iRobot (IRBT) 10-K 13 Feb 15 2014 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
	Dec. 27, 2014	Feb. 09, 2015	Jun. 28, 2014
Document and Entity Information [Abstract]
Entity Registrant Name	IROBOT CORP
Entity Central Index Key	1159167
Document Type	10-K
Document Period End Date	27-Dec-14
Amendment Flag	FALSE
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	-15
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$1,160,000,000
Entity Common Stock, Shares Outstanding		29,672,165

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Dec. 27, 2014	Dec. 28, 2013
In Thousands, unless otherwise specified
Current assets:
Cash and cash equivalents	$185,957	$165,404
Short term investments	36,166	21,954
Accounts receivable, net of allowance of $67 at December 27, 2014 and December 28, 2013	71,056	39,348
Unbilled revenue	2,614	856
Inventory	47,857	46,107
Deferred tax assets	21,505	20,144
Other current assets	9,704	6,848
Total current assets	374,859	300,661
Property and equipment, net	31,297	23,661
Deferred tax assets	8,409	10,095
Goodwill	48,751	48,751
Intangible assets, net	19,146	22,668
Other assets	10,751	10,501
Total assets	493,213	416,337
Current liabilities:
Accounts payable	60,256	41,344
Accrued expenses	18,701	14,880
Accrued compensation	16,235	19,606
Deferred Revenue, Current	3,849	5,085
Total current liabilities	99,041	80,915
Long term liabilities	3,736	4,733
Commitments and contingencies (Note 11):
Redeemable convertible preferred stock, 5,000,000 shares authorized and no shares issued or outstanding	0	0
Common stock, $0.01 par value, 100,000,000 shares authorized; and 29,644,602 and 28,935,253 shares issued and outstanding at December 27, 2014 and December 28, 2013, respectively	297	289
Additional paid-in capital	249,409	227,175
Retained earnings	140,881	103,078
Accumulated other comprehensive income	-151	147
Total stockholders’ equity	390,436	330,689
Total liabilities, redeemable convertible preferred stock and stockholders’ equity	$493,213	$416,337

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Dec. 27, 2014	Dec. 28, 2013
In Thousands, except Share data, unless otherwise specified
Net allowances on Accounts receivable	$67	$67
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
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	29,644,602	28,935,253
Common stock, shares outstanding	29,644,602	28,935,253

Consolidated_Statements_of_Inc

Consolidated Statements of Income (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 27, 2014		Dec. 28, 2013		Dec. 29, 2012
Revenue	$556,846		$487,401		$436,244
Cost of revenue	298,791		266,247		241,896
Gross margin	258,055		221,154		194,348
Operating expenses:
Research and development(1)	69,408	[1]	63,649	[1]	57,066	[1]
Selling and marketing(1)	86,091	[1]	71,529	[1]	66,412	[1]
General and administrative(1)	49,439	[1]	53,358	[1]	45,698	[1]
Total operating expenses	204,938		188,536		169,176
Operating income	53,117		32,618		25,172
Other income (expense), net	-708		-203		435
Income before income taxes	52,409		32,415		25,607
Income tax expense	14,606		4,774		8,310
Net income	37,803		27,641		17,297
Net income per share
Basic (Dollar per share)	$1.28		$0.97		$0.63
Diluted (Dollars per share)	$1.25		$0.94		$0.61
Number of shares used in per share calculations
Basic (In shares)	29,485		28,495		27,577
Diluted (In shares)	30,210		29,354		28,301
Stock-based compensation recorded breaks down by expense classification as follows:
Stock-based compensation	13,778		13,409		10,983
Cost of revenue
Stock-based compensation recorded breaks down by expense classification as follows:
Stock-based compensation	865		700		889
Research and development
Stock-based compensation recorded breaks down by expense classification as follows:
Stock-based compensation	3,359		2,700		1,904
Selling and marketing
Stock-based compensation recorded breaks down by expense classification as follows:
Stock-based compensation	1,296		1,246		808
General and administrative
Stock-based compensation recorded breaks down by expense classification as follows:
Stock-based compensation	$8,258		$8,763		$7,382
[1]	Stock-based compensation recorded in fiscal 2014, 2013 and 2012 breaks down by expense classification as follows: Fiscal Year Ended December 27, 2014 December 28, 2013 December 29, 2012 (In thousands)Cost of revenue$865 $700 $889Research and development3,359 2,700 1,904Selling and marketing1,296 1,246 808General and administrative8,258 8,763 7,382

Consolidated_Statement_of_Comp

Consolidated Statement of Comprehensive Income (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Statement of Comprehensive Income [Abstract]
Net income, as reported	$37,803	$27,641	$17,297
Other comprehensive income (loss), net of tax:
Unrealized gains (losses) on investments, net of tax	-298	-52	48
Total comprehensive income	$37,505	$27,589	$17,345

