Ixia (XXIA) 10-Q 8 May 15 2015 Q1 Quarterly report Financial data

Document_And_Entity_Informatio

Document And Entity Information	3 Months Ended
	Mar. 31, 2015	4-May-15
Document and Entity Information [Abstract]
Entity Registrant Name	Ixia
Document Type	10-Q
Current Fiscal Year End Date	-19
Entity Common Stock, Shares Outstanding		79,426,827
Amendment Flag	FALSE
Entity Central Index Key	1120295
Entity Filer Category	Large Accelerated Filer
Document Period End Date	31-Mar-15
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q1

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Current assets:
Cash and cash equivalents	$72,140	$46,394
Restricted cash	10,000	0
Marketable securities	33,740	79,760
Marketable securities, restricted	80,000	0
Accounts receivable, net of allowances of $694 and $1,011, as of March 31, 2015 and December 31, 2014, respectively	90,755	99,528
Inventories	36,811	44,826
Prepaid expenses and other current assets	48,180	47,077
Total current assets	371,626	317,585
Property and equipment, net	38,444	37,648
Intangible assets, net	134,411	145,108
Goodwill	338,873	338,873
Other assets	27,585	30,697
Total assets	910,939	869,911
Current liabilities:
Accounts payable	12,178	16,902
Accrued expenses and other	46,760	45,271
Deferred revenues	107,392	100,170
Convertible senior notes	200,000	200,000
Term loan	2,000	0
Total current liabilities	368,330	362,343
Deferred revenues	17,601	18,046
Other liabilities	9,812	8,431
Term loan	38,000	0
Total liabilities	433,743	388,820
Commitments and contingencies (Note 11)
Shareholders’ equity:
Common stock, without par value; 200,000 shares authorized at March 31, 2015 and December 31, 2014; 78,866 and 78,575 shares issued and outstanding as of March 31, 2015 and December 31, 2014, respectively	188,048	187,397
Additional paid-in capital	211,908	206,913
Retained earnings	77,963	87,574
Accumulated other comprehensive loss	-723	-793
Total shareholders’ equity	477,196	481,091
Total liabilities and shareholders’ equity	$910,939	$869,911

Condensed_Consolidated_Balance1

Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, except Per Share data, unless otherwise specified
Statement of Financial Position [Abstract]
Allowance for doubtful accounts receivable	$694	$1,011
Common stock, shares authorized	200,000	200,000
Common stock, shares issued	78,866	78,575
Common stock, shares outstanding	78,866	78,575
Common stock, without par value (in dollars per share)	$0	$0

Condensed_Consolidated_Stateme

Condensed Consolidated Statements of Operations (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2015		Mar. 31, 2014
Revenues:
Products	$85,904		$81,165
Services	35,058		32,568
Total revenues	120,962		113,733
Costs and operating expenses:
Cost of revenues – products	24,051	[1]	25,411	[1]
Cost of revenues – services	4,516		3,948
Research and development	27,626		30,035
Sales and marketing	37,521		38,839
General and administrative	18,371		17,882
Amortization of intangible assets	10,923		12,635
Acquisition and other related	582		1,932
Restructuring	-210		3,564
Total costs and operating expenses	123,380	[2]	134,246	[2]
Loss from operations	-2,418		-20,513
Interest income and other, net	-481		337
Interest expense	-2,147		-1,943
Loss before income taxes	-5,046		-22,119
Income tax expense (benefit)	4,565		-2,647
Net loss	-9,611		-19,472
Loss per share:
Basic (in dollars per share)	($0.12)		($0.25)
Diluted (in dollars per share)	($0.12)		($0.25)
Weighted average number of common and common equivalent shares outstanding:
Basic	78,706		76,951
Diluted	78,706		76,951
Cost of revenues - products
Weighted average number of common and common equivalent shares outstanding:
Allocated Share-based Compensation Expense	95		48
Cost of revenues - services
Weighted average number of common and common equivalent shares outstanding:
Allocated Share-based Compensation Expense	36		18
Research and development
Weighted average number of common and common equivalent shares outstanding:
Allocated Share-based Compensation Expense	2,093		1,879
Sales and marketing
Weighted average number of common and common equivalent shares outstanding:
Allocated Share-based Compensation Expense	1,049		1,928
General and administrative
Weighted average number of common and common equivalent shares outstanding:
Allocated Share-based Compensation Expense	$1,874		$945
[1]	Cost of revenues – products excludes amortization of intangible assets related to purchased technologies of $6.4 million and $8.1 million for the three months ended March 31, 2015 and 2014, respectively, which are included in Amortization of intangible assets.
[2]	Stock-based compensation included in: Cost of revenues - products 2015: $95 ; 2014: $48 Cost of revenues - services 2015: $36 ; 2014: $18 Research and development 2015: $2,093 ; 2014: $1,879 Sales and marketing 2015: $1,049 ; 2014: $1,928 General and administrative: 2015: $1,874 ; 2014: $945

Condensed_Consolidated_Stateme1

Condensed Consolidated Statements of Operations (Parenthetical) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Income Statement [Abstract]
Cost of revenues - excluded amortization of intangible assets	$6.40	$8.10

Condensed_Consolidated_Stateme2

Condensed Consolidated Statements of Comprehensive (Loss) Income (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Statement of Comprehensive Income [Abstract]
Net loss	($9,611)	($19,472)
Unrealized gain on investments, net of tax	75	34
Foreign currency translation adjustment	-5	135
Other comprehensive gain	70	169
Comprehensive loss	($9,541)	($19,303)

Condensed_Consolidated_Stateme3

Condensed Consolidated Statements of Cash Flows (Unaudited) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Cash flows from operating activities:
Net loss	($9,611)	($19,472)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation	4,161	3,963
Amortization of intangible assets	10,923	12,635
Realized gain on available-for-sale securities	-29	-18
Stock-based compensation	5,147	4,818
Deferred income taxes	-849	-405
Amortization of deferred issuance costs	335	300
Amortization of investment premiums	12	0
Changes in operating assets and liabilities, net of effect of acquisitions:
Accounts receivable, net	8,773	5,053
Inventories	5,429	797
Prepaid expenses and other current assets	-636	-4,298
Other assets	3,921	3,079
Accounts payable	-4,453	-3,936
Accrued expenses and other	1,797	-2,443
Deferred revenues	6,777	6,675
Other liabilities	1,705	814
Net cash provided by operating activities	33,402	7,562
Cash flows from investing activities:
Purchases of property and equipment	-2,955	-1,718
Purchases of marketable securities	-89,869	-22,172
Proceeds from marketable securities	55,980	18,466
Increase in restricted cash	-10,000	0
Purchases of other intangible assets	-226	-129
Payments in connection with acquisitions, net of cash acquired	0	-895
Net cash used in investing activities	-47,070	-6,448
Cash flows from financing activities:
Proceeds from exercise of stock options	651	1,084
Proceeds from borrowings under term loan	40,000	0
Debt issuance costs	-1,237	0
Net cash provided by financing activities	39,414	1,084
Net increase in cash and cash equivalents	25,746	2,198
Cash and cash equivalents at beginning of period	46,394
Cash and cash equivalents at end of period	72,140
Supplemental disclosure of non-cash investing activities:
Purchased and unpaid property and equipment	509	1,097
Transfers of inventory to property and equipment	$2,586	$2,593

Business

Business	3 Months Ended
	Mar. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Business	Business
	Ixia ("Ixia" or the "Company") was incorporated on May 27, 1997 as a California corporation. Ixia provides application performance and security resilience solutions so that organizations can validate, secure and optimize their physical and virtual networks. Enterprises, service providers, network equipment manufacturers and governments worldwide rely on Ixia’s solutions to deploy new technologies and achieve efficient, secure ongoing operation of their networks. Our product solutions consist of our hardware platforms, such as our chassis, interface cards and appliances, software application tools, and services, including our warranty and maintenance offerings and professional services. We operated within one business segment during the periods presented in the accompanying condensed consolidated financial statements.

Basis_of_Presentation_Signific

Basis of Presentation, Significant Accounting Policies and Recent Accounting Pronouncements	3 Months Ended
	Mar. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation, Significant Accounting Policies and Recent Accounting Pronouncements	Basis of Presentation, Significant Accounting Policies and Recent Accounting Pronouncements
	Basis of Presentation
	The accompanying condensed consolidated financial statements as of March 31, 2015 and for the three months ended March 31, 2015 and 2014, are unaudited and reflect all adjustments (consisting only of normal recurring adjustments) which are, in the opinion of management, necessary for a fair statement of our financial position, operating results, and cash flows for the interim periods presented. The results of operations for the three months ended March 31, 2015 presented are not necessarily indicative of results to be expected for the full year ending December 31, 2015 or any other future period.
	These condensed consolidated financial statements have been prepared in accordance with the rules and regulations of the Securities and Exchange Commission (the "SEC"). Certain information and footnote disclosures normally included in financial statements prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) have been condensed or omitted pursuant to such rules and regulations. The condensed consolidated balance sheet as of December 31, 2014 has been derived from our audited consolidated financial statements included in our Annual Report on Form 10-K for the year ended December 31, 2014 (the “2014 Form 10-K"), but does not include all disclosures required by GAAP. These condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and related notes included in our 2014 Form 10-K.
	Significant Accounting Policies
	The Company’s significant accounting policies are set forth in Note 1 to the audited consolidated financial statements included in our 2014 Form 10-K; however, in this Form 10-Q the Company has included below new disclosures relating to the classification of cash and investments as restricted as a result of restrictions on their use under the terms of the Company’s amended and restated credit agreement entered into in March 2015, as follows:
	Restricted cash and cash equivalents and restricted marketable securities represent amounts restricted under the terms of the Company's amended and restated credit agreement for use only in the repayment of the Company's unsecured convertible senior notes due December 15, 2015. See Note 4 for additional information regarding the Company's credit agreement.
	Recent Accounting Pronouncements
	In April 2015, the Financial Accounting Standards Board (“FASB”) issued Accounting Standard Update (“ASU”) 2015-3, Interest—Imputation of Interest: Simplifying the Presentation of Debt Issuance Costs, which provides new guidance regarding the presentation of debt issuance costs. The new guidance requires debt issuance costs related to a recognized debt liability to be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. The standard will be effective for annual reporting periods beginning after December 15, 2015, including interim periods within those reporting periods. Early application is permitted. The Company is in the process of evaluating the impact of the adoption of this accounting standard update on our consolidated financial statements.
	In August 2014, the FASB issued ASU 2014-15, Presentation of Financial Statements-Going Concern: Disclosure of Uncertainties about an Entity's Ability to Continue as a Going Concern, which provides guidance about management's responsibility to evaluate whether or not there is substantial doubt about the Company's ability to continue as a going concern and to provide related footnote disclosure. The standard will be effective for annual reporting periods beginning after December 15, 2016, including interim periods within those reporting periods. Early application is permitted. The Company is in the process of evaluating the impact of the adoption of this accounting standard update on our consolidated financial statements.
	In June 2014, the FASB issued ASU 2014-12, Accounting for Share-Based Payments When the Terms of an Award Provide that a Performance Target Could Be Achieved after the Requisite Service Period, which provides new guidance regarding share-based compensation. The new guidance clarified that share-based compensation performance targets that could be achieved after the requisite service period should be treated as performance conditions that affect vesting, rather than a condition that affects the grant-date fair value of the award. The standard will be effective for annual reporting periods beginning after December 15, 2015, including interim periods within those reporting periods. Early adoption is permitted. The Company is in the process of evaluating the impact of the adoption of this accounting standard update on our consolidated financial statements.
	During May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers, which provides new guidance on the recognition of revenue and states that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The standard will be effective in annual periods beginning after December 15, 2016 and for interim and annual reporting periods thereafter. Early application is not permitted for public entities. In April 2015, the FASB proposed a one-year delay in the effective date of the standard to January 1, 2018, with an option that would permit companies to adopt the standard as early as the original effective date. Early adoption prior to the original effective date is not permitted. A final decision on the effective date is expected in 2015. The Company has not yet evaluated the impact of the adoption of this accounting standard update on its consolidated financial statements.

