Gigamon (GIMO) 10-Q 3 Nov 17 2017 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2017	Oct. 25, 2017
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q3
Trading Symbol	GIMO
Entity Registrant Name	GIGAMON INC.
Entity Central Index Key	1,484,504
Current Fiscal Year End Date	--12-30
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		37,328,845

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
CURRENT ASSETS:
Cash and cash equivalents	$ 173,182	$ 148,926
Short-term investments	91,380	109,238
Accounts receivable, net of allowance for doubtful accounts and sales returns of $960 and $979, as of September 30, 2017 and December 31, 2016, respectively	71,741	75,522
Inventories	15,472	11,347
Prepaid expenses and other current assets	12,048	9,909
Total current assets	363,823	354,942
Property and equipment, net	20,735	11,809
Deferred tax assets, net	50,734	33,094
Other assets, non-current	1,103	1,154
TOTAL ASSETS	436,395	400,999
CURRENT LIABILITIES:
Accounts payable	5,585	5,208
Accrued liabilities	26,897	34,649
Deferred revenue	69,960	68,997
Total current liabilities	102,442	108,854
Deferred revenue, non-current	32,126	28,785
Deferred and other tax liabilities, non-current	553	201
Other liabilities, non-current	933	499
TOTAL LIABILITIES	136,054	138,339
Commitments and Contingencies (Note 5)
STOCKHOLDERS’ EQUITY
Preferred stock—$0.0001 par value; 20,000 shares authorized, no shares issued or outstanding as of September 30, 2017 and December 31, 2016, respectively.	0	0
Common stock—$0.0001 par value; 1,000,000 shares authorized, 37,309 and 36,303 shares issued and outstanding as of September 30, 2017 and December 31, 2016, respectively.	4	4
Additional paid-in capital	298,400	256,774
Accumulated other comprehensive income (loss)	(75)	(17)
Retained earnings (accumulated deficit)	2,012	5,899
TOTAL STOCKHOLDERS’ EQUITY	300,341	262,660
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	$ 436,395	$ 400,999

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Accounts receivable - allowance	$ 960	$ 979
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	20,000,000	20,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	1,000,000,000	1,000,000,000
Common stock, shares issued	37,309,000	36,303,000
Common stock, shares outstanding	37,309,000	36,303,000

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Oct. 01, 2016	Sep. 30, 2017	Oct. 01, 2016
Revenue:
Product	$ 51,861	$ 59,835	$ 139,063	$ 155,805
Service	27,330	23,677	78,832	70,021
Total revenue	79,191	83,512	217,895	225,826
Cost of revenue:
Product	11,401	12,197	32,429	34,414
Service	3,049	2,141	8,649	6,562
Total cost of revenue	14,450	14,338	41,078	40,976
Gross profit	64,741	69,174	176,817	184,850
Operating expenses:
Research and development	18,783	18,306	59,451	50,914
Sales and marketing	34,914	31,994	105,247	88,494
General and administrative	10,697	8,887	30,033	26,029
Total operating expenses	64,394	59,187	194,731	165,437
Income (loss) from operations	347	9,987	(17,914)	19,413
Interest income	541	235	1,374	661
Other expense, net	(241)	(144)	(433)	(386)
Income (loss) before income tax benefit	647	10,078	(16,973)	19,688
Income tax benefit (provision)	1,531	(3,999)	9,576	23,321
Net income (loss)	$ 2,178	$ 6,079	$ (7,397)	$ 43,009	[1]
Net income (loss) per share:
Basic (in dollars per share)	$ 0.06	$ 0.17	$ (0.20)	$ 1.22
Diluted (in dollars per share)	$ 0.06	$ 0.16	$ (0.20)	$ 1.15
Weighted average shares used in computing net income (loss) per share:
Basic (in shares)	37,196	35,770	36,885	35,171
Diluted (in shares)	39,574	38,113	36,885	37,341
[1]	Reflects the impact of the adoption of the accounting standard update related to Improvements to Employee Share-Based Payment Accounting, which amends Compensation - Stock Compensation.

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Oct. 01, 2016	Sep. 30, 2017	Oct. 01, 2016
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 2,178	$ 6,079	$ (7,397)	$ 43,009	[1]
Other comprehensive income (loss):
Unrealized gain (loss) on available-for-sale investments, net	29	(31)	(58)	83
Comprehensive income (loss)	$ 2,207	$ 6,048	$ (7,455)	$ 43,092
[1]	Reflects the impact of the adoption of the accounting standard update related to Improvements to Employee Share-Based Payment Accounting, which amends Compensation - Stock Compensation.

Condensed Consolidated Stateme6

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Oct. 01, 2016	[1]
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income (loss)	$ (7,397)	$ 43,009
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	6,411	4,815
Stock-based compensation expense	39,991	28,884
Deferred income taxes	(10,147)	(31,570)
Inventory write-down	0	0
Other	148	366
Changes in operating assets and liabilities:
Accounts receivable	3,672	(11,567)
Inventories	(4,761)	(4,316)
Prepaid expenses and other assets	(1,944)	(2,991)
Accounts payable	532	54
Accrued liabilities and other liabilities	(9,308)	3,470
Deferred revenue	4,304	1,015
Net cash provided by (used in) operating activities	21,501	31,169
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchase of short-term investments	(78,099)	(84,773)
Proceeds from maturities of short-term investments	96,012	85,747
Purchase of property and equipment	(12,179)	(6,001)
Net cash provided by (used in) investing activities	5,734	(5,027)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from employee stock purchase plan	9,443	6,785
Proceeds from exercise of stock options	983	9,654
Shares repurchased for tax withholdings on vesting of restricted stock units	(12,592)	(7,240)
Net cash provided by (used in) financing activities	(2,166)	9,199
NET INCREASE (DECREASE) IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH	25,069	35,341
CASH, CASH EQUIVALENTS AND RESTRICTED CASH — Beginning of period	148,926	120,212
CASH, CASH EQUIVALENTS AND RESTRICTED CASH — End of period	173,995	155,553
Reconciliation to cash and cash equivalents and Other assets, non-current
Total cash, cash equivalents and restricted cash	148,926	120,212
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION:
Income taxes paid during the period	1,254	2,843
NONCASH INVESTING AND FINANCING ACTIVITIES:
Unpaid property and equipment purchases	$ 3,194	$ 707
[1]	Reflects the impact of the adoption of the accounting standard update related to Improvements to Employee Share-Based Payment Accounting, which amends Compensation - Stock Compensation.

Description of the Company

Description of the Company	9 Months Ended
	Sep. 30, 2017
Accounting Policies [Abstract]
Description of the Company	Description of the Company The Company Gigamon Inc. (the “Company”) designs, develops and sells products and services that together provide customers visibility and control of network traffic. The Company serves global enterprises, governments and service providers that seek to maintain and improve the security, reliability and performance of their network infrastructure.