Consolidated_Statements_of_Sto

Consolidated Statements of Stockholders' Equity (USD $)	Total	Common Stock	Additional Paid-in Capital	Retained Earnings (Accumulated Deficit)	Accumulated Other Comprehensive Income (Loss)
In Thousands, except Share data
Beginning balance at Dec. 31, 2011	$242,958	$272	$184,395	$58,140	$151
Beginning balance, shares at Dec. 31, 2011		27,216,555
Issuance of common stock for exercise of stock options, shares	390,956	390,956
Issuance of common stock for exercise of stock options, value	4,326	4	4,322
Vesting of restricted stock units, shares		204,053
Vesting of restricted stock units, value	0
Tax benefit of excess stock based compensation deduction	902		902
Deferred Compensation Arrangement with Individual, Compensation Expense	10,983		10,983
Stock withheld to cover tax withholdings requirements upon vesting of restricted stock units, shares		-30,728
Stock withheld to cover tax withholdings requirements upon vesting of restricted stock units, value	-784		-784
Unrealized gain on short term investment	48				48
Director's deferred compensation	87		87
Net income (loss)	17,297			17,297
Ending balance at Dec. 29, 2012	275,817	278	199,903	75,437	199
Ending balance, shares at Dec. 29, 2012		27,781,659
Issuance of common stock for exercise of stock options, shares	840,951	840,951
Issuance of common stock for exercise of stock options, value	13,629	8	13,621
Vesting of restricted stock units, shares		348,141
Vesting of restricted stock units, value	0	-3	-3
Tax benefit of excess stock based compensation deduction	1,413		1,413
Deferred Compensation Arrangement with Individual, Compensation Expense	13,409		13,409
Stock withheld to cover tax withholdings requirements upon vesting of restricted stock units, shares		-45,278
Stock withheld to cover tax withholdings requirements upon vesting of restricted stock units, value	-1,212		-1,212
Unrealized gain on short term investment	-52				-52
Director's deferred compensation	44		44
Net income (loss)	27,641			27,641
Ending balance at Dec. 28, 2013	330,689	289	227,175	103,078	147
Ending balance, shares at Dec. 28, 2013	28,935,253	28,935,253
Issuance of common stock for exercise of stock options, shares	486,252	486,252
Issuance of common stock for exercise of stock options, value	8,943	5	8,938
Vesting of restricted stock units, shares		318,367
Vesting of restricted stock units, value	0	-3	-3
Tax benefit of excess stock based compensation deduction	2,776		2,776
Amortization of deferred compensation relating to stock options	13,778
Deferred Compensation Arrangement with Individual, Compensation Expense			13,778
Stock withheld to cover tax withholdings requirements upon vesting of restricted stock units, shares		-39,297
Stock withheld to cover tax withholdings requirements upon vesting of restricted stock units, value	-1,626		-1,626
Unrealized gain on short term investment	-298				-298
Director's deferred compensation	49		49
Stock Repurchased and Retired During Period, Shares	-55,973
Stock Repurchased and Retired During Period, Value	-1,678		-1,678
Net income (loss)	37,803			37,803
Ending balance at Dec. 27, 2014	$390,436	$297	$249,409	$140,881	($151)
Ending balance, shares at Dec. 27, 2014	29,644,602	29,644,602

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Cash flows from operating activities:
Net income, as reported	$37,803	$27,641	$17,297
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	13,049	12,169	11,672
Loss on disposal of property and equipment	246	189	1,332
Goodwill and Intangible Asset Impairment	0	1,988	0
Stock-based compensation	13,778	13,409	10,983
Increase (Decrease) in Deferred Income Taxes	3,101	-768	-3,763
Tax benefit of excess stock based compensation deductions	-3,051	-2,406	-1,445
Non-cash director deferred compensation	49	44	87
Changes in operating assets and liabilities — (use) source
Accounts receivable	-31,708	-9,935	15,560
Unbilled revenue	-1,758	340	1,166
Inventory	-2,387	-9,365	-807
Other assets	-2,856	1,980	-2,892
Accounts payable	16,249	-1,743	-8,684
Accrued expenses	3,695	1,255	-656
Accrued compensation	-3,371	7,751	-6,106
Deferred revenue	-1,236	-1,172	4,730
Long term liabilities	-997	515	-613
Net cash provided by operating activities	40,606	41,892	37,861
Cash flows from investing activities:
Additions of property and equipment	-13,774	-6,829	-6,770
Payments for (Proceeds from) Other Investing Activities	-250	-2,000	-6,000
Purchase of Evolution Robotics, Inc., net of cash received	0	0	-74,530
Purchase of investments	-31,219	-17,946	-5,086
Sales of investments	16,500	8,044	10,000
Proceeds from Sale of Other Productive Assets	0	650	0
Net cash used in investing activities	-28,743	-18,081	-82,386
Cash flows from financing activities:
Payments Related to Tax Withholding for Share-based Compensation	-1,626	-1,212	-784
Proceeds from stock option exercises	8,943	13,629	4,326
Payments for Repurchase of Common Stock	-1,678	0	0
Tax benefit of excess stock based compensation deductions	3,051	2,406	1,445
Net cash provided by financing activities	8,690	14,823	4,987
Net increase (decrease) in cash and cash equivalents	20,553	38,634	-39,538
Cash and cash equivalents, at beginning of period	165,404	126,770	166,308
Cash and cash equivalents, at end of period	185,957	165,404	126,770
Supplemental disclosure of cash flow information
Cash paid for income taxes	15,508	7,235	11,663
Noncash investing activity, transfer of inventory to property and equipment	$637	$223	$0

