iRobot (IRBT) 10-Q 5 May 17 2017 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Apr. 01, 2017	May 01, 2017
Entity Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Apr. 1, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q1
Trading Symbol	IRBT
Entity Registrant Name	IROBOT CORP
Entity Central Index Key	1,159,167
Current Fiscal Year End Date	--12-30
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		27,417,081

Consolidated Balance Sheets (Un

Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Apr. 01, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 235,728	$ 214,523
Short term investments	39,942	39,930
Accounts receivable, net of allowance of $30 at April 1, 2017 and $29 at December 31, 2016	47,780	72,909
Unbilled revenue	112	139
Inventory	57,125	50,578
Other current assets	7,317	5,591
Total current assets	388,004	383,670
Property and equipment, net	29,250	27,532
Deferred tax assets	31,429	30,585
Goodwill	41,041	41,041
Intangible assets, net	11,343	12,207
Other assets	13,214	12,877
Total assets	514,281	507,912
Current liabilities:
Accounts payable	63,177	67,281
Accrued expenses	21,343	19,854
Accrued compensation	11,348	21,015
Deferred revenue and customer advances	4,202	4,486
Total current liabilities	100,070	112,636
Long term liabilities	5,764	6,320
Commitments and contingencies (Note 7)
Redeemable convertible preferred stock, 5,000,000 shares authorized and none outstanding	0	0
Common stock, $0.01 par value, 100,000,000 shares authorized; 27,409,706 and 27,237,870 shares issued and outstanding at April 1, 2017 and December 31, 2016, respectively	274	272
Additional paid-in capital	164,957	161,885
Retained earnings	243,384	226,950
Accumulated other comprehensive loss	(168)	(151)
Total stockholders’ equity	408,447	388,956
Total liabilities, redeemable convertible preferred stock and stockholders’ equity	$ 514,281	$ 507,912

Consolidated Balance Sheets (U3

Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Apr. 01, 2017	Dec. 31, 2016
Net allowances on Accounts receivables	$ 30	$ 29
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	27,409,706	27,237,870
Common stock, shares outstanding	27,409,706	27,237,870

Consolidated Statements of Inco

Consolidated Statements of Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands		3 Months Ended
		Apr. 01, 2017	Apr. 02, 2016
Revenue		$ 168,467	$ 130,804
Cost of revenue (1)	[1]	81,124	68,843
Gross margin		87,343	61,961
Operating expenses:
Research and development (1)	[1]	25,508	19,728
Selling and marketing (1)	[1]	22,575	19,940
General and administrative (1)	[1]	17,622	16,764
Total operating expenses		65,705	56,432
Operating income		21,638	5,529
Other income, net		3	200
Income before income taxes		21,641	5,729
Income tax expense		5,282	1,797
Net income		$ 16,359	$ 3,932
Net income per share
Basic		$ 0.60	$ 0.14
Diluted		$ 0.58	$ 0.13
Number of weighted average common shares used in calculations per share
Basic		27,304	29,004
Diluted		28,295	29,474
Stock-based compensation		$ 4,331	$ 3,892
Cost of revenue
Number of weighted average common shares used in calculations per share
Stock-based compensation		226	221
Research and development
Number of weighted average common shares used in calculations per share
Stock-based compensation		1,099	829
Selling and marketing
Number of weighted average common shares used in calculations per share
Stock-based compensation		570	485
General and administrative
Number of weighted average common shares used in calculations per share
Stock-based compensation		$ 2,436	$ 2,357
[1]	Total stock-based compensation recorded in the three months ended April 1, 2017 and April 2, 2016 included in the above figures breaks down by expense classification as follows: Three Months Ended April 1, 2017 April 2, 2016Cost of revenue$226 $221Research and development1,099 829Selling and marketing570 485General and administrative2,436 2,357

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Apr. 01, 2017	Apr. 02, 2016
Net income	$ 16,359	$ 3,932
Other comprehensive income, net of tax:
Foreign Currency Translation Adjustments	(52)	0
Unrealized gains on investments, net of tax	35	237
Total comprehensive income	$ 16,342	$ 4,169

Consolidated Statements of Cash

Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Apr. 01, 2017	Apr. 02, 2016
Cash flows from operating activities:
Net income	$ 16,359	$ 3,932
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	3,486	3,375
Loss on disposal of property and equipment	42	0
Loss on equity method investment	11	0
Impairment on cost method investment	155	0
Stock-based compensation	4,331	3,892
Deferred income taxes, net	17	(47)
Tax benefit of excess stock-based compensation deductions	0	(267)
Non-cash director deferred compensation	16	33
Changes in operating assets and liabilities - (use) source
Accounts receivable	25,128	69,879
Unbilled revenue	27	185
Inventory	(6,546)	(3,167)
Other assets	(1,745)	(2,985)
Accounts payable	(5,026)	(20,626)
Accrued expenses	1,016	(2,673)
Accrued compensation	(9,670)	(4,055)
Deferred revenue and customer advances	(284)	1,144
Long term liabilities	(558)	3
Net cash provided by operating activities	26,759	48,623
Cash flows from investing activities:
Additions of property and equipment	(3,008)	(2,390)
Change in other assets	504	523
Purchases of investments	(3,498)	0
Sales and maturities of investments	3,500	2,500
Net cash used in investing activities	(3,510)	(413)
Cash flows from financing activities:
Proceeds from stock option exercises	722	837
Income tax withholding payment associated with restricted stock vesting	(2,778)	(1,218)
Stock repurchases	0	(12,021)
Tax benefit of excess stock-based compensation deductions	0	267
Net cash used in financing activities	(2,056)	(12,135)
Effect of Exchange Rate on Cash	12	0
Net increase in cash and cash equivalents	21,205	36,075
Cash and cash equivalents, at beginning of period	214,523	179,915
Cash and cash equivalents, at end of period	235,728	215,990
Supplemental disclosure of cash flow information:
Cash paid for income taxes	5,563	4,896
Transfer of inventory to property and equipment	0	5
Additions of property and equipment included in accounts payable	$ 2,461	$ 413

Description of Business

Description of Business	3 Months Ended
	Apr. 01, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business	Description of Business iRobot Corporation ("iRobot" or the "Company") designs and builds robots that empower people to do more. The Company develops robotic technology and applies it to produce and market consumer robots. The Company’s revenue is primarily generated from product sales.

