary to perform the currently prescribed quantitative impairment test by comparing the fair value of the indefinite-lived intangible asset with its carrying value. Otherwise, the quantitative impairment test is not required. ASU No. 2012-02 is effective for us in fiscal 2014 and earlier adoption was permitted. The adoption of this guidance in 2014 did not have a significant impact to our condensed consolidated financial statements.

Net_Income_Loss_Per_Common_Sha

Net Income (Loss) Per Common Share	3 Months Ended
	Mar. 31, 2014
Earnings Per Share [Abstract]	'
Net Income Per Common Share	'
	NET INCOME (LOSS) PER COMMON SHARE
	Basic net income (loss) per common share is computed by dividing net income (loss) by the weighted average number of common shares outstanding during the period. Diluted net income (loss) per common share is computed by giving effect to all potential dilutive common shares, including stock awards. The following table sets forth the computation of net income (loss) per share:
		Three months ended
		March 31,
	(in thousands, except per share data)	2014			2013
	Net income (loss)	$	3,288		$	(8,110	)
	Weighted average common shares outstanding - basic	160,190			163,367
	Dilutive effect of employee stock plans	5,123			—
	Weighted average common shares outstanding - diluted	165,313			163,367
	Basic net income (loss) per share	$	0.02		$	(0.05	)
	Diluted net income (loss) per share	$	0.02		$	(0.05	)
	Stock options outstanding with an exercise price higher than our average stock price for the periods presented, represent out-of-the-money awards and are excluded from the calculations of the diluted net income (loss) per common share since the effect would have been anti-dilutive under the treasury stock method.
	In addition, stock options outstanding with an exercise price lower than our average stock price for the periods presented, representing in-the-money awards that would otherwise have a dilutive effect under the treasury stock method, are excluded from the calculations of the diluted loss per common share in periods with a loss since the effect in such periods would have been anti-dilutive.
	The following weighted average outstanding options were excluded from the computation of diluted net income (loss) per common share for the periods presented because including them would have had an anti-dilutive effect:
		Three months ended
		March 31,
	(in thousands)	2014		2013
	Total potential anti-dilutive shares of common stock	7,370		17,355

Fair_Value_Of_Assets

Fair Value Of Assets	3 Months Ended
	Mar. 31, 2014
Assets, Fair Value Disclosure [Abstract]	'
Fair Value Of Assets	'
	4	FAIR VALUE MEASUREMENTS
	We define fair value as the price that would be received from selling an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. When determining the fair value measurements for assets and liabilities required or permitted to be recorded at fair value, we consider the principal or most advantageous market in which it would transact, and it considers assumptions that market participants would use when pricing the asset or liability.
	A fair value hierarchy has been established that prioritizes the inputs to valuation techniques used to measure fair value. The level of an asset or liability in the hierarchy is based on the lowest level of input that is significant to the fair value measurement. Assets and liabilities carried at fair value are classified and disclosed in one of the following three categories:
	Level 1: Valuations based on quoted prices in active markets for identical assets or liabilities with sufficient volume and frequency of transactions.
	Level 2: Valuations based on observable inputs other than Level 1 prices such as quoted prices for similar assets or liabilities, quoted prices in markets that are not active, or model-derived valuations techniques for which all significant inputs are observable in the market or can be corroborated by observable market data, for substantially the full term of the assets or liabilities.
	Level 3: Valuations based on unobservable inputs to the valuation methodology that are significant to the measurement of fair value of assets or liabilities and based on non-binding, broker-provided price quotes and may not have been corroborated by observable market data. As of March 31, 2014 and December 31, 2013, we had no financial assets or liabilities categorized as Level 3.
	The following table sets forth our financial assets and liabilities measured at fair value on a recurring basis as of March 31, 2014:
	(in thousands)		Total		Level 1		Level 2
	Assets:
	Corporate bonds and notes		$	39,383	$	—	$	39,383
	U.S. government-sponsored enterprise obligations		43,745		—		43,745
	Money market funds		38,680		38,680		—
	Cash		123,092		—		—
	Total cash and cash equivalents		244,900		38,680		83,128
	Corporate bonds and notes		68,955		—		68,955
	U.S. government backed securities		34,740		34,740		—
	U.S. government-sponsored enterprise obligations		195,035		—		195,035
	FDIC-backed certificates of deposit		16,023		—		16,023
	Total investments		314,753		34,740		280,013
	Derivative assets		134		—		134
	Total assets		$	559,787	$	73,420	$	363,275
	Liabilities:
	Derivative liabilities		$	18	$	—	$	18
	Borrowings		521,250		—		521,250
	Total liabilities		$	521,268	$	—	$	521,268
	The following table sets forth our financial assets and liabilities measured at fair value on a recurring basis as of December 31, 2013:
	(in thousands)		Total		Level 1		Level 2
	Assets:
	Corporate bonds and notes		$	28,545	$	—	$	28,545
	U.S. government-sponsored enterprise obligations		18,775		—		18,775
	Money market funds		30,009		30,009		—
	Cash		130,693		—		—
	Total cash and cash equivalents		208,022		$	30,009	47,320
	Corporate bonds and notes		74,648		$	—	74,648
	U.S. government backed securities		23,210		23,210		—
	U.S. government-sponsored enterprise obligations		211,094		—		211,094
	FDIC-backed certificates of deposit		15,062		—		15,062
	Total investments		324,014		23,210		300,804
	Derivative assets		331		—		331
	Total assets		$	532,367	$	53,219	$	348,455
	Liabilities:
	Derivative liabilities		$	103	$	—	$	103
	Borrowings		525,000		$	—	525,000
	Total liabilities		$	525,103	$	—	$	525,103
	Our primary financial instruments include its cash, cash equivalents, short-term and long-term investments, restricted cash, accounts receivable, accounts payable, short-term and long-term borrowings, and foreign currency related derivatives. Cash and cash equivalents consist primarily of highly liquid investments in money market mutual funds, government-sponsored enterprise obligations, treasury bills, commercial paper and corporate bonds and notes with remaining maturities at date of purchase of 90 days or less. The estimated fair value of cash, accounts receivable and accounts payable approximates their carrying value due to the short period of time to their maturities. The estimated fair value of our investments is determined as the exit price in the principal market in which we would transact. The estimated fair value of the borrowings has been calculated using an estimate of the interest rate that we would be required to pay on the issuance of debt with similar terms and discounting the cash flows at that rate. Refer to Note 9 for the carrying value and additional disclosures on our borrowings.
	The following tables present the gross unrealized gains and gross unrealized losses of available-for-sale securities as of March 31, 2014 and December 31, 2013:
	(in thousands)		Fair Value		Unrealized		Unrealized
					Gains		Losses
	Corporate bonds and notes		$	108,338	$	3	$	(13	)
	U.S. government backed securities		34,740		21		(3		)
	U.S. government-sponsored enterprise obligations		238,780		71		(44		)
	FDIC-backed certificates of deposit		16,023		—		—
	Total available-for-sale securities at March 31, 2014		$	397,881	$	95	$	(60	)
	Corporate bonds and notes		$	103,193	$	1	$	(24	)
	U.S. government backed securities		23,210		7		(2		)
	U.S. government-sponsored enterprise obligations		229,869		55		(30		)
	FDIC-backed certificates of deposit		15,062		1		—
	Total available-for-sale securities at December 31, 2013		$	371,334	$	64	$	(56	)
	The available-for-sale securities by classification in the condensed consolidated balance sheet is as follows:
	(in thousands)		March 31,		December 31,
			2014		2013
	Cash and cash equivalents		$	83,128	$	47,320
	Short-term investments		229,292		251,339
Long-term investments		85,461		72,675
Total available-for-sale securities		$	397,881	$	371,334
Cash and cash equivalents in the table above excludes cash of $161.8 million and $160.7 million at March 31, 2014 and December 31, 2013, respectively.
We regularly review our investment portfolio to determine if any security is other-than-temporarily impaired, which would require us to record an impairment charge in the period any such determination is made. In making this judgment, we evaluate, among other things, the duration and extent to which the fair value of a security is less than its cost; the financial condition of the issuer and any changes thereto; and our intent and ability to sell, or whether we will more likely than not be required to sell, the security before recovery of its amortized cost basis. We have evaluated our investments as of March 31, 2014 and have determined that no investments with unrealized losses are other-than-temporarily impaired. No investments have been in a continuous loss position greater than one year.