Nature_of_the_Business

Nature of the Business	12 Months Ended
	Dec. 27, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of the Business
	1	Nature of the Business
	iRobot Corporation (“iRobot” or the “Company”) develops robotics and artificial intelligence technologies and applies these technologies in producing and marketing robots. The majority of the Company’s revenue is generated from product sales and, to a lesser extent, government and commercial research and development contracts.

Summary_of_Significant_Account

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 27, 2014
Accounting Policies [Abstract]
Summary of Significant Accounting Policies
	2	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. In addition, certain prior year amounts have been reclassified to conform with the current year presentation. iRobot has prepared the accompanying consolidated financial statements in conformity with accounting principles generally accepted in the United States of America.
	Reorganization
	In fiscal year 2012, the Company initiated a reorganization that resulted in, among other things, the centralization of all of the Company's engineering and operations activities. This reorganization was completed at the beginning of fiscal year 2013. In conjunction with this reorganization, the Company reviewed the financial statement classification of its costs and expenses. As a result of this review, the Company decided to classify certain expenses differently than had been classified and presented in prior periods to provide a more clear understanding of the Company's financial performance. As part of this review, the Company also evaluated the impact of the reorganization on its segment reporting and determined that certain modifications were necessary to present the segment information as now viewed by the Company's chief operating decision maker. Although the classification of certain expenses on the income statement changed in fiscal year 2013 as compared to prior periods, the Company recast the financial results of prior periods in a manner consistent with the fiscal year 2014 and 2013 presentation for comparability purposes. The reclassified amounts reflected in the consolidated statement of income for the year ended December 29, 2012 included herein conforms to the fiscal year 2014 and 2013 presentation. This reclassification of costs and expenses did not impact previously reported net income or earnings per share as the changes only impacted the categorization of costs within the consolidated statements of income for the periods in question. Consequently, the classification changes did not impact previously presented consolidated balance sheets, statements of cash flow or statements of stockholders' equity.
	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, 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 will end on the Saturday that falls closest to the last day of the third month of each quarter.
	Cash and Cash Equivalents
	The Company considers all highly liquid investments with an original or remaining maturity of three months or less at the time of purchase to be cash equivalents. The Company invests its excess cash primarily in money market funds or savings accounts of major financial institutions. Accordingly, its cash equivalents are subject to minimal credit and market risk. At December 27, 2014 and December 28, 2013, cash equivalents were comprised of money market funds totaling $109.8 million and $101.4 million, respectively. These cash equivalents are carried at cost, which approximates fair value.
	Short Term Investments
	The Company’s investments are classified as available-for-sale and are recorded at fair value with any unrealized gain or loss recorded as an element of stockholders’ equity. The fair value of investments is determined based on quoted market prices at the reporting date for those instruments. As of December 27, 2014 and December 28, 2013, investments consisted of:
		December 27,						December 28,
		2014						2013
		Cost			Fair			Cost			Fair
					Market Value						Market Value
		(In thousands)
	Corporate and government bonds	$	36,659		$	36,166		$	22,134		$	21,954
	Total short term investments	$	36,659		$	36,166		$	22,134		$	21,954
	As of December 27, 2014, the Company’s investments had maturity dates ranging from July 2015 to March 2018. The Company invests primarily in investment grade securities and limits the amount of investment in any single issuer.
	Revenue Recognition
	The Company derives its revenue from product sales and, to a lesser extent, 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, provided that collection is determined to be reasonably assured and no significant obligations remain. Sales to domestic and Canadian resellers of home 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. 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. The estimates for rights of return are directly based on specific terms and conditions included in the reseller 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 reseller 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 reseller agreement is modified. 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. The estimates and reserve for rebates and price protection are based on specific programs, expected usage and historical experience. Actual results could differ from these estimates.
	Under cost-plus-fixed-fee (CPFF) type contracts, the Company recognizes revenue based on costs incurred plus a pro rata portion of the total fixed fee. Costs incurred include labor and material that are 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 provisional rates currently in effect, 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 December 27, 2014, fiscal years 2012 through 2014 are open for audit by DCAA. In the situation where the Company’s anticipated actual billing rates will be lower than the provisional rates currently in effect, the Company records a cumulative revenue adjustment in the period in which the rate differential is identified. Revenue on firm fixed price (FFP) contracts is recognized using the percentage-of-completion method. For government product FFP contracts, revenue is recognized as the product is shipped or in accordance with the contract terms. Costs and estimated gross margins on contracts are recorded as revenue as work is performed based on the percentage that incurred costs compare to estimated total costs utilizing the most recent estimates of costs and funding. Changes in job performance, job conditions, and estimated profitability, including those arising from final contract settlements and government audits, may result in revisions to costs and income and are recognized in the period in which the revisions are determined. Since many contracts extend over a long period of time, revisions in cost and funding estimates during the progress of work have the effect of adjusting earnings applicable to past performance in the current period. When the current contract estimate indicates a loss, a provision is made for the total anticipated loss in the current period. Revenue earned in excess of billings, if any, is recorded as unbilled revenue. Billings in excess of revenue earned, if any, are recorded as deferred revenue.