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2017
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Basis of Presentation and Consolidation The Company prepared its condensed consolidated financial statements in accordance with U.S. generally accepted accounting principles (“GAAP”) and applicable rules and regulations of the Securities and Exchange Commission (the “SEC”) regarding interim financial reporting. Certain information and note disclosures normally included in the financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. As such, the unaudited information included in this Quarterly Report on Form 10-Q should be read in conjunction with the audited consolidated financial statements and accompanying notes included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2016 . There have been no changes to the Company’s significant accounting policies described in the Annual Report on Form 10-K that have had a material impact on the Company’s condensed consolidated financial statements and related notes except for the adoption of the accounting standard update related to Improvements to Employee Share-Based Payment Accounting, which amends Compensation - Stock Compensation and the accounting standard update related to restricted cash, which affected the presentation in the condensed consolidated statements of cash flows. Certain prior periods’ amounts were reclassified to conform to the current year’s presentation. None of these reclassifications impacted the reported net income (loss) or earnings per share for any of the periods presented. The Company's fiscal year is 52 or 53 weeks and ends on the last Saturday in December. Fiscal 2016 was a 53-week fiscal year ending on December 31, 2016 ; the first quarter was a 14-week quarter ended on April 2, 2016 and each subsequent quarter was a 13-week quarter. Fiscal 2017 is a 52-week fiscal year ending on December 30, 2017 , with each quarter therein being a 13-week quarter. Unaudited Interim Financial Statements The accompanying unaudited interim condensed consolidated financial statements have been prepared on a basis consistent with the annual consolidated financial statements and, in the opinion of management, reflect all adjustments, which include normal recurring adjustments, necessary to fairly state the Company’s financial position as of September 30, 2017 , its results of operations and comprehensive income (loss) for the three and nine months ended September 30, 2017 and October 1, 2016 , respectively, and cash flows for the nine months ended September 30, 2017 and October 1, 2016 , respectively. The financial data and the other financial information disclosed in the accompanying notes to the condensed consolidated financial statements related to these three and nine month periods are also unaudited. The fiscal year-end condensed consolidated balance sheet data was derived from audited financial statements, but does not include all disclosures required by GAAP. The condensed consolidated statements of operations for the three and nine months ended September 30, 2017 is not necessarily indicative of the results to be expected for the full fiscal year or any other future periods. Principles of Consolidation The condensed consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation. Use of Estimates The preparation of condensed consolidated financial statements in conformity with GAAP requires management to make certain estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenues and expenses during the reported periods. On an ongoing basis, the Company evaluates its estimates, including but not limited to those related to revenue recognition, allowance for doubtful accounts, warranty reserve, excess and obsolete inventory write-downs, stock-based compensation expense, depreciable useful lives and income taxes. The Company bases its estimates on historical experience, projections for future performance and other assumptions that it believes to be reasonable under the circumstances. Actual results could differ materially from those estimates. Concentrations The Company operates in highly competitive and rapidly changing markets that could negatively impact the Company’s operating results. A number of components that meet the Company’s manufacturing requirements are available only from single source suppliers. In addition, the Company relies on two contract manufacturers to manufacture a substantial majority of its products. The inability of its single source suppliers and contract manufacturers to provide the Company with adequate supplies of high-quality components and products could cause a delay in order fulfillment, which could adversely affect the Company’s revenue, cost of revenue and operating results. Financial instruments that potentially subject the Company to significant concentrations of credit risk consist principally of cash, cash equivalents, short-term investments and accounts receivable. The majority of the Company's cash, cash equivalents and short-term investments are held in, or managed by a limited number of major financial institutions in the United States that management believes are creditworthy. Such deposits may exceed the insured limits provided on them. The Company mitigates credit risk associated with its accounts receivable by performing ongoing credit evaluations of its customers and determines if it needs to establish an allowance for doubtful accounts for estimated losses based on management’s assessment of the collectability of customer accounts. The following customers represented more than 10% or more of total revenue or accounts receivable: Three Months Ended Nine Months Ended September 30, 2017 October 1, 2016 September 30, 2017 October 1, 2016 Percent of Revenue: Customer A (distributor) * 38 % 16 % 35 % Customer B (distributor) 36 % 24 % 29 % 25 % Customer C (distributor) 10 % * * * Customer D (end user) * * * 12 % * Represents less than 10% of total revenue As of September 30, 2017 December 31, 2016 Percent of Accounts Receivable: Customer A (distributor) 10 % 16 % Customer B (distributor) 34 % 32 % Customer C (distributor) 16 % * Customer D (end user) * 10 % Recent Accounting Pronouncements New Accounting Updates Recently Adopted The Company has adopted the accounting standard update related to Improvements to Employee Share-Based Payment Accounting, which amends Compensation – Stock Compensation during the first quarter of fiscal 2017. Specifically, the Company elected to account for forfeitures as they occur, rather than estimate expected forfeitures. The net cumulative effect of the change was recognized as a $3.6 million reduction to retained earnings as of January 1, 2017. Stock-based excess tax benefits or shortfalls are now reflected in the results of operations as a component of the income tax benefit (provision), whereas they previously were recognized in equity. The cumulative impact of this change was recorded as a deferred tax asset of $7.6 million for the previously unrecognized excess tax benefits with an adjustment of $7.1 million and $0.5 million to retained earnings and a valuation allowance for a certain jurisdiction, respectively. Additionally, the Company's condensed consolidated statements of cash flows now include excess tax benefits as an operating activity with the prior period adjusted accordingly. The Company has adopted the restricted cash guidance, which requires amounts generally described as restricted cash and restricted cash equivalents be included with cash and cash equivalents when reconciling the total beginning and ending amounts for the periods presented in the condensed consolidated statements of cash flows in the first quarter of fiscal 2017 using a retrospective transition method for each period presented. Recent Accounting Updates Not Yet Effective In May 2014, the Financial Accounting Standards Board (the "FASB") issued an accounting standard update related to revenue from contracts with customers, which supersedes the revenue recognition requirements in the current Accounting Standards Codification. This standard is based on the principle that revenue is recognized to depict the transfer of 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. This standard also requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts, including significant judgments and changes in judgments and assets recognized from costs incurred to obtain or fulfill a contract. In August 2015, the FASB voted to defer the effective date of this standard by one year. Additionally, in March 2016 the FASB issued additional information that clarifies the implementation guidance on principal versus agent considerations. The new standard permits adoption either by using (i) a full retrospective approach for all periods presented in the period of adoption or (ii) a modified retrospective approach with the cumulative effect of initially applying the new standard recognized at the date of initial application and providing certain additional disclosures. The new standard is effective for annual reporting periods beginning after December 15, 2017, with early adoption permitted for annual reporting periods beginning after December 15, 2016. The Company did not elect to early adopt, and accordingly, it will adopt the new standard effective for its fiscal year 2018. The Company is evaluating the impact of the new standard on its accounting policies, processes, and system requirements and currently plans to adopt using the full retrospective approach. However, a final decision regarding the adoption method has not been finalized at this time. The Company's final determination will depend on a number of factors, such as the significance of the impact of the new standard on our financial results, system readiness, including that of software procured from third-party providers, and its ability to accumulate and analyze the information necessary to assess the impact on prior period financial statements, as necessary. Revenue recognition for non-essential software is currently accounted for under the Software Revenue Recognition guidance, which entails allocating the arrangement consideration to deliverables that have established vendor specific objective evidence value (“VSOE”) or fair value and the residual to other deliverables based on third party evidence or best estimates of selling prices. Revenue from each deliverable is then recognized when all requirements are met for that specific deliverable. As the new standard does not retain the concept of VSOE, the Company preliminarily believes it will use the Standalone Selling Price to determine the appropriate amount to be allocated to each separate performance obligation using the Relative Selling Price approach. As part of the Company's preliminary evaluation, it has also considered the impact of the guidance relating to Other Assets and Deferred Costs; Contracts with customers, and the interpretations of the FASB Transition Resource Group for Revenue Recognition ("TRG") from their November 7, 2016 meeting with respect to capitalization and amortization of incremental costs of obtaining a contract. As a result of this new guidance, the Company preliminarily believes that it will capitalize certain costs of obtaining a contract, including additional sales commissions, as the new cost guidance, as interpreted by the TRG, requires the capitalization of all incremental costs that the Company incurs to obtain a contract with a customer that it would not have incurred if the contract had not been obtained, provided it expects to recover the costs. Under the Company's current accounting policy, it expenses the commission costs immediately as incurred. While the Company continues to assess the potential impacts of the new standard, it anticipates this standard could have a material impact on its consolidated financial statements. However, the Company cannot reasonably estimate quantitative information related to the impact of the new standard on its consolidated financial statements at this time. In February 2016, the FASB issued an accounting standard update which amends the existing accounting standards for leases. Consistent with current guidance, the recognition, measurement and presentation of expenses and cash flows arising from a lease by a lessee primarily will depend on its classification. Under the new guidance, a lessee will be required to recognize assets and liabilities for all leases with lease terms of more than 12 months. The effective date of this update will be for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018 using a modified retrospective transition method with early adoption permitted. The Company expects the standard to have a material impact on its assets and liabilities for the addition of right-of-use assets and lease liabilities, but the Company does not expect it to have a material impact on its results of operations or liquidity. In June 2016, the FASB issued new guidance that changes the accounting for recognizing impairments of financial assets. Under the new guidance, credit losses for certain types of financial instruments will be estimated based on expected losses. The new guidance also modifies the impairment models for available-for-sale debt securities and for purchased financial assets with credit deterioration since their origination. The effective date of this standard will be for annual periods ending after December 15, 2019, and interim periods within that reporting period. Early adoption is permitted starting in annual periods ending after December 15, 2018. The Company is evaluating the impact of this guidance on its consolidated financial statements. In October 2016, the FASB issued new guidance that requires a reporting entity to recognize the tax expense from intra-entity asset transfers of assets other than inventory in the selling entity’s tax jurisdiction when the transfer occurs, even though the pre-tax effects of that transaction are eliminated in consolidation. Any deferred tax asset that arises in the buying entity’s jurisdiction would also be recognized at the time of the transfer. The new guidance will likely impact reporting entities’ effective tax rates. The new guidance is effective for interim and annual periods beginning after December 15, 2017 and early adoption is permitted. The amendment should be adopted using the modified retrospective approach with a cumulative-effect adjustment recorded in retained earnings as of the beginning of the period of adoption. The Company is evaluating the impact of this guidance on its consolidated financial statements.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2017
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements The inputs used in the valuation methodologies in measuring fair value are defined in the fair value hierarchy as follows: Level 1 – Quoted prices in active markets for identical assets or liabilities. Level 2 – Inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3 – Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. The categorization of a financial instrument within the valuation hierarchy is based upon the lowest level of input that is significant to the fair value measurement. The carrying value of the Company’s accounts receivable, accounts payable and accrued liabilities approximates their fair value due to the short-term nature of these instruments. Cash Equivalents and Short-Term Investments The components of the Company’s cash equivalents and short-term investments are as follows (in thousands): Fair Value Measured Using September 30, 2017 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Cash equivalents: Money market funds $ 110,008 $ 110,008 $ — Commercial paper 8,418 8,418 Total cash equivalents $ 118,426 $ 110,008 $ 8,418 Short-term investments: Corporate debt securities $ 24,003 $ — $ 24,003 Commercial paper 2,465 2,465 U.S. agency debt securities 3,995 3,995 U.S. government securities 60,917 60,917 Total short-term investments $ 91,380 $ — $ 91,380 Fair Value Measured Using December 31, 2016 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Cash equivalents: Money market funds $ 99,992 $ 99,992 $ — Commercial paper 1,999 — 1,999 Total cash equivalents $ 101,991 $ 99,992 $ 1,999 Short-term investments: Corporate debt securities $ 10,110 $ — $ 10,110 Commercial paper 12,956 — 12,956 U.S. agency debt securities 21,697 — 21,697 U.S. government securities 64,475 — 64,475 Total short-term investments $ 109,238 $ — $ 109,238 The Company considers all highly liquid investments with maturity of three months or less at the time of purchase to be cash equivalents. The Company holds money market funds that invest primarily in high-quality short-term money-market instruments, and these funds are not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Company presents available-for-sale investments as current assets as they are available for the Company's current operations. Money market funds have been classified as Level 1 because these securities are valued based upon quoted prices in active markets. The Company’s Level 2 assets are priced using quoted market prices for similar instruments or non-binding market prices that are corroborated by observable market data. The Company uses inputs such as actual trade data, benchmark yields, broker/dealer quotes or alternative pricing sources with reasonable levels of price transparency which are obtained from quoted market prices, independent pricing vendors or other sources, to determine the ultimate fair value of these assets. The Company has no assets classified as Level 3. The Company’s policy is to recognize transfers among Level 1, Level 2 and Level 3 classifications as of the actual date of the events or change in circumstances that caused the transfers. The Company did not have any transfers between Level 1 and Level 2 in the nine months ended September 30, 2017 . As of September 30, 2017 and December 31, 2016 , the Company had no liabilities measured at fair value. Financial assets measured at amortized cost, gross unrealized gains, gross unrealized losses and fair value by significant investment categories are summarized as follows (in thousands): As of September 30, 2017 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Cash equivalents: Money market funds $ 110,008 $ — $ — $ 110,008 Commercial paper 8,418 8,418 Total cash equivalents $ 118,426 $ — $ — $ 118,426 Short-term investments: Corporate debt securities $ 24,021 $ 1 $ (19 ) $ 24,003 Commercial paper 2,465 — — 2,465 U.S. agency debt securities 3,998 — (3 ) 3,995 U.S. government securities 60,971 1 (55 ) 60,917 Total short-term investments $ 91,455 $ 2 $ (77 ) $ 91,380 As of December 31, 2016 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Cash equivalents: Money market funds $ 99,992 $ — $ — $ 99,992 Commercial paper 1,999 — — 1,999 Total cash equivalents $ 101,991 $ — $ — $ 101,991 Short-term investments: Corporate debt securities $ 10,119 $ — $ (9 ) $ 10,110 Commercial paper 12,956 — — 12,956 U.S. agency debt securities 21,698 1 (2 ) 21,697 U.S. government securities 64,482 8 (15 ) 64,475 Total short-term investments $ 109,255 $ 9 $ (26 ) $ 109,238 The Company had no realized gains or realized losses from sales of securities in the nine months ended September 30, 2017 . There were no securities in a material continuous loss position for 12 months or longer as of September 30, 2017 and December 31, 2016 . The contractual maturity date of the cash equivalents and short-term investments at estimated fair value was as follows (in thousands): As of September 30, 2017 December 31, 2016 Due within one year $ 201,453 $ 205,250 Due between one and five years 8,353 5,979 Total $ 209,806 $ 211,229

Balance Sheet Components

Balance Sheet Components	9 Months Ended
	Sep. 30, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Balance Sheet Components	Balance Sheet Components Inventories Inventories are comprised of the following (in thousands): As of September 30, 2017 December 31, 2016 Raw materials $ 94 $ 50 Finished goods 15,378 11,297 Total inventories $ 15,472 $ 11,347 Inventory is valued at the lower of cost computed on a first-in, first-out basis, or net realizable value. Property and equipment, net Property and equipment, net, are comprised of the following (in thousands): As of September 30, 2017 December 31, 2016 Equipment and machinery $ 25,403 $ 20,611 Furniture and fixtures 1,523 654 Leasehold improvements 9,665 3,367 Software 3,900 2,519 Total property and equipment 40,491 27,151 Less accumulated depreciation and amortization (19,756 ) (15,342 ) Total property and equipment, net $ 20,735 $ 11,809 Depreciation and amortization expense was $5.1 million and $5.3 million for nine months ended September 30, 2017 and fiscal 2016 , respectively. Accrued Liabilities Accrued liabilities are comprised of the following (in thousands): As of September 30, 2017 December 31, 2016 Accrued employee related costs $ 11,145 $ 25,468 Accrued inventory and other purchases 5,203 1,778 Accrued taxes payable 1,075 1,977 Accrued professional services 2,107 667 Other accruals 7,367 4,759 Total accrued liabilities $ 26,897 $ 34,649 Accrued Warranty Warranty activity and accrued warranty is comprised of the following (in thousands): Nine Months Ended September 30, 2017 October 1, 2016 Accrued warranty balance at beginning of period $ 960 $ 807 Accrual for warranty during the period 1,236 1,269 Actual costs incurred (1,247 ) (1,116 ) Accrued warranty balance at end of period $ 949 $ 960 As of Accrued warranty reported as: September 30, 2017 December 31, 2016 Accrued liabilities, current $ 706 $ 653 Other liabilities, non-current 243 307 Total accrued warranty $ 949 $ 960 Deferred Revenue Deferred revenue is comprised of the following (in thousands): As of September 30, 2017 December 31, 2016 Deferred service revenue $ 101,807 $ 97,646 Deferred product revenue 279 136 Total deferred revenue $ 102,086 $ 97,782 Accumulated Other Comprehensive Loss Accumulated other comprehensive loss consists of unrealized gains and losses from available-for-sale securities. The following summarizes the activity within accumulated other comprehensive loss (in thousands): Accumulated Other Comprehensive Loss Balance as of December 31, 2016 $ (17 ) Available-for-sale securities: Unrealized loss (58 ) Total other comprehensive loss (58 ) Balance as of September 30, 2017 $ (75 ) There was no material tax impact on the unrealized gains or losses and total other comprehensive income. There were no material reclassifications out of accumulated other comprehensive loss into the condensed consolidated statements of operations in the nine months ended September 30, 2017 and October 1, 2016 .