Inventory

Inventory	3 Months Ended
	Mar. 31, 2014
Inventory, Gross [Abstract]	'
Inventory	'
	INVENTORY
	Inventory consists primarily of hardware and related component parts and evaluation units located at customer locations, and are stated at the lower of cost (on a first-in, first-out basis) or market. Inventory is comprised of the following:
	(in thousands)	March 31,		December 31,
		2014		2013
	Raw materials	$	3,997	$	5,069
	Finished goods	14,388		15,430
	Evaluation units	2,833		4,526
	Total inventory	$	21,218	$	25,025

Guarantees

Guarantees	3 Months Ended
	Mar. 31, 2014
Guarantees [Abstract]	'
Guarantees	'
	GUARANTEES
	Our agreements with customers, as well as our reseller agreements, generally include certain provisions for indemnifying customers and resellers and their affiliated parties against liabilities if our products infringe a third-party’s intellectual property rights. To date, we have not incurred any material costs as a result of such indemnifications and have not accrued any liabilities related to such obligations in our condensed consolidated financial statements.
	As permitted or required under Delaware law and to the maximum extent allowable under that law, we have certain obligations to indemnify our officers, directors and certain key employees for certain events or occurrences while the officer, director or employee is or was serving at our request in such capacity. These indemnification obligations are valid as long as the director, officer or employee acted in good faith and in a manner the person reasonably believed to be in or not opposed to the best interests of the corporation, and, with respect to any criminal proceeding, had no reasonable cause to believe his or her conduct was unlawful. The maximum potential amount of future payments we could be required to make under these indemnification obligations is unlimited; however, we have a director and officer insurance policy that mitigates our exposure and enables us to recover a portion of any future amounts paid.

Lease_Commitments

Lease Commitments	3 Months Ended
	Mar. 31, 2014
Leases [Abstract]	'
Lease Commitments	'
	LEASE COMMITMENTS
	We lease our facilities under non-cancelable operating lease agreements. Future minimum commitments for these operating leases in place as of March 31, 2014 with a remaining non-cancelable lease term in excess of one year are as follows:
	Fiscal year	(in thousands)
	2014 (remaining 9 months)	$	17,646
	2015	28,585
	2016	27,105
	2017	25,157
	2018	23,411
	Thereafter	93,658
	Total	$	215,562
	The terms of certain lease agreements provide for rental payments on a graduated basis. We recognize rent expense on a straight-line basis over the lease period and have accrued for rent expense incurred but not paid. Rent expense under operating leases was $7.7 million and $5.1 million for the three months ended March 31, 2014 and 2013, respectively.

Derivative_Financial_Instrumen

Derivative Financial Instruments	3 Months Ended
	Mar. 31, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'
Derivative Financial Instruments	'
	DERIVATIVE FINANCIAL INSTRUMENTS
	We use derivative instruments to partially offset our market exposures to fluctuations in certain foreign currency exchange rates, which exist as part of ongoing business operations. Our general practice is to hedge a majority of transaction exposures denominated in British pounds, Euros, Australian dollars and Singapore dollars. These instruments have maturities up to twelve months in the future. We do not enter into derivative instrument transactions for trading or speculative purposes.
	Foreign currency contracts designated as cash flow hedges
	We utilize foreign currency forward contracts to hedge certain forecasted foreign currency transactions relating to cost of service and operating expense. These contracts are designated and documented as cash flow hedges at their inception. All changes in time value are excluded from the cash flow hedge and recorded to Interest and other expense, net in the period incurred. The effective portion of derivative's gains or losses on these hedges is initially included in Accumulated other comprehensive income (loss) and is subsequently reclassified into the cost of service or operating expense, to which the hedged transaction relates, upon the occurrence of the forecasted transaction. We record any ineffectiveness of the hedging instruments in Interest and other expense, net in our condensed consolidated financial statements in the period incurred. No ineffectiveness was recorded during the three months ended March 31, 2014 and 2013.
	The notional amount of these contracts was $54.2 million at March 31, 2014 and $49.0 million at December 31, 2013. Outstanding contracts are recognized as either assets or liabilities on the balance sheet at fair value. The amount remaining in Accumulated other comprehensive income (loss) is expected to be recognized into earnings within the next twelve months. As of March 31, 2014 the amount remaining in Accumulated other comprehensive income (loss) was a loss of $0.2 million. The amount remaining in Accumulated other comprehensive income (loss) as of December 31, 2013 was $0.5 million.
	Derivatives not designated as hedging instruments
	We use foreign currency forward contracts to reduce the variability in gains and losses generated from the re-measurement of certain monetary assets and liabilities denominated in foreign currencies. These hedges do not qualify for hedge accounting treatment. These derivatives are carried at fair value with gains and losses recognized as Interest and other expense, net. Changes in the fair value of the derivatives are largely offset within the condensed consolidated statement of operations by re-measurement of the underlying assets and liabilities. We had a notional value of $11.1 million and $11.7 million in derivative instruments that were non-designated hedges at March 31, 2014 and December 31, 2013, respectively.
	Fair Value of Derivative Instruments
	The derivative assets and liabilities are recorded on a gross basis and included in Other current assets and Other accrued liabilities, respectively, in our condensed consolidated balance sheet.
	The fair value of derivative instruments in our condensed consolidated balance sheets was as follows as of March 31, 2014 and December 31, 2013:
	(in thousands)	March 31,			December 31,
		2014			2013
	Derivative assets:
	Foreign currency contracts designated as cash flow hedges	$	74		$	162
	Derivatives not designated as hedging instruments	60			169
	Total derivative assets	$	134		$	331
	Derivative liabilities:
	Foreign currency contracts designated as cash flow hedges	$	11		$	57
	Derivatives not designated as hedging instruments	7			46
	Total derivative liabilities	$	18		$	103
	The effects of derivatives designated as hedging instruments on our condensed consolidated statements of operations were as follows for the three months ended March 31, 2014 and 2013:
		Three months ended
		March 31,
	(in thousands)	2014			2013
	Amount of gain (loss) recognized in Accumulated other comprehensive income (loss) on derivatives (effective portion)	$	111		$	(959	)
	Amount and location of gain (loss) reclassified from Accumulated other comprehensive income (loss) into earnings (effective portion)
	Cost of support and services	$	(57	)	$	37
	Sales and marketing	(259		)	127
	Research and development	(59		)	33
	General and administrative	(15		)	11
	Total	$	(390	)	$	208
	Amount and location of gain recognized in earnings on derivatives (ineffective portion and amount excluded from effectiveness testing)
	Interest and other expense, net	$	31		$	15
	The effects of derivatives not designated as hedging instruments on our condensed consolidated statements of operations were as follows for the three months ended March 31, 2014 and 2013:
		Three months ended
		March 31,
	(in thousands)	2014			2013
	Interest and other expense, net	$	76		$	(229	)
	We enter into master netting arrangements with certain counterparties, which reduce credit risk by permitting net settlement of transactions with the same counterparty. A master netting arrangement may allow counterparties to net settle amounts owed to each other as a result of multiple, separate derivative transactions. These agreements also provide a right to offset corresponding amounts at the option of the non-defaulting party or non-affected party upon the early termination of these agreements by default, upon certain other termination events and a credit event upon merger. For presentation on the condensed consolidated balance sheets, it is our policy to not offset fair value amounts recognized for derivative instruments under master netting arrangements. As of March 31, 2014, we have posted no collateral for derivative instruments, therefore no amounts exist to offset the fair value amounts recognized for derivative instruments under master netting arrangements.