	Allowance for Doubtful Accounts
	The Company maintains an allowance for doubtful accounts to provide for the estimated amount of accounts receivable that may not be collected. The allowance is based upon an assessment of customer creditworthiness, historical payment experience and the age of outstanding receivables.
	Activity related to the allowance for doubtful accounts was as follows:
		Fiscal Year Ended
		December 27,			December 28,			December 29,
		2014			2013			2012
		(In thousands)
	Balance at beginning of period	$	67		$	111		$	87
	Provision	—			—			37
	Deduction(*)	—			(44		)	(13		)
	Balance at end of period	$	67		$	67		$	111
	_____________________
	(*)	Deductions related to allowance for doubtful accounts represent amounts written off against the allowance, less recoveries.
	Inventory
	Inventory is stated at the lower of cost or net realizable value with cost being determined using the first-in, first-out (FIFO) method. The Company maintains a reserve for inventory items to provide for an estimated amount of excess or obsolete inventory.
	Activity related to the inventory reserve was as follows:
		Fiscal Year Ended
		December 27,			December 28,			December 29,
		2014			2013			2012
		(In thousands)
	Balance at beginning of period	$	5,280		$	6,608		$	2,568
	Provision	1,045			1,571			5,101
	Deduction(*)	(1,074		)	(2,899		)	(1,061		)
	Balance at end of period	$	5,251		$	5,280		$	6,608
	___________________________
	(*)	Deductions related to inventory reserve accounts represent amounts written off against the reserve.
	Property and Equipment
	Property and equipment are recorded at cost and consist primarily of computer equipment, leasehold improvements, business applications software and machinery. Depreciation is computed using the straight-line method over the estimated useful lives as follows:
		Estimated
		Useful Life
	Computer and research equipment	3 years
	Furniture	5
	Machinery	5-Feb
	Tooling	5-Feb
	Business applications software	7-May
	Capital leases and leasehold improvements	Lesser of economic benefit period or term of lease
	Expenditures for additions, renewals and betterments of plant and equipment are capitalized. Expenditures for repairs and maintenance are charged to expense as incurred. As assets are retired or sold, the related cost and accumulated depreciation are removed from the accounts and any resulting gain or loss is credited or charged to operations.
	Long-Lived Assets, including Purchased Intangible Assets
	The Company periodically evaluates the recoverability of long-lived assets, including other purchased intangible assets whenever events and changes in circumstances, such as reductions in demand or significant economic slowdowns in the industry, indicate that the carrying amount of an asset may not be fully recoverable. When indicators of impairment are present, the carrying values of the asset group are evaluated in relation to the future undiscounted cash flows of the underlying business. The net book value of the underlying asset is adjusted to fair value if the sum of the expected discounted cash flows is less than book value. Fair values are based on estimates of market prices and assumptions concerning the amount and timing of estimated future cash flows and assumed discount rates, reflecting varying degrees of perceived risk.
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.
Research and Development
Costs incurred in the research and development of the Company’s products, classified as cost of revenue and research and development, are expensed as incurred.
Internal Use Software
The Company capitalizes costs associated with the development and implementation of software for internal use. At December 27, 2014 and December 28, 2013, the Company had $8.2 million and $8.2 million, respectively, of costs related to enterprise-wide software included in fixed assets. Capitalized costs are being amortized over the assets’ estimated useful lives. The Company has recorded $0.8 million, $0.9 million and $1.0 million of amortization expense for the years ended December 27, 2014, December 28, 2013 and December 29, 2012, respectively.
Concentration of Credit Risk and Significant Customers
Financial instruments which potentially expose the Company to concentrations of credit risk consist of accounts receivable. Management believes its credit policies are prudent and reflect normal industry terms and business risk. At December 27, 2014, two customers accounted for a total of 32% of the Company's accounts receivable balance, each of which was greater than 10% of the balance and each of whom secured their balance with guaranteed letters of credit. At December 28, 2013, two customers accounted for a total of 37% of the Company’s accounts receivable balance, each of which was greater than 10% of the balance and each of whom secured their balance with guaranteed letters of credit. For the years ended December 27, 2014, December 28, 2013 and December 29, 2012, revenue from U.S. federal government orders, contracts and subcontracts, represented 4.3%, 6.2% and 15.1% of total revenue, respectively. For the fiscal years ended December 27, 2014, December 28, 2013 and December 29, 2012, the Company generated an aggregate of 29.8%, 33.2% and 30.6%, respectively, of total revenue from its home robots distributor in Japan and a network of affiliated European distributors of its home robots.
The Company maintains its cash in bank deposit accounts at high quality financial institutions. The individual balances, at times, may exceed federally insured limits.
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 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, net of estimated forfeitures.
Advertising Expense
The Company expenses advertising costs as they are incurred. During the years ended December 27, 2014, December 28, 2013 and December 29, 2012 advertising expense totaled $46.1 million, $38.2 million and $34.9 million, respectively.