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Lease Commitments The Company leases office space for its current headquarters in Santa Clara, California and its United Kingdom subsidiary under non-cancelable operating leases that expire at various dates through fiscal 2025. The Company has also entered into lease agreements for additional office space in India, Sweden and Singapore. The Company recognizes rent expense on a straight-line basis over the lease period. Rent expense related to the Company’s operating leases was $1.5 million and $1.0 million for the three months ended September 30, 2017 and October 1, 2016 , respectively, and $3.8 million and $2.9 million for the nine months ended September 30, 2017 and October 1, 2016 , respectively. No material change in the future minimum lease payments under non-cancelable operating leases has occurred in the nine months ended September 30, 2017 and as reported in the Annual Report on Form 10-K for the fiscal year ended December 31, 2016 . Purchase Commitments The Company has agreements with two contract manufacturers for the manufacture of its products. The agreement with its primary contract manufacturer allows the contract manufacturer to procure components on the Company’s behalf based upon a production forecast provided by the Company. The Company also purchases raw materials directly from suppliers to be used by the contract manufacturers in the production of the Company’s products. The Company may be obligated to purchase component inventory that is non-cancelable. As of September 30, 2017 and December 31, 2016 , the Company’s non-cancelable purchase commitments for such component inventory were $22.2 million and $15.7 million , respectively. Legal Proceedings On January 27, 2017, a purported shareholder class action was filed in the United States District Court for the Northern District of California against the Company and three of its current and former officers. The plaintiff alleges that the Company made false and misleading statements about the Company’s business, operations, and prospects, including statements about the Company’s guidance, for the fourth quarter of 2016. The complaint, which was amended on September 22, 2017, seeks unspecified monetary damages, attorneys' fees and costs and other relief. The Company believes this lawsuit is without merit and intends to defend against it vigorously. The matter is still in the early stages and the Company will defend against the allegations accordingly. Due to the current early stage of the proceedings, the Company cannot reasonably estimate the loss or the range of possible losses, if any. Indemnification Obligations Under the indemnification provisions of its standard sales related contracts, the Company agrees to defend its customers against third-party claims asserting infringement of certain intellectual property rights, which may include patents, copyrights, trademarks, or trade secrets, and to pay judgments entered on such claims. The Company’s exposure under these indemnification provisions is generally limited to the total amount paid by its customer under the agreement. However, certain agreements include indemnification provisions that could potentially expose the Company to losses in excess of the amount received under the agreement. The Company has not incurred any costs as a result of such indemnifications and has not accrued any liabilities related to such obligations in its condensed consolidated financial statements. In addition, the Company indemnifies its officers, directors and certain key employees while they are serving in good faith in the company capacities. To date, there have been no claims under any indemnification provisions.

Stockholders' Equity

Stockholders' Equity	9 Months Ended
	Sep. 30, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stockholders' Equity	Stockholders’ Equity Equity Award Plans 2013 Equity Incentive Plan In May 2013, the Company adopted the 2013 Equity Incentive Plan (the “2013 Equity Plan”). All authorized but unissued shares of the Company’s 2012 Unit Option Plan (the “2012 Plan”) were added to the 2013 Equity Plan’s authorized pool in June 2013. The Company is authorized to issue up to a maximum of 2,929,481 shares of common stock for future issuance, plus up to an additional 4,967,172 shares upon termination of awards under the 2012 Plan. In addition, the 2013 Equity Plan is subject to increase annually on the first day of each of the Company’s fiscal years beginning with fiscal 2014, by an amount equal to the least of (i) 1,464,740 shares, (ii) 5% of the outstanding shares of common stock as of the last day of the immediately preceding fiscal year, or (iii) such other amount as determined by the Company's board of directors. Vested but unexercised options, under the 2013 Equity Plan, expire three months after termination of service with the Company. An additional 1,464,740 shares were authorized during the nine months ended September 30, 2017 . As of September 30, 2017 , outstanding awards under the 2013 Equity Plan and the 2012 Plan covered 3,588,518 shares and 343,037 shares of the Company's common stock, respectively. The 2013 Equity Plan permits the granting of stock options, stock appreciation rights, restricted stock, restricted stock units ("RSUs"), performance units and performance shares to employees, directors and consultants of the Company. Employee Stock Purchase Plan In conjunction with the completion of its initial public offering in June 2013 (the "IPO"), the Company adopted the 2013 Employee Stock Purchase Plan (the “ESPP”). A maximum of 439,422 shares were initially authorized for future issuance. In addition, the ESPP is subject to increase annually on the first day of each of the Company’s fiscal years beginning with fiscal 2014, by an amount equal to the least of (i) 439,422 shares, (i) 1.5% of the outstanding shares of common stock as of the last day of the immediately preceding fiscal year, or (iii) such other amount as determined by the Company’s board of directors. Eligible employees can purchase shares of the Company’s common stock at a discount through payroll deductions of up to 15% of their eligible compensation, subject to plan limitations. Employees are able to purchase shares at 85% of the lower of the fair market value of the Company’s common stock (i) at the date of commencement of the offering period or (ii) at the last day of the purchase period. The ESPP provides for a 24 -month offering period comprised of four purchase periods of approximately six months. The offering periods are scheduled to start on the first trading day on or after February 15 and August 15 of each year, except for the first offering period, which commenced on the first trading day upon the completion of the Company’s IPO, or June 12, 2013, and ended on August 17, 2015. In accordance with the terms of the ESPP, an additional 439,422 shares were authorized for future issuance during the nine months ended September 30, 2017 . The Company recorded stock-based compensation expense for its ESPP of $1.0 million and $4.9 million for the three and nine months ended September 30, 2017 , respectively, and $1.4 million and $2.7 million for the three and nine months ended October 1, 2016 , respectively. For the nine months ended September 30, 2017 there were two purchase periods that resulted in the issuance of 355,800 shares of the Company's common stock at a weighted average purchase price of $26.63 per share. Stock Options Stock options granted under the 2013 Equity Plan and formerly under the 2012 Plan (together, the “Equity Incentive Plans”), are generally subject to a four -year vesting period whereby stock options become 25% vested on the first anniversary of the grant date and then ratably monthly thereafter through the end of the vesting period. Vested stock options may be exercised up to 10 years from the vesting commencement date. Under the 2012 Plan, vested but unexercised stock options expire 30 days after termination of service with the Company. The following table summarizes the stock option activity under the Company’s Equity Incentive Plans: Number of Weighted- Weighted- Aggregate Balance — December 31, 2016 1,391,171 $ 21.19 6.39 $ 35,076 Options granted 177,777 $ 38.43 Options exercised (75,904 ) $ 12.95 Options forfeited/canceled (112,087 ) $ 25.28 Balance — September 30, 2017 1,380,957 $ 23.53 6.17 $ 27,239 Exercisable — September 30, 2017 927,460 $ 17.64 5.69 $ 22,728 Aggregate intrinsic value represents the difference between the exercise price of the awards and the Company’s fair value per share of $42.15 and $45.55 as of September 30, 2017 and December 31, 2016 , respectively, for the total number of underlying options. Restricted Stock Unit Activity RSUs generally vest over a period of one to four years. RSU vesting dates are determined by the Company. The vesting is subject to the employee’s continuing service with the Company over that period. Until vested, RSUs do not have the voting or dividend participation rights of the Company’s common stock and the shares of the Company’s common stock underlying the awards are not considered issued and outstanding. The cost of RSUs is determined using the fair value of the Company’s common stock on the date of the grant. The following table summarizes the RSU activity under the Company’s Equity Incentive Plans: Number of Weighted- Weighted- Aggregate December 31, 2016 2,466,049 $ 26.66 1.39 $ 112,329 RSUs awarded 1,500,180 $ 35.66 RSUs released (867,296 ) $ 25.84 RSUs forfeited (551,779 ) $ 28.60 As of September 30, 2017 2,547,154 $ 31.81 1.43 $ 107,363 Aggregate intrinsic value for RSUs represents the Company’s fair market value per share of $42.15 and $45.55 , as of September 30, 2017 and December 31, 2016 , respectively, for the total number of underlying RSUs. The Company withheld shares totaling $12.6 million in value as a result of employee withholding taxes based on the value of the RSUs on their vesting dates for the nine months ended September 30, 2017 . The total payments for the employees’ tax obligations to the taxing authorities are reflected as financing activities within the condensed consolidated statements of cash flows. Performance-Based Restricted Stock Units During the fiscal year ended December 31, 2016 , the Company awarded 193,000 shares of performance-based RSUs. The vesting conditions of these awards were tied to the Company's fiscal 2016 revenue and operating income performance. These performance-based RSUs could have vested from 0% to 200% of the target grant, based on attainment of the performance goals. The target achievement percentage became known as of December 31, 2016 . On December 31, 2016 , the Company concluded that 149.5% of the target grants were likely to vest. For the three and nine months ended September 30, 2017 , the Company recorded $0.2 million and $1.3 million , respectively, on a graded-vesting basis in stock-based compensation expense related to these performance-based RSU awards. As of September 30, 2017 , there were 66,875 RSUs subject to performance-based vesting criteria. Restricted Stock Award Activity During the nine months ended September 30, 2017 , the Company awarded 254,397 shares of restricted stock awards ("RSAs") at a weighted average grant date fair value of $30.72 , of which 33,345 RSAs with a weighted average grant date fair value of $30.82 vested in the period. RSA vesting dates are determined by the Company. The vesting is subject to the employee’s continuing service with the Company over that period. RSAs have the voting and dividend participation rights of the Company’s common stock. The cost of RSAs is determined using the fair value of the Company’s common stock on the date of the grant. Performance-Based Restricted Stock Awards During the nine months ended, the Company awarded 213,986 shares of performance-based RSAs at a weighted average grant date fair value of $32.01 , of which 6,166 awards with a weighted average grant date fair value of $23.78 vested. The vesting conditions of 166,570 of these awards are tied to the Company's fiscal 2017 revenue and operating income performance. These performance-based RSAs could vest from 0% to 200% of the target grant, based on attainment against the performance goals. Stock-Based Compensation Expense The fair value of the option awards and ESPP purchase rights granted and the assumptions used in the Black-Scholes option pricing model are summarized as follows: Three Months Ended Nine Months Ended September 30, October 1, September 30, October 1, Stock option awards: Expected term (in years) 4.6 0 4.6 4.6 Risk-free interest rate 1.8% —% 1.8% - 1.9% 1.4% Expected volatility 61.6% —% 61.6% - 62.0% 76.1% Expected dividend rate —% —% —% —% Grant date fair value per award $20.33 $— $18.67 - $20.33 $18.62 ESPP purchase right: Expected term (in years) 0.5 - 2.0 0.5 - 2.0 0.5 - 2.0 0.5 - 2.0 Risk-free interest rate 1.12% - 1.32% 0.46% - 0.72% 0.67% - 1.32% 0.42% - 0.74% Expected volatility 45.40% - 58.23% 43.9% - 54.6% 45.40% - 68.64% 43.9% - 67.2% Expected dividend rate —% —% —% —% Grant date fair value per share $11.12 - $18.40 $12.84 - $20.77 $11.12 - $18.40 $7.75 - $20.77 The following table summarizes the stock-based compensation expense recorded in the Company’s condensed consolidated statements of operations (in thousands): Three Months Ended Nine Months Ended September 30, October 1, September 30, October 1, Cost of revenue $ 333 $ 519 $ 1,802 $ 1,527 Research and development $ 4,040 3,397 14,453 9,800 Sales and marketing $ 3,163 3,062 13,108 8,802 General and administrative $ 3,437 3,126 10,628 8,755 Total stock-based compensation expense $ 10,973 $ 10,104 $ 39,991 $ 28,884 As of September 30, 2017 and December 31, 2016 , there was $ 0.4 million and $0.2 million of capitalized stock-based compensation costs, respectively, within the Company's inventory balance. As of September 30, 2017 , unrecognized compensation expense related to stock options, RSUs, RSAs, PSUs, PSAs and ESPP purchase rights was $4.7 million , $44.4 million , $4.1 million , $0.8 million , $0.6 million and $4.5 million , respectively.