Borrowings

Borrowings	3 Months Ended
	Mar. 31, 2014
Debt Disclosure [Abstract]	'
Borrowings	'
	BORROWINGS
	In December 2013, we entered into a credit agreement, related security and other agreements for a $600.0 million credit facility (the 2013 Credit Facility) providing for a $300.0 million senior secured term credit facility and a $300.0 million senior secured revolving credit facility. The 2013 Credit Facility has a five year term. On December 20, 2013, we drew down $300.0 million in term loans and $225.0 million under the revolving credit facility. Pursuant to the issuance of the 2013 Credit Facility, we incurred debt issuance costs of approximately $4.2 million, which is recorded as a deferred asset and will be amortized to interest expense using the effective interest rate method.
	Borrowings under the 2013 Credit Facility bear interest based on the daily balance outstanding at LIBOR (with no rate floor) plus an applicable margin (varying from 1.25% to 2.00%) or, in certain cases a base rate (based on a certain lending institution’s Prime Rate or as otherwise specified in the credit agreement, with no rate floor) plus an applicable margin (varying from 0.25% to 1.00%). The revolving credit facility also carries a commitment fee equal to the unused borrowings multiplied by an applicable margin (varying from 0.25% to 0.30%). The applicable margins are calculated quarterly and vary based on our leverage ratio as set forth in the credit agreement. The interest rate on both the term and revolving loans is LIBOR plus 175 basis points, or 2.0%, as of March 31, 2014 and December 31, 2013. Beginning in 2014, 5% of the initial term loan value is to be paid annually in quarterly installments.
	The term loan contains various customary representations and warranties by us, which include customary use of materiality, material adverse effect and knowledge qualifiers. The 2013 Credit Facility also contains customary affirmative and negative covenants including, among other requirements, negative covenants that restrict our ability to dispose of assets, create liens, incur indebtedness, repurchase stock, pay dividends, make acquisitions and make investments. Further, the 2013 Credit Facility contains financial covenants that require the maintenance of minimum consolidated interest coverage and maximum consolidated leverage ratios. Specifically, we must maintain, as of the end of each fiscal quarter, an interest coverage ratio of (a) EBITDA (as defined in the 2013 Credit Facility) to (b) interest expense for the most recently ended period of four fiscal quarters of not less than 3.50 to 1.00. We must also maintain, at the end of each fiscal quarter, a consolidated leverage ratio of (x) consolidated funded debt to (y) consolidated EBITDA (as defined in the 2013 Credit Facility) as of the last day of any fiscal quarter of the Borrower as set forth in the table below:
	We were in compliance with all covenants of the 2013 Credit Facility as of March 31, 2014.
	As of March 31, 2014 the outstanding borrowings were $521.3 million. For the three months ended March 31, 2014, interest incurred pursuant to the term loan was $2.9 million.
	The following table summarizes the future minimum principal payments on the 2013 Credit Facility outstanding as of December 31, 2013:
	Fiscal year	(in thousands)
	2014 (the nine months ending December 31, 2014)	$	11,250
	2015	15,000
	2016	30,000
	2017	30,000
	2018	435,000
	Total	$	521,250

Common_Stock

Common Stock	3 Months Ended
	Mar. 31, 2014
Share-based Compensation [Abstract]	'
Common Stock	'
	COMMON STOCK
	Stock-Based Compensation Expense
	The following table summarizes stock-based compensation expense for stock options, RSUs and the 2006 Employee Stock Purchase Plan (the Purchase Plan) recorded in our condensed consolidated statement of operations for the three months ended March 31, 2014 and 2013:
		Three months ended
		March 31,
	(in thousands)	2014		2013
	Cost of product	$	331	$	256
	Cost of support and services	2,127		1,828
	Sales and marketing	9,503		10,864
	Research and development	6,787		7,547
	General and administrative	3,001		4,031
	Total	$	21,749	$	24,526
	Share Repurchase Program
	On August 19, 2011, our Board of Directors authorized a Share Repurchase Program (the Program), which authorized us to repurchase up to $150.0 million of our outstanding common stock. On May 17, 2012, the Board of Directors approved a $150.0 million increase to the Program. On August 19, 2013, the Board of Directors announced a $200.0 million increase to the Program. On March 4, 2014, the Board of Directors announced a $250.0 million increase to the Program. The Program does not require us to purchase a minimum number of shares, and may be suspended, modified or discontinued at any time without prior notice. For the three months ended March 31, 2014, we repurchased 1,236,078 shares of common stock under the Program on the open market for an aggregate purchase price of $25.0 million, or a weighted average of $20.23 per share. The timing and amounts of these purchases were based on market conditions and other factors including price, regulatory requirements and capital availability. The share repurchases were financed by available cash balances and cash from operations. The maximum dollar value of shares of common stock that remain available for purchase under the Program is $362.7 million.
	For the three months ended March 31, 2013, we repurchased 1,613,064 shares of common stock under the Program for an aggregate purchase price of $25.0 million, or weighted-average of $15.52 per share.

Income_Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2014
Income Tax Expense (Benefit), Continuing Operations [Abstract]	'
Income Taxes	'
		INCOME TAXES
	Our provision for (benefit from) income taxes is based on our estimated annual effective tax rate, adjusted for discrete tax items recorded in the period. The effective tax rate was 41.3% and 52.6% for the three months ended March 31, 2014 and 2013, respectively. Our provision for (benefit from) income taxes consists of federal, foreign, and state income taxes. The provision for (benefit from) income taxes for the three months ended March 31, 2014 and 2013 was $2.3 million and $(9.0) million, respectively.
	For the three months ended March 31, 2014, our effective tax rate differs from the federal statutory rate due to state taxes and significant permanent differences. Significant permanent differences included taxes in foreign jurisdictions with a tax rate different than the U.S. federal statutory rate, nondeductible stock-based compensation expense, tax charges related to our intercompany transfer of intellectual property rights, and the domestic production activities deduction.
	Our effective tax rate for the three months ended March 31, 2013, differed from the federal statutory rate due to state taxes and significant permanent differences. Significant permanent differences included taxes in foreign jurisdictions with a tax rate different than the U.S. federal statutory rate, nondeductible stock-based compensation expense, tax charges related to our intercompany transfer of intellectual property rights, the domestic production activities deduction, and the federal R&D tax credit. The federal R&D tax credit was retroactively reinstated and extended to December 31, 2013 during the first quarter of 2013. As a result of the reinstatement, we recorded a discrete tax benefit of $4.3 million related to 2012 in the first quarter of 2013.

Accumulated_Other_Comprehensiv

Accumulated Other Comprehensive Income (Loss)	3 Months Ended
	Mar. 31, 2014
Accumulated Other Comprehensive Income (Loss) [Abstract]	'
Comprehensive Income (Loss)	'
	ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)
	The components of accumulated other comprehensive income (loss), net of tax, at the end of the period, as well as the activity during the period were as follows:
	(in thousands)	Unrealized gain (loss) on investments, net of tax			Foreign currency translation adjustment			Derivative instruments gain (loss), net of tax			Total
	Balance as of December 31, 2013	$	(30	)	$	(59	)	$	505		$	416
	Other comprehensive income (loss) before reclassifications	54			31			(655		)	(570		)
	Amounts reclassified from accumulated other comprehensive income (loss)	1			—			390			391
	Net current-period other comprehensive income (loss)	55			31			(265		)	(179		)
	Balance as of March 31, 2014	$	25		$	(28	)	$	240		$	237
	Amounts reclassified from Accumulated other comprehensive income (loss), net to Net income (loss) for unrealized gains or losses on investments are recorded in Interest and other expense, net. Amounts reclassified from Accumulated other comprehensive income (loss) to Net income (loss) for derivatives instrument gains or losses are recorded in Cost of support and services and Operating expenses.