Net Income Per Share
The following table presents the calculation of both basic and diluted net income per share:
	Fiscal Year Ended
	December 27,			December 28,			December 29,
	2014			2013			2012
Net income	$	37,803		$	27,641		$	17,297
Weighted-average shares outstanding	29,485			28,495			27,577
Dilutive effect of employee stock options and restricted shares	725			859			724
Diluted weighted average shares outstanding	30,210			29,354			28,301
Basic income per share	$	1.28		$	0.97		$	0.63
Diluted income per share	$	1.25		$	0.94		$	0.61
Potentially dilutive securities representing approximately 0.2 million, 0.7 million and 0.8 million shares of common stock for the fiscal years ended December 27, 2014, December 28, 2013 and December 29, 2012, 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 federal and state tax authorities is closed for fiscal years prior to 2011. Federal and state carryforward attributes that were generated prior to fiscal year 2011 may still be adjusted upon examination by the Internal Revenue Service (IRS) 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.
As of December 28, 2013, the Company maintained a valuation allowance of $2.1 million related to certain state tax attributes from the Evolution Robotics, Inc. acquisition. During the year ended December 27, 2014, this valuation allowance was released when the realization of these state tax attributes became more likely than not.
Comprehensive Income
Accumulated other comprehensive income includes unrealized gains and losses on certain investments. The differences between net income and comprehensive income were related to unrealized gains (losses) on investments, net of tax.
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
The Company’s financial assets measured at fair value on a recurring basis at December 27, 2014, were as follows:
	Fair Value Measurements as of
	December 27, 2014
Description	Level 1			Level 2			Level 3
	(In thousands)
Assets:
Money market funds	$	109,843		$	—		$	—
Corporate and government bonds	—			36,166			—
Total assets measured at fair value	$	109,843		$	36,166		$	—
The Company’s financial assets measured at fair value on a recurring basis at December 28, 2013, were as follows:
	Fair Value Measurements as of
	December 28, 2013
Description	Level 1			Level 2			Level 3
	(In thousands)
Assets:
Money market funds	$	101,441		$	—		$	—
Corporate and government bonds	—			21,954			—
Total assets measured at fair value	$	101,441		$	21,954		$	—
In each table above, the bond investments are valued based on observable market values as of the Company’s reporting date and are included in Level 2. The bond investments are recorded at fair value and marked-to-market at the end of each reporting period and realized and unrealized gains and losses are included in comprehensive income for that period. The fair value of the Company’s bond investments are included in short term investments in its consolidated balance sheets.
Non-financial Assets
The Company's non-financial assets, which include goodwill, intangible assets, and property and equipment are not required to be measured at fair value on a recurring basis. However, the Company evaluates the non-financial assets for impairment if a trigger event occurs, or when an annual impairment test is performed. If the asset is determined to be impaired, the asset is required to be recorded at fair value.
Recent Accounting Pronouncements
In August 2014, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2014-15, “Presentation of Financial Statements - Going Concern.” ASU No. 2014-15 requires management of public and private companies to evaluate whether there is substantial doubt about the entity’s ability to continue as a going concern and, if so, disclose that fact. Management will also be required to evaluate and disclose whether its plans alleviate that doubt. The new standard is effective for annual periods ending after December 15, 2016, and interim periods within annual periods beginning after December 15, 2016. The Company does not believe that the impact of this amendment will be material to the Company’s consolidated financial statements.
In June 2014, the FASB issued ASU No. 2014-12, “Accounting for Share-Based Payments When the Terms of an Award Provide That a Performance Target Could Be Achieved after the Requisite Service Period.” ASU No. 2014-12 requires a reporting entity to treat a performance target that affects vesting and that could be achieved after the requisite service period as a performance condition. It is effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2015. Early adoption is permitted. The Company is currently assessing the potential impact of ASU No. 2014-12 on its 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 that reporting period. Early application is not permitted. The Company is currently assessing the potential impact of ASU No. 2014-09 on its consolidated financial statements.
On April 10, 2014, the FASB issued ASU No. 2014-08 “Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity.” ASU No. 2014-08 changes the criteria for reporting discontinued operations and modifies related disclosure requirements. The new guidance is effective on a prospective basis for fiscal years beginning after December 15, 2014, and interim periods within annual periods beginning on or after December 15, 2015. Early adoption is permitted for new disposals (or new classifications as held for sale) that have not been reported in financial statements previously issued or available for issuance. The Company is currently assessing the future impact of ASU No. 2014-08 on its consolidated financial statements.
In July 2013, the FASB issued ASU 2013-11 “Presentation of an Unrecognized Tax Benefit when a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Exists”, related to the presentation of an unrecognized tax benefit when a net operating loss carryforward, a similar tax loss, or a tax credit carryforward exists.  This guidance clarifies prior guidance and eliminates diversity in practice on the presentation of unrecognized tax benefits when certain situations exist at the reporting date.  This guidance is effective for annual reporting periods beginning on or after December 15, 2013 and subsequent interim periods.  The impact of this amendment on the Company's consolidated financial statements was not material.
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 the impact of recently issued standards, which are not yet effective, will not have a material impact on its consolidated financial statements upon adoption.