Defined Contribution Plans

Defined Contribution Plans	9 Months Ended
	Sep. 30, 2017
Postemployment Benefits [Abstract]
Defined Contribution Plans	Defined Contribution Plans The Company’s contributions to its 401(k)-defined contribution plan, which are expensed immediately as compensation costs, were $0.9 million and $0.6 million for the three months ended September 30, 2017 and October 1, 2016 , respectively and $2.8 million and $1.7 million for the nine months ended September 30, 2017 and October 1, 2016 , respectively.

Income Tax

Income Tax	9 Months Ended
	Sep. 30, 2017
Income Tax Disclosure [Abstract]
Income Tax	Income Tax The Company recorded an income tax benefit of $1.5 million and $9.6 million for the three and nine months ended September 30, 2017 , respectively, and an income tax provision of $4.0 million and an income tax benefit of $23.3 million for the three and nine months ended October 1, 2016 , respectively. The income tax benefit for the three and nine months ended September 30, 2017 was primarily related to the Company's year-to-date pre-tax loss and a tax benefit related to stock-based compensation. As of September 30, 2017 , the Company considered all positive and negative evidence in making a determination that the Company will more likely than not be able to utilize its U.S. deferred tax assets. Such evidence included, among others, the Company's history of profitability, jurisdictional income recognition trends, forecasted income by jurisdiction and maintaining three years of cumulative taxable income in the U.S. federal tax jurisdiction as of September 30, 2017 . Therefore, the Company determined that there is sufficient positive evidence to conclude that it is more likely than not that it will utilize its U.S. deferred tax assets. Included in the net deferred tax asset balance is a $6.7 million valuation allowance that relates to research and development credits in a jurisdiction with a history of credits in excess of taxable profits. The Company adopted the accounting standard update related to Improvements to Employee Share-Based Payment Accounting, which amends Compensation – Stock Compensation in the first quarter of fiscal 2017 . As a result, the Company recorded a deferred tax asset of $7.6 million for the previously unrecognized excess tax benefits with an adjustment of $7.1 million and $0.5 million to retained earnings and a valuation allowance for a certain jurisdiction, respectively, on the accompanying condensed consolidated balance sheet. Additionally, the adoption resulted in net excess tax benefits in the Company's provision for income taxes of $4.8 million on its condensed consolidated statements of operations for the nine months ended September 30, 2017 . The Company files annual income tax returns in multiple tax jurisdictions worldwide. A number of years may lapse before an uncertain tax position is audited and finally resolved. While it is typically difficult to predict the final outcome or the timing of resolution of any particular uncertain tax position, the Company believes its reserves for income taxes reflect the most likely outcomes. The Company adjusts these reserves, as well as the related interest, in light of changing facts and circumstances. Settlement of any particular position would likely require the use of cash. As of September 30, 2017 , changes to the Company's uncertain tax positions in the next 12 months that are reasonably possible are not expected to have a material impact on the Company's financial position or results of operations. The Company recognizes interest and penalties related to uncertain tax positions as part of the income tax provision. To date, no such interest and penalties have been accrued.

Net Income (Loss) per Share

Net Income (Loss) per Share	9 Months Ended
	Sep. 30, 2017
Earnings Per Share [Abstract]
Net Income (Loss) per Share	Net Income (Loss) per Share Basic net income (loss) per share is computed using the weighted average number of common shares outstanding for the period, excluding unvested restricted stock. Due to the net loss incurred in the nine months ended September 30, 2017 , potential dilutive securities were excluded from the calculation of diluted net loss per share attributable to common stockholders for such period as their effect was anti-dilutive. Diluted net income (loss) per share is computed based upon the weighted average common shares outstanding for the period plus dilutive potential common shares, including unvested stock awards and stock options using the treasury stock method. The following table presents the computation of basic and diluted net income (loss) per share attributable to common stockholders (in thousands, except per share data): Three Months Ended Nine Months Ended September 30, 2017 October 1, 2016 September 30, 2017 October 1, 2016 Numerator: Net income (loss) 2,178 6,079 (7,397 ) 43,009 Denominator: Weighted average shares used for basic net income (loss) per share computation 37,196 35,770 36,885 35,171 Weighted average effect of dilutive securities: Stock options 610 666 — 696 Stock Awards (1) 1,668 1,488 — 1,271 ESPP purchase rights 100 189 — 203 Weighted average shares used for diluted net income (loss) per share computation 39,574 38,113 36,885 37,341 Net income (loss) per share attributable to common stockholders: Basic $ 0.06 $ 0.17 $ (0.20 ) $ 1.22 Diluted $ 0.06 $ 0.16 $ (0.20 ) $ 1.15 (1) Includes RSUs, performance-based RSUs, RSAs and performance-based RSAs The weighted average number of shares outstanding used in the computation of diluted net income (loss) per share does not include the effect of the following shares of potentially outstanding common stock because the effect would have been anti-dilutive for the periods presented (in thousands): Three Months Ended Nine Months Ended September 30, 2017 October 1, 2016 September 30, 2017 October 1, 2016 Equity awards to purchase common stock 258 20 310 74

Segment Information

Segment Information	9 Months Ended
	Sep. 30, 2017
Segment Reporting [Abstract]
Segment Information	Segment Information The Company currently has one operating segment. The Company considers operating segments to be components of the Company’s business for which separate financial information is available that is evaluated regularly by the Company’s chief operating decision maker in deciding how to allocate resources and in assessing performance. The Company has determined that the chief operating decision maker is its chief executive officer. The chief executive officer reviews financial information presented on a consolidated basis for purposes of allocating resources and evaluating financial performance. Accordingly, the Company has determined that it has a single operating and reportable segment. The following table summarizes the Company’s revenue by geographic region, based on shipment location (in thousands): Three Months Ended Nine Months Ended September 30, 2017 October 1, 2016 September 30, 2017 October 1, 2016 United States $ 56,253 $ 67,205 $ 162,661 $ 179,678 Rest of Americas 3,126 2,562 7,886 7,385 Europe, Middle East and Africa 10,392 7,370 26,943 21,349 Asia Pacific 9,420 6,375 20,405 17,414 Total $ 79,191 $ 83,512 $ 217,895 $ 225,826 The Company’s long-lived assets by geographic region are summarized as follows (in thousands): As of September 30, 2017 December 31, 2016 United States $ 18,569 $ 9,907 India 1,496 1,271 Other 670 631 Total $ 20,735 $ 11,809

Subsequent Event

Subsequent Event	9 Months Ended
	Sep. 30, 2017
Subsequent Events [Abstract]
Subsequent Event	Subsequent Event On October 26, 2017, the Company entered into an agreement and plan of merger (“Merger Agreement”) with Ginsberg Holdco, Inc. (“Newco”) and Ginsberg Merger Sub, Inc., a wholly-owned subsidiary of Newco (“Merger Sub”), providing for the merger of Merger Sub with and into the Company (the “Merger”), with the Company surviving the Merger as a wholly-owned subsidiary of Newco. Newco and Merger Sub were formed by Elliott Associates, L.P. and Elliott International, L.P. (the “Elliott Funds”), funds affiliated with Elliott Management Corporation (“Elliott”). Capitalized terms not otherwise defined have the meanings set forth in the Merger Agreement. At the Effective Time of the Merger, each share of common stock of the Company (the Company Common Stock) issued and outstanding as of immediately prior to the Effective Time (including Shares of Restricted Stock and excluding Dissenting Shares) will be cancelled and extinguished and automatically converted into the right to receive cash in an amount equal to $38.50 , without interest thereon (the Per Share Price). Company Options and awards generally will be cancelled and converted into the right to receive the Per Share Price, less, in the case of Company Options, the exercise price per share. Newco has secured committed financing, consisting of a combination of equity financing to be provided by the Elliott Funds and debt financing from Jefferies Finance LLC, the aggregate proceeds of which will be sufficient for Newco to pay the aggregate merger consideration and all related fees and expenses. Newco has committed to use its reasonable best efforts to obtain the debt financing on the terms and conditions described in the debt commitment letter entered into in connection with the Merger Agreement on October 26, 2017. The transaction is not subject to any financing condition. Consummation of the Merger is subject to customary closing conditions, including, without limitation, the absence of certain legal impediments, the expiration or termination of the required waiting periods under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended, and approval by the Company’s stockholders and a minimum cash condition. The Company has made customary representations and warranties in the Merger Agreement and has agreed to customary covenants regarding the operation of the business of the Company and its Subsidiaries prior to the Effective Time. The Company is also subject to customary restrictions on its ability to solicit alternative acquisition proposals from third parties and to provide non-public information to, and participate in discussions and engage in negotiations with, third parties regarding alternative acquisition proposals, with certain exceptions for alternative acquisition proposals that are or are reasonably likely to lead to Superior Proposals. The Merger Agreement contains certain termination rights for the Company and Newco. Upon termination of the Merger Agreement in connection with the Company accepting a Superior Proposal or due to the Company Board’s change or withdrawal of its recommendation of the Merger, the Company will be required to pay Newco a termination fee of $47.2 million . This termination fee will also be payable if the Merger Agreement is terminated because the Company’s stockholders did not vote to adopt the Merger Agreement(or the termination date for the transaction (as described below) occurs before the stockholder approval is obtained) and prior to such termination, a proposal to acquire at least 50% of the Company’s stock or assets is publicly announced (or delivered to the Company’s Board of Directors) and the Company enters into an agreement for, or completes, an alternative acquisition transaction within one year of termination. Upon termination of the Merger Agreement under other specified circumstances, Newco will be required to pay the Company a termination fee of $94.4 million . The termination fee will become payable by Newco if it fails to consummate the Merger after certain conditions are met, if Newco breaches its representations, warranties or covenants in a manner that would cause the related closing conditions to not be met, or if either party terminates because of the termination date, and at the time of such termination, the Company was otherwise entitled to terminate the Merger Agreement for either of the above reasons. The Elliott Funds have provided the Company with a limited guaranty in favor of the Company (the “ Limited Guarantee ”). In the aggregate, the Limited Guarantee guarantees the payment of the termination fee payable by Newco and certain reimbursement obligations that may be owed by Newco to the Company pursuant to the Merger Agreement. The Merger Agreement also provides that, under certain conditions, either party may specifically enforce the other party’s obligations under the Merger Agreement. In addition to the foregoing termination rights, and subject to certain limitations, the Company or Newco may terminate the Merger Agreement if the Merger is not consummated by April 25, 2018. The transaction is expected to close in the first quarter of fiscal 2018.