Restructuring_Costs

Restructuring Costs	3 Months Ended
	Mar. 31, 2015
Restructuring and Related Activities [Abstract]
Restructuring Costs	Restructuring Costs
	During the three months ended March 31, 2015 and 2014, the Company recorded restructuring charges of $0.2 million and $3.6 million, respectively. The Company’s restructuring charges include severance and other employee termination costs, lease termination costs, and other related costs, which are reported in the Restructuring line item on our condensed consolidated statements of operations. In addition, in the three months ended March 31, 2015, the Company recorded a recovery of $0.4 million in the Restructuring line item relating to the receipt of proceeds from an insurance settlement related to costs previously charged to the Restructuring line item. The timing of cash payments associated with restructuring charges depends upon the type of restructuring charge and can extend over multiple periods.
	During the first quarter of 2014, our management approved, committed to and initiated a plan to restructure our operations following our December 5, 2013 acquisition of Net Optics (the “Net Optics Restructuring”). The Net Optics Restructuring included a net reduction in force of approximately 45 positions (primarily impacting our research and development team in Israel and Santa Clara, California), which represented approximately 2.3% of our worldwide work force at that time. We have recognized cumulative restructuring charges of $3.5 million, of which $2.0 million related to employee termination benefits consisting of severance and other related employee costs, $1.1 million related to costs required to terminate our subsidiary's lease in Israel, and approximately $323,000 for other related costs. The Net Optics Restructuring was substantially completed during the second quarter of 2014, and no further charges are expected.
	During the third quarter of 2014, our management approved, committed to and implemented a company-wide initiative (“2014 Corporate Restructuring”) to restructure our operations to better align the Company’s operating costs with its business opportunities. The restructuring includes a reduction in force of approximately 96 positions across multiple business functions, which represented approximately 5% of our then worldwide work force. During 2014, we recognized cumulative restructuring charges of $6.5 million, of which $4.1 million related to one-time expenses for employee termination benefits, approximately $2.2 million for facility related charges in India and Romania, and approximately $137,000 for other related costs. The 2014 Corporate Restructuring was substantially completed during the fourth quarter of 2014, and no significant further charges are expected.
	Activities related to our restructuring plans are as follows (in thousands):
		2014 Corporate			Net Optics			Other			Total
		Restructuring			Restructuring
	Accrual at December 31, 2014	1,940			337			246			2,523
	Charges	142			19			—			161
	Payments	(469		)	(356		)	(35		)	(860		)
	Non-cash items	—			—			(108		)	(108		)
	Accrual at March 31, 2015	$	1,613		$	—		$	103		$	1,716
	At March 31, 2015, the remaining accrual related to our restructuring activities totaled $1.7 million and was included in Accrued expenses and other on our condensed consolidated balance sheets. The remaining accrual primarily relates to severance, other employee termination expenses, and lease termination costs, which are anticipated to be fully paid by the second quarter of 2015.