Segment_Information

Segment Information	3 Months Ended
	Mar. 31, 2014
Segment Reporting [Abstract]	'
Segment Information	'
	SEGMENT AND GEOGRAPHIC INFORMATION
	Operating segments are defined as components of an enterprise about which separate financial information is available that is evaluated regularly by the chief operating decision maker, or decision making group, in deciding how to allocate resources and in assessing performance. Our chief operating decision maker is our Chief Executive Officer. While our Chief Executive Officer evaluates the revenue for certain of our product lines, the information for all product lines is aggregated for analysis on a consolidated level as the primary basis for the allocation of resources and assessment of financial results. Accordingly, the consolidated business is considered to be one operating segment.
	Revenue by Product Line
	We have two product lines: Application Acceleration and Performance Management. Application Acceleration includes our wide area network (WAN) optimization products, including Steelhead and SteelFusion (formerly Granite), our Stingray virtual application delivery controllers (ADCs), and our Whitewater cloud storage delivery products. Performance Management includes application-aware network performance management (NPM) and application performance management (APM) products. The Performance Management product line combines our former Cascade products and the products acquired from OPNET Technologies, Inc.
	The following table presents revenue by product line:
		Three months ended
		March 31,
	(in thousands)	2014		2013
	Revenue:
	Application Acceleration	$	204,456	$	184,962
	Performance Management	60,960		61,177
	Total revenue	$	265,416	$	246,139
	Revenue by Geography
	Revenue by geography is based on the billing address of the customer. The following table sets forth revenue by geographic area:
		Three months ended
		March 31,
	(in thousands)	2014		2013
	Americas
	United States	$	152,962	$	150,597
	Other Americas	7,856		7,545
	Total Americas	160,818		158,142
	Europe, Middle East and Africa
	United Kingdom	34,679		28,176
	Other Europe, Middle East and Africa	34,351		29,658
	Total Europe, Middle East and Africa	69,030		57,834
	Asia Pacific	35,568		30,163
	Total revenue	$	265,416	$	246,139

Legal_Matters

Legal Matters	3 Months Ended
	Mar. 31, 2014
Loss Contingency [Abstract]	'
Legal Matters	'
	LEGAL MATTERS
	On June 1, 2011, we served Silver Peak Systems, Inc. with a lawsuit, filed in the United States District Court for the District of Delaware, alleging infringement of certain patents. The lawsuit seeks unspecified damages and injunctive relief. On July 22, 2011, Silver Peak Systems denied the allegations and requested declaratory judgments of invalidity and non-infringement. On December 21, 2011, we amended our lawsuit against Silver Peak Systems to allege infringement of an additional patent. Our lawsuit against Silver Peak Systems currently alleges infringement of three patents. Trial of our claims against Silver Peak Systems in this matter is currently stayed pending a separate U.S. Patent and Trademark Office proceeding.
	On August 17, 2011, Silver Peak Systems amended its counterclaims against us, alleging infringement by Riverbed of three U.S. patents: 7,630,295, titled “Network Device Continuity”; 7,945,736, titled “Dynamic Load Management of Network Memory”; and 7,948,921, titled “Automatic Network Optimization.” Silver Peak subsequently dropped its claims with respect to U.S. patent 7,630,295, titled “Network Device Continuity.” The trial on the remaining two patents commenced on March 24, 2014. On April 1, 2014, the jury rendered a verdict of infringement on U.S. patents 7,948,921 and 7,945,736 based on certain features offered on Riverbed Steelhead products. We disagree with the verdict, and expect to prevail before the District Court on post-trial motions. In the event that we do not prevail on post-trial motions, we intend to appeal to the Federal Circuit. There has been no trial or discovery on damages, and such a trial and discovery would be scheduled only if we lose on appeal to the Federal Circuit. In addition to damages, Silver Peak is seeking an injunction prohibiting Riverbed from offering those features.
	At this time we are unable to estimate any range of reasonably possible loss relating to these actions.
	On June 28, 2013, we served Silver Peak Systems with an additional lawsuit, filed in the United States District Court for the Northern District of California, alleging infringement of two patents that are not covered by the lawsuit in Delaware. The California lawsuit seeks unspecified damages and injunctive relief. On July 22, 2013, Silver Peak Systems denied the allegations and requested declaratory judgments of invalidity and non-infringement. On August 12, 2013, Silver Peak Systems amended its counterclaims against us, alleging infringement by Riverbed of U.S. patent 8,392,684, titled “Data Encryption in a Network Memory Architecture for Providing Data Based on Local Accessibility”. On August 26, 2013 we denied Silver Peak Systems’ allegations and requested declaratory judgments of invalidity and non-infringement. These actions are currently stayed pending separate U.S. Patent and Trademark Office proceedings. At this time we are unable to estimate any range of reasonably possible loss relating to these actions. We believe that we have meritorious defenses to the counterclaims against us, and we intend to vigorously contest these counterclaims.
	In connection with our July 2011 acquisition of the outstanding securities of Zeus Technology Limited (Zeus), the share purchase agreement provided for certain additional potential payments (acquisition-related contingent consideration) totaling up to $27.0 million in cash, based on achievement of certain bookings targets related to Zeus products for the period from July 20, 2011 through July 31, 2012 (the Zeus Earn-Out period). The share purchase agreement also provided for a potential $3.0 million payment as an incentive bonus to former employees of Zeus, based on achievement of certain bookings targets related to Zeus products for the Zeus Earn-Out period.
	In October 2012 we served the representative of the Zeus shareholders, as lead defendant and proposed defendant class representative for all other similarly situated former shareholders of Zeus, with a lawsuit, filed in the Superior Court of the State of California, for declaratory relief.  The lawsuit seeks declaratory judgment that, among other things, (a) Riverbed is not in breach of the share purchase agreement, and (b) Riverbed does not owe any acquisition-related contingent consideration under the share purchase agreement because the necessary conditions precedent to the payment of acquisition-related contingent consideration did not occur. In November 2012, the representative of the Zeus shareholders filed a cross-complaint against Riverbed and Riverbed Technology Limited in the Superior Court of the State of California. The cross-complaint claims breach of contract and breach of the covenant of good faith and fair dealing, and seeks declaratory judgment that Riverbed has breached the share purchase agreement and that the entire $27.0 million in contingent consideration is payable to Zeus shareholders. Discovery is ongoing, and the Court has approved a class treatment of the former shareholders, though several have declined to participate. The trial is currently scheduled for November 3, 2014. We believe that the contention of the representative of the Zeus shareholders, and the Court-appointed class representatives for shareholders, is without merit and intend to vigorously defend our determination.
	In November 2012 we received a grand jury subpoena issued by the United States District Court for the Eastern District of Virginia. The subpoena requested documents related to certain federal government contracting matters, including $19 million transaction involving the sale of our products and services by a Riverbed reseller to an agency of the federal government in 2009. In January 2014 we received a notice that the Civil Division of the United States Attorney’s Office for the Eastern District of Virginia has opened a civil investigation into the same matters.
	From time to time, we are subject to various legal proceedings, claims and litigation arising in the ordinary course of business. There are no currently pending legal proceedings at March 31, 2014 that, in the opinion of management, would have a material adverse effect on our financial position, results of operations or cash flows. There can be no assurance that existing or future legal proceedings arising in the ordinary course of business or otherwise will not have a material adverse effect on our financial position, results of operations, or cash flows.