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Apr. 01, 2017
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Basis of Presentation The accompanying consolidated financial statements include those of iRobot and its subsidiaries, after elimination of all intercompany accounts and transactions. iRobot has prepared the accompanying unaudited consolidated financial statements in conformity with accounting principles generally accepted in the United States of America. The accompanying unaudited financial data as of April 1, 2017 , and for the three months ended April 1, 2017 and April 2, 2016 have been prepared by the Company pursuant to the rules and regulations of the Securities and Exchange Commission (SEC). Certain information and footnote disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States have been condensed or omitted pursuant to such rules and regulations. However, the Company believes that the disclosures are adequate to make the information presented not misleading. The year-end balance sheet data were derived from audited financial statements, but do not include all disclosures required by accounting principles generally accepted in the United States. These consolidated financial statements should be read in conjunction with the Company’s audited consolidated financial statements and the notes thereto included in its Annual Report on Form 10-K for the fiscal year ended December 31, 2016 , filed with the SEC on February 17, 2017. In the opinion of management, all adjustments necessary to state fairly the Company's statement of financial position as of April 1, 2017 and results of operations, comprehensive income and cash flows for the periods ended April 1, 2017 and April 2, 2016 have been made. The results of operations, comprehensive income and cash flows for any interim period are not necessarily indicative of the operating results, comprehensive income and cash flows for the full fiscal year or any future periods. Use of Estimates The preparation of these financial statements in conformity with accounting principles generally accepted in the United States requires the Company to make estimates and judgments that affect the reported amounts of assets, liabilities, revenues and expenses, and disclosure of contingent assets and liabilities. On an ongoing basis, management evaluates these estimates and judgments, including those related to revenue recognition, sales returns, price protection, bad debts, warranty claims, inventory reserves, valuation of investments, valuation of goodwill and intangible assets, assumptions used in valuing stock-based compensation instruments and income taxes. The Company bases these estimates on historical and anticipated results and trends, and on various other assumptions that the Company believes are reasonable under the circumstances, including assumptions as to future events. These estimates form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. By their nature, estimates are subject to an inherent degree of uncertainty. Actual results may differ from the Company’s estimates. Fiscal Year-End The Company operates and reports using a 52 -53 week fiscal year ending on the Saturday closest to December 31. Accordingly, the Company’s fiscal quarters end on the Saturday that falls closest to the last day of the third month of each quarter. Revenue Recognition The Company primarily derives its revenue from product sales. Until the divestiture of the defense and security business unit on April 4, 2016 (see Note 11), the Company also generated minimal revenue from government and commercial research and development contracts. The Company sells products directly to customers and indirectly through resellers and distributors. The Company recognizes revenue from sales of robots under the terms of the customer agreement upon transfer of title and risk of loss to the customer, net of estimated returns and allowances, provided that collection is determined to be reasonably assured and no significant obligations remain. Beginning in the third quarter of 2015, the Company introduced its first connected robot. Each sale of a connected robot represents a multi-element arrangement containing the robot, an app and potential future unspecified software upgrades. Revenue is allocated to the deliverables based on their relative selling prices which have been determined using best estimate of selling price (BESP), as the Company has not been able to establish vendor specific objective evidence (VSOE) or obtain relevant third party evidence (TPE). Revenue allocated to the app and unspecified software upgrades is then deferred and recognized on a straight-line basis over the period in which the Company expects to provide the upgrades over the estimated life of the robot. Sales to domestic and Canadian resellers of consumer robots are typically subject to agreements allowing for limited rights of return, rebates and price protection. The Company also provides limited rights of returns for direct-to-consumer sales generated through its on-line stores and one international distributor. Accordingly, the Company reduces revenue for its estimates of liabilities for these rights of return, rebates and price protection at the time the related sale is recorded. These estimates for rights of return are directly based on specific terms and conditions included in the customer agreements, historical returns experience and various other assumptions that the Company believes are reasonable under the circumstances. In the case of new product introductions, the estimates for returns applied to the new products are based upon the estimates for the most similar predecessor products until such time that the Company has enough actual returns experience for the new products, which is typically two holiday return cycles. At that time, the Company incorporates that data into the development of returns estimates for the new products. The Company updates its analysis of returns on a quarterly basis. If actual returns differ significantly from the Company's estimates, or if modifications to individual customer agreements are entered into that impact their rights of returns, such differences could result in an adjustment to previously established reserves and could have a material impact, either favorably or unfavorably, on the Company’s results of operations for the period in which the actual returns become known or the agreement is modified. Except for the one international distributor noted above, the Company's international distributor agreements do not currently allow for product returns and, as a result, no reserve for returns is established for this group of customers. In 2016, the Company began selling to one domestic distributor under an agreement that provides product return privileges. As a result, the Company recognizes revenue from sales to this distributor when the product is resold by the distributor. The estimates and adjustments for rebates and price protection are based on specific programs, expected usage and historical experience. Actual results could differ from these estimates. Prior to the Company's divestiture of the defense and security business unit on April 4, 2016 (see Note 11), the Company generated minimal revenue from government contracts. Under cost-plus-fixed-fee (CPFF) type contracts, the Company recognized revenue based on costs incurred plus a pro rata portion of the total fixed fee. Costs incurred included labor and material that were directly associated with individual CPFF contracts plus indirect overhead and general and administrative type costs based upon billing rates submitted by the Company to the Defense Contract Management Agency (DCMA). Annually, the Company submits final indirect billing rates to DCMA based upon actual costs incurred throughout the year. In the situation where the Company’s final actual billing rates are greater than the estimated rates used, the Company records a cumulative revenue adjustment in the period in which the rate differential is collected from the customer. These final billing rates are subject to audit by the Defense Contract Audit Agency (DCAA), which can occur several years after the final billing rates are submitted and may result in material adjustments to revenue recognized based on estimated final billing rates. As of April 1, 2017 , fiscal year 2015 is open for audit by DCAA. In the situation where the Company’s anticipated actual billing rates will be lower than the provisional rates used, the Company records a cumulative revenue adjustment in the period in which the rate differential is identified. Revenue on firm fixed price (FFP) contracts was recognized using the percentage-of-completion method. For government product FFP contracts, revenue was recognized as the product was shipped or in accordance with the contract terms. Costs and estimated gross margins on contracts were recorded as revenue as work was performed based on the percentage that incurred costs compared to estimated total costs utilizing the most recent estimates of costs and funding. Revenue earned in excess of billings, if any, was recorded as unbilled revenue. Billings in excess of revenue earned, if any, were recorded as deferred revenue. Stock-Based Compensation The Company accounts for stock-based compensation through recognition of the fair value of the stock-based compensation as a charge against earnings. Stock-based compensation cost for stock options is estimated at the grant date based on each option's fair value as calculated by the Black-Scholes option-pricing model. Stock-based compensation cost for restricted stock awards, time-based restricted stock units and performance-based restricted stock units is measured based on the closing fair market value of the Company's common stock on the date of grant. For performance-based restricted stock units, the compensation costs will be subsequently adjusted for assumptions of achievement during the period in which the assumption of achievement changes, as applicable. The Company recognizes stock-based compensation cost as expense ratably on a straight-line basis over the requisite service period. The Company has elected to account for forfeitures as they occur, rather than applying an estimated forfeiture rate, upon adoption of ASU 2016-09. Net Income Per Share The following table presents the calculation of both basic and diluted net income per share: Three Months Ended (In thousands, except per share amounts) April 1, 2017 April 2, 2016 Net income $ 16,359 $ 3,932 Weighted-average shares outstanding 27,304 29,004 Dilutive effect of employee stock options and restricted shares 991 470 Diluted weighted-average shares outstanding 28,295 29,474 Basic income per share $ 0.60 $ 0.14 Diluted income per share $ 0.58 $ 0.13 Restricted stock units and stock options representing approximately 32.1 thousand and 0.7 million shares of common stock for the three-month periods ended April 1, 2017 and April 2, 2016 , respectively, were excluded from the computation of diluted earnings per share for these periods because their effect would have been antidilutive. Income Taxes The Company is subject to taxation in the United States and various states and foreign jurisdictions. The statute of limitations for examinations by the Internal Revenue Service is closed for fiscal years prior to 2013. The statute of limitations for examinations by state tax authorities is closed for fiscal years prior to 2012. Federal carryforward attributes that were generated prior to fiscal year 2013 and state carryforward attributes that were generated prior to fiscal year 2012 may still be adjusted upon examination by the federal or state tax authorities if they either have been or will be used in a period for which the statute of limitations is still open. Deferred taxes are determined based on the difference between the financial statement and tax basis of assets and liabilities using enacted tax rates in effect in the years in which the differences are expected to reverse. Valuation allowances are provided if, based upon the weight of available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. The Company monitors the realization of its deferred tax assets based on changes in circumstances, for example, recurring periods of income for tax purposes following historical periods of cumulative losses, generation of tax credits compared to future utilization of credits, or changes in tax laws or regulations. The Company's income tax provision and its assessment of the ability to realize its deferred tax assets involve significant judgments and estimates. The Company is currently generating state research credits that exceed the amount being utilized. As a result of this trend, a valuation allowance may be needed in the future related to these state tax credits. The Company recorded a tax provision of $5.3 million and $1.8 million for the three months ended April 1, 2017 and April 2, 2016 , respectively. The $5.3 million provision for the three months ended April 1, 2017 resulted in an effective income tax rate of 24.4% . The $1.8 million provision for the three months ended April 2, 2016 resulted in an effective income tax rate of 31.4% . The difference between the effective income tax rate of 24.4% for the three months ended April 1, 2017 and 31.4% for the three months ended April 2, 2016 was primarily due to a $1.7 million tax benefit related to recording excess tax benefits of stock-based compensation as a result of the adoption of ASU 2016-09, "Improvements to Employee Share-Based Payment Accounting," on the first day of the three months ended April 1, 2017 . Fair Value Measurements The authoritative guidance for fair value establishes a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value. These tiers include: Level 1, defined as observable inputs such as quoted prices in active markets; Level 2, defined as inputs other than quoted prices in active markets that are either directly or indirectly observable; and Level 3, defined as unobservable inputs in which little or no market data exists, therefore requiring an entity to develop its own assumptions. Financial Assets and Liabilities The Company’s financial assets measured at fair value on a recurring basis at April 1, 2017 , were as follows: Fair Value Measurements as of April 1, 2017 Level 1 Level 2 Level 3 (In thousands) Description Assets: Cash and cash equivalents Money market funds $ 187,302 $ — $ — Short term investments Corporate and government bonds (1) — 39,942 — Other current assets Derivative instruments (Note 6) (2) — 111 — Total assets measured at fair value $ 187,302 $ 40,053 $ — The Company’s financial assets and liabilities measured at fair value on a recurring basis at December 31, 2016 , were as follows: Fair Value Measurements as of Level 1 Level 2 Level 3 (In thousands) Description Assets: Cash and cash equivalents Money market funds $ 156,980 $ — $ — Short term investments Corporate and government bonds (1) — 39,930 — Other current assets Derivative instruments (Note 6) (2) — 180 — Total assets measured at fair value $ 156,980 $ 39,930 $ — Liabilities: Accrued Expenses Derivative instruments (Note 6) (2) $ — $ 43 $ — Total liabilities measured at fair value $ — $ 43 $ — (1) The bond investments are valued based on observable market values as of the Company’s reporting date. The bond investments are recorded at fair value and marked-to-market at the end of each reporting period. The realized and unrealized gains and losses are included in comprehensive income for that period. (2) Derivative instruments are valued using an income approach based on the present value of the forward rate less the contract rate multiplied by the notional amount. Goodwill Goodwill is recorded as the difference, if any, between the aggregate consideration paid for an acquisition and the fair value of the net tangible and intangible assets acquired. The Company evaluates goodwill for impairment at the reporting unit level (operating segment or one level below an operating segment) annually or more frequently if the Company believes indicators of impairment exist. In accordance with the guidance, the Company is permitted to first assess qualitative factors to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount. If the Company concludes that it is more likely than not that the fair value of a reporting unit is less than its carrying amount, then a two-step goodwill impairment test is performed. The first step of the impairment test involves comparing the fair values of the applicable reporting units with their aggregate carrying values, including goodwill. If the carrying amount of a reporting unit exceeds the reporting unit’s fair value, the Company performs the second step of the goodwill impairment test to determine the amount of impairment loss. The second step of the goodwill impairment test involves comparing the implied fair value of the affected reporting unit’s goodwill with the carrying value of that goodwill. The Company completes the annual impairment evaluation during the fourth quarter each year, or more frequently, if necessary, upon identification of a triggering event. Recent Accounting Pronouncements In January 2017, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2017-04, "Intangibles - Goodwill and Other." ASU 2017-04 eliminates step 2 from the goodwill impairment test, instead requiring that an entity recognize an impairment charge for the amount by which the carrying amount of goodwill exceeds the reporting unit's fair value. ASU 2017-04 is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years, with early adoption permitted. The Company does not believe the standard will have a material effect on its consolidated financial statements. In January 2017, the FASB issued ASU No. 2017-01, "Business Combinations; Clarifying the Definition of a Business." ASU 2017-01 clarifies the definition of a business with the objective of adding guidance to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. The definition of a business affects many areas of accounting including acquisitions, disposals, goodwill, and consolidation. The guidance is effective for annual periods beginning after December 15, 2017, including interim periods within those periods. The Company is currently evaluating the impact of the standard on its consolidated financial statements. In October 2016, the FASB issued ASU No. 2016-16, "Income Taxes: Intra-Entity Transfers of Assets Other Than Inventory." ASU 2016-16 clarifies the accounting for the current and deferred income taxes for an intra-entity transfer of an asset other than inventory. ASU 2016-16 is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years, with early adoption permitted. The Company is currently evaluating the impact of the standard on its consolidated financial statements. In August 2016, the FASB issued ASU No. 2016-15, "Statement of Cash Flows: Classification of Certain Cash Receipts and Cash Payments." ASU 2016-15 refines how companies classify certain aspects of the cash flow statement in regards to debt prepayment, settlement of debt instruments, contingent consideration payments, proceeds from insurance claims and life insurance policies, distribution from equity method investees, beneficial interests in securitization transactions and separately identifiable cash flows. ASU 2016-15 is effective for annual periods beginning after December 15, 2017, and for interim periods within fiscal years beginning after December 15, 2018. Early adoption is permitted. The Company is currently evaluating the impact of the standard on its consolidated financial statements. In March 2016, the FASB issued ASU No. 2016-09, "Improvements to Employee Share-Based Payment Accounting," which simplifies several aspects of the accounting for employee share-based payment transactions, including the accounting for income taxes, forfeitures, and statutory tax withholding requirements, as well as classification in the statement of cash flows. As a result of the adoption, on a prospective basis, the Company recognized $1.7 million of excess tax benefits from stock-based compensation as a discrete item in its provision for income taxes for the three months ended April 1, 2017. Additionally, the Company elected to account for forfeitures of share-based payments as they occur. In February 2016, the FASB issued ASU No. 2016-02, "Leases." ASU 2016-02 requires lessees to recognize the assets and liabilities on their balance sheet for the rights and obligations created by most leases and continue to recognize expenses on their income statements over the lease term. It will also require disclosures designed to give financial statement users information on the amount, timing, and uncertainty of cash flows arising from leases. The guidance is effective for annual reporting periods beginning after December 15, 2018 and interim periods within those fiscal years, with early adoption permitted. The Company is currently evaluating the impact of the standard on its consolidated financial statements. In July 2015, the FASB issued ASU No. 2015-11, "Inventory: Simplifying the Measurement of Inventory." ASU 2015-11 applies only to inventory for which cost is determined by methods other than last-in, first-out and the retail inventory method, which includes inventory that is measured using first-in, first-out or average cost. Inventory within the scope of this standard is required to be measured at the lower of cost and net realizable value. Net realizable value is the estimated selling prices in the ordinary course of business, less reasonably predictable costs of completion, disposal, and transportation. The Company adopted ASU 2015-11 effective January 1, 2017. The adoption of this standard did not have a material impact on the Company's consolidated financial statements. In May 2014, the FASB issued ASU No. 2014-09, "Revenue from Contracts with Customers," which provides guidance for revenue recognition. The standard’s core principle is that a company will recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. The new guidance is effective for annual reporting periods beginning after December 15, 2016, including interim periods within those annual reporting periods. In July 2015, the FASB voted to defer the effective date of the new accounting guidance related to revenue recognition by one year to December 17, 2017 for annual reporting periods beginning after that date and permitted early adoption of the standard, but not before the original effective date of December 15, 2016. The standard will be effective for the Company beginning in the first quarter of 2018. The Company is continuing to evaluate the impact that the adoption of the new revenue recognition standard will have on its consolidated financial statements, but anticipates that the additional disclosure requirements will represent a significant change from current guidance. The Company currently anticipates adopting the standard using the modified retrospective method. From time to time, new accounting pronouncements are issued by FASB that are adopted by the Company as of the specified effective date. Unless otherwise discussed, the Company believes that recently issued standards, which are not yet effective, will not have a material impact on the Company’s consolidated financial statements upon adoption.