Debt

Debt	3 Months Ended
	Mar. 31, 2015
Debt Disclosure [Abstract]
Debt	Debt
	Unsecured Convertible Senior Notes
	On December 7, 2010, we issued $200 million in aggregate principal amount of 3.00% Convertible Senior Notes due December 15, 2015 unless earlier repurchased or converted (the “Notes”). The unsecured Notes were offered and sold only to qualified institutional buyers pursuant to Rule 144A under the Securities Act of 1933, as amended (the “Securities Act”). The Notes are governed by the terms of an indenture dated December 7, 2010 (the “Indenture”), which was filed with the SEC on December 8, 2010.
	The Notes bear interest at a rate of 3.00% per year, payable semiannually in arrears on June 15 and December 15 of each year, which payments began on June 15, 2011. We may in certain instances be required to pay additional interest in connection with any events of default relating to our failure to comply with our reporting obligations to the trustee under the Indenture and to the SEC. After any such default under the Indenture, if the trustee or the holders of at least 25% in aggregate principal amount of the Notes give us notice of, and direct us to cure, the default and the default is not cured within 60 days thereafter, then unless a waiver is obtained from the holders of more than 50% in aggregate principal amount of the Notes, an event of default will occur under the Indenture. Upon any such event of default, we may elect that for the first 180 days (or such lesser amount of time during which the event of default continues), the sole remedy be the payment of additional interest at an annual rate equal to 0.50%. In the event that such additional interest becomes payable because of our failure to timely file certain reports with the SEC and the trustee, the filing of such reports will cure the event of default and the interest rate will be reduced (so long as no other events of default then exist). If we elect to pay such additional interest and the event of default is not cured within the 180-day period, or if we do not make such an election to pay additional interest when the event of default first occurs, the trustee or the holders of at least 25% in aggregate principal amount of the Notes may declare the Notes to be due and payable immediately.
	Amortization recorded to interest expense pertaining to deferred issuance costs for the three months ended March 31, 2015 and 2014 was $300,000 and $300,000, respectively.
	The Notes are convertible at any time prior to the close of business on the third business day immediately preceding the maturity date, at the holder’s option, into shares of our common stock at an initial conversion rate of 51.4536 shares per $1,000 principal amount of Notes, which represents an initial conversion price of approximately $19.43 per share. The conversion rate is subject to adjustment for certain events that occur prior to maturity, such as a change in control transaction as defined in the Indenture.
	We may not redeem the Notes prior to the maturity date. If a fundamental change (such as a change in control event or if our Common Stock ceases to be listed or quoted on any of the New York Stock Exchange, the Nasdaq Global Select Market or the Nasdaq Global Market or any of their respective successors) occurs prior to the maturity date, holders may require us to repurchase for cash all or part of their Notes at a repurchase price equal to 100% of the principal amount of the Notes to be repurchased, plus accrued and unpaid interest to, but excluding, the fundamental change repurchase date.
	The Indenture provides for customary events of default (subject in certain cases to grace and cure periods) including, without limitation, (i) the failure to pay amounts due under the Notes, (ii) the failure to deliver the shares of our Common Stock due upon conversion of any Note, (iii) our failure to comply with other agreements contained in the Indenture or in the Notes, including our agreement to timely file certain reports with the trustee, (iv) payment defaults on, or acceleration of, other indebtedness, (v) the failure to pay certain judgments, and (vi) certain events of bankruptcy, insolvency or reorganization with respect to the Company. An event of default under the Indenture (other than an event of default related to certain events of bankruptcy, insolvency or reorganization) will allow either the trustee or the holders of at least 25% in aggregate principal amount of the then outstanding Notes to cause the acceleration of the Notes. An event of default related to certain events of bankruptcy, insolvency or reorganization with respect to the Company will automatically cause the acceleration of the Notes.
	As of March 31, 2015, the estimated fair value of our Notes was approximately $200.4 million. The fair value of the Notes was estimated using market prices of the Notes, which are based on Level 2 inputs.
	Senior Secured Credit Agreement
	2015 Credit Agreement
	On March 2, 2015 (the “Closing Date”), we entered into an amended and restated credit agreement (the “Credit Agreement”) by and among the Company, as borrower, certain of the Company’s wholly owned direct and indirect subsidiaries, as guarantors, Silicon Valley Bank, as administrative agent, swingline lender and letter of credit issuer, and the other lenders parties thereto (Silicon Valley Bank and the other lenders hereinafter collectively referred to as the “Lenders”). The Credit Agreement amended and restated our prior credit agreement dated as of December 21, 2012, as amended (the “Prior Credit Agreement”), by and among Ixia, the guarantors, Silicon Valley Bank, as administrative agent, swingline lender, and letter of credit issuer (as successor to Bank of America, N.A. in such capacities), and the other lenders party thereto.
	The Credit Agreement provides for a (i) term loan (the “Term Loan”) in the aggregate principal amount of $40 million, which amount was advanced to the Company on March 3, 2015, and (ii) revolving credit facility (the “Revolving Credit Facility” and, together with the Term Loan, the “Credit Facility”) in an aggregate amount of up to $60 million, with sub-limits of $25 million for the issuance of standby letters of credit and $15 million for swingline loans. The aggregate amount available under the Credit Facility may, upon our request and subject to the receipt of increased commitments from the Lenders or additional lenders, be increased by an aggregate amount of up to $80 million. We are permitted to voluntarily prepay outstanding loans under the Credit Facility at any time without premium or penalty. Prior to the maturity of the Credit Facility, we may re-borrow amounts under the Revolving Credit Facility, but we may not re-borrow amounts that are repaid or prepaid under the Term Loan.
	The maturity date of the Credit Facility is February 15, 2018; provided, however, that if, at any time between June 15, 2015 and the maturity date for the Notes (i.e., December 15, 2015), we do not have total available liquidity (defined as cash, cash equivalents, and marketable securities plus availability under the Revolving Credit Facility) of $25 million in excess of the amount then required to repay our Notes in full, all amounts outstanding under the Credit Facility will become due and payable and the Revolving Credit Facility will terminate, on September 14, 2015 (or if such date has passed, within 2 business days after the date we fail to have the required total available liquidity). If subsequent to June 15, 2015 and prior to September 14, 2015 we do not have the required total available liquidity but thereafter (and prior to September 14, 2015) achieve and maintain such liquidity level, the accelerated maturity date of September 14, 2015 shall not apply.
	Debt issuance costs were approximately $1.2 million, which were capitalized to deferred issuance costs and are being amortized to interest expense over the three year term of the Credit Facility using the effective interest method. During the three months ended March 31, 2015, amortization recorded to interest expense pertaining to deferred issuance costs was not material.
	As required by the terms of the Credit Agreement, we have deposited the funds advanced under the Term Loan of $40 million, together with additional cash, cash equivalents and marketable securities in the aggregate amount of $50 million, in collateral accounts (the “Collateral Accounts”). The $90 million deposited in the Collateral Accounts as of March 31, 2015 consists of $10 million in cash and cash equivalents, which is included in the Restricted cash line item on our condensed consolidated balance sheet, and $80 million in marketable securities, which is included in the Marketable securities, restricted line item on our condensed consolidated balance sheet. Subsequent to March 31, 2015, as required under the Credit Agreement, we deposited additional cash, cash equivalents and marketable securities in the Collateral Accounts in the aggregate amount of $25 million. We may only withdraw amounts deposited in the Collateral Accounts for the repurchase or repayment of the Notes. We may use the proceeds of the Revolving Credit Facility for (i) working capital, capital expenditures and general corporate purposes, (ii) share repurchases, (iii) the partial refinancing of the Notes, and/or (iv) acquisitions, in each case as permitted by applicable law and the Credit Agreement. The restrictions on acquisitions as set forth in the Credit Agreement include a restriction that precludes the Company from funding an acquisition in whole or in part with cash unless the Company will have, after giving effect to the transaction, cash, cash equivalents and marketable securities in an amount not less than $75 million in excess of the amount then required to be on deposit in the Collateral Accounts.
	The Company plans to satisfy its repayment obligations under the Notes, and to pay the purchase price for any earlier Note repurchases (whether mandatory or negotiated by the Company) using some combination of (i) cash, cash equivalents and marketable securities, including those deposited in the Collateral Accounts, (ii) borrowings under the Revolving Credit Facility, and/or (iii) future cash flows from operations.
	The Term Loan requires quarterly repayments of principal on the last day of the eleven fiscal quarters following the Closing Date, commencing with the fiscal quarter ending June 30, 2015. The first four payments will be in the amount of $500,000 each, the following four payments will be in the amount of $1.0 million each, and the next three payments will be in the amount of $1.5 million each. The remaining principal balance of the Term Loan will be due and payable on the maturity date of the Credit Facility.
	The Company’s and the guarantors’ obligations under the Credit Agreement are secured by (i) a first priority perfected security interest in substantially all existing and after acquired tangible and intangible personal property of the Company and the guarantors and (ii) the pledge by the Company and the guarantors of (a) all outstanding equity securities of their existing and future domestic subsidiaries, including, in the case of the Company, the outstanding equity securities of each of the guarantors, and (b) 65% of the outstanding equity securities of their existing and future respective first-tier foreign subsidiaries, including, in the case of Catapult Communications Corporation (one of our wholly owned domestic subsidiaries), 65% of the outstanding equity securities of Ixia Technologies International Limited, a company organized under the laws of Ireland.
	Interest rates for the Term Loan and for the first year of the Revolving Credit Facility are established, at our option, at a rate per annum of (i) 4.25% above the Eurodollar rate or (ii) 3.25% above a defined base rate. After the first anniversary of the Closing Date, interest rates for the Revolving Credit Facility are established, at the Company’s option, based on the Eurodollar rate or the defined base rate. Such interest rates range from 2.0% to 3.0% above the Eurodollar rate for Eurodollar-based borrowings and from 1.0% to 2.0% above the defined base rate for base rate borrowings, in each case depending on the Company’s leverage ratio. We are also required to pay a quarterly commitment fee, ranging from 0.30% to 0.50% per annum, on the undrawn portion of the Revolving Credit Facility. Letter of credit fees accrue based on the daily amount available to be drawn under outstanding letters of credit and range from 2.0% to 3.0%, depending on our leverage ratio. Swingline loans bear interest at the defined base rate plus the applicable margin for loans under the Revolving Credit Facility based on the defined base rate. If we default under the Credit Facility, the Lenders may increase the interest rate(s) to 2.0% more than the rate(s) otherwise applicable. The weighted average interest rate applicable to the Term Loan for the three months ended March 31, 2015 was 4.42%, which was based on the one month Eurodollar rate plus 4.25%.
	The Credit Agreement requires the Company to comply with certain covenants, including maintaining (i) a fixed charge coverage ratio (as defined in the Credit Agreement) of not less than 1.25 to 1.00, measured quarterly on a trailing 12 months basis, (ii) a consolidated senior leverage ratio (as defined in the Credit Agreement) of not greater than 2.50 to 1.00 through December 31, 2015 and 2.25 to 1.00 thereafter, measured quarterly on a trailing 12 months basis, and (iii) a consolidated total leverage ratio (as defined in the Credit Agreement) of not greater than 3.00 to 1.00, measured quarterly on a trailing 12 months basis. The consolidated funded indebtedness (as defined in the Credit Agreement) used in the calculation of the consolidated leverage ratio is reduced by the amounts deposited in the Collateral Accounts (except in connection with the calculation of the applicable margin for loans).
	The Credit Agreement also contains reporting covenants typical for transactions comparable to the Credit Facility provided for therein, including covenants to furnish the lenders with financial statements, business plans, annual budgets, and other financial and business information and with notice of certain material events and information regarding collateral. The Credit Agreement also contains customary affirmative covenants, including covenants relating to the payment of obligations, preservation of the existence of and registrations for patents, trademarks, trade names and copyrights, maintenance of properties and insurance, compliance with laws and material contractual obligations, books and records, inspection rights, use of proceeds, addition of subsidiary guarantors, and security for the Credit Facility. The Credit Agreement contains customary negative covenants, including restrictions relating to liens and additional indebtedness, investments, mergers, liquidations and other fundamental changes, the sale and other disposition of properties and assets, restricted payments, changes in lines of business, transactions with affiliates, entering into certain burdensome agreements, and use of proceeds.
	The Credit Agreement provides for customary events of default, including the non-payment of amounts due, failure to perform under covenants, breaches of representations and warranties, cross-defaults relating to certain indebtedness, institution of insolvency proceedings, inability to pay debts as they become due, entry of certain judgments, events relating to the Employee Retirement Income Security Act of 1974, as amended, invalidity of loan documents, change of control events, and ineffectiveness of subordination provisions. The occurrence of an event of default may result in the acceleration of all of our outstanding obligations under the Credit Agreement and in an increase in the applicable interest rate(s) as described above.
	Prior Credit Agreement
	The Company’s Prior Credit Agreement provided for a credit facility (the “Prior Credit Facility”) that originally consisted of a revolving loan commitment of up to $150 million. As a result of the termination of certain lenders’ commitments under the Prior Credit Facility, the aggregate loan amount was reduced to $67.5 million in January 2015 and further reduced to $46.5 million in March 2015 prior to the date of the amendment and restatement of the Prior Credit Facility on March 2, 2015. As described below and due to our defaults under the Prior Credit Agreement, we were at the time of its amendment and restatement blocked from borrowing and obtaining letters of credit under the Prior Credit Facility. As of December 31, 2014, and immediately prior to the March 2015 amendment and restatement of the Prior Credit Agreement, no amounts were outstanding under the Prior Credit Facility.
	The Prior Credit Facility was originally scheduled to mature on December 21, 2016, subject to earlier termination under certain circumstances relating to our available liquidity. On December 12, 2014, the maturity date for the Prior Credit Facility was advanced to January 31, 2015, and on January 30, 2015, the maturity date was extended to March 2, 2015.
	The Prior Credit Agreement required that we comply with certain covenants, including maintaining an interest coverage ratio and a maximum leverage ratio, timely providing certain periodic financial statements to the lenders, and complying with the Indenture governing our Notes, which Indenture requires us to timely file certain reports with the trustee. For the quarters ended September 30, 2014 and December 31, 2014, our leverage ratio exceeded 3.00 to 1.00 and therefore constituted events of default under the Prior Credit Agreement. During 2014, the administrative agent under the Prior Credit Agreement provided us with notices that we were in default under the Prior Credit Agreement as a result of our failure to timely deliver to the administrative agent our financial statements and a related compliance certificate for the quarter ended June 30, 2014 and a compliance certificate relating to the quarter ended September 30, 2014, the event of default that had occurred under the Indenture as a result of our failure to timely file our Quarterly Report on Form 10-Q for the quarter ended June 30, 2014 with the trustee and the SEC, and our not being in compliance with the leverage ratio requirements as of September 30, 2014. In connection with such events of default, we were, commencing on or about August 29, 2014, blocked from borrowing and obtaining letters of credit under the Prior Credit Facility.

Selected_Balance_Sheet_Data

Selected Balance Sheet Data	3 Months Ended
	Mar. 31, 2015
Balance Sheet Related Disclosures [Abstract]
Selected Balance Sheet Data	Selected Balance Sheet Data
	Investments in Marketable Securities
	Investments in marketable securities as of March 31, 2015 consisted of the following (in thousands):
		Amortized		Gross Unrealized		Gross Unrealized			Fair
		Cost		Gains		Losses			Value
	Available-for-sale – short-term:
	U.S. Treasury, government and agency debt	$	60,621	$	28	$	(1	)	$	60,648
	securities
	Corporate debt securities	53,050		62		(20		)	53,092
	Total	$	113,671	$	90	$	(21	)	$	113,740
	Investments in marketable securities as of December 31, 2014 consisted of the following (in thousands):
		Amortized		Gross Unrealized		Gross Unrealized			Fair
		Cost		Gains		Losses			Value
	Available-for-sale – short-term:
	U.S. Treasury, government and agency debt	$	42,289	$	9	$	(17	)	$	42,281
	securities
	Corporate debt securities	37,476		41		(38		)	37,479
	Total	$	79,765	$	50	$	(55	)	$	79,760
	As of March 31, 2015, $80 million of our marketable securities were restricted under the terms of the Credit Agreement for use only in the repayment of or satisfaction of other obligations relating to the Notes due December 15, 2015 and are classified as Marketable securities, restricted on our condensed consolidated balance sheet as of March 31, 2015. See Note 4 for additional information regarding the restrictions under our Credit Agreement relating to these marketable securities.
	As of March 31, 2015 and December 31, 2014, our available-for-sale securities had a weighted remaining contractual maturity of 1.42 and 1.69 years, respectively. For the three months ended March 31, 2015 and March 31, 2014, gross realized gains and gross realized losses were not significant. See Note 7 for information on the unrealized holding gains (losses) on available-for-sale securities reclassified out of accumulated other comprehensive loss into the condensed consolidated statements of operations.
	The amortized cost and fair value of our marketable securities at March 31, 2015, by contractual years-to-maturity, are as follows (in thousands):
		Amortized Cost		Fair Value
	Due in less than 1 year	$	37,644	$	37,660
	Due within 1-2 years	55,354		55,399
	Due within 2-5 years	20,138		20,146
	Due after 5 years	535		535
	Total	$	113,671	$	113,740
	Inventories
	Inventories consist of the following (in thousands):
		31-Mar-15		31-Dec-14
	Raw materials	$	4,821	$	5,502
	Work in process	12,337		18,047
	Finished goods	19,653		21,277
		$	36,811	$	44,826
	Accrued expenses and other
	As of March 31, 2015 and December 31, 2014, accrued compensation and related expenses totaled $12.9 million and $9.9 million, respectively. As of March 31, 2015 and December 31, 2014, accrued vacation totaled $7.8 million and $7.5 million, respectively.