Summary of Significant Accoun18

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2017
Accounting Policies [Abstract]
Basis of Presentation and Consolidation	Basis of Presentation and Consolidation The Company prepared its condensed consolidated financial statements in accordance with U.S. generally accepted accounting principles (“GAAP”) and applicable rules and regulations of the Securities and Exchange Commission (the “SEC”) regarding interim financial reporting. Certain information and note disclosures normally included in the financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. As such, the unaudited information included in this Quarterly Report on Form 10-Q should be read in conjunction with the audited consolidated financial statements and accompanying notes included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2016 . There have been no changes to the Company’s significant accounting policies described in the Annual Report on Form 10-K that have had a material impact on the Company’s condensed consolidated financial statements and related notes except for the adoption of the accounting standard update related to Improvements to Employee Share-Based Payment Accounting, which amends Compensation - Stock Compensation and the accounting standard update related to restricted cash, which affected the presentation in the condensed consolidated statements of cash flows. Certain prior periods’ amounts were reclassified to conform to the current year’s presentation. None of these reclassifications impacted the reported net income (loss) or earnings per share for any of the periods presented.
Fiscal Period Policy	The Company's fiscal year is 52 or 53 weeks and ends on the last Saturday in December. Fiscal 2016 was a 53-week fiscal year ending on December 31, 2016 ; the first quarter was a 14-week quarter ended on April 2, 2016 and each subsequent quarter was a 13-week quarter. Fiscal 2017 is a 52-week fiscal year ending on December 30, 2017 , with each quarter therein being a 13-week quarter.
Unaudited Interim Financial Statements	Unaudited Interim Financial Statements The accompanying unaudited interim condensed consolidated financial statements have been prepared on a basis consistent with the annual consolidated financial statements and, in the opinion of management, reflect all adjustments, which include normal recurring adjustments, necessary to fairly state the Company’s financial position as of September 30, 2017 , its results of operations and comprehensive income (loss) for the three and nine months ended September 30, 2017 and October 1, 2016 , respectively, and cash flows for the nine months ended September 30, 2017 and October 1, 2016 , respectively. The financial data and the other financial information disclosed in the accompanying notes to the condensed consolidated financial statements related to these three and nine month periods are also unaudited. The fiscal year-end condensed consolidated balance sheet data was derived from audited financial statements, but does not include all disclosures required by GAAP. The condensed consolidated statements of operations for the three and nine months ended September 30, 2017 is not necessarily indicative of the results to be expected for the full fiscal year or any other future periods.
Principles of Consolidation	Principles of Consolidation The condensed consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation.
Use of Estimates	Use of Estimates The preparation of condensed consolidated financial statements in conformity with GAAP requires management to make certain estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenues and expenses during the reported periods. On an ongoing basis, the Company evaluates its estimates, including but not limited to those related to revenue recognition, allowance for doubtful accounts, warranty reserve, excess and obsolete inventory write-downs, stock-based compensation expense, depreciable useful lives and income taxes. The Company bases its estimates on historical experience, projections for future performance and other assumptions that it believes to be reasonable under the circumstances. Actual results could differ materially from those estimates.
Concentrations	Concentrations The Company operates in highly competitive and rapidly changing markets that could negatively impact the Company’s operating results. A number of components that meet the Company’s manufacturing requirements are available only from single source suppliers. In addition, the Company relies on two contract manufacturers to manufacture a substantial majority of its products. The inability of its single source suppliers and contract manufacturers to provide the Company with adequate supplies of high-quality components and products could cause a delay in order fulfillment, which could adversely affect the Company’s revenue, cost of revenue and operating results. Financial instruments that potentially subject the Company to significant concentrations of credit risk consist principally of cash, cash equivalents, short-term investments and accounts receivable. The majority of the Company's cash, cash equivalents and short-term investments are held in, or managed by a limited number of major financial institutions in the United States that management believes are creditworthy. Such deposits may exceed the insured limits provided on them. The Company mitigates credit risk associated with its accounts receivable by performing ongoing credit evaluations of its customers and determines if it needs to establish an allowance for doubtful accounts for estimated losses based on management’s assessment of the collectability of customer accounts.
Recent Accounting Pronouncements	Recent Accounting Pronouncements New Accounting Updates Recently Adopted The Company has adopted the accounting standard update related to Improvements to Employee Share-Based Payment Accounting, which amends Compensation – Stock Compensation during the first quarter of fiscal 2017. Specifically, the Company elected to account for forfeitures as they occur, rather than estimate expected forfeitures. The net cumulative effect of the change was recognized as a $3.6 million reduction to retained earnings as of January 1, 2017. Stock-based excess tax benefits or shortfalls are now reflected in the results of operations as a component of the income tax benefit (provision), whereas they previously were recognized in equity. The cumulative impact of this change was recorded as a deferred tax asset of $7.6 million for the previously unrecognized excess tax benefits with an adjustment of $7.1 million and $0.5 million to retained earnings and a valuation allowance for a certain jurisdiction, respectively. Additionally, the Company's condensed consolidated statements of cash flows now include excess tax benefits as an operating activity with the prior period adjusted accordingly. The Company has adopted the restricted cash guidance, which requires amounts generally described as restricted cash and restricted cash equivalents be included with cash and cash equivalents when reconciling the total beginning and ending amounts for the periods presented in the condensed consolidated statements of cash flows in the first quarter of fiscal 2017 using a retrospective transition method for each period presented. Recent Accounting Updates Not Yet Effective In May 2014, the Financial Accounting Standards Board (the "FASB") issued an accounting standard update related to revenue from contracts with customers, which supersedes the revenue recognition requirements in the current Accounting Standards Codification. This standard is based on the principle that revenue is recognized to depict the transfer of 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. This standard also requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts, including significant judgments and changes in judgments and assets recognized from costs incurred to obtain or fulfill a contract. In August 2015, the FASB voted to defer the effective date of this standard by one year. Additionally, in March 2016 the FASB issued additional information that clarifies the implementation guidance on principal versus agent considerations. The new standard permits adoption either by using (i) a full retrospective approach for all periods presented in the period of adoption or (ii) a modified retrospective approach with the cumulative effect of initially applying the new standard recognized at the date of initial application and providing certain additional disclosures. The new standard is effective for annual reporting periods beginning after December 15, 2017, with early adoption permitted for annual reporting periods beginning after December 15, 2016. The Company did not elect to early adopt, and accordingly, it will adopt the new standard effective for its fiscal year 2018. The Company is evaluating the impact of the new standard on its accounting policies, processes, and system requirements and currently plans to adopt using the full retrospective approach. However, a final decision regarding the adoption method has not been finalized at this time. The Company's final determination will depend on a number of factors, such as the significance of the impact of the new standard on our financial results, system readiness, including that of software procured from third-party providers, and its ability to accumulate and analyze the information necessary to assess the impact on prior period financial statements, as necessary. Revenue recognition for non-essential software is currently accounted for under the Software Revenue Recognition guidance, which entails allocating the arrangement consideration to deliverables that have established vendor specific objective evidence value (“VSOE”) or fair value and the residual to other deliverables based on third party evidence or best estimates of selling prices. Revenue from each deliverable is then recognized when all requirements are met for that specific deliverable. As the new standard does not retain the concept of VSOE, the Company preliminarily believes it will use the Standalone Selling Price to determine the appropriate amount to be allocated to each separate performance obligation using the Relative Selling Price approach. As part of the Company's preliminary evaluation, it has also considered the impact of the guidance relating to Other Assets and Deferred Costs; Contracts with customers, and the interpretations of the FASB Transition Resource Group for Revenue Recognition ("TRG") from their November 7, 2016 meeting with respect to capitalization and amortization of incremental costs of obtaining a contract. As a result of this new guidance, the Company preliminarily believes that it will capitalize certain costs of obtaining a contract, including additional sales commissions, as the new cost guidance, as interpreted by the TRG, requires the capitalization of all incremental costs that the Company incurs to obtain a contract with a customer that it would not have incurred if the contract had not been obtained, provided it expects to recover the costs. Under the Company's current accounting policy, it expenses the commission costs immediately as incurred. While the Company continues to assess the potential impacts of the new standard, it anticipates this standard could have a material impact on its consolidated financial statements. However, the Company cannot reasonably estimate quantitative information related to the impact of the new standard on its consolidated financial statements at this time. In February 2016, the FASB issued an accounting standard update which amends the existing accounting standards for leases. Consistent with current guidance, the recognition, measurement and presentation of expenses and cash flows arising from a lease by a lessee primarily will depend on its classification. Under the new guidance, a lessee will be required to recognize assets and liabilities for all leases with lease terms of more than 12 months. The effective date of this update will be for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018 using a modified retrospective transition method with early adoption permitted. The Company expects the standard to have a material impact on its assets and liabilities for the addition of right-of-use assets and lease liabilities, but the Company does not expect it to have a material impact on its results of operations or liquidity. In June 2016, the FASB issued new guidance that changes the accounting for recognizing impairments of financial assets. Under the new guidance, credit losses for certain types of financial instruments will be estimated based on expected losses. The new guidance also modifies the impairment models for available-for-sale debt securities and for purchased financial assets with credit deterioration since their origination. The effective date of this standard will be for annual periods ending after December 15, 2019, and interim periods within that reporting period. Early adoption is permitted starting in annual periods ending after December 15, 2018. The Company is evaluating the impact of this guidance on its consolidated financial statements. In October 2016, the FASB issued new guidance that requires a reporting entity to recognize the tax expense from intra-entity asset transfers of assets other than inventory in the selling entity’s tax jurisdiction when the transfer occurs, even though the pre-tax effects of that transaction are eliminated in consolidation. Any deferred tax asset that arises in the buying entity’s jurisdiction would also be recognized at the time of the transfer. The new guidance will likely impact reporting entities’ effective tax rates. The new guidance is effective for interim and annual periods beginning after December 15, 2017 and early adoption is permitted. The amendment should be adopted using the modified retrospective approach with a cumulative-effect adjustment recorded in retained earnings as of the beginning of the period of adoption. The Company is evaluating the impact of this guidance on its consolidated financial statements.