Inventory

Inventory	12 Months Ended
	Dec. 27, 2014
Inventory Disclosure [Abstract]
Inventory
	3	Inventory
	Inventory consists of the following at:
		December 27,		December 28,
		2014		2013
		(In thousands)
	Raw materials	$	9,455	$	8,520
	Work in process	—		—
	Finished goods	38,402		37,587
		$	47,857	$	46,107

Property_and_Equipment

Property and Equipment	12 Months Ended
	Dec. 27, 2014
Property, Plant and Equipment [Abstract]
Property and Equipment
	4	Property and Equipment
	Property and equipment consists of the following at:
		December 27,		December 28,
		2014		2013
		(In thousands)
	Computer and equipment	$	15,173	$	13,715
	Furniture	2,297		1,845
	Machinery	5,307		3,705
	Tooling	18,614		12,228
	Leasehold improvements	20,833		15,983
	Business applications software	8,214		8,162
		70,438		55,638
	Less: accumulated depreciation	39,141		31,977
		$	31,297	$	23,661
	Depreciation expense for the years ended December 27, 2014, December 28, 2013 and December 29, 2012 was $9.2 million, $8.1 million, and $9.9 million, respectively.

Other_Assets

Other Assets	12 Months Ended
	Dec. 27, 2014
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Other Assets
	5	Other Assets
	At December 27, 2014, other assets consisted of three investments totaling $10.8 million. At December 28, 2013, other assets consisted of two investments totaling $10.5 million. These investments are accounted for at cost. The Company regularly monitors these investments to determine if facts and circumstances have changed in a manner that would require a change in accounting methodology. Additionally, the Company regularly evaluates whether or not these investments have been impaired by considering such factors as economic environment, market conditions, operational performance and other specific factors relating to the businesses underlying the investments. If any such impairment is identified, a reduction in the carrying value of the investments would be recorded at that time. Since the Company believes the fair value of its investments is greater than the carrying value of its investments, it has not impaired these investments.

Accrued_Expenses

Accrued Expenses	12 Months Ended
	Dec. 27, 2014
Accrued Liabilities, Current [Abstract]
Accrued Expenses
	6	Accrued Expenses
	Accrued expenses consist of the following at:
		December 27,		December 28,
		2014		2013
		(In thousands)
	Accrued warranty	$	7,769	$	6,497
	Accrued direct fulfillment costs	1,346		1,362
	Accrued sales tax	867		831
	Accrued customer deposits	702		103
	Accrued rent	701		726
	Accrued sales commissions	531		539
	Accrued contractors	217		509
	Accrued other	6,568		4,313
		$	18,701	$	14,880
	Accrued compensation consists of the following at:
		December 27,		December 28,
		2014		2013
		(In thousands)
	Accrued bonus	$	8,455	$	13,002
	Accrued other compensation	7,780		6,604
		$	16,235	$	19,606

Revolving_Line_of_Credit

Revolving Line of Credit	12 Months Ended
	Dec. 27, 2014
Debt Disclosure [Abstract]
Revolving Line of Credit
	7	Revolving Line of Credit
	The Company has an unsecured revolving credit facility with Bank of America, N.A., which is available to fund working capital and other corporate purposes. As of December 27, 2014, the total amount available for borrowing under its credit facility was $75.0 million and the full amount was available for borrowing. The interest on loans under the credit facility will accrue, at the Company's election, at either (1) LIBOR plus a margin, currently equal to 1.0%, based on the Company's ratio of indebtedness to Adjusted EBITDA (the "Eurodollar Rate"), or (2) the lender's base rate. The lender's base rate is equal to the highest of (1) the federal funds rate plus 0.5%, (2) the lender's prime rate and (3) the Eurodollar Rate plus 1.0%. The credit facility will terminate and all amounts outstanding thereunder will be due and payable in full on December 20, 2018.
	As of December 27, 2014, the Company had no borrowings under its revolving credit facility. This credit facility contains customary terms and conditions for credit facilities of this type, including restrictions on the Company's ability to incur or guaranty additional indebtedness, create liens, enter into transactions with affiliates, make loans or investments, sell assets, pay dividends or make distributions on, or repurchase, the Company's stock, and consolidate or merge with other entities.
	In addition, the Company is required to meet certain financial covenants customary with this type of agreement, including maintaining a minimum ratio of indebtedness to Adjusted EBITDA and a minimum specified interest coverage ratio.
	This credit facility contains customary events of default, including for payment defaults, breaches of representations, breaches of affirmative or negative covenants, cross defaults to other material indebtedness, bankruptcy and failure to discharge certain judgments. If a default occurs and is not cured within any applicable cure period or is not waived, the Company's obligations under the credit facility may be accelerated.
	As of December 27, 2014, the Company was in compliance with all covenants under its credit facility.