Inventory

Inventory	3 Months Ended
	Apr. 01, 2017
Inventory Disclosure [Abstract]
Inventory	Inventory Inventory consists of the following: April 1, 2017 December 31, 2016 (In thousands) Raw materials $ 2,838 $ 4,717 Finished goods 54,287 45,861 Total $ 57,125 $ 50,578

Stock Option Plans

Stock Option Plans	3 Months Ended
	Apr. 01, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock Option Plans	Stock Option Plans and Stock-Based Compensation The Company has options outstanding under three stock incentive plans: the 2005 Stock Option and Incentive Plan (the "2005 Plan"), the Evolution Robotics, Inc. 2007 Stock Plan (the "2007 Plan") and the 2015 Stock Option and Incentive Plan (the "2015 Plan" and together with the 2005 Plan and the 2007 Plan, the "Plans"). The Company also has restricted stock units outstanding under the 2005 Plan and the 2015 Plan. The 2015 Plan is the only one of the three plans under which new awards may currently be granted. Under the 2015 Plan, which became effective May 20, 2015 , 3,100,000 shares were initially reserved for issuance in the form of incentive stock options, non-qualified stock options, stock appreciation rights, deferred stock awards, restricted stock units, unrestricted stock awards, cash-based awards, performance share awards and dividend equivalent rights. Stock awards returned to the Plans, with the exception of those issued under the 2007 Plan, as a result of their expiration, cancellation or termination are automatically made available for issuance under the 2015 Plan. Eligibility for incentive stock options is limited to those individuals whose employment status would qualify them for the tax treatment associated with incentive stock options in accordance with the Internal Revenue Code of 1986, as amended. As of April 1, 2017 , there were 1,038,883 shares available for future grant under the 2015 Plan. Options granted under the Plans are subject to terms and conditions as determined by the compensation committee of the board of directors, including vesting periods. Options granted under the Plans are exercisable in full at any time subsequent to vesting, generally vest over four years, and expire five or ten years from the date of grant or, if earlier, 60 or 90 days from employee termination. The exercise price of stock options is equal to the closing price on the NASDAQ Global Select Market on the date of grant. Other awards granted under the Plans generally vest over periods from one to four years. On March 10, 2017, the Company issued stock-based grants to certain employees, including executive officers. These grants included stock options totaling 10,975 shares of the Company's common stock, 182,637 time-based restricted stock units, and 105,650 performance based restricted stock units. Each of the above stock options has a per share exercise price of $57.33 , the closing price of the Company's common stock on the NASDAQ Global Select Market on March 10, 2017.

Accrued Expenses

Accrued Expenses	3 Months Ended
	Apr. 01, 2017
Accrued Liabilities, Current [Abstract]
Accrued Expenses	Accrued Expenses Accrued expenses consist of the following: April 1, 2017 December 31, 2016 (In thousands) Accrued warranty $ 8,728 $ 8,464 Accrued federal and state income taxes 1,413 1,059 Accrued customer deposits 1,273 $ 1,171 Accrued direct fulfillment costs 1,191 1,722 Accrued accounting fees 1,087 686 Accrued rent 597 327 Accrued sales tax 196 422 Accrued sales commissions 132 404 Accrued other 6,726 5,599 Total $ 21,343 $ 19,854

Derivative Instruments (Notes)

Derivative Instruments (Notes)	3 Months Ended
	Apr. 01, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments and Hedging Activities Disclosure [Text Block]	Derivative Instruments The Company is exposed to adverse changes in foreign currency exchange rates, primarily related to sales in the Canadian Dollar and the Euro. As a result, the Company periodically enters into foreign currency forward contracts to minimize the impact of fluctuating exchange rates on results of operations. These derivative instruments have maturities of two months or less and have not qualified for hedge accounting. In addition, during 2016, the Company entered into a foreign currency option to hedge the Japanese Yen purchase price of its previously-announced acquisition of the iRobot-related distribution business of Sales On Demand Corporation (see Note 12). The instrument matured in the three months ended April 1, 2017 and did not qualify for hedge accounting. Notional amounts and fair values of derivative instruments are as follows: Notional amount Fair Value Classification April 1, 2017 December 31, 2016 April 1, 2017 December 31, 2016 (In thousands) Foreign currency option contracts Other current assets $ — $ 396 $ — $ 180 Foreign currency forward contracts Other current assets $ 20,668 $ — $ 111 $ — Foreign currency forward contracts Accrued expenses $ — $ 7,680 $ — $ 43 Losses associated with derivative instruments are as follows: Three Months Ended Classification April 1, 2017 April 2, 2016 (In thousands) Derivatives not designated as hedging instruments Loss recognized in income Other income, net $ (225 ) $ (380 )

