Riverbed Technology 10-Q 31 Jul 14 2014 Q2 Quarterly report Financial data

Document_And_Entity_Informatio

Document And Entity Information	6 Months Ended
	Jun. 30, 2014	Jul. 24, 2014
Document And Entity Information [Abstract]	'	'
Document Type	'10-Q	'
Amendment Flag	'false	'
Document Period End Date	30-Jun-14	'
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q2	'
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	'	159,716,102

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (USD $)	Jun. 30, 2014	Dec. 31, 2013
Current assets:	'	'
Cash and cash equivalents	$217,611,000	$208,022,000
Short-term investments	207,162,000	251,339,000
Trade receivables, net of allowances of $1,577 and $1,996 as of June 30, 2014 and December 31, 2013, respectively	108,560,000	93,836,000
Inventory	17,504,000	25,025,000
Deferred tax assets	17,255,000	7,222,000
Prepaid expenses and other current assets	62,905,000	49,016,000
Total current assets	630,997,000	634,460,000
Long-term investments	95,092,000	72,675,000
Fixed assets, net	75,953,000	57,810,000
Goodwill	704,305,000	704,305,000
Intangibles, net	361,129,000	404,467,000
Other assets	21,435,000	23,881,000
Total assets	1,888,911,000	1,897,598,000
Current liabilities:	'	'
Accounts payable	41,390,000	45,518,000
Accrued compensation and benefits	40,816,000	51,988,000
Other accrued liabilities	52,639,000	36,520,000
Current maturities of long-term borrowings	15,000,000	15,000,000
Deferred revenue	231,142,000	217,131,000
Total current liabilities	380,987,000	366,157,000
Deferred revenue, non-current	87,863,000	95,344,000
Borrowings, non-current, net of current maturities	502,500,000	510,000,000
Deferred tax liabilities, non-current	42,789,000	48,548,000
Other long-term liabilities	50,993,000	48,910,000
Total long-term liabilities	684,145,000	702,802,000
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; 159,709 and 159,845 shares issued and outstanding as of June 30, 2014 and December 31, 2013, respectively	688,133,000	702,928,000
Retained earnings	135,348,000	125,295,000
Accumulated other comprehensive income	298,000	416,000
Total stockholders' equity	823,779,000	828,639,000
Total liabilities and stockholders' equity	$1,888,911,000	$1,897,598,000

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Jun. 30, 2014	Dec. 31, 2013
In Thousands, except Per Share data, unless otherwise specified
Statement of Financial Position [Abstract]	'	'
Trade receivables, allowances	$1,577	$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
Common stock, shares issued	159,709	159,845
Common stock, shares outstanding	159,709	159,845

Condensed_Consolidated_Stateme

Condensed Consolidated Statements Of Operations (USD $)	3 Months Ended		6 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Revenue:	'	'	'	'
Product	$144,914	$143,483	$295,075	$291,523
Support and services	119,112	106,427	234,367	204,526
Total revenue	264,026	249,910	529,442	496,049
Cost of revenue:	'	'	'	'
Cost of product	36,388	40,463	74,669	81,363
Cost of support and services	32,633	29,893	64,264	57,935
Total cost of revenue	69,021	70,356	138,933	139,298
Gross profit	195,005	179,554	390,509	356,751
Operating expenses:	'	'	'	'
Sales and marketing	110,690	113,373	225,435	229,094
Research and development	51,298	51,018	101,945	99,979
General and administrative	20,279	18,321	39,404	37,435
Acquisition-related costs	272	7,067	2,940	11,203
Total operating expenses	182,539	189,779	369,724	377,711
Operating income (loss)	12,466	-10,225	20,785	-20,960
Interest and other expense, net	-2,713	-5,909	-5,426	-12,273
Income (loss) before provision for income taxes	9,753	-16,134	15,359	-33,233
Provision (benefit) for income taxes	2,988	387	5,306	-8,602
Net income (loss)	$6,765	($16,521)	$10,053	($24,631)
Net income (loss) per common share:	'	'	'	'
Basic (in usd per shares)	$0.04	($0.10)	$0.06	($0.15)
Diluted (in usd per shares)	$0.04	($0.10)	$0.06	($0.15)
Shares used in computing net income (loss) per common share:	'	'	'	'
Basic (in shares)	160,580	163,995	160,385	163,681
Diluted (in shares)	164,650	163,995	164,982	163,681

Condensed_Consolidated_Stateme1

Condensed Consolidated Statements of Comprehensive Income (USD $)	3 Months Ended		6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Net income (loss)	$6,765	($16,521)	$10,053	($24,631)
Unrealized gain (loss) on investments, net of tax	-5	-73	50	-232
Foreign currency translation adjustment	-15	-83	16	-716
Derivative instruments gain (loss), net of tax	81	224	-184	-489
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	61	68	-118	-1,437
Comprehensive income (loss)	$6,826	($16,453)	$9,935	($26,068)

Condensed_Consolidated_Stateme2

Condensed Consolidated Statements Of Cash Flows (USD $)	6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013
Operating Activities:	'	'
Net income (loss)	$10,053	($24,631)
Adjustments to reconcile net income to net cash provided by operating activities:	'	'
Depreciation and amortization	57,047	62,780
Stock-based compensation	43,321	50,055
Deferred taxes	-15,715	-32,867
Excess tax benefit from employee stock plans	-5,245	-4,683
Other noncash items	454	1,213
Increase (Decrease) in Operating Capital [Abstract]	'	'
Trade receivables	-14,724	19,915
Inventory	7,521	-3,690
Prepaid expenses and other assets	-11,008	-6,136
Accounts payable	-4,771	-8,282
Accrued and other liabilities	7,029	-11,384
Income taxes payable	1,602	-1,974
Deferred revenues	6,530	40,257
Net cash provided by operating activities	82,094	80,573
Investing Activities:	'	'
Capital expenditures	-31,208	-12,627
Purchase of available for sale securities	-170,606	-229,009
Proceeds from maturities of available for sale securities	166,314	161,250
Proceeds from sales of available for sale securities	25,145	15,045
Acquisitions, net of cash and cash equivalents acquired	0	-1,000
Net cash used in investing activities	-10,355	-66,341
Financing Activities:	'	'
Proceeds from issuance of common stock under employee stock plans	48,491	49,813
Taxes paid related to net shares settlement of equity awards	-8,171	-4,289
Payments for repurchases of common stock	-100,038	-75,078
Payments of borrowings	-7,500	-50,015
Excess tax benefit from employee stock plans	5,245	4,683
Net cash used in financing activities	-61,973	-74,886
Effect of exchange rate changes on cash and cash equivalents	-177	-1,192
Net increase (decrease) in cash and cash equivalents	9,589	-61,846
Cash and cash equivalents at beginning of period	208,022	280,509
Cash and cash equivalents at end of period	$217,611	$218,663