Summary of Significant Accoun19

Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2017
Accounting Policies [Abstract]
Customers Representing Major Revenue and Accounts Receivable	The following customers represented more than 10% or more of total revenue or accounts receivable: Three Months Ended Nine Months Ended September 30, 2017 October 1, 2016 September 30, 2017 October 1, 2016 Percent of Revenue: Customer A (distributor) * 38 % 16 % 35 % Customer B (distributor) 36 % 24 % 29 % 25 % Customer C (distributor) 10 % * * * Customer D (end user) * * * 12 % * Represents less than 10% of total revenue As of September 30, 2017 December 31, 2016 Percent of Accounts Receivable: Customer A (distributor) 10 % 16 % Customer B (distributor) 34 % 32 % Customer C (distributor) 16 % * Customer D (end user) * 10 %

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2017
Fair Value Disclosures [Abstract]
Components of Cash and Cash Equivalents	The components of the Company’s cash equivalents and short-term investments are as follows (in thousands): Fair Value Measured Using September 30, 2017 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Cash equivalents: Money market funds $ 110,008 $ 110,008 $ — Commercial paper 8,418 8,418 Total cash equivalents $ 118,426 $ 110,008 $ 8,418 Short-term investments: Corporate debt securities $ 24,003 $ — $ 24,003 Commercial paper 2,465 2,465 U.S. agency debt securities 3,995 3,995 U.S. government securities 60,917 60,917 Total short-term investments $ 91,380 $ — $ 91,380 Fair Value Measured Using December 31, 2016 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Cash equivalents: Money market funds $ 99,992 $ 99,992 $ — Commercial paper 1,999 — 1,999 Total cash equivalents $ 101,991 $ 99,992 $ 1,999 Short-term investments: Corporate debt securities $ 10,110 $ — $ 10,110 Commercial paper 12,956 — 12,956 U.S. agency debt securities 21,697 — 21,697 U.S. government securities 64,475 — 64,475 Total short-term investments $ 109,238 $ — $ 109,238
Schedule of Amortized Cost, Gross Unrealized Gains and Losses and Fair Value of Investments	Financial assets measured at amortized cost, gross unrealized gains, gross unrealized losses and fair value by significant investment categories are summarized as follows (in thousands): As of September 30, 2017 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Cash equivalents: Money market funds $ 110,008 $ — $ — $ 110,008 Commercial paper 8,418 8,418 Total cash equivalents $ 118,426 $ — $ — $ 118,426 Short-term investments: Corporate debt securities $ 24,021 $ 1 $ (19 ) $ 24,003 Commercial paper 2,465 — — 2,465 U.S. agency debt securities 3,998 — (3 ) 3,995 U.S. government securities 60,971 1 (55 ) 60,917 Total short-term investments $ 91,455 $ 2 $ (77 ) $ 91,380 As of December 31, 2016 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Cash equivalents: Money market funds $ 99,992 $ — $ — $ 99,992 Commercial paper 1,999 — — 1,999 Total cash equivalents $ 101,991 $ — $ — $ 101,991 Short-term investments: Corporate debt securities $ 10,119 $ — $ (9 ) $ 10,110 Commercial paper 12,956 — — 12,956 U.S. agency debt securities 21,698 1 (2 ) 21,697 U.S. government securities 64,482 8 (15 ) 64,475 Total short-term investments $ 109,255 $ 9 $ (26 ) $ 109,238
Schedule of Contractual Maturity Date of Marketable Securities	The contractual maturity date of the cash equivalents and short-term investments at estimated fair value was as follows (in thousands): As of September 30, 2017 December 31, 2016 Due within one year $ 201,453 $ 205,250 Due between one and five years 8,353 5,979 Total $ 209,806 $ 211,229

Balance Sheet Components (Table

Balance Sheet Components (Tables)	9 Months Ended
	Sep. 30, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Inventories	Inventories are comprised of the following (in thousands): As of September 30, 2017 December 31, 2016 Raw materials $ 94 $ 50 Finished goods 15,378 11,297 Total inventories $ 15,472 $ 11,347
Property and Equipment, Net	Property and equipment, net, are comprised of the following (in thousands): As of September 30, 2017 December 31, 2016 Equipment and machinery $ 25,403 $ 20,611 Furniture and fixtures 1,523 654 Leasehold improvements 9,665 3,367 Software 3,900 2,519 Total property and equipment 40,491 27,151 Less accumulated depreciation and amortization (19,756 ) (15,342 ) Total property and equipment, net $ 20,735 $ 11,809
Accrued Liabilities	Accrued liabilities are comprised of the following (in thousands): As of September 30, 2017 December 31, 2016 Accrued employee related costs $ 11,145 $ 25,468 Accrued inventory and other purchases 5,203 1,778 Accrued taxes payable 1,075 1,977 Accrued professional services 2,107 667 Other accruals 7,367 4,759 Total accrued liabilities $ 26,897 $ 34,649
Accrued Warranty Liability	Warranty activity and accrued warranty is comprised of the following (in thousands): Nine Months Ended September 30, 2017 October 1, 2016 Accrued warranty balance at beginning of period $ 960 $ 807 Accrual for warranty during the period 1,236 1,269 Actual costs incurred (1,247 ) (1,116 ) Accrued warranty balance at end of period $ 949 $ 960 As of Accrued warranty reported as: September 30, 2017 December 31, 2016 Accrued liabilities, current $ 706 $ 653 Other liabilities, non-current 243 307 Total accrued warranty $ 949 $ 960
Deferred Revenue	Deferred revenue is comprised of the following (in thousands): As of September 30, 2017 December 31, 2016 Deferred service revenue $ 101,807 $ 97,646 Deferred product revenue 279 136 Total deferred revenue $ 102,086 $ 97,782
Accumulated Other Comprehensive Loss	The following summarizes the activity within accumulated other comprehensive loss (in thousands): Accumulated Other Comprehensive Loss Balance as of December 31, 2016 $ (17 ) Available-for-sale securities: Unrealized loss (58 ) Total other comprehensive loss (58 ) Balance as of September 30, 2017 $ (75 )

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	9 Months Ended
	Sep. 30, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Stock Options Activity	The following table summarizes the stock option activity under the Company’s Equity Incentive Plans: Number of Weighted- Weighted- Aggregate Balance — December 31, 2016 1,391,171 $ 21.19 6.39 $ 35,076 Options granted 177,777 $ 38.43 Options exercised (75,904 ) $ 12.95 Options forfeited/canceled (112,087 ) $ 25.28 Balance — September 30, 2017 1,380,957 $ 23.53 6.17 $ 27,239 Exercisable — September 30, 2017 927,460 $ 17.64 5.69 $ 22,728
Schedule of RSU Activity	The following table summarizes the RSU activity under the Company’s Equity Incentive Plans: Number of Weighted- Weighted- Aggregate December 31, 2016 2,466,049 $ 26.66 1.39 $ 112,329 RSUs awarded 1,500,180 $ 35.66 RSUs released (867,296 ) $ 25.84 RSUs forfeited (551,779 ) $ 28.60 As of September 30, 2017 2,547,154 $ 31.81 1.43 $ 107,363
Schedule of Fair Values of the Options Awards and ESPP Purchase Rights Granted	The fair value of the option awards and ESPP purchase rights granted and the assumptions used in the Black-Scholes option pricing model are summarized as follows: Three Months Ended Nine Months Ended September 30, October 1, September 30, October 1, Stock option awards: Expected term (in years) 4.6 0 4.6 4.6 Risk-free interest rate 1.8% —% 1.8% - 1.9% 1.4% Expected volatility 61.6% —% 61.6% - 62.0% 76.1% Expected dividend rate —% —% —% —% Grant date fair value per award $20.33 $— $18.67 - $20.33 $18.62 ESPP purchase right: Expected term (in years) 0.5 - 2.0 0.5 - 2.0 0.5 - 2.0 0.5 - 2.0 Risk-free interest rate 1.12% - 1.32% 0.46% - 0.72% 0.67% - 1.32% 0.42% - 0.74% Expected volatility 45.40% - 58.23% 43.9% - 54.6% 45.40% - 68.64% 43.9% - 67.2% Expected dividend rate —% —% —% —% Grant date fair value per share $11.12 - $18.40 $12.84 - $20.77 $11.12 - $18.40 $7.75 - $20.77
Summary of Stock-based Compensation Expense	The following table summarizes the stock-based compensation expense recorded in the Company’s condensed consolidated statements of operations (in thousands): Three Months Ended Nine Months Ended September 30, October 1, September 30, October 1, Cost of revenue $ 333 $ 519 $ 1,802 $ 1,527 Research and development $ 4,040 3,397 14,453 9,800 Sales and marketing $ 3,163 3,062 13,108 8,802 General and administrative $ 3,437 3,126 10,628 8,755 Total stock-based compensation expense $ 10,973 $ 10,104 $ 39,991 $ 28,884

Net Income (Loss) per Share (Ta

Net Income (Loss) per Share (Tables)	9 Months Ended
	Sep. 30, 2017
Earnings Per Share [Abstract]
Schedule of Net Income (Loss) Per Share, Basic and Diluted	The following table presents the computation of basic and diluted net income (loss) per share attributable to common stockholders (in thousands, except per share data): Three Months Ended Nine Months Ended September 30, 2017 October 1, 2016 September 30, 2017 October 1, 2016 Numerator: Net income (loss) 2,178 6,079 (7,397 ) 43,009 Denominator: Weighted average shares used for basic net income (loss) per share computation 37,196 35,770 36,885 35,171 Weighted average effect of dilutive securities: Stock options 610 666 — 696 Stock Awards (1) 1,668 1,488 — 1,271 ESPP purchase rights 100 189 — 203 Weighted average shares used for diluted net income (loss) per share computation 39,574 38,113 36,885 37,341 Net income (loss) per share attributable to common stockholders: Basic $ 0.06 $ 0.17 $ (0.20 ) $ 1.22 Diluted $ 0.06 $ 0.16 $ (0.20 ) $ 1.15 (1) Includes RSUs, performance-based RSUs, RSAs and performance-based RSAs
Schedule of Antidilutive Securities Excluded from Computation of Net Income (Loss) Per Share	The weighted average number of shares outstanding used in the computation of diluted net income (loss) per share does not include the effect of the following shares of potentially outstanding common stock because the effect would have been anti-dilutive for the periods presented (in thousands): Three Months Ended Nine Months Ended September 30, 2017 October 1, 2016 September 30, 2017 October 1, 2016 Equity awards to purchase common stock 258 20 310 74

Segment Information (Tables)

Segment Information (Tables)	9 Months Ended
	Sep. 30, 2017
Segment Reporting [Abstract]
Revenue and Long-Lived Assets by Geographic Region	The following table summarizes the Company’s revenue by geographic region, based on shipment location (in thousands): Three Months Ended Nine Months Ended September 30, 2017 October 1, 2016 September 30, 2017 October 1, 2016 United States $ 56,253 $ 67,205 $ 162,661 $ 179,678 Rest of Americas 3,126 2,562 7,886 7,385 Europe, Middle East and Africa 10,392 7,370 26,943 21,349 Asia Pacific 9,420 6,375 20,405 17,414 Total $ 79,191 $ 83,512 $ 217,895 $ 225,826 The Company’s long-lived assets by geographic region are summarized as follows (in thousands): As of September 30, 2017 December 31, 2016 United States $ 18,569 $ 9,907 India 1,496 1,271 Other 670 631 Total $ 20,735 $ 11,809

Summary of Significant Accoun25

Summary of Significant Accounting Policies - Customers Representing Major Revenue and Accounts Receivable (Details)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2017	Oct. 01, 2016	Sep. 30, 2017	Oct. 01, 2016	Dec. 31, 2016
Total Revenue | Customer A (distributor)
Concentration Risk [Line Items]
Concentration risk		38.00%	16.00%	35.00%
Total Revenue | Customer B (distributor)
Concentration Risk [Line Items]
Concentration risk	36.00%	24.00%	29.00%	25.00%
Total Revenue | Customer C (distributor)
Concentration Risk [Line Items]
Concentration risk	10.00%
Total Revenue | Customer D (end user)
Concentration Risk [Line Items]
Concentration risk				12.00%
Accounts Receivable | Customer A (distributor)
Concentration Risk [Line Items]
Concentration risk			10.00%		16.00%
Accounts Receivable | Customer B (distributor)
Concentration Risk [Line Items]
Concentration risk			34.00%		32.00%
Accounts Receivable | Customer C (distributor)
Concentration Risk [Line Items]
Concentration risk			16.00%
Accounts Receivable | Customer D (end user)
Concentration Risk [Line Items]
Concentration risk					10.00%

Summary of Significant Accoun26

Summary of Significant Accounting Policies - Narrative (Details) $ in Millions	9 Months Ended
	Sep. 30, 2017customer	Apr. 01, 2017USD ($)	Dec. 31, 2016USD ($)
Schedule Of Significant Accounting Policies [Line Items]
Concentration risk, number of customer | customer	2
Accounting Standards Update 2016-09, Excess Tax Benefit Component
Schedule Of Significant Accounting Policies [Line Items]
Deferred tax assets, net		$ 7.6
Deferred tax assets valuation allowance		0.5
Retained Earnings | Accounting Standards Update 2016-09, Excess Tax Benefit Component
Schedule Of Significant Accounting Policies [Line Items]
Cumulative effect of new accounting principle in period of adoption		$ 7.1	$ (3.6)