Goodwill_and_Other_Intangible_

Goodwill and Other Intangible Assets	3 Months Ended
	Mar. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangible Assets	Goodwill and Other Intangible Assets
	There was no activity related to goodwill for the three months ended March 31, 2015. We have not had any historical goodwill impairment charges.
	The following table presents our purchased intangible assets (in thousands) as of March 31, 2015:
		Weighted		Gross		Accumulated			Net
		Average				Amortization
		Useful Life
		(in years)
	Other intangible assets:
	Technology	5.5		$	185,665	$	(112,592	)	$	73,073
	Customer relationships	6		71,700		(43,945		)	27,755
	Service agreements	6.4		30,100		(9,751		)	20,349
	Trademark	5.1		11,300		(5,525		)	5,775
	Non-compete	4		8,000		(4,141		)	3,859
	Other	4.2		5,109		(1,509		)	3,600
				$	311,874	$	(177,463	)	$	134,411
	The following table presents our purchased intangible assets (in thousands) as of December 31, 2014:
		Weighted		Gross		Accumulated			Net
		Average				Amortization
		Useful Life
		(in years)
	Other intangible assets:
	Technology	5.5		$	185,665	$	(106,953	)	$	78,712
	Customer relationships	6		71,700		(40,938		)	30,762
	Service agreements	6.4		30,100		(8,577		)	21,523
	Trademark	5.1		11,300		(5,033		)	6,267
	Non-compete agreements	4		8,000		(3,641		)	4,359
	Other	4.2		4,883		(1,398		)	3,485
				$	311,648	$	(166,540	)	$	145,108
	The estimated future amortization expense of purchased intangible assets as of March 31, 2015 is as follows (in thousands):
	Remaining in 2015	$	31,351
	2016	37,859
	2017	31,861
	2018	20,586
	2019	7,351
	2020	3,727
	Thereafter	1,676
		$	134,411

Shareholders_Equity

Shareholders' Equity	3 Months Ended
	Mar. 31, 2015
Stockholders' Equity Note [Abstract]
Shareholders' Equity	Shareholders’ Equity
	The following table summarizes the changes in our accumulated other comprehensive loss, by component, net of income taxes (in thousands):
		Gains and Losses on Available-for-			Foreign Currency			Total
		Sale			Items
		Securities (a)
	Beginning balance, December 31, 2014	$	(32	)	$	(761	)	$	(793	)
	Other comprehensive income before reclassifications	93			(5		)	88
	Amounts reclassified from accumulated other comprehensive loss (b)	(18		)	—			(18		)
	Net current period other comprehensive income	75			(5		)	70
	Ending balance, March 31, 2015	$	43		$	(766	)	$	(723	)
	(a)	All amounts are net-of-tax. Amounts in parentheses indicate reductions.
	(b)	Amount represents gain on the sale of securities and is included as a component of Interest income and other, net in the condensed consolidated statements of operations.

Loss_Per_Share

Loss Per Share	3 Months Ended
	Mar. 31, 2015
Earnings Per Share [Abstract]
Loss Per Share	Loss Per Share
	Basic loss per common share is computed by dividing net loss by the weighted average number of common shares outstanding during the period. Diluted loss per common share is computed by giving effect to all potential dilutive common shares, including stock-based awards.
	The following table sets forth the computation of basic and diluted loss per share for the three months ended March 31, 2015 and 2014 (in thousands, except per share data):
		Three months ended
		March 31,
		2015			2014
	Basic presentation:
	Numerator for basic loss per share:
	Net loss	$	(9,611	)	$	(19,472	)
	Denominator for basic loss per share:
	Weighted average common shares outstanding	78,706			76,951
	Basic loss per share	$	(0.12	)	$	(0.25	)
	Diluted presentation:
	Numerator for diluted loss per share:
	Net loss	(9,611		)	(19,472		)
	Interest expense on convertible senior notes, net of tax	—			—
	Net loss used for diluted loss per share	$	(9,611	)	$	(19,472	)
	Denominator for dilutive loss per share:
	Weighted average common shares outstanding	78,706			76,951
	Effect of dilutive securities:
	Stock options and other share-based awards	—			—
	Convertible senior notes	—			—
	Dilutive common shares	78,706			76,951
	Diluted loss per share	$	(0.12	)	$	(0.25	)
	The diluted loss per share computation for the three months ended March 31, 2015 and 2014 excludes (i) the weighted average number of shares underlying our Notes of 10.3 million shares as such shares are considered anti-dilutive because of the net losses incurred for the periods then ended, and (ii) the weighted average number of shares underlying our employee stock options and other share-based awards of 4.8 million shares and 3.9 million shares, respectively, which are anti-dilutive because, in general, the exercise prices of these awards (to the extent such awards have exercise prices) exceeds the average closing sales price per share of our common stock during the applicable period or were anti-dilutive because the Company reported a net loss for the applicable period.

Concentrations

Concentrations	3 Months Ended
	Mar. 31, 2015
Risks and Uncertainties [Abstract]
Concentrations	Concentrations
	Revenue by Product Line
	We have two product lines: Network Test Solutions and Network Visibility Solutions. Our Network Test Solutions products include our multi-slot test chassis and appliances, our traffic generation interface cards, our suite of test applications, and the related technical support, warranty and software maintenance services, including our Application and Threat Intelligence (ATI) service. Our Network Visibility Solutions products include our network packet brokers, bypass switches, virtual and physical taps, and the related technical support, warranty and software maintenance services. The following table presents revenue by product line (in thousands):
		Three months ended
		March 31,
		2015			2014
	Network Test Solutions	$	85,347		$	89,525
	Network Visibility Solutions	35,615			24,208
		$	120,962		$	113,733
	Significant Customers
	The following customers accounted for more than 10% of total revenue for the three months ended March 31, 2015 and, for Customer A, for the three months ended March 31, 2014:
		Three months ended
		March 31,
		2015		2014
	Customer A	10.1	%	10.3	%
	Customer B	11.6	%	*
	* Less than 10%
	As of March 31, 2015 and December 31, 2014, the percentages of our total receivables from Customer B were below 10%. The percentages of our total receivables from Customers A as of such dates were as follows:
		31-Mar-15		31-Dec-14
	Customer A	15.2	%	*
	* Less than 10%
	International Data
	For the three months ended March 31, 2015 and 2014, the percentages of total revenues consisting of international revenues based on customer location consisted of the following:
		Three months ended
		March 31,
		2015		2014
	International revenues	38.4	%	41	%
	As of March 31, 2015 and December 31, 2014, our property and equipment, net were geographically located as follows (in thousands):
		31-Mar-15			31-Dec-14
	United States	$	25,175		$	24,697
	India	6,167			6,035
	Romania	3,758			3,857
	Other	3,344			3,059
	Total	$	38,444		$	37,648

Fair_Value_Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2015
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements
	Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in the principal or most advantageous market for an asset or liability in an orderly transaction between market participants at the measurement date. The hierarchy below lists three levels of fair value based on the extent to which inputs used in measuring fair value are observable in the market. We categorize each of our fair value measurements in one of these three levels based on the lowest level input that is significant to the fair value measurement in its entirety. This hierarchy prioritizes the inputs into three broad levels as follows:
	Level 1.	Observable inputs such as quoted prices in active markets;
	Level 2.	Inputs, other than quoted prices in active markets, that are observable either directly or indirectly; and
	Level 3.	Unobservable inputs in which there is little or no market data, which require the reporting entity to develop its own assumptions.
	Financial assets carried at fair value as of March 31, 2015 are classified in the table below in one of the three categories described above (in thousands):
		March 31, 2015
		Fair Value		Quoted Prices		Significant		Significant
				in Active		Other		Unobservable
				Markets for		Observable		Inputs
				Identical		Inputs		(Level 3)
				Assets		(Level 2)
				(Level 1)
	Cash equivalents:
	Money market funds	$	915	$	915	$	—	$	—
	Corporate debt securities	16,945		—		16,945		—
	Short-term marketable securities:
	U.S. Treasury, government and agency debt securities	60,648		—		60,648		—
	Corporate debt securities	53,092		—		53,092		—
	Total financial assets	$	131,600	$	915	$	130,685	$	—
	Financial assets carried at fair value as of December 31, 2014 are classified in the table below in one of the three categories described above (in thousands):
		December 31, 2014
		Fair Value		Quoted Prices		Significant		Significant
				in Active		Other		Unobservable
				Markets for		Observable		Inputs
				Identical		Inputs		(Level 3)
				Assets		(Level 2)
				(Level 1)
	Cash equivalents:
	Money market funds	$	267	$	267	$	—	$	—
	Corporate debt securities	5,349		—		5,349		—
	Short-term marketable securities:
	U.S. Treasury, government and agency debt securities	42,281		—		42,281		—
	Corporate debt securities	37,479		—		37,479		—
	Total financial assets	$	85,376	$	267	$	85,109	$	—
	Our cash and investment instruments are classified within Level 1 or Level 2 of the fair value hierarchy based on quoted market prices, broker or dealer quotations, or alternative pricing sources with reasonable levels of price transparency.
	The fair values of our money market funds, U.S. treasury, government and agency debt securities, and corporate debt securities are based on quoted market prices as shown in our investment brokerage/custodial statements. To the extent deemed necessary, we may also obtain non-binding dealer quotes to corroborate the estimated fair values reflected in our investment brokerage/custodial statements.
	There were no transfers of assets between levels within the fair value hierarchy for the three month period ended March 31, 2015, and there were no Level 3 assets held at March 31, 2015.