Organization_And_Significant_A

Organization And Significant Accounting Policies	6 Months Ended
	Jun. 30, 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 June 30, 2014, the condensed consolidated statements of operations for the three and six months ended June 30, 2014 and 2013, the condensed consolidated statements of comprehensive income (loss) for the three and six months ended June 30, 2014 and 2013, and the condensed consolidated statements of cash flows for the six months ended June 30, 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) and 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 June 30, 2014, and our results of operations, comprehensive income (loss) and our cash flows for the six months ended June 30, 2014 and 2013. All adjustments are of a normal recurring nature. The results for the six months ended June 30, 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 and six months ended June 30, 2014, there have been no significant changes in our significant accounting policies from 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)	6 Months Ended
	Jun. 30, 2014
Recent accounting pronouncements [Abstract]	'
New Accounting Pronouncements	'
	RECENT ACCOUNTING PRONOUNCEMENTS
	In May 2014, the Financial Accounting Standards Board (FASB) released Accounting Standards Update (ASU) No. 2014-09, Revenue from Contracts with Customers, requiring an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to customers. The guidance in ASU No. 2014-09 supersedes the revenue recognition requirements in Accounting Standards Codification Topic 605, Revenue Recognition and permits the use of either the retrospective or cumulative effect transition method. We are required to adopt this standard starting in the first quarter of fiscal 2017. We have not yet selected a transition method and we are currently in the process of determining the impact of ASU No. 2014-09 on our condensed consolidated financial statements.
	In July 2013, the FASB released 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. ASU No. 2013-11 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 our condensed consolidated financial statements.

Net_Income_Loss_Per_Common_Sha

Net Income (Loss) Per Common Share	6 Months Ended
	Jun. 30, 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						Six months ended
		June 30,						June 30,
	(in thousands, except per share data)	2014			2013			2014		2013
	Net income (loss)	$	6,765		$	(16,521	)	$	10,053	$	(24,631	)
	Weighted average common shares outstanding - basic	160,580			163,995			160,385		163,681
	Dilutive effect of employee stock plans	4,070			—			4,597		—
	Weighted average common shares outstanding - diluted	164,650			163,995			164,982		163,681
	Basic net income (loss) per share	$	0.04		$	(0.10	)	$	0.06	$	(0.15	)
	Diluted net income (loss) per share	$	0.04		$	(0.10	)	$	0.06	$	(0.15	)
	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					Six months ended
		June 30,					June 30,
	(in thousands)	2014		2013			2014		2013
	Total potential anti-dilutive shares of common stock	8,440		17,722			9,844		18,986

Fair_Value_Of_Assets

Fair Value Of Assets	6 Months Ended
	Jun. 30, 2014
Assets, Fair Value Disclosure [Abstract]	'
Fair Value Of Assets	'
	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 June 30, 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 June 30, 2014:
	(in thousands)	Total		Level 1		Level 2
	Assets:
	Corporate bonds and notes	$	35,345	$	—	$	35,345
	U.S. government-sponsored enterprise obligations	34,070		—		34,070
	Money market funds	25,071		25,071		—
	Cash	123,125		—		—
	Total cash and cash equivalents	217,611		25,071		69,415
	Corporate bonds and notes	60,422		—		60,422
	U.S. government backed securities	30,915		30,915		—
	U.S. government-sponsored enterprise obligations	191,732		—		191,732
	FDIC-backed certificates of deposit	19,185		—		19,185
	Total investments	302,254		30,915		271,339
	Derivative assets	404		—		404
	Total assets	$	520,269	$	55,986	$	341,158
	Liabilities:
	Derivative liabilities	$	159	$	—	$	159
	Borrowings	517,500		—		517,500
	Total liabilities	$	517,659	$	—	$	517,659
	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 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 June 30, 2014 and December 31, 2013:
	(in thousands)	Fair Value		Unrealized		Unrealized
				Gains		Losses
	Corporate bonds and notes	$	95,767	$	2	$	(13	)
	U.S. government backed securities	30,915		23		(2		)
	U.S. government-sponsored enterprise obligations	225,802		51		(36		)
	FDIC-backed certificates of deposit	19,185		—		—
	Total available-for-sale securities at June 30, 2014	$	371,669	$	76	$	(51	)
	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)	June 30,		December 31,
		2014		2013
	Cash and cash equivalents	$	69,415	$	47,320
	Short-term investments	207,162		251,339
Long-term investments	95,092		72,675
Total available-for-sale securities	$	371,669	$	371,334
Cash and cash equivalents in the table above excludes cash of $148.2 million and $160.7 million at June 30, 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 June 30, 2014 and have determined that no investments with unrealized losses are other-than-temporarily impaired. No investments have been in a continuous loss position for greater than one year.

Inventory

Inventory	6 Months Ended
	Jun. 30, 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)	June 30,		December 31,
		2014		2013
	Raw materials	$	2,754	$	5,069
	Finished goods	12,557		15,430
	Evaluation units	2,193		4,526
	Total inventory	$	17,504	$	25,025

Guarantees

Guarantees	6 Months Ended
	Jun. 30, 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	6 Months Ended
	Jun. 30, 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 June 30, 2014 with a remaining non-cancelable lease term in excess of one year are as follows:
	Fiscal year	(in thousands)
	2014 (remaining 6 months)	$	11,312
	2015	28,941
	2016	27,464
	2017	25,560
	2018	23,813
	Thereafter	93,788
	Total	$	210,878
	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 $7.2 million and $5.2 million for the three months ended June 30, 2014 and 2013, respectively, and $14.8 million and $10.3 million for the six months ended June 30, 2014 and 2013, respectively.