Fair Value Measurements - Compo

Fair Value Measurements - Components of Cash and Cash Equivalents (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Short-term investments:
Short-term investments	$ 91,380	$ 109,238
Money market funds
Cash and cash equivalents:
Cash and cash equivalents	110,008	99,992
Commercial papers
Cash and cash equivalents:
Cash and cash equivalents	8,418	1,999
Short-term investments:
Short-term investments	2,465	12,956
Total cash equivalents
Cash and cash equivalents:
Cash and cash equivalents	118,426	101,991
Corporate debt securities
Short-term investments:
Short-term investments	24,003	10,110
U.S. agency debt securities
Short-term investments:
Short-term investments	3,995	21,697
U.S. government securities
Short-term investments:
Short-term investments	60,917	64,475
Quoted Prices in Active Markets for Identical Assets (Level 1)
Short-term investments:
Short-term investments	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Money market funds
Cash and cash equivalents:
Cash and cash equivalents	110,008	99,992
Quoted Prices in Active Markets for Identical Assets (Level 1) | Commercial papers
Cash and cash equivalents:
Cash and cash equivalents		0
Short-term investments:
Short-term investments		0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Total cash equivalents
Cash and cash equivalents:
Cash and cash equivalents	110,008	99,992
Quoted Prices in Active Markets for Identical Assets (Level 1) | Corporate debt securities
Short-term investments:
Short-term investments	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. agency debt securities
Short-term investments:
Short-term investments		0
Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. government securities
Short-term investments:
Short-term investments		0
Significant Other Observable Inputs (Level 2)
Short-term investments:
Short-term investments	91,380	109,238
Significant Other Observable Inputs (Level 2) | Money market funds
Cash and cash equivalents:
Cash and cash equivalents	0	0
Significant Other Observable Inputs (Level 2) | Commercial papers
Cash and cash equivalents:
Cash and cash equivalents	8,418	1,999
Short-term investments:
Short-term investments	2,465	12,956
Significant Other Observable Inputs (Level 2) | Total cash equivalents
Cash and cash equivalents:
Cash and cash equivalents	8,418	1,999
Significant Other Observable Inputs (Level 2) | Corporate debt securities
Short-term investments:
Short-term investments	24,003	10,110
Significant Other Observable Inputs (Level 2) | U.S. agency debt securities
Short-term investments:
Short-term investments	3,995	21,697
Significant Other Observable Inputs (Level 2) | U.S. government securities
Short-term investments:
Short-term investments	$ 60,917	$ 64,475

Fair Value Measurements - Finan

Fair Value Measurements - Financial Instruments Measured at Amortized Costs, Gross Unrealized Gain, Gross Unrealized Loss and Fair Value by Significant Investment Categories (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Cash equivalents:
Cash And Cash Equivalents And Short Term Investments [Line Items]
Amortized Cost	$ 118,426	$ 101,991
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	118,426	101,991
Cash equivalents: | Money market funds
Cash And Cash Equivalents And Short Term Investments [Line Items]
Amortized Cost	110,008	99,992
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	110,008	99,992
Cash equivalents: | Commercial papers
Cash And Cash Equivalents And Short Term Investments [Line Items]
Amortized Cost	8,418	1,999
Gross Unrealized Gains		0
Gross Unrealized Losses		0
Fair Value	8,418	1,999
Short-term investments:
Cash And Cash Equivalents And Short Term Investments [Line Items]
Amortized Cost	91,455	109,255
Gross Unrealized Gains	2	9
Gross Unrealized Losses	(77)	(26)
Fair Value	91,380	109,238
Short-term investments: | Commercial papers
Cash And Cash Equivalents And Short Term Investments [Line Items]
Amortized Cost	2,465	12,956
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	2,465	12,956
Short-term investments: | Corporate debt securities
Cash And Cash Equivalents And Short Term Investments [Line Items]
Amortized Cost	24,021	10,119
Gross Unrealized Gains	1	0
Gross Unrealized Losses	(19)	(9)
Fair Value	24,003	10,110
Short-term investments: | U.S. agency debt securities
Cash And Cash Equivalents And Short Term Investments [Line Items]
Amortized Cost	3,998	21,698
Gross Unrealized Gains	0	1
Gross Unrealized Losses	(3)	(2)
Fair Value	3,995	21,697
Short-term investments: | U.S. government securities
Cash And Cash Equivalents And Short Term Investments [Line Items]
Amortized Cost	60,971	64,482
Gross Unrealized Gains	1	8
Gross Unrealized Losses	(55)	(15)
Fair Value	$ 60,917	$ 64,475

Fair Value Measurements - Narra

Fair Value Measurements - Narrative (Details)	9 Months Ended
	Sep. 30, 2017USD ($)security	Dec. 31, 2016security
Fair Value Disclosures [Abstract]
Realized gains from sale of securities | $	$ 0
Number of securities in a material continuous loss position for 12 months or longer | security	0	0

Fair Value Measurements - Contr

Fair Value Measurements - Contractual Maturity Date of Short-Term Investments (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Contractual Maturity Date of Short-Term Investments [Abstract]
Due within one year	$ 201,453	$ 205,250
Due between one and five years	8,353	5,979
Total	$ 209,806	$ 211,229

Balance Sheet Components - Inve

Balance Sheet Components - Inventories (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Raw materials	$ 94	$ 50
Finished goods	15,378	11,297
Total inventories	$ 15,472	$ 11,347

Balance Sheet Components - Prop

Balance Sheet Components - Property and equipment (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Equipment and machinery	$ 25,403	$ 20,611
Furniture and fixtures	1,523	654
Leasehold improvements	9,665	3,367
Software	3,900	2,519
Total property and equipment	40,491	27,151
Less accumulated depreciation and amortization	(19,756)	(15,342)
Total property and equipment, net	20,735	11,809
Depreciation and amortization expense	$ 5,100	$ 5,300

Balance Sheet Components - Accr

Balance Sheet Components - Accrued Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Accrued employee related costs	$ 11,145	$ 25,468
Accrued inventory and other purchases	5,203	1,778
Accrued taxes payable	1,075	1,977
Accrued professional services	2,107	667
Other accruals	7,367	4,759
Total accrued liabilities	$ 26,897	$ 34,649

Balance Sheet Components - Ac34

Balance Sheet Components - Accrued Warranty (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Oct. 01, 2016	Dec. 31, 2016
Movement in Standard Product Warranty Accrual [Roll Forward]
Accrued warranty balance at beginning of period	$ 960	$ 807
Accrual for warranty during the period	1,236	1,269
Actual costs incurred	(1,247)	(1,116)
Accrued warranty balance at end of period	949	$ 960
Product Warranty Accrual, Balance Sheet Classification [Abstract]
Accrued liabilities, current	706		$ 653
Other liabilities, non-current	243		307
Total accrued warranty	$ 949		$ 960

Balance Sheet Components - Defe

Balance Sheet Components - Deferred Revenues (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Deferred Revenue Arrangement [Line Items]
Deferred Revenue	$ 102,086	$ 97,782
Deferred service revenue
Deferred Revenue Arrangement [Line Items]
Deferred Revenue	101,807	97,646
Deferred product revenue
Deferred Revenue Arrangement [Line Items]
Deferred Revenue	$ 279	$ 136

Balance Sheet Components - Accu

Balance Sheet Components - Accumulated Other Comprehensive Loss (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2017USD ($)
Net Unrealized Loss
Beginning balance	$ 262,660
Ending balance	300,341
Accumulated Net Unrealized Investment Gain (Loss)
Net Unrealized Loss
Available-for-sale securities, Unrealized loss	(58)
Total other comprehensive loss	(58)
Accumulated Other Comprehensive Income (Loss)
Net Unrealized Loss
Beginning balance	(17)
Ending balance	$ (75)

Commitments and Contingencies (

Commitments and Contingencies (Details) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017USD ($)	Oct. 01, 2016USD ($)	Sep. 30, 2017USD ($)commitment	Oct. 01, 2016USD ($)	Dec. 31, 2016USD ($)
Commitments and Contingencies Disclosure [Abstract]
Rent expense	$ 1.5	$ 1	$ 3.8	$ 2.9
Number of contract manufacturers in purchase commitments | commitment			2
Purchase commitments with vendors	$ 22.2		$ 22.2		$ 15.7

Stockholders' Equity - 2013 Equ

Stockholders' Equity - 2013 Equity Incentive Plan (Details) - shares	1 Months Ended
	May 31, 2013	Sep. 30, 2017
2013 Equity Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized (in shares)	2,929,481	1,464,740
Additional shares issuable upon termination of awards under Plan (in shares)	4,967,172
Number of additional shares allowable for future authorization per year	1,464,740
Percentage of outstanding stock, maximum	5.00%
Expiration period after termination of employment	3 months
Common stock, capital shares reserved for future issuance (in shares)		3,588,518
2012 Equity Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, capital shares reserved for future issuance (in shares)		343,037

Stockholders' Equity - Employee

Stockholders' Equity - Employee Stock Purchase Plan (Details) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Jun. 30, 2013Periodshares	Sep. 30, 2017USD ($)$ / shares	Oct. 01, 2016USD ($)	Sep. 30, 2017USD ($)Period$ / sharesshares	Oct. 01, 2016USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense | $		$ 10,973	$ 10,104	$ 39,991	$ 28,884
ESPP purchase rights
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized (in shares)	439,422
Number of additional shares allowable for future authorization per year	439,422
Percentage of outstanding stock, maximum	1.50%
Maximum percentage of compensation to purchase shares by eligible participants	15.00%
Percentage of purchase price of common stock	85.00%
Employee Stock Purchase Plan offering period	24 months
Number of purchase periods in subscription | Period	4
Share-base compensation, term of purchase period	6 months
Additional shares issuable upon termination of awards under Plan (in shares)				439,422
Stock-based compensation expense | $		$ 1,000	$ 1,400	$ 4,900	$ 2,700
Number of purchase periods | Period				2
Shares issued in period (in shares)				355,800
Per share weighted average price of shares purchased (in dollars per share) | $ / shares		$ 26.63		$ 26.63

Stockholders' Equity - Stock Op

Stockholders' Equity - Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	9 Months Ended	12 Months Ended
	May 31, 2013	Sep. 30, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share price (in dollars per share)		$ 42.15	$ 45.55
Stock options
Number of Stock Options Outstanding
Beginning Balance (in shares)		1,391,171
Options granted (in shares)		177,777
Options exercised (in shares)		(75,904)
Options canceled (in shares)		(112,087)
Ending Balance (in shares)		1,380,957	1,391,171
Options exercisable (in shares)		927,460
Weighted- Average Exercise Price
Weighted average exercise price, outstanding, beginning balance (in dollars per share)		$ 21.19
Weighted average exercise price, options granted (in dollars per share)		38.43
Weighted average exercise price, options exercised (in dollars per share)		12.95
Weighted average exercise price, options canceled (in dollars per share)		25.28
Weighted average exercise price, outstanding, ending balance (in dollars per share)		23.53	$ 21.19
Weighted average exercise price, options exercisable (in dollars per share)		$ 17.64
Weighted- Average Remaining Contractual Life (Years)
Weighted average remaining contractual term		6 years 2 months 1 day	6 years 4 months 21 days
Weighted average remaining contractual term, options exercisable		5 years 8 months 8 days
Aggregate Intrinsic Value (in Thousands)
Intrinsic value, beginning balance		$ 35,076
Intrinsic value, ending balance		27,239	$ 35,076
Intrinsic value, options exercisable		$ 22,728
2013 Equity Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration period after termination of employment	3 months
2013 Equity Plan | Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period		4 years
Award vesting rights (percent)		25.00%
Expiration period		10 years
2012 Equity Plan | Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration period after termination of employment		30 days