Commitments_and_Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies
	Securities Class Action
	On November 14, 2013, a purported securities class action complaint captioned Felix Santore v. Ixia, Victor Alston, Atul Bhatnagar, Thomas B. Miller, and Errol Ginsberg was filed against us and certain of our current and former officers and directors in the U.S. District Court for the Central District of California. The lawsuit purports to be a class action brought on behalf of purchasers of the Company’s securities during the period from April 10, 2010 through October 14, 2013. The initial complaint alleged that the defendants violated the Securities Exchange Act of 1934, as amended (the “Exchange Act”), by making materially false and misleading statements concerning the Company’s recognition of revenues related to its warranty and software maintenance contracts and the academic credentials and employment history of the Company’s former President and Chief Executive Officer, Victor Alston. The complaint also alleged that the defendants made false and misleading statements, and failed to make certain disclosures, regarding the Company’s business, operations and prospects, including regarding the financial statements and internal financial controls that were the subject of the Company’s April 2013 restatement of certain of its prior period financial statements. The complaint further alleged that the Company lacked adequate internal financial controls and issued materially false and misleading financial statements for the fiscal years ended December 31, 2010 and 2011, and the fiscal quarters ended March 31, 2011, June 30, 2011, September 30, 2011, March 31, 2012, June 30, 2012 and September 30, 2012. The complaint, which purported to assert claims for violations of Sections 10(b) and 20(a) of the Exchange Act and Rule 10b-5 promulgated thereunder, sought, on behalf of the purported class, an unspecified amount of monetary damages, interest, fees and expenses of attorneys and experts, and other relief.
	On March 24, 2014, following a proceeding to select a lead plaintiff in the matter, the court issued an order appointing Oklahoma Firefighters Pension & Retirement System and Oklahoma Law Enforcement Retirement System (the “Oklahoma Group”) as lead plaintiffs.
	On June 11, 2014, the Oklahoma Group filed a first amended complaint, which asserted claims against the same defendants under the same legal theories set forth in the initial complaint. The first amended complaint also contained allegations that certain of the individual defendants increased their trading in the Company’s stock during February, March, April and May of 2011 and during February and March of 2013, and that the defendants sought to inflate the Company’s reported deferred revenues during the period of February 4, 2011 through April 3, 2013.
	On July 18, 2014, all named defendants moved to dismiss the first amended complaint for failure to state a claim under the Federal Rules of Civil Procedure and the Private Securities Law Reform Act of 1995 (“PSLRA”). After briefing and a hearing on October 6, 2014, the court issued an order dismissing the first amended complaint in its entirety without prejudice. The court gave the Oklahoma Group 30 days in which to file an amended complaint.
	On November 5, 2014, the Oklahoma Group filed a second amended complaint. On January 6, 2015, the named defendants moved to dismiss the second amended complaint. After briefing and a hearing on April 13, 2015, the court issued an order dismissing the second amended complaint in its entirety without prejudice. The court gave the Oklahoma Group 30 days in which to file an amended complaint.
	On April 24, 2015, the court issued an order staying the class action until July 31, 2015, pending the outcome of a mediation scheduled for July 23, 2015 to explore a possible settlement.
	Although the Company denies the material allegations of the amended complaint and intends to vigorously pursue its defenses, we are in the very early stages of this litigation, and are unable to predict the outcome of the case or to estimate the amount of or potential range of loss with respect to this case. Accordingly, no liability has been accrued in the financial statements related to this matter. However, the ultimate disposition of the case could have a material adverse impact on the Company’s financial condition, results of operations and cash flows.
	Shareholder Derivative Action
	A consolidated shareholder derivative action, captioned In re Ixia Shareholder Derivative Litigation, is pending in the U.S. District Court for the Central District of California. This action is the consolidation of two lawsuits, namely: (i) Erie County Employees' Retirement System, Derivatively on behalf of Nominal Defendant IXIA v. Victor Alston, Errol Ginsberg, Laurent Asscher, Jonathan Fram, Gail Hamilton, Jon Rager, Atul Bhatnagar, and Thomas B. Miller, defendants, and Ixia, nominal defendant and (ii) Colleen Witmer, derivatively on behalf of Ixia v. Victor Alston, Atul Bhatnagar, Thomas B. Miller, Errol Ginsberg, Jonathan Fram, Laurent Asscher, Gail Hamilton, Jon F. Rager, Christopher Lee Williams, Alan Grahame, Raymond De Graaf, Walker H. Colston II, and Ronald W. Buckly, defendants, and Ixia, nominal defendant. Both were filed in the U.S. District Court for the Central District of California in May 2014.
	Co-lead plaintiffs Erie County Employees’ Retirement System and Colleen Witmer filed a consolidated complaint on September 2, 2014. The consolidated complaint includes many allegations similar to those made in the purported class action complaint described above. Among other things, the complaint alleges that some or all (depending upon the claim) of the individual defendants breached their fiduciary duties to the Company by causing or allowing the Company to disseminate misleading financial statements, ignoring problems with the Company’s financial controls, making stock sales on the basis of material non-public information, and violating the Company’s code of conduct. As relief, among other things, the complaint seeks an unspecified amount of monetary damages, disgorgement and restitution of stock sale proceeds and an award under California Corporations Code Sections 24502 and 25502.5, as well as unspecified equitable and declaratory relief.
	On October 15, 2014, the Company, on whose behalf the derivative action claims are purportedly brought, moved to dismiss the consolidated complaint on the grounds that the derivative plaintiffs did not file the claims in accordance with applicable laws governing the filing of derivative actions. The individual defendants joined in that motion and also filed motions to dismiss the claims against them for failure to state a claim. Before any ruling by the court on those motions, the plaintiffs filed an amended consolidated complaint on January 26, 2015. On March 12, 2015, the Company filed a motion to dismiss the amended consolidated complaint on the same grounds as it had set forth with respect to the first consolidated complaint, and the individual defendants joined in that motion and also filed motions to dismiss the claims against them for failure to state a claim. On April 24, 2015, before the scheduled hearing on the motion to dismiss, the Court issued an order staying the shareholder derivative action until July 31, 2015, pending the outcome of a mediation scheduled for July 23, 2015 in connection with both the derivative action and the securities class action discussed above. If no settlement is reached, the plaintiffs’ omnibus opposition to the pending motions to dismiss will be due on August 3, 2015, and the reply briefs of the Company and the individual defendants will be due on August 10, 2015. No hearing date on the motions to dismiss is currently scheduled.
	As we are in the very early stages of this litigation, we are unable to predict the outcome of the litigation or to estimate the amount of or potential range of loss with respect to the consolidated complaint. No liability has been accrued in the financial statements related to this matter.
	SEC Investigation
	In July 2014, the Staff of the SEC’s Division of Enforcement requested that the Company produce certain documents and information in connection with an investigation of the Company. The SEC has also subsequently issued subpoenas to the Company seeking certain additional documents and has issued subpoenas to certain of the Company’s current and former employees seeking certain documents and their testimony. Based on the documents requested by the Staff, the Company believes that the investigation relates to the matters addressed by (i) the previously disclosed accounting-related investigation conducted by the Audit Committee of the Company’s Board of Directors (the “Board”) that was completed in February 2014 and (ii) a separate internal investigation conducted by a Special Committee of the Board of stock sales during February and March 2013 by then current executive officers and directors of the Company. The Special Committee, which completed its investigation in June 2014, did not find with respect to such sales that there had been any insider trading based upon material non-public information. The Special Committee, however, made no finding with respect to the Company's former President and Chief Executive Officer, Victor Alston, because he declined to be interviewed by the Special Committee's counsel (both the Special Committee and the Audit Committee were assisted by independent counsel in their investigations). The Company is continuing to cooperate fully with the SEC in this matter. The Company cannot predict the duration, scope or outcome of the SEC’s investigation.
	Indemnifications
	In the normal course of business, the Company provides certain indemnifications, commitments and guarantees of varying scope to customers, including against claims of intellectual property infringement made by third parties arising from the use of the Company's products. The Company also has certain obligations to indemnify its officers, directors and employees for certain events or occurrences while the officers, directors or employees are or were serving at the Company's request in such capacity. The duration of these indemnifications, commitments and guarantees varies and in certain cases, is indefinite. Many of these indemnifications, commitments and guarantees do not provide for any limitation of the maximum potential future payments that the Company could be obligated to make. However, the Company's director and officer insurance policy may enable it to recover a portion of any future payments related to its officer, director or employee indemnifications. Historically, costs related to these indemnifications, commitments and guarantees have not been significant. With the exception of the product warranty accrual associated with the Company's initial standard warranty, no liabilities have been recorded for these indemnifications, commitments and guarantees.

Income_Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2015
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes
	The Company accounts for its provision for income taxes in accordance with Accounting Standard Codification (“ASC”) 740, Income Taxes. In accordance with ASC 740, the Company uses an estimate of its annual effective rate for the full fiscal year in computing the year-to-date provision for income taxes for the interim periods, including federal, foreign, state, and local income taxes.
	As of March 31, 2015 and December 31, 2014, current deferred tax assets totaled $15.9 million and $15.5 million, respectively, and were included within the Prepaid expenses and other current assets line item on our condensed consolidated balance sheets. As of March 31, 2015 and December 31, 2014, long-term deferred tax assets totaled $11.9 million and were included within the Other assets line item on our condensed consolidated balance sheets. As of March 31, 2015 and December 31, 2014, long-term deferred tax liabilities totaling $1.1 million and $1.4 million, respectively, were included within the Other liabilities line item on our condensed consolidated balance sheets.