Derivative_Financial_Instrumen

Derivative Financial Instruments	6 Months Ended
	Jun. 30, 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 expense and other, 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 expense and other, net in our condensed consolidated financial statements in the period incurred. No ineffectiveness was recorded during the three and six months ended June 30, 2014 and 2013.
	The notional amount of these contracts was $71.8 million at June 30, 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 June 30, 2014 the amount remaining in Accumulated other comprehensive income (loss) was a loss of $0.3 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 expense and other, 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 $11.9 million and $11.7 million in derivative instruments that were non-designated hedges at June 30, 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 June 30, 2014 and December 31, 2013:
	(in thousands)	June 30,			December 31,
		2014			2013
	Derivative assets:
	Foreign currency contracts designated as cash flow hedges	$	304		$	162
	Derivatives not designated as hedging instruments	100			169
	Total derivative assets	$	404		$	331
	Derivative liabilities:
	Foreign currency contracts designated as cash flow hedges	$	115		$	57
	Derivatives not designated as hedging instruments	44			46
	Total derivative liabilities	$	159		$	103
	The effects of derivatives designated as hedging instruments on our condensed consolidated statements of operations were as follows for the three and six months ended June 30, 2014 and 2013:
		Three months ended						Six months ended
		June 30,						June 30,
	(in thousands)	2014			2013			2014			2013
	Amount of gain (loss) recognized in Accumulated other comprehensive income (loss) on derivatives (effective portion)	$	342		$	(146	)	$	453		$	(1,104	)
	Amount and location of gain (loss) reclassified from Accumulated other comprehensive income (loss) into earnings (effective portion)
	Cost of support and services	$	(44	)	$	(79	)	$	(101	)	$	(115	)
	Sales and marketing	(173		)	(252		)	(432		)	(379		)
	Research and development	(33		)	(35		)	(93		)	(67		)
	General and administrative	(7		)	(16		)	(21		)	(29		)
	Total	$	(257	)	$	(382	)	$	(647	)	$	(590	)
	Amount and location of gain recognized in earnings on derivatives
	Interest expense and other, net	$	60		$	25		$	91		$	40
	The effects of derivatives not designated as hedging instruments on our condensed consolidated statements of operations were as follows for the three and six months ended June 30, 2014 and 2013:
		Three months ended						Six months ended
		June 30,						June 30,
	(in thousands)	2014			2013			2014			2013
	Interest expense and other, net	$	61		$	(48	)	$	137		$	(277	)
	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 June 30, 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	6 Months Ended
	Jun. 30, 2014
Borrowings [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 June 30, 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 June 30, 2014.
	As of June 30, 2014 the outstanding borrowings were $517.5 million. For the three and six months ended June 30, 2014, interest incurred pursuant to the 2013 Credit Facility was $2.8 million and $5.7 million, respectively. For the three and six months ended June 30, 2013, interest incurred pursuant to a credit facility entered into in 2012 (and paid off in connection with entering into the 2013 Credit Facility) was $5.8 million and $12.1 million, respectively.
	The following table summarizes the future minimum principal payments on the portion of the 2013 Credit Facility outstanding as of June 30, 2014:
	Fiscal year	(in thousands)
	2014 (the six months ending December 31, 2014)	$	7,500
	2015	15,000
	2016	30,000
	2017	30,000
	2018	435,000
	Total	$	517,500

Common_Stock

Common Stock	6 Months Ended
	Jun. 30, 2014
Share-based Compensation [Abstract]	'
Common Stock	'
	COMMON STOCK
	Stock-Based Compensation Expense
	The following table summarizes stock-based compensation expense for stock options, restricted stock units (RSUs) and the 2006 Employee Stock Purchase Plan (the Purchase Plan) recorded in our condensed consolidated statement of operations for the three and six months ended June 30, 2014 and 2013:
		Three months ended				Six months ended
		June 30,				June 30,
	(in thousands)	2014		2013		2014		2013
	Cost of product	$	383	$	311	$	714	$	567
	Cost of support and services	2,266		2,389		4,401		4,217
	Sales and marketing	8,171		10,191		17,673		21,055
	Research and development	7,074		9,121		13,862		16,668
	General and administrative	3,678		3,517		6,671		7,548
	Total	$	21,572	$	25,529	$	43,321	$	50,055
	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 June 30, 2014, we repurchased 3,784,600 shares of common stock under the Program on the open market for an aggregate purchase price of $75.0 million, or a weighted average of $19.83 per share. For the six months ended June 30, 2014, we repurchased 5,020,678 shares of common stock under the Program on the open market for an aggregate purchase price of $100.0 million, or a weighted average of $19.93 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. As of June 30, 2014, $287.7 million. remained available for share repurchase under the Program.
	For the three months ended June 30, 2013, we repurchased 3,207,878 shares of common stock under the Program for an aggregate purchase price of $50.0 million, or weighted-average of $15.60 per share. For the six months ended June 30, 2013, we repurchased 4,820,942 shares of common stock under the Program for an aggregate purchase price of $75.1 million, or weighted-average of $15.57 per share.

Income_Taxes

Income Taxes	6 Months Ended
	Jun. 30, 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 30.6% and (2.4)% for the three months ended June 30, 2014 and 2013, respectively. The effective tax rate was 34.5% and 25.9% for the six months ended June 30, 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 June 30, 2014 and 2013 was $3.0 million and $0.4 million, respectively. The provision for (benefit from) income taxes for the six months ended June 30, 2014 and 2013 was $5.3 million and $(8.6) million, respectively.
	Our effective tax rate for the three and six months ended June 30, 2014, 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, and the domestic production activities deduction.
	Our effective tax rate for the three and six months ended June 30, 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. In the second quarter of 2013, we recorded a discrete tax benefit of $6.2 million as a result of a change in tax status of one of our subsidiaries, acquired from OPNET Technologies, Inc. (OPNET).