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Apr. 01, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Lease Obligations Rental expense under operating leases for the three months ended April 1, 2017 and April 2, 2016 were $1.6 million and $1.4 million , respectively. Future minimum rental payments under operating leases were as follows as of April 1, 2017 : Operating Leases (In thousands) Remainder of 2017 $ 3,960 2018 4,647 2019 4,417 2020 2,334 2021 1,382 Thereafter 2,082 Total minimum lease payments $ 18,822 Outstanding Purchase Orders At April 1, 2017 , the Company had outstanding purchase orders aggregating approximately $127.6 million . These purchase orders, the majority of which are with contract manufacturers for the purchase of inventory in the normal course of business, are for manufacturing and non-manufacturing related goods and services, and are generally cancelable without penalty. In circumstances where we determine that we have financial exposure associated with any of these commitments, we record a liability in the period in which that exposure is identified. Guarantees and Indemnification Obligations The Company enters into standard indemnification agreements in the ordinary course of business. Pursuant to these agreements, the Company indemnifies and agrees to reimburse the indemnified party for losses incurred by the indemnified party, generally the Company’s customers, in connection with any patent, copyright, trade secret or other proprietary right infringement claim by any third party. The term of these indemnification agreements is generally perpetual after execution of the agreement. The maximum potential amount of future payments the Company could be required to make under these indemnification agreements is unlimited. The Company has never incurred costs to defend lawsuits or settle claims related to these indemnification agreements. As a result, the Company believes the estimated fair value of these agreements is minimal. Accordingly, the Company has no liabilities recorded for these agreements as of April 1, 2017 and December 31, 2016 , respectively. Warranty The Company provides warranties on most products and has established a reserve for warranties based on estimated warranty costs. The reserve is included as part of accrued expenses (Note 5) in the accompanying balance sheets. Activity related to the warranty accrual was as follows: Three Months Ended April 1, 2017 April 2, 2016 (In thousands) Balance at beginning of period $ 8,464 $ 6,907 Provision 1,994 877 Warranty usage (1) $ (1,730 ) $ (1,430 ) Liability held for sale — (101 ) Balance at end of period $ 8,728 $ 6,253 (1) Warranty usage includes costs incurred for warranty obligations. Sales Taxes The Company collects and remits sales tax in jurisdictions in which it has a physical presence or it believes nexus exists, which therefore obligates the Company to collect and remit sales tax. The Company continually evaluates whether it has established nexus in new jurisdictions with respect to sales tax. The Company records a liability for potential material exposures in states where there is uncertainty about the point in time at which the Company established a sufficient business connection to create nexus. The Company continues to analyze possible sales tax exposure, but does not currently believe that any individual claim or aggregate claims that might arise will ultimately have a material effect on its consolidated results of operations, financial position or cash flows.

Industry Segment, Geographic In

Industry Segment, Geographic Information and Significant Customers	3 Months Ended
	Apr. 01, 2017
Segment Reporting [Abstract]
Industry Segment, Geographic Information and Significant Customers	Industry Segment, Geographic Information and Significant Customers Prior to completing the sale of the Company's defense and security business (see Note 11), the Company’s reportable segments consisted of the home business unit and the defense and security business unit. Following this divestiture, which was completed on April 4, 2016, the Company now operates as one business segment, consumer robots, the results of which are included in the Company's consolidated statements of income and comprehensive income. The Company's consumer robots products are offered to consumers through a network of retail businesses throughout the United States, to various countries through international distributors and retailers, and through the Company's on-line store. Geographic Information For the three months ended April 1, 2017 and April 2, 2016 , sales to non-U.S. customers accounted for 49.5% and 50.1% of total revenue, respectively. Significant Customers For the three months ended April 1, 2017 , the Company generated 13.5% and 10.5% of total revenue from a network of affiliated European distributors (Robopolis SAS) and its distributor in Japan (Sales On Demand Corporation), respectively. The Company generated 10.0% of total revenue from one of its domestic retailers (Bed Bath & Beyond). For the three months ended April 2, 2016 , the Company generated 13.7% and 11.2% of total revenue from a network of affiliated European distributors (Robopolis SAS) and its distributor in Japan (Sales On Demand Corporation), respectively. On April 3, 2017, the Company closed its previously-announced acquisition of the iRobot-related distribution business of Sales On Demand Corporation (see Note 12).

Goodwill, Other Intangible Asse

Goodwill, Other Intangible Assets and Other Assets	3 Months Ended
	Apr. 01, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill, Other Intangible Assets and Other Assets	Goodwill and Other Intangible Assets Goodwill The carrying amount of the Company's goodwill at April 1, 2017 was $41.1 million , which resulted from the acquisition of Evolution Robotics, Inc. The Company's goodwill balance as of January 2, 2016 was $48.8 million , which consisted of the $41.1 million from the acquisition of Evolution Robotics, Inc. and was assigned to the home robots reporting unit and $7.7 million related to the acquisition of Nekton Research, LLC completed in September 2008 and was assigned to the defense and security reporting unit. On April 4, 2016, the Company completed the sale of its defense and security business unit and therefore the goodwill balance assigned to the defense and security business unit was written off during the three months ended July 2, 2016. Other Intangible Assets Other intangible assets include the value assigned to completed technology and a trade name. The estimated useful lives for all of these intangible assets are three to ten years. The intangible assets are being amortized on a straight-line basis, which is consistent with the pattern that the economic benefits of the intangible assets are expected to be utilized. Intangible assets at April 1, 2017 and December 31, 2016 consisted of the following: April 1, 2017 December 31, 2016 Cost Accumulated Amortization Net Cost Accumulated Amortization Net (In thousands) Completed technology $ 26,900 $ 15,557 $ 11,343 $ 26,900 $ 14,693 $ 12,207 Trade name 100 100 — 100 100 — Total $ 27,000 $ 15,657 $ 11,343 $ 27,000 $ 14,793 $ 12,207 Amortization expense related to acquired intangible assets was $0.9 million and $0.9 million for the three months ended April 1, 2017 and April 2, 2016 , respectively. The estimated future amortization expense is expected to be as follows: (In thousands) Remainder of 2017 $ 2,593 2018 3,457 2019 2,818 2020 900 2021 900 Thereafter 675 Total $ 11,343

Restructuring (Notes)

Restructuring (Notes)	3 Months Ended
	Apr. 01, 2017
Restructuring Cost and Reserve [Line Items]
Restructuring, Impairment, and Other Activities Disclosure [Text Block]	Restructuring Charges During the three months ended July 2, 2016, the Company decided to fully exit its remote presence business. As a result, the Company incurred restructuring charges of approximately $1.9 million related to the write-off of certain inventory, workforce reductions and the write-off of certain fixed assets. The activity for the restructuring programs is presented below: Three Months Ended April 1, 2017 (in thousands) Balance at beginning of period $ 188 Charges — Utilization (27 ) Balance at end of period $ 161

Divestiture (Notes)

Divestiture (Notes)	3 Months Ended
	Apr. 01, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Groups, Including Discontinued Operations, Disclosure [Text Block]	Divestiture On April 4, 2016, the Company completed the sale of the defense and security business unit to iRobot Defense Holdings, Inc., a portfolio company of Arlington Capital Partners. The final purchase price, including adjustments for working capital and indebtedness, was $24.5 million . The Company recognized a gain of $0.4 million on the sale of assets. The sale of the defense and security business did not meet the criteria for discontinued operations presentation as it did not represent a strategic shift that had a major effect on the Company's operations and financial results. The Company and iRobot Defense Holdings, Inc. also entered into a Transition Services Agreement (TSA), pursuant to which the Company continued to perform certain functions on iRobot Defense Holdings Inc.’s behalf during a transition period not to exceed 12 months. The TSA provided for the reimbursement of the Company for direct costs incurred in order to provide such functions and was recorded as a component of other income. The transition period was completed during the three months ended April 1, 2017. The Company recognized approximately $0.1 million of TSA reimbursement during the three months ended April 1, 2017.

Subsequent Event (Notes)

Subsequent Event (Notes)	3 Months Ended
	Apr. 01, 2017
Subsequent Event [Line Items]
Subsequent Events [Text Block]	Subsequent Event On April 3, 2017, the Company closed its previously-announced acquisition of the iRobot-related distribution business of Sales On Demand Corporation for approximately $18 million in cash, equal to the book value of the acquired assets. The acquisition price is subject to adjustments and will be finalized no later than May 18, 2017.