Basis_of_Presentation_Signific1

Basis of Presentation, Significant Accounting Policies and Recent Accounting Pronouncements (Policies)	3 Months Ended
	Mar. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation
	The accompanying condensed consolidated financial statements as of March 31, 2015 and for the three months ended March 31, 2015 and 2014, are unaudited and reflect all adjustments (consisting only of normal recurring adjustments) which are, in the opinion of management, necessary for a fair statement of our financial position, operating results, and cash flows for the interim periods presented. The results of operations for the three months ended March 31, 2015 presented are not necessarily indicative of results to be expected for the full year ending December 31, 2015 or any other future period.
	These condensed consolidated financial statements have been prepared in accordance with the rules and regulations of the Securities and Exchange Commission (the "SEC"). Certain information and footnote disclosures normally included in financial statements prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) have been condensed or omitted pursuant to such rules and regulations. The condensed consolidated balance sheet as of December 31, 2014 has been derived from our audited consolidated financial statements included in our Annual Report on Form 10-K for the year ended December 31, 2014 (the “2014 Form 10-K"), but does not include all disclosures required by GAAP. These condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and related notes included in our 2014 Form 10-K.
Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy	Restricted cash and cash equivalents and restricted marketable securities represent amounts restricted under the terms of the Company's amended and restated credit agreement for use only in the repayment of the Company's unsecured convertible senior notes due December 15, 2015. See Note 4 for additional information regarding the Company's credit agreement.
Recent Accounting Pronouncements	Recent Accounting Pronouncements
	In April 2015, the Financial Accounting Standards Board (“FASB”) issued Accounting Standard Update (“ASU”) 2015-3, Interest—Imputation of Interest: Simplifying the Presentation of Debt Issuance Costs, which provides new guidance regarding the presentation of debt issuance costs. The new guidance requires debt issuance costs related to a recognized debt liability to be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. The standard will be effective for annual reporting periods beginning after December 15, 2015, including interim periods within those reporting periods. Early application is permitted. The Company is in the process of evaluating the impact of the adoption of this accounting standard update on our consolidated financial statements.
	In August 2014, the FASB issued ASU 2014-15, Presentation of Financial Statements-Going Concern: Disclosure of Uncertainties about an Entity's Ability to Continue as a Going Concern, which provides guidance about management's responsibility to evaluate whether or not there is substantial doubt about the Company's ability to continue as a going concern and to provide related footnote disclosure. The standard will be effective for annual reporting periods beginning after December 15, 2016, including interim periods within those reporting periods. Early application is permitted. The Company is in the process of evaluating the impact of the adoption of this accounting standard update on our consolidated financial statements.
	In June 2014, the FASB issued ASU 2014-12, Accounting for Share-Based Payments When the Terms of an Award Provide that a Performance Target Could Be Achieved after the Requisite Service Period, which provides new guidance regarding share-based compensation. The new guidance clarified that share-based compensation performance targets that could be achieved after the requisite service period should be treated as performance conditions that affect vesting, rather than a condition that affects the grant-date fair value of the award. The standard will be effective for annual reporting periods beginning after December 15, 2015, including interim periods within those reporting periods. Early adoption is permitted. The Company is in the process of evaluating the impact of the adoption of this accounting standard update on our consolidated financial statements.
	During May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers, which provides new guidance on the recognition of revenue and states that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The standard will be effective in annual periods beginning after December 15, 2016 and for interim and annual reporting periods thereafter. Early application is not permitted for public entities. In April 2015, the FASB proposed a one-year delay in the effective date of the standard to January 1, 2018, with an option that would permit companies to adopt the standard as early as the original effective date. Early adoption prior to the original effective date is not permitted. A final decision on the effective date is expected in 2015. The Company has not yet evaluated the impact of the adoption of this accounting standard update on its consolidated financial statements.

Restructuring_Costs_Tables

Restructuring Costs (Tables)	3 Months Ended
	Mar. 31, 2015
Restructuring and Related Activities [Abstract]
Restructuring and Related Costs	Activities related to our restructuring plans are as follows (in thousands):
		2014 Corporate			Net Optics			Other			Total
		Restructuring			Restructuring
	Accrual at December 31, 2014	1,940			337			246			2,523
	Charges	142			19			—			161
	Payments	(469		)	(356		)	(35		)	(860		)
	Non-cash items	—			—			(108		)	(108		)
	Accrual at March 31, 2015	$	1,613		$	—		$	103		$	1,716

Selected_Balance_Sheet_Data_Ta

Selected Balance Sheet Data (Tables)	3 Months Ended
	Mar. 31, 2015
Balance Sheet Related Disclosures [Abstract]
Available-for-sale Securities	Investments in marketable securities as of March 31, 2015 consisted of the following (in thousands):
		Amortized		Gross Unrealized		Gross Unrealized			Fair
		Cost		Gains		Losses			Value
	Available-for-sale – short-term:
	U.S. Treasury, government and agency debt	$	60,621	$	28	$	(1	)	$	60,648
	securities
	Corporate debt securities	53,050		62		(20		)	53,092
	Total	$	113,671	$	90	$	(21	)	$	113,740
	Investments in marketable securities as of December 31, 2014 consisted of the following (in thousands):
		Amortized		Gross Unrealized		Gross Unrealized			Fair
		Cost		Gains		Losses			Value
	Available-for-sale – short-term:
	U.S. Treasury, government and agency debt	$	42,289	$	9	$	(17	)	$	42,281
	securities
	Corporate debt securities	37,476		41		(38		)	37,479
	Total	$	79,765	$	50	$	(55	)	$	79,760
Investments Classified by Contractual Maturity Date	The amortized cost and fair value of our marketable securities at March 31, 2015, by contractual years-to-maturity, are as follows (in thousands):
		Amortized Cost		Fair Value
	Due in less than 1 year	$	37,644	$	37,660
	Due within 1-2 years	55,354		55,399
	Due within 2-5 years	20,138		20,146
	Due after 5 years	535		535
	Total	$	113,671	$	113,740
Schedule of Inventory, Current	Inventories consist of the following (in thousands):
		31-Mar-15		31-Dec-14
	Raw materials	$	4,821	$	5,502
	Work in process	12,337		18,047
	Finished goods	19,653		21,277
		$	36,811	$	44,826

Goodwill_and_Other_Intangible_1

Goodwill and Other Intangible Assets (Tables)	3 Months Ended
	Mar. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Finite-Lived Intangible Assets	The following table presents our purchased intangible assets (in thousands) as of March 31, 2015:
		Weighted		Gross		Accumulated			Net
		Average				Amortization
		Useful Life
		(in years)
	Other intangible assets:
	Technology	5.5		$	185,665	$	(112,592	)	$	73,073
	Customer relationships	6		71,700		(43,945		)	27,755
	Service agreements	6.4		30,100		(9,751		)	20,349
	Trademark	5.1		11,300		(5,525		)	5,775
	Non-compete	4		8,000		(4,141		)	3,859
	Other	4.2		5,109		(1,509		)	3,600
				$	311,874	$	(177,463	)	$	134,411
	The following table presents our purchased intangible assets (in thousands) as of December 31, 2014:
		Weighted		Gross		Accumulated			Net
		Average				Amortization
		Useful Life
		(in years)
	Other intangible assets:
	Technology	5.5		$	185,665	$	(106,953	)	$	78,712
	Customer relationships	6		71,700		(40,938		)	30,762
	Service agreements	6.4		30,100		(8,577		)	21,523
	Trademark	5.1		11,300		(5,033		)	6,267
	Non-compete agreements	4		8,000		(3,641		)	4,359
	Other	4.2		4,883		(1,398		)	3,485
				$	311,648	$	(166,540	)	$	145,108
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense	The estimated future amortization expense of purchased intangible assets as of March 31, 2015 is as follows (in thousands):
	Remaining in 2015	$	31,351
	2016	37,859
	2017	31,861
	2018	20,586
	2019	7,351
	2020	3,727
	Thereafter	1,676
		$	134,411

Shareholders_Equity_Tables

Shareholders' Equity (Tables)	3 Months Ended
	Mar. 31, 2015
Stockholders' Equity Note [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss)	The following table summarizes the changes in our accumulated other comprehensive loss, by component, net of income taxes (in thousands):
		Gains and Losses on Available-for-			Foreign Currency			Total
		Sale			Items
		Securities (a)
	Beginning balance, December 31, 2014	$	(32	)	$	(761	)	$	(793	)
	Other comprehensive income before reclassifications	93			(5		)	88
	Amounts reclassified from accumulated other comprehensive loss (b)	(18		)	—			(18		)
	Net current period other comprehensive income	75			(5		)	70
	Ending balance, March 31, 2015	$	43		$	(766	)	$	(723	)
	(a)	All amounts are net-of-tax. Amounts in parentheses indicate reductions.
	(b)	Amount represents gain on the sale of securities and is included as a component of Interest income and other, net in the condensed consolidated statements of operations.

Loss_Per_Share_Tables

Loss Per Share (Tables)	3 Months Ended
	Mar. 31, 2015
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	The following table sets forth the computation of basic and diluted loss per share for the three months ended March 31, 2015 and 2014 (in thousands, except per share data):
		Three months ended
		March 31,
		2015			2014
	Basic presentation:
	Numerator for basic loss per share:
	Net loss	$	(9,611	)	$	(19,472	)
	Denominator for basic loss per share:
	Weighted average common shares outstanding	78,706			76,951
	Basic loss per share	$	(0.12	)	$	(0.25	)
	Diluted presentation:
	Numerator for diluted loss per share:
	Net loss	(9,611		)	(19,472		)
	Interest expense on convertible senior notes, net of tax	—			—
	Net loss used for diluted loss per share	$	(9,611	)	$	(19,472	)
	Denominator for dilutive loss per share:
	Weighted average common shares outstanding	78,706			76,951
	Effect of dilutive securities:
	Stock options and other share-based awards	—			—
	Convertible senior notes	—			—
	Dilutive common shares	78,706			76,951
	Diluted loss per share	$	(0.12	)	$	(0.25	)

Concentrations_Tables

Concentrations (Tables)	3 Months Ended
	Mar. 31, 2015
Note 10 - Concentrations (Tables) [Line Items]
Reconciliation of Revenue from Segments to Consolidated	The following table presents revenue by product line (in thousands):
		Three months ended
		March 31,
		2015			2014
	Network Test Solutions	$	85,347		$	89,525
	Network Visibility Solutions	35,615			24,208
		$	120,962		$	113,733
Schedule of Revenue from External Customers Attributed to Foreign Countries by Geographic Area	For the three months ended March 31, 2015 and 2014, the percentages of total revenues consisting of international revenues based on customer location consisted of the following:
		Three months ended
		March 31,
		2015		2014
	International revenues	38.4	%	41	%
Schedule of Disclosure on Geographic Areas, Long-Lived Assets in Individual Foreign Countries by Country	As of March 31, 2015 and December 31, 2014, our property and equipment, net were geographically located as follows (in thousands):
		31-Mar-15			31-Dec-14
	United States	$	25,175		$	24,697
	India	6,167			6,035
	Romania	3,758			3,857
	Other	3,344			3,059
	Total	$	38,444		$	37,648
Sales Revenue, Goods, Net | Customer Concentration Risk
Note 10 - Concentrations (Tables) [Line Items]
Schedules of Concentration of Risk, by Risk Factor	The following customers accounted for more than 10% of total revenue for the three months ended March 31, 2015 and, for Customer A, for the three months ended March 31, 2014:
		Three months ended
		March 31,
		2015		2014
	Customer A	10.1	%	10.3	%
	Customer B	11.6	%	*
	* Less than 10%
Accounts Receivable | Customer Concentration Risk
Note 10 - Concentrations (Tables) [Line Items]
Schedules of Concentration of Risk, by Risk Factor	As of March 31, 2015 and December 31, 2014, the percentages of our total receivables from Customer B were below 10%. The percentages of our total receivables from Customers A as of such dates were as follows:
		31-Mar-15		31-Dec-14
	Customer A	15.2	%	*
	* Less than 10%