Accumulated_Other_Comprehensiv

Accumulated Other Comprehensive Income (Loss)	6 Months Ended
	Jun. 30, 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	52			16			(831		)	(763		)
	Amounts reclassified from accumulated other comprehensive income (loss)	(2		)	—			647			645
	Net current-period other comprehensive income (loss)	50			16			(184		)	(118		)
	Balance as of June 30, 2014	$	20		$	(43	)	$	321		$	298
	Amounts reclassified from Accumulated other comprehensive income (loss), net to Net income (loss) for unrealized gains or losses on investments are recorded in Interest expense and other, 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	6 Months Ended
	Jun. 30, 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 SteelApp (formerly Stingray) virtual application delivery controllers (ADCs), and our SteelStore (formerly Whitewater) cloud storage delivery products. Performance Management includes our SteelCentral performance management and control suite. The Performance Management product line combines our former Cascade products and the products acquired from OPNET.
	The following table presents revenue by product line:
		Three months ended				Six months ended
		June 30,				June 30,
	(in thousands)	2014		2013		2014		2013
	Revenue:
	Application Acceleration	$	205,037	$	196,506	$	409,493	$	381,468
	Performance Management	58,989		53,404		119,949		114,581
	Total revenue	$	264,026	$	249,910	$	529,442	$	496,049
	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				Six months ended
		June 30,				June 30,
	(in thousands)	2014		2013		2014		2013
	Americas
	United States	$	145,223	$	147,371	$	298,184	$	297,968
	Other Americas	9,521		9,479		17,378		17,024
	Total Americas	154,744		156,850		315,562		314,992
	Europe, Middle East and Africa
	United Kingdom	32,365		29,931		67,044		58,107
	Other Europe, Middle East and Africa	37,056		29,466		71,407		59,124
	Total Europe, Middle East and Africa	69,421		59,397		138,451		117,231
	Asia Pacific	39,861		33,663		75,429		63,826
	Total revenue	$	264,026	$	249,910	$	529,442	$	496,049

Legal_Matters

Legal Matters	6 Months Ended
	Jun. 30, 2014
Commitments and Contingencies Disclosure [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. 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. On July 29, 2014, the Court lifted the stay that was in place on our action against Silver Peak, though no trial date has been set. The action against us is currently stayed pending a separate U.S. Patent and Trademark Office proceeding. 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 August 31, 2015, though may be rescheduled to an earlier date pending the Court’s availability. 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 a $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 June 30, 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)	6 Months Ended
	Jun. 30, 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 June 30, 2014, the condensed consolidated statements of operations for the three and six months ended June 30, 2014 and 2013, the condensed consolidated statements of comprehensive income (loss) for the three and six months ended June 30, 2014 and 2013, and the condensed consolidated statements of cash flows for the six months ended June 30, 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) and 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 June 30, 2014, and our results of operations, comprehensive income (loss) and our cash flows for the six months ended June 30, 2014 and 2013. All adjustments are of a normal recurring nature. The results for the six months ended June 30, 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 and six months ended June 30, 2014, there have been no significant changes in our significant accounting policies from 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)	6 Months Ended
	Jun. 30, 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						Six months ended
		June 30,						June 30,
	(in thousands, except per share data)	2014			2013			2014		2013
	Net income (loss)	$	6,765		$	(16,521	)	$	10,053	$	(24,631	)
	Weighted average common shares outstanding - basic	160,580			163,995			160,385		163,681
	Dilutive effect of employee stock plans	4,070			—			4,597		—
	Weighted average common shares outstanding - diluted	164,650			163,995			164,982		163,681
	Basic net income (loss) per share	$	0.04		$	(0.10	)	$	0.06	$	(0.15	)
	Diluted net income (loss) per share	$	0.04		$	(0.10	)	$	0.06	$	(0.15	)
Antidilutive Securities Excluded From Computation Of Diluted Net Income Per Common Share	'
	:
		Three months ended					Six months ended
		June 30,					June 30,
	(in thousands)	2014		2013			2014		2013
	Total potential anti-dilutive shares of common stock	8,440		17,722			9,844		18,986

Fair_Value_Of_Assets_Tables

Fair Value Of Assets (Tables)	6 Months Ended
	Jun. 30, 2014
Assets, Fair Value Disclosure [Abstract]	'
Fair Value Measurements Of Cash, Cash Equivalents And Investments	'
	s of June 30, 2014:
	(in thousands)	Total		Level 1		Level 2
	Assets:
	Corporate bonds and notes	$	35,345	$	—	$	35,345
	U.S. government-sponsored enterprise obligations	34,070		—		34,070
	Money market funds	25,071		25,071		—
	Cash	123,125		—		—
	Total cash and cash equivalents	217,611		25,071		69,415
	Corporate bonds and notes	60,422		—		60,422
	U.S. government backed securities	30,915		30,915		—
	U.S. government-sponsored enterprise obligations	191,732		—		191,732
	FDIC-backed certificates of deposit	19,185		—		19,185
	Total investments	302,254		30,915		271,339
	Derivative assets	404		—		404
	Total assets	$	520,269	$	55,986	$	341,158
	Liabilities:
	Derivative liabilities	$	159	$	—	$	159
	Borrowings	517,500		—		517,500
	Total liabilities	$	517,659	$	—	$	517,659
	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 June 30, 2014 and December 31, 2013:
	(in thousands)	Fair Value		Unrealized		Unrealized
				Gains		Losses
	Corporate bonds and notes	$	95,767	$	2	$	(13	)
	U.S. government backed securities	30,915		23		(2		)
	U.S. government-sponsored enterprise obligations	225,802		51		(36		)
	FDIC-backed certificates of deposit	19,185		—		—
	Total available-for-sale securities at June 30, 2014	$	371,669	$	76	$	(51	)
	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)	June 30,		December 31,
		2014		2013
	Cash and cash equivalents	$	69,415	$	47,320
	Short-term investments	207,162		251,339
	Long-term investments	95,092		72,675
	Total available-for-sale securities	$	371,669	$	371,334
	Cash and cash equivalents in the table above excludes cash of $148.2 million and $160.7 million at June 30, 2014 and December 31, 2013, respectively.