Organization_And_Significant_A1

Organization And Significant Accounting Policies (Policy)	3 Months Ended
	Mar. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Basis of Presentation	'
	Basis of Presentation
	The condensed consolidated financial statements include our accounts and the accounts of our wholly-owned subsidiaries. Intercompany transactions and balances have been eliminated. The accompanying condensed consolidated balance sheet as of March 31, 2014, the condensed consolidated statements of operations for the three months ended March 31, 2014 and 2013, the condensed consolidated statements of comprehensive income (loss) for the three months ended March 31, 2014 and 2013, and the condensed consolidated statements of cash flows for the three months ended March 31, 2014 and 2013 are unaudited. The accompanying statements should be read in conjunction with the audited consolidated financial statements and related notes contained in our Annual Report on Form 10-K for the year ended December 31, 2013.
	The accompanying condensed consolidated financial statements have been prepared in accordance with United States generally accepted accounting principles (GAAP) pursuant to the rules and regulations of the Securities and Exchange Commission (SEC). They do not include all of the financial information and footnotes required by GAAP for complete financial statements. We believe the unaudited condensed consolidated financial statements have been prepared on the same basis as the audited financial statements and include all adjustments necessary for the fair presentation of our balance sheet as of March 31, 2014, our results of operations, comprehensive income (loss) and our cash flows for the three months ended March 31, 2014 and 2013. All adjustments are of a normal recurring nature. The results for the three months ended March 31, 2014 are not necessarily indicative of the results to be expected for any subsequent quarter or for the year ending December 31, 2014.
	During the three months ended March 31, 2014, there have been no significant changes in our significant accounting policies that were described in our Annual Report on Form 10-K for the year ended December 31, 2013.
Use Of Estimates	'
	Use of Estimates
	These accounting principles require us to make certain estimates and judgments that can affect the reported amounts of assets and liabilities as of the date of the condensed consolidated financial statements, as well as the reported amounts of revenue and expenses during the periods presented. Significant estimates and assumptions made by management include the determination of the fair value of stock awards issued, inventory valuation, the accounting for income taxes, including the determination of the valuation allowance related to our deferred tax asset balances, goodwill and other intangible assets, reserves for uncertain tax positions, and the accounting for business combinations. We believe that the estimates and judgments upon which we rely are reasonable based upon information available to us at the time that these estimates and judgments were made. To the extent there are material differences between these estimates and actual results, our condensed consolidated financial statements will be affected.

Net_Income_Loss_Per_Common_Sha1

Net Income (Loss) Per Common Share (Tables)	3 Months Ended
	Mar. 31, 2014
Earnings Per Share [Abstract]	'
Computation Of Net Income (Loss) Per Share	'
	The following table sets forth the computation of net income (loss) per share:
		Three months ended
		March 31,
	(in thousands, except per share data)	2014			2013
	Net income (loss)	$	3,288		$	(8,110	)
	Weighted average common shares outstanding - basic	160,190			163,367
	Dilutive effect of employee stock plans	5,123			—
	Weighted average common shares outstanding - diluted	165,313			163,367
	Basic net income (loss) per share	$	0.02		$	(0.05	)
	Diluted net income (loss) per share	$	0.02		$	(0.05	)
Antidilutive Securities Excluded From Computation Of Diluted Net Income Per Common Share	'
	:
		Three months ended
		March 31,
	(in thousands)	2014		2013
	Total potential anti-dilutive shares of common stock	7,370		17,355

Fair_Value_Of_Assets_Tables

Fair Value Of Assets (Tables)	3 Months Ended
	Mar. 31, 2014
Assets, Fair Value Disclosure [Abstract]	'
Fair Value Measurements Of Cash, Cash Equivalents And Investments	'
	s of March 31, 2014:
	(in thousands)	Total		Level 1		Level 2
	Assets:
	Corporate bonds and notes	$	39,383	$	—	$	39,383
	U.S. government-sponsored enterprise obligations	43,745		—		43,745
	Money market funds	38,680		38,680		—
	Cash	123,092		—		—
	Total cash and cash equivalents	244,900		38,680		83,128
	Corporate bonds and notes	68,955		—		68,955
	U.S. government backed securities	34,740		34,740		—
	U.S. government-sponsored enterprise obligations	195,035		—		195,035
	FDIC-backed certificates of deposit	16,023		—		16,023
	Total investments	314,753		34,740		280,013
	Derivative assets	134		—		134
	Total assets	$	559,787	$	73,420	$	363,275
	Liabilities:
	Derivative liabilities	$	18	$	—	$	18
	Borrowings	521,250		—		521,250
	Total liabilities	$	521,268	$	—	$	521,268
	The following table sets forth our financial assets and liabilities measured at fair value on a recurring basis as of December 31, 2013:
	(in thousands)	Total		Level 1		Level 2
	Assets:
	Corporate bonds and notes	$	28,545	$	—	$	28,545
	U.S. government-sponsored enterprise obligations	18,775		—		18,775
	Money market funds	30,009		30,009		—
	Cash	130,693		—		—
	Total cash and cash equivalents	208,022		$	30,009	47,320
	Corporate bonds and notes	74,648		$	—	74,648
	U.S. government backed securities	23,210		23,210		—
	U.S. government-sponsored enterprise obligations	211,094		—		211,094
	FDIC-backed certificates of deposit	15,062		—		15,062
	Total investments	324,014		23,210		300,804
	Derivative assets	331		—		331
	Total assets	$	532,367	$	53,219	$	348,455
	Liabilities:
	Derivative liabilities	$	103	$	—	$	103
	Borrowings	525,000		$	—	525,000
	Total liabilities	$	525,103	$	—	$	525,103
Gross Unrealized Gains And Gross Unrealized Losses	'
	The following tables present the gross unrealized gains and gross unrealized losses of available-for-sale securities as of March 31, 2014 and December 31, 2013:
	(in thousands)	Fair Value		Unrealized		Unrealized
				Gains		Losses
	Corporate bonds and notes	$	108,338	$	3	$	(13	)
	U.S. government backed securities	34,740		21		(3		)
	U.S. government-sponsored enterprise obligations	238,780		71		(44		)
	FDIC-backed certificates of deposit	16,023		—		—
	Total available-for-sale securities at March 31, 2014	$	397,881	$	95	$	(60	)
	Corporate bonds and notes	$	103,193	$	1	$	(24	)
	U.S. government backed securities	23,210		7		(2		)
	U.S. government-sponsored enterprise obligations	229,869		55		(30		)
	FDIC-backed certificates of deposit	15,062		1		—
	Total available-for-sale securities at December 31, 2013	$	371,334	$	64	$	(56	)
	The available-for-sale securities by classification in the condensed consolidated balance sheet is as follows:
	(in thousands)	March 31,		December 31,
		2014		2013
	Cash and cash equivalents	$	83,128	$	47,320
	Short-term investments	229,292		251,339
	Long-term investments	85,461		72,675
	Total available-for-sale securities	$	397,881	$	371,334
	Cash and cash equivalents in the table above excludes cash of $161.8 million and $160.7 million at March 31, 2014 and December 31, 2013, respectively.