Common_Stock

Common Stock	12 Months Ended
	Dec. 27, 2014
Dividends, Common Stock [Abstract]
Common Stock
	8	Common Stock
	Common stockholders are entitled to one vote for each share held and to receive dividends if and when declared by the Board of Directors and subject to and qualified by the rights of holders of the preferred stock. Upon dissolution or liquidation of the Company, holders of common stock will be entitled to receive all available assets subject to any preferential rights of any then outstanding preferred stock.
	On April 2, 2014, the Company announced a stock repurchase program. Under the program, the Company may purchase up to $50 million of its common stock from May 1, 2014 to April 30, 2015. Through December 27, 2014, the Company has repurchased 55,973 shares totaling $1.7 million in the open market under this stock repurchase plan.

Stock_Options_Plans_and_StockB

Stock Options Plans and Stock-Based Compensation	12 Months Ended
	Dec. 27, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock Options Plans and Stock-Based Compensation
	9	Stock Option Plans and Stock-Based Compensation
	The Company has options outstanding under three stock incentive plans: the 2004 Stock Option and Incentive Plan (the “2004 Plan”), the 2005 Stock Option and Incentive Plan (the "2005 Plan") and the Evolution Robotics, Inc. 2007 Stock Plan (the "2007 Plan" and together with the 2004 Plan and the 2005 Plan, the “Plans”). All options that remained outstanding under the 1994 Stock Option Plan as of December 28, 2013 were exercised during fiscal 2014. The 2005 Plan is the only one of the four plans under which new awards may currently be granted. Under the 2005 Plan, which became effective October 10, 2005, 1,583,682 shares were initially reserved for issuance in the form of incentive stock options, non-qualified stock options, stock appreciation rights, deferred stock awards and restricted stock awards. Additionally, the 2005 Plan provides that the number of shares reserved and available for issuance under the plan will automatically increase each January 1, beginning in 2007, by 4.5% of the outstanding number of shares of common stock on the immediately preceding December 31. Stock options returned to the Plans, with the exception of the 2007 Plan, as a result of their expiration, cancellation or termination are automatically made available for issuance under the 2005 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 December 27, 2014, there were 4,762,446 shares available for future grant under the 2005 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 periods from one to five years , and expire seven or ten years from the date of grant or, if earlier, 60 or 90 days from employee termination. The exercise price of incentive stock options is typically equal to the closing price on the NASDAQ Global Market on the date of grant. The exercise price of nonstatutory options may be set at a price other than the fair market value of the common stock.
	In conjunction with the acquisition of Evolution Robotics, Inc. on October 1, 2012, each outstanding and unvested incentive stock option held by Evolution employees as of the acquisition date was automatically converted into stock options of the Company under the same terms and conditions as were applicable to the original Evolution grants. The number of replacement options granted and the associated exercise prices were determined utilizing a conversion ratio as defined in the merger agreement. There were 114,248 incentive stock options issued by the Company as a result of this automatic conversion with exercise prices ranging from $2.55 to $4.81. All of these options were granted from the 2007 Plan, which was assumed by the Company as a result of the acquisition.
	The Company recognized $4.1 million of stock-based compensation expense during the fiscal year ended December 27, 2014 for stock options. The unamortized fair value as of December 27, 2014 associated with these grants was $6.6 million with a weighted-average remaining recognition period of 2.47 years. The Company expects to recognize associated stock-based compensation expense of $2.9 million, $2.2 million, $1.1 million and $0.4 million in 2015, 2016, 2017 and 2018, respectively.
	The fair value of each option grant for the fiscal years ended December 27, 2014, December 28, 2013 and December 29, 2012 was computed on the grant date using the Black-Scholes option-pricing model with the following assumptions:
		Fiscal Year Ended
		December 27,		December 28,		December 29,
		2014		2013		2012
	Risk-free interest rate	1.65% — 1.69%		0.90% — 1.77%		0.63% — 0.90%