Inventory_Tables

Inventory (Tables)	6 Months Ended
	Jun. 30, 2014
Inventory, Gross [Abstract]	'
Components Of Inventory	'
	Inventory is comprised of the following:
	(in thousands)	June 30,		December 31,
		2014		2013
	Raw materials	$	2,754	$	5,069
	Finished goods	12,557		15,430
	Evaluation units	2,193		4,526
	Total inventory	$	17,504	$	25,025

Lease_Commitments_Tables

Lease Commitments (Tables)	6 Months Ended
	Jun. 30, 2014
Leases [Abstract]	'
Operating Leases, Future Minimum Commitments	'
	Future minimum commitments for these operating leases in place as of June 30, 2014 with a remaining non-cancelable lease term in excess of one year are as follows:
	Fiscal year	(in thousands)
	2014 (remaining 6 months)	$	11,312
	2015	28,941
	2016	27,464
	2017	25,560
	2018	23,813
	Thereafter	93,788
	Total	$	210,878

Derivative_Financial_Instrumen1

Derivative Financial Instruments (Tables)	6 Months Ended
	Jun. 30, 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 June 30, 2014 and December 31, 2013:
	(in thousands)	June 30,			December 31,
		2014			2013
	Derivative assets:
	Foreign currency contracts designated as cash flow hedges	$	304		$	162
	Derivatives not designated as hedging instruments	100			169
	Total derivative assets	$	404		$	331
	Derivative liabilities:
	Foreign currency contracts designated as cash flow hedges	$	115		$	57
	Derivatives not designated as hedging instruments	44			46
	Total derivative liabilities	$	159		$	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 and six months ended June 30, 2014 and 2013:
		Three months ended						Six months ended
		June 30,						June 30,
	(in thousands)	2014			2013			2014			2013
	Amount of gain (loss) recognized in Accumulated other comprehensive income (loss) on derivatives (effective portion)	$	342		$	(146	)	$	453		$	(1,104	)
	Amount and location of gain (loss) reclassified from Accumulated other comprehensive income (loss) into earnings (effective portion)
	Cost of support and services	$	(44	)	$	(79	)	$	(101	)	$	(115	)
	Sales and marketing	(173		)	(252		)	(432		)	(379		)
	Research and development	(33		)	(35		)	(93		)	(67		)
	General and administrative	(7		)	(16		)	(21		)	(29		)
	Total	$	(257	)	$	(382	)	$	(647	)	$	(590	)
	Amount and location of gain recognized in earnings on derivatives
	Interest expense and other, net	$	60		$	25		$	91		$	40
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 and six months ended June 30, 2014 and 2013:
		Three months ended						Six months ended
		June 30,						June 30,
	(in thousands)	2014			2013			2014			2013
	Interest expense and other, net	$	61		$	(48	)	$	137		$	(277	)

Borrowings_Tables

Borrowings (Tables)	6 Months Ended
	Jun. 30, 2014
Borrowings [Abstract]	'
Schedule of Maturities of Long-term Debt	'
	The following table summarizes the future minimum principal payments on the portion of the 2013 Credit Facility outstanding as of June 30, 2014:
	Fiscal year	(in thousands)
	2014 (the six months ending December 31, 2014)	$	7,500
	2015	15,000
	2016	30,000
	2017	30,000
	2018	435,000
	Total	$	517,500

Common_Stock_Tables

Common Stock (Tables)	6 Months Ended
	Jun. 30, 2014
Share-based Compensation [Abstract]	'
Summary Of Stock-Based Compensation Expense	'
	The following table summarizes stock-based compensation expense for stock options, restricted stock units (RSUs) and the 2006 Employee Stock Purchase Plan (the Purchase Plan) recorded in our condensed consolidated statement of operations for the three and six months ended June 30, 2014 and 2013:
		Three months ended				Six months ended
		June 30,				June 30,
	(in thousands)	2014		2013		2014		2013
	Cost of product	$	383	$	311	$	714	$	567
	Cost of support and services	2,266		2,389		4,401		4,217
	Sales and marketing	8,171		10,191		17,673		21,055
	Research and development	7,074		9,121		13,862		16,668
	General and administrative	3,678		3,517		6,671		7,548
	Total	$	21,572	$	25,529	$	43,321	$	50,055

Accumulated_Other_Comprehensiv1

Accumulated Other Comprehensive Income (Loss) (Tables)	6 Months Ended
	Jun. 30, 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	52			16			(831		)	(763		)
	Amounts reclassified from accumulated other comprehensive income (loss)	(2		)	—			647			645
	Net current-period other comprehensive income (loss)	50			16			(184		)	(118		)
	Balance as of June 30, 2014	$	20		$	(43	)	$	321		$	298

Segment_Information_Tables

Segment Information (Tables)	6 Months Ended
	Jun. 30, 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 SteelApp (formerly Stingray) virtual application delivery controllers (ADCs), and our SteelStore (formerly Whitewater) cloud storage delivery products. Performance Management includes our SteelCentral performance management and control suite. The Performance Management product line combines our former Cascade products and the products acquired from OPNET.
	The following table presents revenue by product line:
		Three months ended				Six months ended
		June 30,				June 30,
	(in thousands)	2014		2013		2014		2013
	Revenue:
	Application Acceleration	$	205,037	$	196,506	$	409,493	$	381,468
	Performance Management	58,989		53,404		119,949		114,581
	Total revenue	$	264,026	$	249,910	$	529,442	$	496,049
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				Six months ended
		June 30,				June 30,
	(in thousands)	2014		2013		2014		2013
	Americas
	United States	$	145,223	$	147,371	$	298,184	$	297,968
	Other Americas	9,521		9,479		17,378		17,024
	Total Americas	154,744		156,850		315,562		314,992
	Europe, Middle East and Africa
	United Kingdom	32,365		29,931		67,044		58,107
	Other Europe, Middle East and Africa	37,056		29,466		71,407		59,124
	Total Europe, Middle East and Africa	69,421		59,397		138,451		117,231
	Asia Pacific	39,861		33,663		75,429		63,826
	Total revenue	$	264,026	$	249,910	$	529,442	$	496,049