Inventory_Tables

Inventory (Tables)	3 Months Ended
	Mar. 31, 2014
Inventory, Gross [Abstract]	'
Components Of Inventory	'
	Inventory is comprised of the following:
	(in thousands)	March 31,		December 31,
		2014		2013
	Raw materials	$	3,997	$	5,069
	Finished goods	14,388		15,430
	Evaluation units	2,833		4,526
	Total inventory	$	21,218	$	25,025

Lease_Commitments_Tables

Lease Commitments (Tables)	3 Months Ended
	Mar. 31, 2014
Leases [Abstract]	'
Operating Leases, Future Minimum Commitments	'
	Future minimum commitments for these operating leases in place as of March 31, 2014 with a remaining non-cancelable lease term in excess of one year are as follows:
	Fiscal year	(in thousands)
	2014 (remaining 9 months)	$	17,646
	2015	28,585
	2016	27,105
	2017	25,157
	2018	23,411
	Thereafter	93,658
	Total	$	215,562

Derivative_Financial_Instrumen1

Derivative Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'
Schedule of Derivative Instruments in Condensed Consolidated Balance Sheet	'
	The fair value of derivative instruments in our condensed consolidated balance sheets was as follows as of March 31, 2014 and December 31, 2013:
	(in thousands)	March 31,			December 31,
		2014			2013
	Derivative assets:
	Foreign currency contracts designated as cash flow hedges	$	74		$	162
	Derivatives not designated as hedging instruments	60			169
	Total derivative assets	$	134		$	331
	Derivative liabilities:
	Foreign currency contracts designated as cash flow hedges	$	11		$	57
	Derivatives not designated as hedging instruments	7			46
	Total derivative liabilities	$	18		$	103
Schedule of Derivative Instruments Designated as Hedging Instruments on Statement of Operations	'
	The effects of derivatives designated as hedging instruments on our condensed consolidated statements of operations were as follows for the three months ended March 31, 2014 and 2013:
		Three months ended
		March 31,
	(in thousands)	2014			2013
	Amount of gain (loss) recognized in Accumulated other comprehensive income (loss) on derivatives (effective portion)	$	111		$	(959	)
	Amount and location of gain (loss) reclassified from Accumulated other comprehensive income (loss) into earnings (effective portion)
	Cost of support and services	$	(57	)	$	37
	Sales and marketing	(259		)	127
	Research and development	(59		)	33
	General and administrative	(15		)	11
	Total	$	(390	)	$	208
	Amount and location of gain recognized in earnings on derivatives (ineffective portion and amount excluded from effectiveness testing)
	Interest and other expense, net	$	31		$	15
Schedule of Derivatives Not Designated as Hedging Instruments, Effect on Statement of Operations	'
	The effects of derivatives not designated as hedging instruments on our condensed consolidated statements of operations were as follows for the three months ended March 31, 2014 and 2013:
		Three months ended
		March 31,
	(in thousands)	2014			2013
	Interest and other expense, net	$	76		$	(229	)

Borrowings_Tables

Borrowings (Tables)	3 Months Ended
	Mar. 31, 2014
Borrowings [Abstract]	'
Schedule of Maturities of Long-term Debt	'
	The following table summarizes the future minimum principal payments on the 2013 Credit Facility outstanding as of December 31, 2013:
	Fiscal year	(in thousands)
	2014 (the nine months ending December 31, 2014)	$	11,250
	2015	15,000
	2016	30,000
	2017	30,000
	2018	435,000
	Total	$	521,250

Common_Stock_Tables

Common Stock (Tables)	3 Months Ended
	Mar. 31, 2014
Share-based Compensation [Abstract]	'
Summary Of Stock-Based Compensation Expense	'
	The following table summarizes stock-based compensation expense for stock options, RSUs and the 2006 Employee Stock Purchase Plan (the Purchase Plan) recorded in our condensed consolidated statement of operations for the three months ended March 31, 2014 and 2013:
		Three months ended
		March 31,
	(in thousands)	2014		2013
	Cost of product	$	331	$	256
	Cost of support and services	2,127		1,828
	Sales and marketing	9,503		10,864
	Research and development	6,787		7,547
	General and administrative	3,001		4,031
	Total	$	21,749	$	24,526

Accumulated_Other_Comprehensiv1

Accumulated Other Comprehensive Income (Loss) (Tables)	3 Months Ended
	Mar. 31, 2014
Accumulated Other Comprehensive Income (Loss) [Abstract]	'
Schedule of Accumulated Other Comprehensive Income (Loss)	'
	The components of accumulated other comprehensive income (loss), net of tax, at the end of the period, as well as the activity during the period were as follows:
	(in thousands)	Unrealized gain (loss) on investments, net of tax			Foreign currency translation adjustment			Derivative instruments gain (loss), net of tax			Total
	Balance as of December 31, 2013	$	(30	)	$	(59	)	$	505		$	416
	Other comprehensive income (loss) before reclassifications	54			31			(655		)	(570		)
	Amounts reclassified from accumulated other comprehensive income (loss)	1			—			390			391
	Net current-period other comprehensive income (loss)	55			31			(265		)	(179		)
	Balance as of March 31, 2014	$	25		$	(28	)	$	240		$	237

Segment_Information_Tables

Segment Information (Tables)	3 Months Ended
	Mar. 31, 2014
Segment Reporting [Abstract]	'
Schedule of Segment Reporting Information, by Segment	'
	Revenue by Product Line
	We have two product lines: Application Acceleration and Performance Management. Application Acceleration includes our wide area network (WAN) optimization products, including Steelhead and SteelFusion (formerly Granite), our Stingray virtual application delivery controllers (ADCs), and our Whitewater cloud storage delivery products. Performance Management includes application-aware network performance management (NPM) and application performance management (APM) products. The Performance Management product line combines our former Cascade products and the products acquired from OPNET Technologies, Inc.
	The following table presents revenue by product line:
		Three months ended
		March 31,
	(in thousands)	2014		2013
	Revenue:
	Application Acceleration	$	204,456	$	184,962
	Performance Management	60,960		61,177
	Total revenue	$	265,416	$	246,139
Schedule of Segment Information by Geographic Area	'
	Revenue by Geography
	Revenue by geography is based on the billing address of the customer. The following table sets forth revenue by geographic area:
		Three months ended
		March 31,
	(in thousands)	2014		2013
	Americas
	United States	$	152,962	$	150,597
	Other Americas	7,856		7,545
	Total Americas	160,818		158,142
	Europe, Middle East and Africa
	United Kingdom	34,679		28,176
	Other Europe, Middle East and Africa	34,351		29,658
	Total Europe, Middle East and Africa	69,030		57,834
	Asia Pacific	35,568		30,163
	Total revenue	$	265,416	$	246,139

Net_Income_Loss_Per_Common_Sha2

Net Income (Loss) Per Common Share (Computation Of Net Income Per Share) (Details) (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Earnings Per Share [Abstract]	'	'
Net income (loss)	$3,288	($8,110)
Weighted average common shares outstanding - basic	160,190	163,367
Dilutive effect of employee stock plans	5,123	0
Weighted average common shares outstanding - diluted	165,313	163,367
Basic net income (loss) per share (in usd per share)	$0.02	($0.05)
Diluted net income (loss) per share (in usd per share)	$0.02	($0.05)

Net_Income_Loss_Per_Common_Sha3

Net Income (Loss) Per Common Share (Antidilutive Securities Excluded From Computation Of Diluted Net Income Per Common Share) (Details)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Earnings Per Share [Abstract]	'	'
Total potential anti-dilutive shares of common stock	7,370	17,355

Fair_Value_Of_Assets_Narrative

Fair Value Of Assets (Narrative) (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013	Dec. 31, 2012
Assets, Fair Value Disclosure [Abstract]	'	'	'	'
Investments other than temporarily impaired	$0	'	'	'
Investments in continuous unrealized loss position, 12 months or longer	0	'	'	'
Cash and cash equivalents	$244,899,000	$208,022,000	$227,347,000	$280,509,000