Summary of Significant Accoun19

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Apr. 01, 2017
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying consolidated financial statements include those of iRobot and its subsidiaries, after elimination of all intercompany accounts and transactions. iRobot has prepared the accompanying unaudited consolidated financial statements in conformity with accounting principles generally accepted in the United States of America. The accompanying unaudited financial data as of April 1, 2017 , and for the three months ended April 1, 2017 and April 2, 2016 have been prepared by the Company pursuant to the rules and regulations of the Securities and Exchange Commission (SEC). Certain information and footnote disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States have been condensed or omitted pursuant to such rules and regulations. However, the Company believes that the disclosures are adequate to make the information presented not misleading. The year-end balance sheet data were derived from audited financial statements, but do not include all disclosures required by accounting principles generally accepted in the United States. These consolidated financial statements should be read in conjunction with the Company’s audited consolidated financial statements and the notes thereto included in its Annual Report on Form 10-K for the fiscal year ended December 31, 2016 , filed with the SEC on February 17, 2017. In the opinion of management, all adjustments necessary to state fairly the Company's statement of financial position as of April 1, 2017 and results of operations, comprehensive income and cash flows for the periods ended April 1, 2017 and April 2, 2016 have been made. The results of operations, comprehensive income and cash flows for any interim period are not necessarily indicative of the operating results, comprehensive income and cash flows for the full fiscal year or any future periods.
Use of Estimates	Use of Estimates The preparation of these financial statements in conformity with accounting principles generally accepted in the United States requires the Company to make estimates and judgments that affect the reported amounts of assets, liabilities, revenues and expenses, and disclosure of contingent assets and liabilities. On an ongoing basis, management evaluates these estimates and judgments, including those related to revenue recognition, sales returns, price protection, bad debts, warranty claims, inventory reserves, valuation of investments, valuation of goodwill and intangible assets, assumptions used in valuing stock-based compensation instruments and income taxes. The Company bases these estimates on historical and anticipated results and trends, and on various other assumptions that the Company believes are reasonable under the circumstances, including assumptions as to future events. These estimates form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. By their nature, estimates are subject to an inherent degree of uncertainty. Actual results may differ from the Company’s estimates.
Fiscal Year-End	Fiscal Year-End The Company operates and reports using a 52 -53 week fiscal year ending on the Saturday closest to December 31. Accordingly, the Company’s fiscal quarters end on the Saturday that falls closest to the last day of the third month of each quarter.
Revenue Recognition	Revenue Recognition The Company primarily derives its revenue from product sales. Until the divestiture of the defense and security business unit on April 4, 2016 (see Note 11), the Company also generated minimal revenue from government and commercial research and development contracts. The Company sells products directly to customers and indirectly through resellers and distributors. The Company recognizes revenue from sales of robots under the terms of the customer agreement upon transfer of title and risk of loss to the customer, net of estimated returns and allowances, provided that collection is determined to be reasonably assured and no significant obligations remain. Beginning in the third quarter of 2015, the Company introduced its first connected robot. Each sale of a connected robot represents a multi-element arrangement containing the robot, an app and potential future unspecified software upgrades. Revenue is allocated to the deliverables based on their relative selling prices which have been determined using best estimate of selling price (BESP), as the Company has not been able to establish vendor specific objective evidence (VSOE) or obtain relevant third party evidence (TPE). Revenue allocated to the app and unspecified software upgrades is then deferred and recognized on a straight-line basis over the period in which the Company expects to provide the upgrades over the estimated life of the robot. Sales to domestic and Canadian resellers of consumer robots are typically subject to agreements allowing for limited rights of return, rebates and price protection. The Company also provides limited rights of returns for direct-to-consumer sales generated through its on-line stores and one international distributor. Accordingly, the Company reduces revenue for its estimates of liabilities for these rights of return, rebates and price protection at the time the related sale is recorded. These estimates for rights of return are directly based on specific terms and conditions included in the customer agreements, historical returns experience and various other assumptions that the Company believes are reasonable under the circumstances. In the case of new product introductions, the estimates for returns applied to the new products are based upon the estimates for the most similar predecessor products until such time that the Company has enough actual returns experience for the new products, which is typically two holiday return cycles. At that time, the Company incorporates that data into the development of returns estimates for the new products. The Company updates its analysis of returns on a quarterly basis. If actual returns differ significantly from the Company's estimates, or if modifications to individual customer agreements are entered into that impact their rights of returns, such differences could result in an adjustment to previously established reserves and could have a material impact, either favorably or unfavorably, on the Company’s results of operations for the period in which the actual returns become known or the agreement is modified. Except for the one international distributor noted above, the Company's international distributor agreements do not currently allow for product returns and, as a result, no reserve for returns is established for this group of customers. In 2016, the Company began selling to one domestic distributor under an agreement that provides product return privileges. As a result, the Company recognizes revenue from sales to this distributor when the product is resold by the distributor. The estimates and adjustments for rebates and price protection are based on specific programs, expected usage and historical experience. Actual results could differ from these estimates. Prior to the Company's divestiture of the defense and security business unit on April 4, 2016 (see Note 11), the Company generated minimal revenue from government contracts. Under cost-plus-fixed-fee (CPFF) type contracts, the Company recognized revenue based on costs incurred plus a pro rata portion of the total fixed fee. Costs incurred included labor and material that were directly associated with individual CPFF contracts plus indirect overhead and general and administrative type costs based upon billing rates submitted by the Company to the Defense Contract Management Agency (DCMA). Annually, the Company submits final indirect billing rates to DCMA based upon actual costs incurred throughout the year. In the situation where the Company’s final actual billing rates are greater than the estimated rates used, the Company records a cumulative revenue adjustment in the period in which the rate differential is collected from the customer. These final billing rates are subject to audit by the Defense Contract Audit Agency (DCAA), which can occur several years after the final billing rates are submitted and may result in material adjustments to revenue recognized based on estimated final billing rates. As of April 1, 2017 , fiscal year 2015 is open for audit by DCAA. In the situation where the Company’s anticipated actual billing rates will be lower than the provisional rates used, the Company records a cumulative revenue adjustment in the period in which the rate differential is identified. Revenue on firm fixed price (FFP) contracts was recognized using the percentage-of-completion method. For government product FFP contracts, revenue was recognized as the product was shipped or in accordance with the contract terms. Costs and estimated gross margins on contracts were recorded as revenue as work was performed based on the percentage that incurred costs compared to estimated total costs utilizing the most recent estimates of costs and funding. Revenue earned in excess of billings, if any, was recorded as unbilled revenue. Billings in excess of revenue earned, if any, were recorded as deferred revenue.
Accounting for Share-Based Payments	Stock-Based Compensation The Company accounts for stock-based compensation through recognition of the fair value of the stock-based compensation as a charge against earnings. Stock-based compensation cost for stock options is estimated at the grant date based on each option's fair value as calculated by the Black-Scholes option-pricing model. Stock-based compensation cost for restricted stock awards, time-based restricted stock units and performance-based restricted stock units is measured based on the closing fair market value of the Company's common stock on the date of grant. For performance-based restricted stock units, the compensation costs will be subsequently adjusted for assumptions of achievement during the period in which the assumption of achievement changes, as applicable. The Company recognizes stock-based compensation cost as expense ratably on a straight-line basis over the requisite service period. The Company has elected to account for forfeitures as they occur, rather than applying an estimated forfeiture rate, upon adoption of ASU 2016-09.
Net Income Per Share	Net Income Per Share The following table presents the calculation of both basic and diluted net income per share: Three Months Ended (In thousands, except per share amounts) April 1, 2017 April 2, 2016 Net income $ 16,359 $ 3,932 Weighted-average shares outstanding 27,304 29,004 Dilutive effect of employee stock options and restricted shares 991 470 Diluted weighted-average shares outstanding 28,295 29,474 Basic income per share $ 0.60 $ 0.14 Diluted income per share $ 0.58 $ 0.13 Restricted stock units and stock options representing approximately 32.1 thousand and 0.7 million shares of common stock for the three-month periods ended April 1, 2017 and April 2, 2016 , respectively, were excluded from the computation of diluted earnings per share for these periods because their effect would have been antidilutive.
Income Taxes	Income Taxes The Company is subject to taxation in the United States and various states and foreign jurisdictions. The statute of limitations for examinations by the Internal Revenue Service is closed for fiscal years prior to 2013. The statute of limitations for examinations by state tax authorities is closed for fiscal years prior to 2012. Federal carryforward attributes that were generated prior to fiscal year 2013 and state carryforward attributes that were generated prior to fiscal year 2012 may still be adjusted upon examination by the federal or state tax authorities if they either have been or will be used in a period for which the statute of limitations is still open. Deferred taxes are determined based on the difference between the financial statement and tax basis of assets and liabilities using enacted tax rates in effect in the years in which the differences are expected to reverse. Valuation allowances are provided if, based upon the weight of available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. The Company monitors the realization of its deferred tax assets based on changes in circumstances, for example, recurring periods of income for tax purposes following historical periods of cumulative losses, generation of tax credits compared to future utilization of credits, or changes in tax laws or regulations. The Company's income tax provision and its assessment of the ability to realize its deferred tax assets involve significant judgments and estimates. The Company is currently generating state research credits that exceed the amount being utilized. As a result of this trend, a valuation allowance may be needed in the future related to these state tax credits. The Company recorded a tax provision of $5.3 million and $1.8 million for the three months ended April 1, 2017 and April 2, 2016 , respectively. The $5.3 million provision for the three months ended April 1, 2017 resulted in an effective income tax rate of 24.4% . The $1.8 million provision for the three months ended April 2, 2016 resulted in an effective income tax rate of 31.4% . The difference between the effective income tax rate of 24.4% for the three months ended April 1, 2017 and 31.4% for the three months ended April 2, 2016 was primarily due to a $1.7 million tax benefit related to recording excess tax benefits of stock-based compensation as a result of the adoption of ASU 2016-09, "Improvements to Employee Share-Based Payment Accounting," on the first day of the three months ended April 1, 2017 .
Fair Value Measurement, Policy [Policy Text Block]	Fair Value Measurements The authoritative guidance for fair value establishes a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value. These tiers include: Level 1, defined as observable inputs such as quoted prices in active markets; Level 2, defined as inputs other than quoted prices in active markets that are either directly or indirectly observable; and Level 3, defined as unobservable inputs in which little or no market data exists, therefore requiring an entity to develop its own assumptions. Financial Assets and Liabilities The Company’s financial assets measured at fair value on a recurring basis at April 1, 2017 , were as follows: Fair Value Measurements as of April 1, 2017 Level 1 Level 2 Level 3 (In thousands) Description Assets: Cash and cash equivalents Money market funds $ 187,302 $ — $ — Short term investments Corporate and government bonds (1) — 39,942 — Other current assets Derivative instruments (Note 6) (2) — 111 — Total assets measured at fair value $ 187,302 $ 40,053 $ — The Company’s financial assets and liabilities measured at fair value on a recurring basis at December 31, 2016 , were as follows: Fair Value Measurements as of Level 1 Level 2 Level 3 (In thousands) Description Assets: Cash and cash equivalents Money market funds $ 156,980 $ — $ — Short term investments Corporate and government bonds (1) — 39,930 — Other current assets Derivative instruments (Note 6) (2) — 180 — Total assets measured at fair value $ 156,980 $ 39,930 $ — Liabilities: Accrued Expenses Derivative instruments (Note 6) (2) $ — $ 43 $ — Total liabilities measured at fair value $ — $ 43 $ — (1) The bond investments are valued based on observable market values as of the Company’s reporting date. The bond investments are recorded at fair value and marked-to-market at the end of each reporting period. The realized and unrealized gains and losses are included in comprehensive income for that period. (2) Derivative instruments are valued using an income approach based on the present value of the forward rate less the contract rate multiplied by the notional amount.
Goodwill	Goodwill Goodwill is recorded as the difference, if any, between the aggregate consideration paid for an acquisition and the fair value of the net tangible and intangible assets acquired. The Company evaluates goodwill for impairment at the reporting unit level (operating segment or one level below an operating segment) annually or more frequently if the Company believes indicators of impairment exist. In accordance with the guidance, the Company is permitted to first assess qualitative factors to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount. If the Company concludes that it is more likely than not that the fair value of a reporting unit is less than its carrying amount, then a two-step goodwill impairment test is performed. The first step of the impairment test involves comparing the fair values of the applicable reporting units with their aggregate carrying values, including goodwill. If the carrying amount of a reporting unit exceeds the reporting unit’s fair value, the Company performs the second step of the goodwill impairment test to determine the amount of impairment loss. The second step of the goodwill impairment test involves comparing the implied fair value of the affected reporting unit’s goodwill with the carrying value of that goodwill. The Company completes the annual impairment evaluation during the fourth quarter each year, or more frequently, if necessary, upon identification of a triggering event.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In January 2017, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2017-04, "Intangibles - Goodwill and Other." ASU 2017-04 eliminates step 2 from the goodwill impairment test, instead requiring that an entity recognize an impairment charge for the amount by which the carrying amount of goodwill exceeds the reporting unit's fair value. ASU 2017-04 is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years, with early adoption permitted. The Company does not believe the standard will have a material effect on its consolidated financial statements. In January 2017, the FASB issued ASU No. 2017-01, "Business Combinations; Clarifying the Definition of a Business." ASU 2017-01 clarifies the definition of a business with the objective of adding guidance to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. The definition of a business affects many areas of accounting including acquisitions, disposals, goodwill, and consolidation. The guidance is effective for annual periods beginning after December 15, 2017, including interim periods within those periods. The Company is currently evaluating the impact of the standard on its consolidated financial statements. In October 2016, the FASB issued ASU No. 2016-16, "Income Taxes: Intra-Entity Transfers of Assets Other Than Inventory." ASU 2016-16 clarifies the accounting for the current and deferred income taxes for an intra-entity transfer of an asset other than inventory. ASU 2016-16 is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years, with early adoption permitted. The Company is currently evaluating the impact of the standard on its consolidated financial statements. In August 2016, the FASB issued ASU No. 2016-15, "Statement of Cash Flows: Classification of Certain Cash Receipts and Cash Payments." ASU 2016-15 refines how companies classify certain aspects of the cash flow statement in regards to debt prepayment, settlement of debt instruments, contingent consideration payments, proceeds from insurance claims and life insurance policies, distribution from equity method investees, beneficial interests in securitization transactions and separately identifiable cash flows. ASU 2016-15 is effective for annual periods beginning after December 15, 2017, and for interim periods within fiscal years beginning after December 15, 2018. Early adoption is permitted. The Company is currently evaluating the impact of the standard on its consolidated financial statements. In March 2016, the FASB issued ASU No. 2016-09, "Improvements to Employee Share-Based Payment Accounting," which simplifies several aspects of the accounting for employee share-based payment transactions, including the accounting for income taxes, forfeitures, and statutory tax withholding requirements, as well as classification in the statement of cash flows. As a result of the adoption, on a prospective basis, the Company recognized $1.7 million of excess tax benefits from stock-based compensation as a discrete item in its provision for income taxes for the three months ended April 1, 2017. Additionally, the Company elected to account for forfeitures of share-based payments as they occur. In February 2016, the FASB issued ASU No. 2016-02, "Leases." ASU 2016-02 requires lessees to recognize the assets and liabilities on their balance sheet for the rights and obligations created by most leases and continue to recognize expenses on their income statements over the lease term. It will also require disclosures designed to give financial statement users information on the amount, timing, and uncertainty of cash flows arising from leases. The guidance is effective for annual reporting periods beginning after December 15, 2018 and interim periods within those fiscal years, with early adoption permitted. The Company is currently evaluating the impact of the standard on its consolidated financial statements. In July 2015, the FASB issued ASU No. 2015-11, "Inventory: Simplifying the Measurement of Inventory." ASU 2015-11 applies only to inventory for which cost is determined by methods other than last-in, first-out and the retail inventory method, which includes inventory that is measured using first-in, first-out or average cost. Inventory within the scope of this standard is required to be measured at the lower of cost and net realizable value. Net realizable value is the estimated selling prices in the ordinary course of business, less reasonably predictable costs of completion, disposal, and transportation. The Company adopted ASU 2015-11 effective January 1, 2017. The adoption of this standard did not have a material impact on the Company's consolidated financial statements. In May 2014, the FASB issued ASU No. 2014-09, "Revenue from Contracts with Customers," which provides guidance for revenue recognition. The standard’s core principle is that a company will recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. The new guidance is effective for annual reporting periods beginning after December 15, 2016, including interim periods within those annual reporting periods. In July 2015, the FASB voted to defer the effective date of the new accounting guidance related to revenue recognition by one year to December 17, 2017 for annual reporting periods beginning after that date and permitted early adoption of the standard, but not before the original effective date of December 15, 2016. The standard will be effective for the Company beginning in the first quarter of 2018. The Company is continuing to evaluate the impact that the adoption of the new revenue recognition standard will have on its consolidated financial statements, but anticipates that the additional disclosure requirements will represent a significant change from current guidance. The Company currently anticipates adopting the standard using the modified retrospective method. From time to time, new accounting pronouncements are issued by FASB that are adopted by the Company as of the specified effective date. Unless otherwise discussed, the Company believes that recently issued standards, which are not yet effective, will not have a material impact on the Company’s consolidated financial statements upon adoption.