Net_Income_Loss_Per_Common_Sha2

Net Income (Loss) Per Common Share (Computation Of Net Income Per Share) (Details) (USD $)	3 Months Ended		6 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Earnings Per Share [Abstract]	'	'	'	'
Net income (loss)	$6,765	($16,521)	$10,053	($24,631)
Weighted average common shares outstanding - basic	160,580	163,995	160,385	163,681
Dilutive effect of employee stock plans	4,070	0	4,597	0
Weighted average common shares outstanding - diluted	164,650	163,995	164,982	163,681
Basic net income (loss) per share (in usd per share)	$0.04	($0.10)	$0.06	($0.15)
Diluted net income (loss) per share (in usd per share)	$0.04	($0.10)	$0.06	($0.15)

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		6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Earnings Per Share [Abstract]	'	'	'	'
Total potential anti-dilutive shares of common stock	8,440	17,722	9,844	18,986

Fair_Value_Of_Assets_Narrative

Fair Value Of Assets (Narrative) (Details) (USD $)	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 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	$217,611,000	$208,022,000	$218,663,000	$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 $)	3 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale Securities	$371,669	$371,334
Available-for-sale Securities, Gross Unrealized Gain	76	64
Available-for-sale Securities, Gross Unrealized Loss	51	56
Total cash and cash equivalents	217,611	208,022
Total investments	302,254	324,014
Derivative asset	404	331
Assets, Fair Value Disclosure, Recurring	520,269	532,367
Derivative liabilities	159	103
Borrowings	517,500	525,000
Liabilities, Fair Value Disclosure, Recurring	517,659	525,103
Level 1 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total cash and cash equivalents	25,071	30,009
Total investments	30,915	23,210
Derivative asset	'	'
Assets, Fair Value Disclosure, Recurring	55,986	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	69,415	47,320
Total investments	271,339	300,804
Derivative asset	404	331
Assets, Fair Value Disclosure, Recurring	341,158	348,455
Derivative liabilities	159	103
Borrowings	517,500	525,000
Liabilities, Fair Value Disclosure, Recurring	517,659	525,103
Corporate Bonds And Notes [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale Securities	95,767	103,193
Total cash and cash equivalents	35,345	28,545
Total investments	60,422	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	35,345	28,545
Total investments	60,422	74,648
Corporate Bonds And Notes [Member] | Unrealized Gains [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale Securities, Gross Unrealized Gain	2	1
Corporate Bonds And Notes [Member] | Unrealized Losses [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale Securities, Gross Unrealized Loss	13	24
Certificates of Deposit [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale Securities	19,185	15,062
Total investments	19,185	15,062
Certificates of Deposit [Member] | Level 1 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total investments	'	'
Certificates of Deposit [Member] | Level 2 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total investments	19,185	15,062
Certificates of Deposit [Member] | Unrealized Gains [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale Securities, Gross Unrealized Gain	0	1
Certificates of Deposit [Member] | Unrealized Losses [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale Securities, Gross Unrealized Loss	0	0
US Government-sponsored Enterprises Debt Securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale Securities	225,802	229,869
Total cash and cash equivalents	34,070	18,775
Total investments	191,732	211,094
US Government-sponsored Enterprises Debt Securities [Member] | Level 1 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total cash and cash equivalents	'	'
Total investments	'	'
US Government-sponsored Enterprises Debt Securities [Member] | Level 2 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total cash and cash equivalents	34,070	18,775
Total investments	191,732	211,094
US Government-sponsored Enterprises Debt Securities [Member] | Unrealized Gains [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale Securities, Gross Unrealized Gain	51	55
US Government-sponsored Enterprises Debt Securities [Member] | Unrealized Losses [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale Securities, Gross Unrealized Loss	36	30
US Government Debt Securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total investments	30,915	23,210
US Government Debt Securities [Member] | Level 1 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total investments	30,915	23,210
US Government Debt Securities [Member] | Level 2 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total investments	'	'
Money Market Funds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total cash and cash equivalents	25,071	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	25,071	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	'	'