Fair_Value_Of_Assets_Fair_Valu

Fair Value Of Assets (Fair Value Measurements Of Cash, Cash Equivalents, Investments, Derivative assets and liabilities, and Borrowings) (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total cash and cash equivalents	$244,900	$208,022
Total investments	314,753	324,014
Derivative asset	134	331
Assets, Fair Value Disclosure, Recurring	559,787	532,367
Derivative liabilities	18	103
Borrowings	521,250	525,000
Liabilities, Fair Value Disclosure, Recurring	521,268	525,103
Level 1 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total cash and cash equivalents	38,680	30,009
Total investments	34,740	23,210
Derivative asset	'	'
Assets, Fair Value Disclosure, Recurring	73,420	53,219
Derivative liabilities	'	'
Borrowings	'	'
Liabilities, Fair Value Disclosure, Recurring	0	0
Level 2 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total cash and cash equivalents	83,128	47,320
Total investments	280,013	300,804
Derivative asset	134	331
Assets, Fair Value Disclosure, Recurring	363,275	348,455
Derivative liabilities	18	103
Borrowings	521,250	525,000
Liabilities, Fair Value Disclosure, Recurring	521,268	525,103
Corporate Bonds And Notes [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total cash and cash equivalents	39,383	28,545
Total investments	68,955	74,648
Corporate Bonds And Notes [Member] | Level 1 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total cash and cash equivalents	'	'
Total investments	'	'
Corporate Bonds And Notes [Member] | Level 2 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total cash and cash equivalents	39,383	28,545
Total investments	68,955	74,648
U.S. Government Backed Securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total investments	34,740	23,210
U.S. Government Backed Securities [Member] | Level 1 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total investments	34,740	23,210
U.S. Government Backed Securities [Member] | Level 2 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total investments	'	'
U.S. Government-Sponsored Enterprise Obligations [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total cash and cash equivalents	43,745	18,775
Total investments	195,035	211,094
U.S. Government-Sponsored Enterprise Obligations [Member] | Level 1 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total cash and cash equivalents	'	'
Total investments	'	'
U.S. Government-Sponsored Enterprise Obligations [Member] | Level 2 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total cash and cash equivalents	43,745	18,775
Total investments	195,035	211,094
Money Market Funds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total cash and cash equivalents	38,680	30,009
Money Market Funds [Member] | Level 1 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total cash and cash equivalents	38,680	30,009
Money Market Funds [Member] | Level 2 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total cash and cash equivalents	'	'
FDIC-Backed Certificates Of Deposit [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total investments	16,023	15,062
FDIC-Backed Certificates Of Deposit [Member] | Level 1 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total investments	'	'
FDIC-Backed Certificates Of Deposit [Member] | Level 2 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total investments	16,023	15,062
Cash [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total cash and cash equivalents	123,092	130,693
Cash [Member] | Level 1 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total cash and cash equivalents	'	'
Cash [Member] | Level 2 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total cash and cash equivalents	'	'

Fair_Value_Of_Assets_Gross_Unr

Fair Value Of Assets (Gross Unrealized Gains And Gross Unrealized Losses) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013	Dec. 31, 2012
Gross Unrealized Gains (Losses) [Line Items]	'	'	'	'
Cash and Cash Equivalents, at Carrying Value	$244,899	$227,347	$208,022	$280,509
Fair Value	397,881	'	371,334	'
Unrealized Gains	95	64	'	'
Unrealized Losses	-60	-56	'	'
Short-term Investments	229,292	'	251,339	'
Long-term Investments	85,461	'	72,675	'
Unrealized Gains [Member] | Corporate Bonds And Notes [Member]	'	'	'	'
Gross Unrealized Gains (Losses) [Line Items]	'	'	'	'
Fair Value	108,338	'	103,193	'
Unrealized Gains	3	1	'	'
Unrealized Gains [Member] | U.S. Government Backed Securities [Member]	'	'	'	'
Gross Unrealized Gains (Losses) [Line Items]	'	'	'	'
Fair Value	34,740	'	23,210	'
Unrealized Gains	21	7	'	'
Unrealized Gains [Member] | U.S. Government-Sponsored Enterprise Obligations [Member]	'	'	'	'
Gross Unrealized Gains (Losses) [Line Items]	'	'	'	'
Fair Value	238,780	'	229,869	'
Unrealized Gains	71	55	'	'
Unrealized Gains [Member] | FDIC-Backed Certificates Of Deposit [Member]	'	'	'	'
Gross Unrealized Gains (Losses) [Line Items]	'	'	'	'
Fair Value	16,023	'	15,062	'
Unrealized Gains	0	1	'	'
Unrealized Losses [Member] | Corporate Bonds And Notes [Member]	'	'	'	'
Gross Unrealized Gains (Losses) [Line Items]	'	'	'	'
Unrealized Losses	-13	-24	'	'
Unrealized Losses [Member] | U.S. Government Backed Securities [Member]	'	'	'	'
Gross Unrealized Gains (Losses) [Line Items]	'	'	'	'
Unrealized Losses	-3	-2	'	'
Unrealized Losses [Member] | U.S. Government-Sponsored Enterprise Obligations [Member]	'	'	'	'
Gross Unrealized Gains (Losses) [Line Items]	'	'	'	'
Unrealized Losses	-44	-30	'	'
Unrealized Losses [Member] | FDIC-Backed Certificates Of Deposit [Member]	'	'	'	'
Gross Unrealized Gains (Losses) [Line Items]	'	'	'	'
Unrealized Losses	0	0	'	'
Cash [Member]	'	'	'	'
Gross Unrealized Gains (Losses) [Line Items]	'	'	'	'
Cash and Cash Equivalents, at Carrying Value	161,772	'	160,702	'
Cash Equivalents [Member]	'	'	'	'
Gross Unrealized Gains (Losses) [Line Items]	'	'	'	'
Cash and Cash Equivalents, at Carrying Value	$83,128	'	$47,320	'

Inventory_Components_Of_Invent

Inventory (Components Of Inventory) (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Inventory, Gross [Abstract]	'	'
Raw materials	$3,997	$5,069
Finished goods	14,388	15,430
Evaluation units	2,833	4,526
Total inventory	$21,218	$25,025

Lease_Commitments_Details

Lease Commitments (Details) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Leases [Abstract]	'	'
2014 (the nine months ending December 31)	$17,646,000	'
2015	28,585,000	'
2016	27,105,000	'
2017	25,157,000	'
2018	23,411,000	'
Thereafter	93,658,000	'
Total	215,562,000	'
Rent expense under operating leases	$7,700,000	$5,100,000

Derivative_Financial_Instrumen2

Derivative Financial Instruments (Narrative) (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
Derivatives, Fair Value [Line Items]	'	'
Accumulated other comprehensive income	$237,000	$416,000
Derivative, Notional Amount	54,200,000	49,000,000
Foreign currency derivative instruments not designated as hedging instruments at fair value, net	11,100,000	11,700,000
Accumulated Net Unrealized Derivative Gains (Losses) [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, Effect Net of Tax	$240,000	$505,000

Derivative_Financial_Instrumen3

Derivative Financial Instruments (Fair Value of Derivative Instruments, Balance Sheet) (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Derivative [Line Items]	'	'
Derivative Assets	$134	$331
Derivative Liabilities	18	103
Foreign currency contracts designated as cash flow hedges	'	'
Derivative [Line Items]	'	'
Derivative Assets	74	162
Derivative Liabilities	11	57
Derivatives not designated as hedging instruments	'	'
Derivative [Line Items]	'	'
Derivative Assets	60	169
Derivative Liabilities	$7	$46

Derivative_Financial_Instrumen4

Derivative Financial Instruments (Fair Value of Derivative Instruments, Statement of Income) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Derivative Instruments, Gain (Loss) [Line Items]	'	'
Amount of Gain (Loss) Recognized in Accumulated OCI on Derivatives (Effective Portion)	$111	($959)
Amount and Location of Gain (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	-390	208
Cost of support and services	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'
Amount and Location of Gain (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	-57	37
Sales and Marketing	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'
Amount and Location of Gain (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	-259	127
Research and Development	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'
Amount and Location of Gain (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	-59	33
General and Administrative	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'
Amount and Location of Gain (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	-15	11
Other Income (expense), net	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'
Amount and Location of Gain (Loss) Recognized in Income on Derivatives (Ineffective Portion and Amount Excluded from Effectiveness Testing)	$31	$15

Derivative_Financial_Instrumen5

Derivative Financial Instruments (Effects of Derivatives not Designated as Hedges) (Details) (Derivatives not designated as hedging instruments, Other Income [Member], USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Derivatives not designated as hedging instruments | Other Income [Member]	'	'
Derivative [Line Items]	'	'
Interest and other expense, net	$76	($229)