Summary of Significant Accoun20

Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Apr. 01, 2017
Accounting Policies [Abstract]
Basic and Diluted Net Income Per Share	The following table presents the calculation of both basic and diluted net income per share: Three Months Ended (In thousands, except per share amounts) April 1, 2017 April 2, 2016 Net income $ 16,359 $ 3,932 Weighted-average shares outstanding 27,304 29,004 Dilutive effect of employee stock options and restricted shares 991 470 Diluted weighted-average shares outstanding 28,295 29,474 Basic income per share $ 0.60 $ 0.14 Diluted income per share $ 0.58 $ 0.13
Fair Value Assets Measured on Recurring Basis	The Company’s financial assets measured at fair value on a recurring basis at April 1, 2017 , were as follows: Fair Value Measurements as of April 1, 2017 Level 1 Level 2 Level 3 (In thousands) Description Assets: Cash and cash equivalents Money market funds $ 187,302 $ — $ — Short term investments Corporate and government bonds (1) — 39,942 — Other current assets Derivative instruments (Note 6) (2) — 111 — Total assets measured at fair value $ 187,302 $ 40,053 $ — The Company’s financial assets and liabilities measured at fair value on a recurring basis at December 31, 2016 , were as follows: Fair Value Measurements as of Level 1 Level 2 Level 3 (In thousands) Description Assets: Cash and cash equivalents Money market funds $ 156,980 $ — $ — Short term investments Corporate and government bonds (1) — 39,930 — Other current assets Derivative instruments (Note 6) (2) — 180 — Total assets measured at fair value $ 156,980 $ 39,930 $ — Liabilities: Accrued Expenses Derivative instruments (Note 6) (2) $ — $ 43 $ — Total liabilities measured at fair value $ — $ 43 $ — (1) The bond investments are valued based on observable market values as of the Company’s reporting date. The bond investments are recorded at fair value and marked-to-market at the end of each reporting period. The realized and unrealized gains and losses are included in comprehensive income for that period. (2) Derivative instruments are valued using an income approach based on the present value of the forward rate less the contract rate multiplied by the notional amount.