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	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2013	Dec. 31, 2012
Gross Unrealized Gains (Losses) [Line Items]	'	'	'	'
Cash and Cash Equivalents, at Carrying Value	$217,611	$208,022	$218,663	$280,509
Fair Value	371,669	371,334	'	'
Available-for-sale Securities, Gross Unrealized Gain	76	64	'	'
Unrealized Losses	-51	-56	'	'
Short-term Investments	207,162	251,339	'	'
Long-term Investments	95,092	72,675	'	'
Cash [Member]	'	'	'	'
Gross Unrealized Gains (Losses) [Line Items]	'	'	'	'
Cash and Cash Equivalents, at Carrying Value	148,200	160,700	'	'
Cash Equivalents [Member]	'	'	'	'
Gross Unrealized Gains (Losses) [Line Items]	'	'	'	'
Cash and Cash Equivalents, at Carrying Value	69,415	47,320	'	'
US Government Agencies Debt Securities [Member]	'	'	'	'
Gross Unrealized Gains (Losses) [Line Items]	'	'	'	'
Fair Value	30,915	23,210	'	'
US Government Agencies Debt Securities [Member] | Unrealized Gains [Member]	'	'	'	'
Gross Unrealized Gains (Losses) [Line Items]	'	'	'	'
Available-for-sale Securities, Gross Unrealized Gain	23	7	'	'
US Government Agencies Debt Securities [Member] | Unrealized Losses [Member]	'	'	'	'
Gross Unrealized Gains (Losses) [Line Items]	'	'	'	'
Unrealized Losses	-2	-2	'	'
Certificates of Deposit [Member]	'	'	'	'
Gross Unrealized Gains (Losses) [Line Items]	'	'	'	'
Fair Value	19,185	15,062	'	'
Certificates of Deposit [Member] | Unrealized Gains [Member]	'	'	'	'
Gross Unrealized Gains (Losses) [Line Items]	'	'	'	'
Available-for-sale Securities, Gross Unrealized Gain	0	1	'	'
Certificates of Deposit [Member] | Unrealized Losses [Member]	'	'	'	'
Gross Unrealized Gains (Losses) [Line Items]	'	'	'	'
Unrealized Losses	0	0	'	'
Corporate Bonds And Notes [Member]	'	'	'	'
Gross Unrealized Gains (Losses) [Line Items]	'	'	'	'
Fair Value	95,767	103,193	'	'
Corporate Bonds And Notes [Member] | Unrealized Gains [Member]	'	'	'	'
Gross Unrealized Gains (Losses) [Line Items]	'	'	'	'
Available-for-sale Securities, Gross Unrealized Gain	2	1	'	'
Corporate Bonds And Notes [Member] | Unrealized Losses [Member]	'	'	'	'
Gross Unrealized Gains (Losses) [Line Items]	'	'	'	'
Unrealized Losses	-13	-24	'	'
US Government-sponsored Enterprises Debt Securities [Member]	'	'	'	'
Gross Unrealized Gains (Losses) [Line Items]	'	'	'	'
Fair Value	225,802	229,869	'	'
US Government-sponsored Enterprises Debt Securities [Member] | Unrealized Gains [Member]	'	'	'	'
Gross Unrealized Gains (Losses) [Line Items]	'	'	'	'
Available-for-sale Securities, Gross Unrealized Gain	51	55	'	'
US Government-sponsored Enterprises Debt Securities [Member] | Unrealized Losses [Member]	'	'	'	'
Gross Unrealized Gains (Losses) [Line Items]	'	'	'	'
Unrealized Losses	($36)	($30)	'	'

Inventory_Components_Of_Invent

Inventory (Components Of Inventory) (Details) (USD $)	Jun. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Inventory, Gross [Abstract]	'	'
Raw materials	$2,754	$5,069
Finished goods	12,557	15,430
Evaluation units	2,193	4,526
Total inventory	$17,504	$25,025

Lease_Commitments_Details

Lease Commitments (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Leases [Abstract]	'	'	'	'
2014 (the six months ending December 31)	$11,312,000	'	$11,312,000	'
2015	28,941,000	'	28,941,000	'
2016	27,464,000	'	27,464,000	'
2017	25,560,000	'	25,560,000	'
2018	23,813,000	'	23,813,000	'
Thereafter	93,788,000	'	93,788,000	'
Total	210,878,000	'	210,878,000	'
Rent expense under operating leases	$7,200,000	$5,200,000	$14,800,000	$10,300,000

Derivative_Financial_Instrumen2

Derivative Financial Instruments (Narrative) (Details) (USD $)	Jun. 30, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'	'
Derivative, Notional Amount	$71.80	$49
Foreign currency derivative instruments not designated as hedging instruments at fair value, net	$11.90	$11.70

Derivative_Financial_Instrumen3

Derivative Financial Instruments (Fair Value of Derivative Instruments, Balance Sheet) (Details) (USD $)	Jun. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Derivative [Line Items]	'	'
Derivative Assets	$404	$331
Derivative Liabilities	159	103
Foreign currency contracts designated as cash flow hedges	'	'
Derivative [Line Items]	'	'
Derivative Assets	304	162
Derivative Liabilities	115	57
Derivatives not designated as hedging instruments	'	'
Derivative [Line Items]	'	'
Derivative Assets	100	169
Derivative Liabilities	$44	$46

Derivative_Financial_Instrumen4

Derivative Financial Instruments (Fair Value of Derivative Instruments, Statement of Income) (Details) (USD $)	3 Months Ended		6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Derivative Instruments, Gain (Loss) [Line Items]	'	'	'	'
Amount of Gain (Loss) Recognized in Accumulated OCI on Derivatives (Effective Portion)	$342	($146)	$453	($1,104)
Amount and Location of Gain (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	-257	-382	-647	-590
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)	-44	-79	-101	-115
Sales and Marketing	'	'	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'	'	'
Amount and Location of Gain (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	-173	-252	-432	-379
Research and Development	'	'	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'	'	'
Amount and Location of Gain (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	-33	-35	-93	-67
General and Administrative	'	'	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'	'	'
Amount and Location of Gain (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	-7	-16	-21	-29
Interest expense and other, 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)	$60	$25	$91	$40

Derivative_Financial_Instrumen5

Derivative Financial Instruments (Effects of Derivatives not Designated as Hedges) (Details) (Derivatives not designated as hedging instruments, Interest expense and other, net [Member], USD $)	3 Months Ended		6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Derivatives not designated as hedging instruments | Interest expense and other, net [Member]	'	'	'	'
Derivative [Line Items]	'	'	'	'
Interest expense and other, net	$61	($48)	$137	($277)

Borrowings_Details

Borrowings (Details) (USD $)	3 Months Ended				6 Months Ended
	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2013	Dec. 31, 2012	Jun. 30, 2014	Jun. 30, 2013
Debt Instrument [Line Items]	'	'	'	'	'	'
Debt instrument, loan term	'	'5 years	'	'	'	'
Debt Issuance Cost	'	'	'	$4,200,000	'	'
Line of Credit Facility, Maximum Borrowing Capacity	'	600,000,000	'	'	'	'
Debt instrument, current interest rate	2.00%	'	'	'	2.00%	'
Debt instrument, periodic payment, percentage of initial loan value	'	'	'	'	'0.05	'
Interest expense	2,800,000	'	5,800,000	'	5,700,000	12,100,000
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months	7,500,000	'	'	'	7,500,000	'
Long-term Debt, Maturities, Repayments of Principal in Year Two	15,000,000	'	'	'	15,000,000	'
Long-term Debt, Maturities, Repayments of Principal in Year Three	30,000,000	'	'	'	30,000,000	'
Long-term Debt, Maturities, Repayments of Principal in Year Four	30,000,000	'	'	'	30,000,000	'
Long-term Debt, Maturities, Repayments of Principal in Year Five	435,000,000	'	'	'	435,000,000	'
Debt, Long-term and Short-term, Combined Amount	517,500,000	'	'	'	517,500,000	'
Credit Facility [Domain]	'	'	'	'	'	'
Debt Instrument [Line Items]	'	'	'	'	'	'
Line of Credit Facility, Amount Outstanding	225,000,000	'	'	'	225,000,000	'
Line of Credit Facility, Maximum Borrowing Capacity	300,000,000	'	'	'	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 instrument, face amount	300,000,000	'	'	'	300,000,000	'
Debt, Long-term and Short-term, Combined Amount	$0	'	'	'	$0	'
London Interbank Offered Rate (LIBOR) [Member]	'	'	'	'	'	'
Debt Instrument [Line Items]	'	'	'	'	'	'
Debt instrument, basis spread on variable rate	1.75%	'	'	'	'	'