Stockholders' Equity - Restrict

Stockholders' Equity - Restricted Stock Unit Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended			12 Months Ended
	Sep. 30, 2017	Oct. 01, 2016	[1]	Dec. 31, 2016
Aggregate Intrinsic Value (in Thousands)
Share price (in dollars per share)	$ 42.15			$ 45.55
Payments related to tax withholding for share-based compensation	$ 12,592	$ 7,240
Restricted Stock Units (RSUs)
Number of RSUs Outstanding
RSUs, beginning balance (in shares)	2,466,049
RSUs awarded (in shares)	1,500,180
RSUs released (in shares)	(867,296)
RSUs forfeited (in shares)	(551,779)
RSUs, ending balance (in shares)	2,547,154			2,466,049
Weighted- Average Grant Date Fair Value
Weighted average grant date fair value - Beginning balance (in dollars per share)	$ 26.66
Weighted average grant date fair value, Granted (in dollars per share)	35.66
Weighted average grant date fair value, Released (in dollars per share)	25.84
Weighted average grant date fair value, Forfeited (in dollars per share)	28.60
Weighted average grant date fair value - Ending balance (in dollars per share)	$ 31.81			$ 26.66
Weighted- Average Remaining Contractual Life (Years)
Weighted average remaining contractual life	1 year 5 months 4 days			1 year 4 months 21 days
Aggregate Intrinsic Value (in Thousands)
Aggregate intrinsic value - Beginning balance	$ 107,363			$ 112,329
Aggregate intrinsic value - Ending balance	$ 107,363			$ 112,329
Minimum | Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	1 year
Maximum | Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	4 years
[1]	Reflects the impact of the adoption of the accounting standard update related to Improvements to Employee Share-Based Payment Accounting, which amends Compensation - Stock Compensation.

Stockholders' Equity - Performa

Stockholders' Equity - Performance-Based Stock Units (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended			12 Months Ended
	Sep. 30, 2017	Sep. 30, 2017	Oct. 01, 2016	[1]	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense		$ 39,991	$ 28,884
Performance Units (PSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares granted in period (in shares)					193,000
Award vesting rights (percent)					149.50%
Stock-based compensation expense	$ 200	$ 1,300
Nonvested shares outstanding (in shares)	66,875	66,875
Minimum | Performance Units (PSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights (percent)					0.00%
Maximum | Performance Units (PSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights (percent)					200.00%
[1]	Reflects the impact of the adoption of the accounting standard update related to Improvements to Employee Share-Based Payment Accounting, which amends Compensation - Stock Compensation.

Stockholders' Equity - Restri43

Stockholders' Equity - Restricted Stock Award Activity (Details) - Restricted Stock	9 Months Ended
	Sep. 30, 2017$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares granted in period (in shares) | shares	254,397
Weighted average grant date fair value, Granted (in dollars per share) | $ / shares	$ 30.72
Number of shares vested during period (in shares) | shares	33,345
Weighted average grant date fair value for vested shares (in dollars per share) | $ / shares	$ 30.82

Stockholders' Equity - Perfor44

Stockholders' Equity - Performance-Based Stock Awards (Details) - Performance Shares	9 Months Ended
	Sep. 30, 2017$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares granted in period (in shares)	213,986
Weighted average grant date fair value, Granted (in dollars per share) | $ / shares	$ 32.01
Number of shares vested during period (in shares)	6,166
Weighted average grant date fair value for vested shares (in dollars per share) | $ / shares	$ 23.78
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights (percent)	0.00%
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights (percent)	200.00%
2017 Revenue and operating income performance
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares granted in period (in shares)	166,570

Stockholders' Equity - Fair Val

Stockholders' Equity - Fair Value Measurement Assumptions (Details) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Oct. 01, 2016	Sep. 30, 2017	Oct. 01, 2016
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	4 years 7 months 6 days	0 years	4 years 7 months 6 days	4 years 7 months 6 days
Risk-free interest rate	1.80%	0.00%		1.40%
Expected volatility (percent)	61.60%	0.00%		76.10%
Expected dividend rate (percent)	0.00%	0.00%	0.00%	0.00%
Grant date fair value per award (in dollars per share)	$ 20.33	$ 0		$ 18.62
ESPP purchase rights
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected dividend rate (percent)	0.00%	0.00%	0.00%	0.00%
Minimum | Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate			1.80%
Expected volatility (percent)			61.60%
Grant date fair value per award (in dollars per share)			$ 18.67
Minimum | ESPP purchase rights
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	6 months	6 months	6 months	6 months
Risk-free interest rate	1.12%	0.46%	0.67%	0.42%
Expected volatility (percent)	45.40%	43.90%	45.40%	43.90%
Grant date fair value per share (in dollars per share)	$ 11.12	$ 12.84	$ 11.12	$ 7.75
Maximum | Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate			1.90%
Expected volatility (percent)			62.00%
Grant date fair value per award (in dollars per share)			$ 20.33
Maximum | ESPP purchase rights
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	2 years	2 years	2 years	2 years
Risk-free interest rate	1.32%	0.72%	1.32%	0.74%
Expected volatility (percent)	58.23%	54.60%	68.64%	67.20%
Grant date fair value per share (in dollars per share)	$ 18.40	$ 20.77	$ 18.40	$ 20.77

Stockholders' Equity - Stock-ba

Stockholders' Equity - Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2017	Oct. 01, 2016	Sep. 30, 2017	Oct. 01, 2016	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	$ 10,973	$ 10,104	$ 39,991	$ 28,884
Cost of revenue
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	333	519	1,802	1,527
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	4,040	3,397	14,453	9,800
Sales and marketing
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	3,163	3,062	13,108	8,802
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	3,437	3,126	10,628	8,755
Inventories
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Amount of capitalized stock-based compensation costs			400		$ 200
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost not yet recognized	4,700		4,700
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost not yet recognized	44,400		44,400
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost not yet recognized	4,100		4,100
Performance Units (PSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost not yet recognized	800		800
Performance Shares (PSAs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost not yet recognized	600		600
ESPP purchase rights
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	1,000	$ 1,400	4,900	$ 2,700
Compensation cost not yet recognized	$ 4,500		$ 4,500

Defined Contribution Plans (Det

Defined Contribution Plans (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Oct. 01, 2016	Sep. 30, 2017	Oct. 01, 2016
Postemployment Benefits [Abstract]
Defined benefit plan, contributions by employer	$ 0.9	$ 0.6	$ 2.8	$ 1.7

Income Tax (Details)

Income Tax (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Oct. 01, 2016	Sep. 30, 2017	Oct. 01, 2016	Apr. 01, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Income tax benefit (provision)	$ 1,531	$ (3,999)	$ 9,576	$ 23,321
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Employee service share-based compensation, tax benefit realized			4,800
Research and development credits
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred tax assets valuation allowance	$ 6,700		$ 6,700
Accounting Standards Update 2016-09, Excess Tax Benefit Component
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred tax assets valuation allowance					$ 500
Deferred tax assets, net					7,600
Accounting Standards Update 2016-09, Excess Tax Benefit Component | Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of new accounting principle in period of adoption					$ 7,100	$ (3,600)

Net Income (Loss) per Share (De

Net Income (Loss) per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Oct. 01, 2016	Sep. 30, 2017	Oct. 01, 2016
Numerator:
Net income (loss)	$ 2,178	$ 6,079	$ (7,397)	$ 43,009	[1]
Denominator:
Weighted average shares used for basic net income (loss) per share computation (in shares)	37,196	35,770	36,885	35,171
Incremental Weighted Average Shares Attributable to Dilutive Effect [Abstract]
Weighted average shares used for diluted net income (loss) per share computation Diluted (in shares)	39,574	38,113	36,885	37,341
Net income (loss) per share attributable to common stockholders:
Basic (in dollars per share)	$ 0.06	$ 0.17	$ (0.20)	$ 1.22
Diluted (in dollars per share)	$ 0.06	$ 0.16	$ (0.20)	$ 1.15
Stock options
Incremental Weighted Average Shares Attributable to Dilutive Effect [Abstract]
Incremental common shares attributable to dilutive effect of share-based payment arrangements (in shares)	610	666	0	696
Stock Awards
Incremental Weighted Average Shares Attributable to Dilutive Effect [Abstract]
Incremental common shares attributable to dilutive effect of share-based payment arrangements (in shares)	1,668	1,488	0	1,271
ESPP purchase rights
Incremental Weighted Average Shares Attributable to Dilutive Effect [Abstract]
Incremental common shares attributable to dilutive effect of share-based payment arrangements (in shares)	100	189	0	203
Equity awards to purchase common stock
Net income (loss) per share attributable to common stockholders:
Antidilutive securities excluded from computation of earnings per share (in shares)	258	20	310	74
[1]	Reflects the impact of the adoption of the accounting standard update related to Improvements to Employee Share-Based Payment Accounting, which amends Compensation - Stock Compensation.

Segment Information - Revenue a

Segment Information - Revenue and Long-Lived Assets by Geographic Region (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017USD ($)	Oct. 01, 2016USD ($)	Sep. 30, 2017USD ($)Segment	Oct. 01, 2016USD ($)	Dec. 31, 2016USD ($)
Segment Reporting [Abstract]
Number of operating segments | Segment			1
Number of reportable segments | Segment			1
Segment Reporting Revenue Reconciling Item [Line Items]
Total revenue	$ 79,191	$ 83,512	$ 217,895	$ 225,826
Long-lived assets	20,735		20,735		$ 11,809
United States
Segment Reporting Revenue Reconciling Item [Line Items]
Total revenue	56,253	67,205	162,661	179,678
Long-lived assets	18,569		18,569		9,907
Rest of Americas
Segment Reporting Revenue Reconciling Item [Line Items]
Total revenue	3,126	2,562	7,886	7,385
Europe, Middle East and Africa
Segment Reporting Revenue Reconciling Item [Line Items]
Total revenue	10,392	7,370	26,943	21,349
Asia Pacific
Segment Reporting Revenue Reconciling Item [Line Items]
Total revenue	9,420	$ 6,375	20,405	$ 17,414
India
Segment Reporting Revenue Reconciling Item [Line Items]
Long-lived assets	1,496		1,496		1,271
Other
Segment Reporting Revenue Reconciling Item [Line Items]
Long-lived assets	$ 670		$ 670		$ 631

Subsequent Event (Details)

Subsequent Event (Details) - Newco - Gigamon Inc. - Subsequent Event $ / shares in Units, $ in Millions	Oct. 26, 2017USD ($)$ / shares
Subsequent Event [Line Items]
Share price for issued and outstanding shares to be converted to cash (dollars per share) | $ / shares	$ 38.50
Termination fee Company pays if withdraw from merger	$ 47.2
Termination fee to be received from NewCo if merger is terminated	$ 94.4
Minimum
Subsequent Event [Line Items]
Percentage of assets sold in alternative transaction within one year that triggers termination fee by Company	50.00%

Uncategorized Items - gimo-2017

Label	Element	Value
Restricted Cash and Cash Equivalents	us-gaap_RestrictedCashAndCashEquivalents	$ 0	[1]
Restricted Cash and Cash Equivalents	us-gaap_RestrictedCashAndCashEquivalents	$ 813,000
[1]	Reflects the impact of the adoption of the accounting standard update related to Improvements to Employee Share-Based Payment Accounting, which amends Compensation - Stock Compensation.