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2015
Fair Value Disclosures [Abstract]
Fair Value, Assets Measured on Recurring Basis	Financial assets carried at fair value as of March 31, 2015 are classified in the table below in one of the three categories described above (in thousands):
		March 31, 2015
		Fair Value		Quoted Prices		Significant		Significant
				in Active		Other		Unobservable
				Markets for		Observable		Inputs
				Identical		Inputs		(Level 3)
				Assets		(Level 2)
				(Level 1)
	Cash equivalents:
	Money market funds	$	915	$	915	$	—	$	—
	Corporate debt securities	16,945		—		16,945		—
	Short-term marketable securities:
	U.S. Treasury, government and agency debt securities	60,648		—		60,648		—
	Corporate debt securities	53,092		—		53,092		—
	Total financial assets	$	131,600	$	915	$	130,685	$	—
	Financial assets carried at fair value as of December 31, 2014 are classified in the table below in one of the three categories described above (in thousands):
		December 31, 2014
		Fair Value		Quoted Prices		Significant		Significant
				in Active		Other		Unobservable
				Markets for		Observable		Inputs
				Identical		Inputs		(Level 3)
				Assets		(Level 2)
				(Level 1)
	Cash equivalents:
	Money market funds	$	267	$	267	$	—	$	—
	Corporate debt securities	5,349		—		5,349		—
	Short-term marketable securities:
	U.S. Treasury, government and agency debt securities	42,281		—		42,281		—
	Corporate debt securities	37,479		—		37,479		—
	Total financial assets	$	85,376	$	267	$	85,109	$	—

Business_Details

Business (Details)	3 Months Ended
	Mar. 31, 2015
	segment
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of business segments	1

Restructuring_Costs_Details

Restructuring Costs (Details) (USD $)	3 Months Ended			12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Sep. 30, 2014	Dec. 31, 2014
			position
Restructuring Cost and Reserve [Line Items]
Restructuring	$210,000	($3,564,000)
Insurance gain	400,000
Restructuring reserve	1,716,000			2,523,000
Corporate Restructuring 2014
Restructuring Cost and Reserve [Line Items]
Restructuring			-6,500,000
Number of positions eliminated			96
Workforce reduction (as a percent)			5.00%
Employee Severance | Corporate Restructuring 2014
Restructuring Cost and Reserve [Line Items]
Restructuring				-3,500,000
Facility Closing | Corporate Restructuring 2014
Restructuring Cost and Reserve [Line Items]
Restructuring			-2,200,000
Other | Corporate Restructuring 2014
Restructuring Cost and Reserve [Line Items]
Restructuring			-137,000
Net Optics, Inc.
Restructuring Cost and Reserve [Line Items]
Number of positions eliminated		45
Workforce reduction (as a percent)		2.30%
Net Optics, Inc. | Employee Severance
Restructuring Cost and Reserve [Line Items]
Restructuring			-4,100,000	-2,000,000
Net Optics, Inc. | Facility Closing
Restructuring Cost and Reserve [Line Items]
Restructuring				-1,100,000
Net Optics, Inc. | Other
Restructuring Cost and Reserve [Line Items]
Restructuring				($323,000)

Restructuring_Costs_Activity_R

Restructuring Costs - Activity Related to Restructuring Plan (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015
Restructuring Reserve [Roll Forward]
Accrual at beginning of period	$2,523
Charges	161
Payments	-860
Non-cash items	-108
Accrual at end of period	1,716
2014 Corporate Restructuring
Restructuring Reserve [Roll Forward]
Accrual at beginning of period	1,940
Charges	142
Payments	-469
Non-cash items	0
Accrual at end of period	1,613
Net Optics Restructuring
Restructuring Reserve [Roll Forward]
Accrual at beginning of period	337
Charges	19
Payments	-356
Non-cash items	0
Accrual at end of period	0
Other
Restructuring Reserve [Roll Forward]
Accrual at beginning of period	246
Charges	0
Payments	-35
Non-cash items	-108
Accrual at end of period	$103

Debt_Convertible_Senior_Notes_

Debt - Convertible Senior Notes (Details) (USD $)	0 Months Ended	3 Months Ended
	Dec. 07, 2010	Mar. 31, 2015	Mar. 31, 2014	Dec. 07, 2010
Debt Instrument [Line Items]
Amortization		$335,000	$300,000
Convertible Notes Payable | Senior Notes
Debt Instrument [Line Items]
Aggregate principal amount	200,000,000			200,000,000
Stated rate (as a percent)	3.00%			3.00%
Minimum aggregate principal amount of outstanding notes threshold (as a percent)	25.00%			25.00%
Default period (in days)	60 days
Waiver on notes outstanding (as a percent)	50.00%			50.00%
Remedy period (in days)	180 days
Interest rate change (as a percent)	0.50%
Amortization		300,000	300,000
Conversion ratio	51.4536
Convertible principal amount	1,000			1,000
Conversion price (in dollars per share)	$19.43			$19.43
Redemption percentage	100.00%
Convertible Notes Payable | Senior Notes | Fair Value, Inputs, Level 2
Debt Instrument [Line Items]
Estimated fair value		$200,400,000

Debt_2015_Credit_Agreement_Det

Debt - 2015 Credit Agreement (Details) (USD $)	3 Months Ended		0 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Mar. 02, 2015	Mar. 03, 2015	7-May-15
			quarter
Debt Instrument [Line Items]
Amortization	$335,000	$300,000
Notes Payable to Banks | 2015 Credit Agreement
Debt Instrument [Line Items]
Aggregate principal amount				40,000,000
Collateral amounts	90,000,000		50,000,000
Minimum available liquidity in case of business acquisition			75,000,000
Number of quarters			11
Fixed charge coverage ratio	1.25
Consolidated total leverage ratio	3
Notes Payable to Banks | 2015 Credit Agreement | Restricted Cash
Debt Instrument [Line Items]
Collateral amounts	10,000,000
Notes Payable to Banks | 2015 Credit Agreement | Marketable Securities
Debt Instrument [Line Items]
Collateral amounts	80,000,000
Notes Payable to Banks | 2015 Credit Agreement | Minimum
Debt Instrument [Line Items]
Commitment fee (as a percent)			0.30%
Notes Payable to Banks | 2015 Credit Agreement | Maximum
Debt Instrument [Line Items]
Commitment fee (as a percent)			0.50%
Notes Payable to Banks | 2015 Credit Agreement | First-tier Foreign Subsidiaries
Debt Instrument [Line Items]
Outstanding equity (as a percent)			65.00%
Notes Payable to Banks | 2015 Credit Agreement | Ixia Technologies International Limited
Debt Instrument [Line Items]
Outstanding equity (as a percent)			65.00%
Notes Payable to Banks | 2015 Credit Agreement | First Four Quarters
Debt Instrument [Line Items]
Number of quarters			4
Quarterly principal payments			500,000
Notes Payable to Banks | 2015 Credit Agreement | Next Four Quarters
Debt Instrument [Line Items]
Number of quarters	4
Quarterly principal payments			1,000,000
Notes Payable to Banks | 2015 Credit Agreement | Last Three Quarters
Debt Instrument [Line Items]
Number of quarters			3
Quarterly principal payments			1,500,000
Notes Payable to Banks | 2015 Credit Agreement | Through December 31, 2015
Debt Instrument [Line Items]
Consolidated senior leverage ratio	2.5
Notes Payable to Banks | 2015 Credit Agreement | After December 31, 2015
Debt Instrument [Line Items]
Consolidated senior leverage ratio	2.25
Notes Payable to Banks | 2015 Credit Agreement | Eurodollar
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)			4.25%
Weighted average interest rate (as a percent)	4.42%
Notes Payable to Banks | 2015 Credit Agreement | Eurodollar | After First Anniversary of Closing Date | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)			2.00%
Notes Payable to Banks | 2015 Credit Agreement | Eurodollar | After First Anniversary of Closing Date | Maximum
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)			3.00%
Notes Payable to Banks | 2015 Credit Agreement | Base Rate
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)			3.25%
Notes Payable to Banks | 2015 Credit Agreement | Base Rate | After First Anniversary of Closing Date | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)			1.00%
Notes Payable to Banks | 2015 Credit Agreement | Base Rate | After First Anniversary of Closing Date | Maximum
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)			2.00%
Notes Payable to Banks | 2015 Credit Agreement | One-month Eurodollar
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)	4.25%
Line of Credit | Revolving Credit Facility | Silicon Valley Bank
Debt Instrument [Line Items]
Line of credit maximum borrowing capacity			60,000,000
Increased commitments			80,000,000
Minimum total available liquidity			25,000,000
Minimum total available liquidity, number of days			2
Capitalized debt issuance cost			1,200,000
Amortization period (in years)			3 years
Line of Credit | Revolving Credit Facility | Silicon Valley Bank | Leverage Ratio | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)			2.00%
Line of Credit | Revolving Credit Facility | Silicon Valley Bank | Leverage Ratio | Maximum
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)			3.00%
Line of Credit | Revolving Credit Facility | Silicon Valley Bank | Upon Default
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)			2.00%
Line of Credit | Standby Letter of Credit | Silicon Valley Bank
Debt Instrument [Line Items]
Line of credit maximum borrowing capacity			25,000,000
Line of Credit | Swingline Loans | Silicon Valley Bank
Debt Instrument [Line Items]
Line of credit maximum borrowing capacity			15,000,000
Subsequent Event | Notes Payable to Banks | 2015 Credit Agreement
Debt Instrument [Line Items]
Collateral payment period (in days)					$25,000,000

Debt_Prior_Credit_Facility_Det

Debt - Prior Credit Facility (Details) (Prior Revolving Credit Facility, Line of Credit, USD $)	3 Months Ended
	Mar. 31, 2015	Jan. 31, 2015	Dec. 31, 2014
Prior Revolving Credit Facility | Line of Credit
Debt Instrument [Line Items]
Line of credit maximum borrowing capacity	$46,500,000	$67,500,000	$150,000,000
Leverage ratio	3

Selected_Balance_Sheet_Data_In

Selected Balance Sheet Data - Investments in Marketable Securities (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Available-for-sale – short-term:
Amortized Cost	$113,671	$79,765
Gross Unrealized Gains	90	50
Gross Unrealized Losses	-21	-55
Fair Value	113,740	79,760
Short-term marketable securities: | U.S. Treasury, government and agency debt securities
Available-for-sale – short-term:
Amortized Cost	60,621	42,289
Gross Unrealized Gains	28	9
Gross Unrealized Losses	-1	-17
Fair Value	60,648	42,281
Short-term marketable securities: | Corporate debt securities
Available-for-sale – short-term:
Amortized Cost	53,050	37,476
Gross Unrealized Gains	62	41
Gross Unrealized Losses	-20	-38
Fair Value	$53,092	$37,479