Common_Stock_Summary_Of_StockB

Common Stock (Summary Of Stock-Based Compensation Expense) (Details) (USD $)	3 Months Ended		6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'
Share-based Compensation	$21,572	$25,529	$43,321	$50,055
Cost of Goods, Total [Member]	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'
Share-based Compensation	383	311	714	567
Cost Of Support And Services [Member]	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'
Share-based Compensation	2,266	2,389	4,401	4,217
Selling and Marketing Expense [Member]	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'
Share-based Compensation	8,171	10,191	17,673	21,055
Research and Development Expense [Member]	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'
Share-based Compensation	7,074	9,121	13,862	16,668
General and Administrative Expense [Member]	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'
Share-based Compensation	$3,678	$3,517	$6,671	$7,548

Common_Stock_Narrative_Details

Common Stock (Narrative) (Details) (USD $)	0 Months Ended				3 Months Ended		6 Months Ended
In Millions, except Share data, unless otherwise specified	Mar. 05, 2014	Aug. 19, 2013	17-May-12	Aug. 19, 2011	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Class of Stock [Line Items]	'	'	'	'	'	'	'	'
Stock Repurchase Program, Authorized Amount	'	'	'	$150	'	'	'	'
Stock Repurchase Program, Increased Authorized Amount	250	200	150	'	'	'	'	'
Stock Repurchased During Period, Shares	'	'	'	'	3,784,600	3,207,878	5,020,678	4,820,942
Stock Repurchased During Period, Value	'	'	'	'	75	50	100	75.1
Weighted Average Purchase Price Per Share	'	'	'	'	19.83	15.6	19.93	15.57
Share Repurchase Program [Member]	'	'	'	'	'	'	'	'
Class of Stock [Line Items]	'	'	'	'	'	'	'	'
Stock Repurchase Program, Remaining Authorized Repurchase Amount	'	'	'	'	$287.70	'	'	'

Income_Taxes_Narrative_Details

Income Taxes (Narrative) (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Income Tax Expense (Benefit), Continuing Operations [Abstract]	'	'	'	'
Effective tax rate	30.60%	-2.40%	34.50%	25.90%
Income tax expense (benefit)	$2,988,000	$387,000	$5,306,000	($8,602,000)
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount	'	$6,200,000	'	'

Accumulated_Other_Comprehensiv2

Accumulated Other Comprehensive Income (Loss) (Details) (USD $)	3 Months Ended		6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'	'	'
Accumulated Other Comprehensive Income (Loss), Net of Tax	$298	'	$298	'	$416
Other comprehensive income before reclassifications	'	'	-763	'	'
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	'	'	645	'	'
Unrealized gain (loss) on investments, net of tax	-5	-73	50	-232	'
Foreign currency translation adjustment	-15	-83	16	-716	'
Derivative instruments gain (loss), net of tax	81	224	-184	-489	'
Other Comprehensive Income (Loss), Net of Tax	'	'	-118	'	'
Accumulated Net Unrealized Investment Gain (Loss) [Member]	'	'	'	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'	'	'
Other comprehensive income before reclassifications	'	'	52	'	'
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	'	'	-2	'	'
Accumulated Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax	20	'	20	'	-30
Accumulated Net Unrealized Foreign Currency Gains (Losses) [Member]	'	'	'	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'	'	'
Other comprehensive income before reclassifications	'	'	16	'	'
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	'	'	0	'	'
Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Net of Tax	-43	'	-43	'	-59
Accumulated Net Unrealized Derivative Gains (Losses) [Member]	'	'	'	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'	'	'
Other comprehensive income before reclassifications	'	'	-831	'	'
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	'	'	647	'	'
Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, Effect Net of Tax	$321	'	$321	'	$505

Segment_Information_Segment_In

Segment Information (Segment Information, by Product Line) (Details) (USD $)	3 Months Ended		6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Revenue:	'	'	'	'
Revenue	$264,026	$249,910	$529,442	$496,049
Application Acceleration [Member]	'	'	'	'
Revenue:	'	'	'	'
Revenue	205,037	196,506	409,493	381,468
Performance Management [Member]	'	'	'	'
Revenue:	'	'	'	'
Revenue	$58,989	$53,404	$119,949	$114,581

Segment_Information_Segment_In1

Segment Information (Segment Information, Revenue By Geographic Area) (Details) (USD $)	3 Months Ended		6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Segment Reporting Information [Line Items]	'	'	'	'
Total revenue	$264,026	$249,910	$529,442	$496,049
United States [Member]	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Total revenue	145,223	147,371	298,184	297,968
Other Americas [Member]	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Total revenue	9,521	9,479	17,378	17,024
Total Americas [Member]	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Total revenue	154,744	156,850	315,562	314,992
United Kingdom [Member]	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Total revenue	32,365	29,931	67,044	58,107
Other Europe Middle East And Africa [Member]	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Total revenue	37,056	29,466	71,407	59,124
Total Europe, Middle East And Africa [Member]	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Total revenue	69,421	59,397	138,451	117,231
Asia Pacific [Member]	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Total revenue	$39,861	$33,663	$75,429	$63,826

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	'	'	'