Inventory (Tables)

Inventory (Tables)	3 Months Ended
	Apr. 01, 2017
Inventory Disclosure [Abstract]
Components of Inventory	Inventory consists of the following: April 1, 2017 December 31, 2016 (In thousands) Raw materials $ 2,838 $ 4,717 Finished goods 54,287 45,861 Total $ 57,125 $ 50,578

Accrued Expenses (Tables)

Accrued Expenses (Tables)	3 Months Ended
	Apr. 01, 2017
Accrued Liabilities, Current [Abstract]
Components of Accrued Expenses	Accrued expenses consist of the following: April 1, 2017 December 31, 2016 (In thousands) Accrued warranty $ 8,728 $ 8,464 Accrued federal and state income taxes 1,413 1,059 Accrued customer deposits 1,273 $ 1,171 Accrued direct fulfillment costs 1,191 1,722 Accrued accounting fees 1,087 686 Accrued rent 597 327 Accrued sales tax 196 422 Accrued sales commissions 132 404 Accrued other 6,726 5,599 Total $ 21,343 $ 19,854

Derivative Instruments (Tables)

Derivative Instruments (Tables)	3 Months Ended
	Apr. 01, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) [Table Text Block]	Losses associated with derivative instruments are as follows: Three Months Ended Classification April 1, 2017 April 2, 2016 (In thousands) Derivatives not designated as hedging instruments Loss recognized in income Other income, net $ (225 ) $ (380 )

Derivative Instruments Schedule

Derivative Instruments Schedule of Derivative Instruments (Tables)	3 Months Ended
	Apr. 01, 2017
Derivative [Line Items]
Schedule of Derivative Instruments [Table Text Block]	Notional amounts and fair values of derivative instruments are as follows: Notional amount Fair Value Classification April 1, 2017 December 31, 2016 April 1, 2017 December 31, 2016 (In thousands) Foreign currency option contracts Other current assets $ — $ 396 $ — $ 180 Foreign currency forward contracts Other current assets $ 20,668 $ — $ 111 $ — Foreign currency forward contracts Accrued expenses $ — $ 7,680 $ — $ 43

Commitments and Contingencies (

Commitments and Contingencies (Tables)	3 Months Ended
	Apr. 01, 2017
Commitments and Contingencies Disclosure [Abstract]
Summary of Future Minimum Rental Payments under Operating Leases	Future minimum rental payments under operating leases were as follows as of April 1, 2017 : Operating Leases (In thousands) Remainder of 2017 $ 3,960 2018 4,647 2019 4,417 2020 2,334 2021 1,382 Thereafter 2,082 Total minimum lease payments $ 18,822
Activity Related to the Warranty Accrual	Activity related to the warranty accrual was as follows: Three Months Ended April 1, 2017 April 2, 2016 (In thousands) Balance at beginning of period $ 8,464 $ 6,907 Provision 1,994 877 Warranty usage (1) $ (1,730 ) $ (1,430 ) Liability held for sale — (101 ) Balance at end of period $ 8,728 $ 6,253 (1) Warranty usage includes costs incurred for warranty obligations

Industry Segment, Geographic 26

Industry Segment, Geographic Information and Significant Customers (Tables)	3 Months Ended
	Apr. 01, 2017
Segment Reporting [Abstract]
Segment Information about Revenue, Cost of Revenue, Gross Margin and Income before Income Taxes	Prior to completing the sale of the Company's defense and security business (see Note 11), the Company’s reportable segments consisted of the home business unit and the defense and security business unit. Following this divestiture, which was completed on April 4, 2016, the Company now operates as one business segment, consumer robots, the results of which are included in the Company's consolidated statements of income and comprehensive income. The Company's consumer robots products are offered to consumers through a network of retail businesses throughout the United States, to various countries through international distributors and retailers, and through the Company's on-line store.

Goodwill, Other Intangible As27

Goodwill, Other Intangible Assets and Other Assets (Tables)	3 Months Ended
	Apr. 01, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Other Intangible Assets	Intangible assets at April 1, 2017 and December 31, 2016 consisted of the following: April 1, 2017 December 31, 2016 Cost Accumulated Amortization Net Cost Accumulated Amortization Net (In thousands) Completed technology $ 26,900 $ 15,557 $ 11,343 $ 26,900 $ 14,693 $ 12,207 Trade name 100 100 — 100 100 — Total $ 27,000 $ 15,657 $ 11,343 $ 27,000 $ 14,793 $ 12,207
Estimated Future Amortization Expense Related to Current Intangible Assets	The estimated future amortization expense is expected to be as follows: (In thousands) Remainder of 2017 $ 2,593 2018 3,457 2019 2,818 2020 900 2021 900 Thereafter 675 Total $ 11,343

Restructuring (Tables)

Restructuring (Tables)	3 Months Ended
	Apr. 01, 2017
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Costs [Table Text Block]	The activity for the restructuring programs is presented below: Three Months Ended April 1, 2017 (in thousands) Balance at beginning of period $ 188 Charges — Utilization (27 ) Balance at end of period $ 161

Divestiture (Tables)

Divestiture (Tables)	3 Months Ended
	Apr. 01, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Groups, Including Discontinued Operations [Table Text Block]	On April 4, 2016, the Company completed the sale of the defense and security business unit to iRobot Defense Holdings, Inc., a portfolio company of Arlington Capital Partners. The final purchase price, including adjustments for working capital and indebtedness, was $24.5 million . The Company recognized a gain of $0.4 million on the sale of assets. The sale of the defense and security business did not meet the criteria for discontinued operations presentation as it did not represent a strategic shift that had a major effect on the Company's operations and financial results. The Company and iRobot Defense Holdings, Inc. also entered into a Transition Services Agreement (TSA), pursuant to which the Company continued to perform certain functions on iRobot Defense Holdings Inc.’s behalf during a transition period not to exceed 12 months. The TSA provided for the reimbursement of the Company for direct costs incurred in order to provide such functions and was recorded as a component of other income. The transition period was completed during the three months ended April 1, 2017. The Company recognized approximately $0.1 million of TSA reimbursement during the three months ended April 1, 2017.

Summary of Significant Accoun30

Summary of Significant Accounting Policies - Basic and Diluted Net Income Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Apr. 01, 2017	Apr. 02, 2016
Schedule Of Computation Of Basic And Diluted Earnings Per Common Share [Line Items]
Net income	$ 16,359	$ 3,932
Weighted-average shares outstanding	27,304	29,004
Dilutive effect of employee stock options and restricted shares	991	470
Diluted weighted-average shares outstanding	28,295	29,474
Basic income per share	$ 0.60	$ 0.14
Diluted income per share	$ 0.58	$ 0.13
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0	700

Summary of Significant Accoun31

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands	Apr. 01, 2017	Dec. 31, 2016
Disclosure Summary Of Significant Accounting Policies Additional Information [Abstract]
Finite-Lived Intangible Assets, Gross	$ 27,000	$ 27,000
Finite-Lived Intangible Assets, Net	$ 11,343	$ 12,207

Summary of Significant Accoun32

Summary of Significant Accounting Policies - Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended
	Apr. 01, 2017	Apr. 02, 2016
Tax provision	$ 5,282	$ 1,797
Effective income tax rate	24.40%	31.40%

Summary of Significant Accoun33

Summary of Significant Accounting Policies - Fair Value Assets and Liabilities Measured on Recurring Basis (Detail) - USD ($) $ in Thousands		Apr. 01, 2017	Dec. 31, 2016
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure, Recurring		$ 187,302	$ 156,980
Fair Value, Inputs, Level 1 [Member] | Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure, Recurring		187,302	156,980
Fair Value, Inputs, Level 1 [Member] | Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure, Recurring	[1]	0	0
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure, Recurring		40,053	39,930
Liabilities, Fair Value Disclosure, Recurring			43
Fair Value, Inputs, Level 2 [Member] | Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure, Recurring		0	0
Fair Value, Inputs, Level 2 [Member] | Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure, Recurring	[1]	39,942	39,930
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure, Recurring		0	0
Liabilities, Fair Value Disclosure, Recurring			0
Fair Value, Inputs, Level 3 [Member] | Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure, Recurring		0	0
Fair Value, Inputs, Level 3 [Member] | Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure, Recurring	[1]	0	0
Derivative Financial Instruments, Liabilities [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities, Fair Value Disclosure, Recurring	[2]		0
Derivative Financial Instruments, Liabilities [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities, Fair Value Disclosure, Recurring	[2]		43
Derivative Financial Instruments, Liabilities [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities, Fair Value Disclosure, Recurring	[2]		0
Derivative Financial Instruments, Assets [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure, Recurring	[2]	0	0
Derivative Financial Instruments, Assets [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure, Recurring	[2]	111	180
Derivative Financial Instruments, Assets [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure, Recurring	[2]	$ 0	$ 0
[1]	(1)The bond investments are valued based on observable market values as of the Company’s reporting date. The bond investments are recorded at fair value and marked-to-market at the end of each reporting period. The realized and unrealized gains and losses are included in comprehensive income for that period.
[2]	(2)Derivative instruments are valued using an income approach based on the present value of the forward rate less the contract rate multiplied by the notional amount.