Selected_Balance_Sheet_Data_Am

Selected Balance Sheet Data - Amortized Cost and Fair Value of Investments (Details) (USD $)	Mar. 31, 2015
In Thousands, unless otherwise specified
Amortized Cost
Due in less than 1 year	$37,644
Due within 1-2 years	55,354
Due within 2-5 years	20,138
Due after 5 years	535
Total	113,671
Fair Value
Due in less than 1 year	37,660
Due within 1-2 years	55,399
Due within 2-5 years	20,146
Due after 5 years	535
Total	$113,740

Selected_Balance_Sheet_Data_In1

Selected Balance Sheet Data - Inventories (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Balance Sheet Related Disclosures [Abstract]
Raw materials	$4,821	$5,502
Work in process	12,337	18,047
Finished goods	19,653	21,277
Inventories	$36,811	$44,826

Selected_Balance_Sheet_Data_De

Selected Balance Sheet Data (Details) (USD $)	3 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Balance Sheet Related Disclosures [Abstract]
Marketable securities pledged as collateral	$80
Weighted average contractual maturity (in years)	1 year 153 days	1 year 252 days
Accrued compensation and related expenses	12.9	9.9
Accrued vacation	$7.80	$7.50

Goodwill_and_Other_Intangible_2

Goodwill and Other Intangible Assets - Purchased Intangible Assets (Details) (USD $)	3 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Other intangible assets:
Gross	$311,874	$311,648
Accumulated Amortization	-177,463	-166,540
Net	134,411	145,108
Technology
Other intangible assets:
Weighted Average Useful Life (in years)	5 years 6 months	5 years 6 months
Gross	185,665	185,665
Accumulated Amortization	-112,592	-106,953
Net	73,073	78,712
Customer relationships
Other intangible assets:
Weighted Average Useful Life (in years)	6 years	6 years
Gross	71,700	71,700
Accumulated Amortization	-43,945	-40,938
Net	27,755	30,762
Service agreements
Other intangible assets:
Weighted Average Useful Life (in years)	6 years 146 days	6 years 146 days
Gross	30,100	30,100
Accumulated Amortization	-9,751	-8,577
Net	20,349	21,523
Trademark
Other intangible assets:
Weighted Average Useful Life (in years)	4 years	5 years 36 days
Gross	8,000	11,300
Accumulated Amortization	-4,141	-5,033
Net	3,859	6,267
Non-compete
Other intangible assets:
Weighted Average Useful Life (in years)	5 years 36 days	4 years
Gross	11,300	8,000
Accumulated Amortization	-5,525	-3,641
Net	5,775	4,359
Other
Other intangible assets:
Weighted Average Useful Life (in years)	4 years 73 days	4 years 73 days
Gross	5,109	4,883
Accumulated Amortization	-1,509	-1,398
Net	$3,600	$3,485

Goodwill_and_Other_Intangible_3

Goodwill and Other Intangible Assets - Estimated Future Amortization Expense of Purchased Intangible Assets (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Goodwill and Intangible Assets Disclosure [Abstract]
Remaining in 2015	$31,351
2016	37,859
2017	31,861
2018	20,586
2019	7,351
2020	3,727
Thereafter	1,676
Net	$134,411	$145,108

Shareholders_Equity_Summary_of

Shareholders' Equity - Summary of Comprehensive Income (Loss) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Other comprehensive gain	$70	$169
Gains and Losses on Available-for- Sale Securities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	-32
Other comprehensive income before reclassifications	93
Amounts reclassified from accumulated other comprehensive loss	-18
Other comprehensive gain	75
Balance at end of period	43
Foreign Currency Items
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	-761
Other comprehensive income before reclassifications	-5
Amounts reclassified from accumulated other comprehensive loss	0
Other comprehensive gain	-5
Balance at end of period	-766
Total
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	-793
Other comprehensive income before reclassifications	88
Amounts reclassified from accumulated other comprehensive loss	-18
Other comprehensive gain	70
Balance at end of period	($723)

Loss_Per_Share_Computation_of_

Loss Per Share - Computation of Basic and Diluted Earnings Per Share (Details) (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Basic presentation:
Net loss	($9,611)	($19,472)
Weighted average common shares outstanding	78,706	76,951
Basic loss per share (in dollars per share)	($0.12)	($0.25)
Diluted presentation:
Net loss	-9,611	-19,472
Interest expense on convertible senior notes, net of tax	0	0
Net loss used for diluted loss per share	($9,611)	($19,472)
Denominator for dilutive (loss) earnings per share: (in shares)
Stock options and other share-based awards	0	0
Convertible senior notes	0	0
Dilutive common shares	78,706	76,951
Diluted loss per share (in dollars per share)	($0.12)	($0.25)

Loss_Per_Share_Details

Loss Per Share (Details)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Dec. 07, 2010
Convertible Debt Securities
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Securities excluded (in shares)	10.3	10.3
Equity Option
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Securities excluded (in shares)	4.8	3.9
Senior Notes | Convertible Notes Payable
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stated rate (as a percent)			3.00%

Concentrations_Revenue_Concent

Concentrations - Revenue Concentration, Product Lines (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	$120,962	$113,733
Network Test Solutions
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	85,347	89,525
Network Visibility Solutions
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	$35,615	$24,208

Concentrations_Revenue_Concent1

Concentrations - Revenue Concentration, Customers (Details) (Sales Revenue, Goods, Net, Customer Concentration Risk)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Customer A
Concentration Risk [Line Items]
Customer (as a percent)	10.10%	10.30%
Customer B
Concentration Risk [Line Items]
Customer (as a percent)	11.60%

Concentrations_Total_Receivabl

Concentrations - Total Receivables, Customers (Details) (Customer A, Accounts Receivable, Customer Concentration Risk)	3 Months Ended
	Mar. 31, 2015
Customer A | Accounts Receivable | Customer Concentration Risk
Concentration Risk [Line Items]
Customer A	15.20%

Concentrations_Geographic_Conc

Concentrations - Geographic Concentration (Details) (Sales Revenue, Net, Geographic Concentration Risk, International)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Sales Revenue, Net | Geographic Concentration Risk | International
Note 10 - Concentrations (Details) - Geographic Concentration [Line Items]
International revenues	38.40%	41.00%

Concentrations_Geographical_Lo

Concentrations - Geographical Locations of Property, Equipment, Net (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Note 10 - Concentrations (Details) - Geographical Locations of Property, Equipment, Net [Line Items]
Property and equipment, net	$38,444	$37,648
United States
Note 10 - Concentrations (Details) - Geographical Locations of Property, Equipment, Net [Line Items]
Property and equipment, net	25,175	24,697
India
Note 10 - Concentrations (Details) - Geographical Locations of Property, Equipment, Net [Line Items]
Property and equipment, net	6,167	6,035
Romania
Note 10 - Concentrations (Details) - Geographical Locations of Property, Equipment, Net [Line Items]
Property and equipment, net	3,758	3,857
Other
Note 10 - Concentrations (Details) - Geographical Locations of Property, Equipment, Net [Line Items]
Property and equipment, net	$3,344	$3,059

Fair_Value_Measurements_Financ

Fair Value Measurements - Financial Assets Carried at Fair Value (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Short-term marketable securities:
Investments	$113,740	$79,760
Total financial assets	131,600	85,376
Cash equivalents: | Money market funds
Cash equivalents:
Cash equivalents:	915	267
Cash equivalents: | Corporate debt securities
Cash equivalents:
Cash equivalents:	16,945	5,349
Short-term marketable securities: | Corporate debt securities
Short-term marketable securities:
Investments	53,092	37,479
Short-term marketable securities: | U.S. Treasury, government and agency debt securities
Short-term marketable securities:
Investments	60,648	42,281
Quoted Prices in Active Markets for Identical Assets (Level 1)
Short-term marketable securities:
Total financial assets	915	267
Quoted Prices in Active Markets for Identical Assets (Level 1) | Cash equivalents: | Money market funds
Cash equivalents:
Cash equivalents:	915	267
Quoted Prices in Active Markets for Identical Assets (Level 1) | Cash equivalents: | Corporate debt securities
Cash equivalents:
Cash equivalents:	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Short-term marketable securities: | Corporate debt securities
Short-term marketable securities:
Investments	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Short-term marketable securities: | U.S. Treasury, government and agency debt securities
Short-term marketable securities:
Investments	0	0
Significant Other Observable Inputs (Level 2)
Short-term marketable securities:
Total financial assets	130,685	85,109
Significant Other Observable Inputs (Level 2) | Cash equivalents: | Money market funds
Cash equivalents:
Cash equivalents:	0	0
Significant Other Observable Inputs (Level 2) | Cash equivalents: | Corporate debt securities
Cash equivalents:
Cash equivalents:	16,945	5,349
Significant Other Observable Inputs (Level 2) | Short-term marketable securities: | Corporate debt securities
Short-term marketable securities:
Investments	53,092	37,479
Significant Other Observable Inputs (Level 2) | Short-term marketable securities: | U.S. Treasury, government and agency debt securities
Short-term marketable securities:
Investments	60,648	42,281
Significant Unobservable Inputs (Level 3)
Short-term marketable securities:
Total financial assets	0	0
Significant Unobservable Inputs (Level 3) | Cash equivalents: | Money market funds
Cash equivalents:
Cash equivalents:	0	0
Significant Unobservable Inputs (Level 3) | Cash equivalents: | Corporate debt securities
Cash equivalents:
Cash equivalents:	0	0
Significant Unobservable Inputs (Level 3) | Short-term marketable securities: | Corporate debt securities
Short-term marketable securities:
Investments	0	0
Significant Unobservable Inputs (Level 3) | Short-term marketable securities: | U.S. Treasury, government and agency debt securities
Short-term marketable securities:
Investments	$0	$0

Commitments_and_Contingencies_

Commitments and Contingencies (Details) (Pending Litigation)	0 Months Ended		3 Months Ended
	Nov. 05, 2014	Jul. 18, 2014	Mar. 31, 2015
			lawsuit
Securities Class Action
Loss Contingencies [Line Items]
Number of days to respond	30 days	30 days
Shareholder Derivative Action
Loss Contingencies [Line Items]
Number of lawsuits			2

Income_Taxes_Details

Income Taxes (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Prepaid Expenses and Other Current Assets
Income Taxes (Details) [Line Items]
Current deferred tax assets	$15.90	$15.50
Other Assets
Income Taxes (Details) [Line Items]
Noncurrent deferred tax assets	11.9	11.9
Other Liabilities
Income Taxes (Details) [Line Items]
Noncurrent deferred tax liabilities	$1.10	$1.40