Borrowings_Details

Borrowings (Details) (USD $)	3 Months Ended
	Mar. 31, 2014	Dec. 31, 2012	Dec. 31, 2013
Debt Instrument [Line Items]	'	'	'
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months	$11,250,000	'	'
Debt, Long-term and Short-term, Combined Amount	521,250,000	'	600,000,000
Debt instrument, loan term	'5 years	'	'
Debt Issuance Cost	'	4,200,000	'
Debt instrument, current interest rate	2.00%	'	'
Debt instrument, periodic payment, percentage of initial loan value	'0.05	'	'
Interest expense	2,900,000	'	'
Long-term Debt, Maturities, Repayments of Principal in Year Two	15,000,000	'	'
Long-term Debt, Maturities, Repayments of Principal in Year Three	30,000,000	'	'
Long-term Debt, Maturities, Repayments of Principal in Year Four	30,000,000	'	'
Long-term Debt, Maturities, Repayments of Principal in Year Five	435,000,000	'	'
Credit Facility [Domain]	'	'	'
Debt Instrument [Line Items]	'	'	'
Line of Credit Facility, Amount Outstanding	225,000,000	'	'
Line of Credit Facility, Maximum Borrowing Capacity	300,000,000	'	'
Credit Facility [Domain] | Minimum [Member]	'	'	'
Debt Instrument [Line Items]	'	'	'
Line of Credit Facility, Commitment Fee Percentage	0.25%	'	'
Credit Facility [Domain] | Minimum [Member] | London Interbank Offered Rate (LIBOR) [Member]	'	'	'
Debt Instrument [Line Items]	'	'	'
Debt instrument, basis spread on variable rate	1.25%	'	'
Credit Facility [Domain] | Minimum [Member] | Prime Rate [Member]	'	'	'
Debt Instrument [Line Items]	'	'	'
Debt instrument, basis spread on variable rate	0.25%	'	'
Credit Facility [Domain] | Maximum [Member]	'	'	'
Debt Instrument [Line Items]	'	'	'
Line of Credit Facility, Commitment Fee Percentage	0.30%	'	'
Credit Facility [Domain] | Maximum [Member] | London Interbank Offered Rate (LIBOR) [Member]	'	'	'
Debt Instrument [Line Items]	'	'	'
Debt instrument, basis spread on variable rate	2.00%	'	'
Credit Facility [Domain] | Maximum [Member] | Prime Rate [Member]	'	'	'
Debt Instrument [Line Items]	'	'	'
Debt instrument, basis spread on variable rate	1.00%	'	'
Secured Debt [Member] | Credit Facility [Domain]	'	'	'
Debt Instrument [Line Items]	'	'	'
Debt, Long-term and Short-term, Combined Amount	300,000,000	'	'
Debt instrument, face amount	$300,000,000	'	'
London Interbank Offered Rate (LIBOR) [Member]	'	'	'
Debt Instrument [Line Items]	'	'	'
Debt instrument, basis spread on variable rate	1.75%	'	'

Common_Stock_Narrative_Details

Common Stock (Narrative) (Details) (USD $)	3 Months Ended		0 Months Ended				3 Months Ended
In Millions, except Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013	Mar. 05, 2014	Aug. 19, 2013	17-May-12	Aug. 19, 2011	Mar. 31, 2014
			Share Repurchase Program [Member]	Share Repurchase Program [Member]	Share Repurchase Program [Member]	Share Repurchase Program [Member]	Share Repurchase Program [Member]
Class of Stock [Line Items]	'	'	'	'	'	'	'
Share repurchase program, authorized amount	'	'	'	'	'	$150	'
Stock repurchase program, increased authorized amount	'	'	250	200	150	'	'
Number of common stock shares repurchased	1,236,078	1,613,064	'	'	'	'	'
Value of common stock repurchased	25	25	'	'	'	'	'
Weighted average purchase price per share	20.23	15.52	'	'	'	'	'
Stock repurchase program, remaining authorized repurchase amount	'	'	'	'	'	'	$362.70

Common_Stock_Summary_Of_StockB

Common Stock (Summary Of Stock-Based Compensation Expense) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Total stock-based compensation expense	$21,749	$24,526
General and Administrative Expense [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Total stock-based compensation expense	3,001	4,031
Research and Development Expense [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Total stock-based compensation expense	6,787	7,547
Selling and Marketing Expense [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Total stock-based compensation expense	9,503	10,864
Cost Of Support And Services [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Total stock-based compensation expense	2,127	1,828
Cost of Goods, Total [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Total stock-based compensation expense	$331	$256

Income_Taxes_Narrative_Details

Income Taxes (Narrative) (Details) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Income Tax Expense (Benefit), Continuing Operations [Abstract]	'	'
Effective tax rate	41.30%	52.60%
Income tax expense (benefit)	$2,318,000	($8,989,000)
Income tax reconciliation, tax credits, research	'	$4,300,000

Accumulated_Other_Comprehensiv2

Accumulated Other Comprehensive Income (Loss) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'
Accumulated Other Comprehensive Income (Loss), Net of Tax	$237	'	$416
Other comprehensive income before reclassifications	-570	'	'
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	391	'	'
Unrealized gain (loss) on investments, net of tax	'	-159	'
Foreign currency translation adjustment	'	-633	'
Derivative instruments gain (loss), net of tax	'	-713	'
Other Comprehensive Income (Loss), Net of Tax	-179	'	'
Accumulated Net Unrealized Investment Gain (Loss) [Member]	'	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'
Other comprehensive income before reclassifications	54	'	'
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	1	'	'
Unrealized gain (loss) on investments, net of tax	55	'	'
Accumulated Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax	25	'	-30
Accumulated Net Unrealized Foreign Currency Gains (Losses) [Member]	'	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'
Other comprehensive income before reclassifications	31	'	'
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0	'	'
Foreign currency translation adjustment	31	'	'
Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Net of Tax	-28	'	-59
Accumulated Net Unrealized Derivative Gains (Losses) [Member]	'	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'
Other comprehensive income before reclassifications	-655	'	'
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	390	'	'
Derivative instruments gain (loss), net of tax	-265	'	'
Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, Effect Net of Tax	$240	'	$505

Segment_Information_Segment_In

Segment Information (Segment Information, by Product Line) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Revenue:	'	'
Revenue	$265,416	$246,139
Application Acceleration [Member]	'	'
Revenue:	'	'
Revenue	204,456	184,962
Performance Management [Member]	'	'
Revenue:	'	'
Revenue	$60,960	$61,177

Segment_Information_Segment_In1

Segment Information (Segment Information, Revenue By Geographic Area) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Segment Reporting Information [Line Items]	'	'
Total revenue	$265,416	$246,139
United States [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Total revenue	152,962	150,597
Other Americas [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Total revenue	7,856	7,545
Total Americas [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Total revenue	160,818	158,142
United Kingdom [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Total revenue	34,679	28,176
Other Europe Middle East And Africa [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Total revenue	34,351	29,658
Total Europe, Middle East And Africa [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Total revenue	69,030	57,834
Asia Pacific [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Total revenue	$35,568	$30,163

Legal_Matters_Details

Legal Matters (Details) (USD $)	1 Months Ended
In Millions, unless otherwise specified	Nov. 30, 2012	Nov. 30, 2012	Jul. 31, 2012	Jul. 31, 2012
		Zeus Technology, Ltd. [Member]	Zeus Technology, Ltd. [Member]	Zeus Incentive Bonus [Member]
Loss Contingencies [Line Items]	'	'	'	'
Maximum potential incentive bonus paid to former employees of Zeus	'	'	'	$3
Contingent consideration disputed amount	'	27	27	'
Transaction with agency of federal government, amount	$19	'	'	'