Summary of Significant Accoun34

Summary of Significant Accounting Policies - Fair Value Assets Measured on a Nonrecurring Basis (Details) - USD ($) $ in Thousands	Apr. 01, 2017	Dec. 31, 2016	Jan. 02, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Goodwill	$ 41,041	$ 41,041	$ 48,800
Finite-Lived Intangible Assets, Gross	27,000	27,000
Finite-Lived Intangible Assets, Net	$ 11,343	$ 12,207

Inventory (Details)

Inventory (Details) - USD ($) $ in Thousands	Apr. 01, 2017	Dec. 31, 2016
Inventory Disclosure [Abstract]
Inventory, Raw Materials, Net of Reserves	$ 2,838	$ 4,717
Inventory, Finished Goods, Net of Reserves	54,287	45,861
Inventory	$ 57,125	$ 50,578

Stock Option Plans - Additional

Stock Option Plans - Additional Information (Detail) - $ / shares	May 20, 2015	Apr. 01, 2017	Mar. 10, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Effective date for stock options plan	May 20, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross		10,975
Share Price			$ 57.33
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period for options		1 year
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period for options		4 years
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Minimum period for expiration of options in case of employee termination		60 days
Maximum period for expiration of options in case of employee termination		90 days
Employee Stock Option [Member] | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Minimum expiration period for options		5 years
Employee Stock Option [Member] | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period for options		4 years
Minimum expiration period for options		10 years
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units granted		182,637
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units granted		105,650
Two Thousand Fifteen Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for issuance in different forms	3,100,000
Share based compensation arrangement shares available for grant		1,038,883

Accrued Expenses (Details)

Accrued Expenses (Details) - USD ($) $ in Thousands	Apr. 01, 2017	Dec. 31, 2016
Accounts Payable, Current [Abstract]
Accrued warranty	$ 8,728	$ 8,464
Accrued Income Taxes, Current	1,413	1,059
Accrued Sales Tax	196	422
Accrued rent	597	327
Accrued direct fulfillment costs	1,191	1,722
Accrued customer deposits	1,273	1,171
Accrued sales commissions	132	404
Accrued accounting fees	1,087	686
Accrued other	6,726	5,599
Accrued expenses	21,343	19,854
Accrued compensation	$ 11,348	$ 21,015

Derivative Instruments (Details

Derivative Instruments (Details) - USD ($) $ in Thousands	3 Months Ended
	Apr. 01, 2017	Apr. 02, 2016
Foreign Exchange Forward [Member] | Other Nonoperating Income (Expense) [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Loss	$ (225)	$ (380)

Derivative Instruments Schedu39

Derivative Instruments Schedule of Derivative Instruments (Details) - USD ($) $ in Thousands	Apr. 01, 2017	Dec. 31, 2016
Other Current Assets [Member] | Foreign Exchange Option [Member]
Derivative [Line Items]
Derivative, Notional Amount	$ 0	$ 396
Derivative, Fair Value, Net	0	180
Other Current Assets [Member] | Foreign Exchange Forward [Member]
Derivative [Line Items]
Derivative, Notional Amount	20,668	0
Derivative, Fair Value, Net	111	0
Accrued Liabilities [Member] | Foreign Exchange Forward [Member]
Derivative [Line Items]
Derivative, Notional Amount	0	7,680
Derivative, Fair Value, Net	$ 0	$ 43

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) $ in Millions	Apr. 01, 2017USD ($)
Outstanding POs [Abstract]
Contractual Obligation	$ 127.6

Commitments and Contingencies41

Commitments and Contingencies - Summary of Future Minimum Rental Payments under Operating Leases (Detail) - USD ($) $ in Thousands	3 Months Ended
	Apr. 01, 2017	Apr. 02, 2016
Commitments and Contingencies Disclosure [Abstract]
Rental expense under operating leases	$ 1,600	$ 1,400
Disclosure Summary Of Future Minimum Rental Payments Under Operating Leases [Abstract]
Remainder of 2017	3,960
2,018	4,647
2,019	4,417
2,020	2,334
2,021	1,382
Thereafter	2,082
Total minimum lease payments	$ 18,822

Commitments and Contingencies42

Commitments and Contingencies - Activity Related to Warranty Accrual (Detail) - USD ($) $ in Thousands	3 Months Ended
	Apr. 01, 2017	Apr. 02, 2016
Movement in Standard Product Warranty Accrual [Roll Forward]
Balance at beginning of period	$ 8,464	$ 6,907
Provision	1,994	877
Warranty usage	(1,730)	(1,430)
Balance at end of period	8,728	6,253
Warranty accrual adjustment, liability held for sale	$ 0	$ (101)

Industry Segment, Geographic 43

Industry Segment, Geographic Information and Significant Customers - Segment Information about Revenue, Cost of Revenue, Gross Margin and Income before Income Taxes (Detail) $ in Thousands		3 Months Ended
		Apr. 01, 2017USD ($)segment	Apr. 02, 2016USD ($)
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Number of Reportable Segments | segment		1
Revenue		$ 168,467	$ 130,804
Cost of revenue	[1]	81,124	68,843
Gross margin		87,343	61,961
Research and development	[1]	25,508	19,728
Selling and marketing	[1]	22,575	19,940
General and administrative	[1]	17,622	16,764
Other income, net		3	200
Income before income taxes		$ 21,641	$ 5,729
[1]	Total stock-based compensation recorded in the three months ended April 1, 2017 and April 2, 2016 included in the above figures breaks down by expense classification as follows: Three Months Ended April 1, 2017 April 2, 2016Cost of revenue$226 $221Research and development1,099 829Selling and marketing570 485General and administrative2,436 2,357

Industry Segment, Geographic 44

Industry Segment, Geographic Information and Significant Customers - Additional Information (Detail) - Customer Concentration Risk [Member]	3 Months Ended
	Apr. 01, 2017	Apr. 02, 2016
Domestic Customer [Domain]
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration Risk, Percentage	10.00%
Customer Concentration Risk [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration Risk, Percentage	49.50%	50.10%
International distributors of home robots products | Distributor One
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration Risk, Percentage	10.50%	11.20%
International distributors of home robots products | Distributor Two
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration Risk, Percentage	13.50%	13.70%

Goodwill, Other Intangible As45

Goodwill, Other Intangible Assets and Other Assets - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Apr. 01, 2017	Apr. 02, 2016	Dec. 31, 2016	Jan. 02, 2016
Business Acquisition [Line Items]
Goodwill, Gross	$ 41,100
Goodwill	41,041		$ 41,041	$ 48,800
Amortization of Acquired Intangible Assets	$ 900	$ 900
Minimum
Business Acquisition [Line Items]
Estimated useful life of intangible assets	3 years
Maximum
Business Acquisition [Line Items]
Estimated useful life of intangible assets	10 years
Home Robots | Evolution Robotics, Inc. (ER)
Business Acquisition [Line Items]
Goodwill				41,100
Defense & Security | Nekton Research LLC [Member]
Business Acquisition [Line Items]
Goodwill				$ 7,700

Goodwill, Other Intangible As46

Goodwill, Other Intangible Assets and Other Assets - Other Intangible Assets (Detail) - USD ($) $ in Thousands	3 Months Ended
	Apr. 01, 2017	Apr. 02, 2016	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	$ 27,000		$ 27,000
Intangible assets accumulated amortization	15,657		14,793
Intangible Assets, Net	11,343		12,207
Amortization of Acquired Intangible Assets	900	$ 900
Completed technology
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	26,900		26,900
Intangible assets accumulated amortization	15,557		14,693
Intangible Assets, Net	11,343		12,207
Trade Names
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	100		100
Intangible assets accumulated amortization	100		100
Intangible Assets, Net	$ 0		$ 0

Goodwill, Other Intangible As47

Goodwill, Other Intangible Assets and Other Assets - Estimated Future Amortization Expense Related to Current Intangible Assets (Detail) - USD ($) $ in Thousands	Apr. 01, 2017	Dec. 31, 2016
Disclosure Estimated Future Amortization Expense Related To Current Intangible Assets [Abstract]
Remainder of 2017	$ 2,593
2,017	3,457
2,018	2,818
2,019	900
2,020	900
Thereafter	675
Intangible Assets, Net	$ 11,343	$ 12,207

Restructuring (Details)

Restructuring (Details) - USD ($) $ in Thousands	3 Months Ended
	Apr. 01, 2017	Dec. 31, 2016
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	$ 161	$ 188
Restructuring and Related Cost, Expected Cost	0
Restructuring and Related Cost, Incurred Cost	$ 27

Divestiture (Details)

Divestiture (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Apr. 01, 2017	Dec. 31, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Groups, Including Discontinued Operations [Table Text Block]	On April 4, 2016, the Company completed the sale of the defense and security business unit to iRobot Defense Holdings, Inc., a portfolio company of Arlington Capital Partners. The final purchase price, including adjustments for working capital and indebtedness, was $24.5 million . The Company recognized a gain of $0.4 million on the sale of assets. The sale of the defense and security business did not meet the criteria for discontinued operations presentation as it did not represent a strategic shift that had a major effect on the Company's operations and financial results. The Company and iRobot Defense Holdings, Inc. also entered into a Transition Services Agreement (TSA), pursuant to which the Company continued to perform certain functions on iRobot Defense Holdings Inc.’s behalf during a transition period not to exceed 12 months. The TSA provided for the reimbursement of the Company for direct costs incurred in order to provide such functions and was recorded as a component of other income. The transition period was completed during the three months ended April 1, 2017. The Company recognized approximately $0.1 million of TSA reimbursement during the three months ended April 1, 2017.
Proceeds from Divestiture of Businesses, Net of Cash Divested		$ 24.5
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal		$ 0.4
Disposal Group, Including Discontinued Operation, Other Income	$ 0.1

Subsequent Event (Details)

Subsequent Event (Details) $ in Millions	Apr. 03, 2017USD ($)
Subsequent Event [Member]
Subsequent Event [Line Items]
Business Combination, Consideration Transferred	$ 18