	Expected dividend yield	—		—		—
	Expected life	3.91 — 4.00 years		4.03 — 4.21 years		4.12 — 4.18 years
	Expected volatility	52.8% — 56.0%		54.0% — 58.0%		63.0% — 64.0%
	The risk-free interest rate is derived from the average U.S. Treasury constant maturity rate, which approximates the rate in effect at the time of grant, commensurate with the expected life of the instrument. The dividend yield is zero based upon the fact the Company has never paid and has no present intention to pay cash dividends. The Company utilizes company specific historical data for purposes of establishing expected volatility and expected term.
	Based upon the above assumptions, the weighted average fair value of each stock option granted for the fiscal years ended December 27, 2014, December 28, 2013 and December 29, 2012 was $15.87, $11.17 and $13.23, respectively.
	The table below summarizes stock option plan activity:
		Number of			Weighted Average			Weighted  Average	Aggregate
		Shares			Exercise Price			Remaining	Intrinsic
								Contractual Term	Value(1)
	Outstanding at December 31, 2011	2,561,292			$	17.17
	Granted	547,948			19.7
	Exercised	(390,956	)		11.07
	Canceled	(214,617	)		21.91
	Outstanding at December 29, 2012	2,503,667			$	18.27
	Granted	293,325			24.6
	Exercised	(840,951	)		16.21
	Canceled	(185,666	)		22.16
	Outstanding at December 28, 2013	1,770,375			$	19.89
	Granted	233,181			37.1
	Exercised	(486,252	)		18.39
	Canceled	(43,984	)		27.17
	Outstanding at December 27, 2014	1,473,320			$	22.89		3.87 years	$18.2 million
	Vested and expected to vest at December 27, 2014	1,419,559			$	22.61		3.79 years	$17.8 million
	Exercisable as of December 27, 2014	917,340			$	19.32		2.82 years	$14.2 million
	Weighted average fair value of options granted during the fiscal year ended December 27, 2014				$	15.87
	Options available for future grant at December 27, 2014	4,762,446
	_________________________
	-1	The aggregate intrinsic value on the table was calculated based upon the positive difference between the closing market value of the Company’s stock on December 27, 2014 of $34.81 and the exercise price of the underlying option.
	During fiscal years 2014, 2013, and 2012, the total intrinsic value of stock options exercised was $10.5 million, $12.1 million and $6.2 million, respectively. No amounts relating to stock-based compensation have been capitalized.
	The following table summarizes information about stock options outstanding at December 27, 2014:
			Options Outstanding							Options Exercisable
	Range of Exercise Prices		Number			Weighted Average	Weighted  Average			Number	Weighted Average
			Outstanding			Remaining	Exercise Price			Exercisable	Exercise Price
						Contractual Life
	$  3.54 - $ 7.76		156,380			3.68 years	$	6.08		134,520	$	6.29
	8.10 - 14.13		100,551			1.1	13.36			100,551	13.36
	14.52 - 14.52		164,442			2.26	14.52			164,442	14.52
	14.54 - 22.20		182,584			3.63	19.17			113,901	19.54
	22.86 - 22.86		194,508			5.09	22.86			79,614	22.86
	24.00 - 25.99		199,546			2.66	24.75			153,876	24.46
	26.59 - 33.48		264,971			4.3	31.19			156,756	31.05
	33.72 - 35.96		121,445			6.1	35.01			13,680	34.34
	37.08 - 37.08		34,500			6.84	37.08			—	—
	43.35 -  43.35		54,393			6.19	43.35			—	—
	$ 3.54 -  $43.35		1,473,320			3.87 years	$	22.89		917,340	$	19.32
	During the fiscal year ended December 27, 2014, the Company recognized $9.7 million of stock-based compensation expense associated with restricted stock units. As of December 27, 2014, December 28, 2013 and December 29, 2012, the unamortized fair value of all restricted stock units was $20.1 million, $17.5 million and $17.9 million, respectively. The Company expects to recognize associated stock-based compensation expense of $8.3 million, $6.4 million, $4.0 million and $1.4 million in 2015, 2016, 2017 and 2018, respectively.
	The table below summarizes activity relating to restricted stock units:
		Number of			Weighted Average
		Shares Underlying			Grant Date Fair
		Restricted Stock			Value
	Outstanding at December 31, 2011	607,505			$	22.77
	Granted	685,529			24.62
	Vested	(204,053	)		21.24
Forfeited	(147,951	)		25.07
Outstanding at December 29, 2012	941,030			$	24.09
Granted	521,056			25.87
Vested	(348,141	)		22.57
Forfeited	(186,291	)		24.91
Outstanding at December 28, 2013	927,654			$	25.5
Granted	372,159			38.25
Vested	(318,367	)		25.38
Forfeited	(71,591	)		28.42
Outstanding at December 27, 2014	909,855			$	30.53

Income_Taxes

Income Taxes	12 Months Ended
	Dec. 27, 2014
Income Tax Disclosure [Abstract]
Income Taxes
	10	Income Taxes
	The components of income tax expense were as follows:
		Fiscal Year Ended
		December 27,			December 28,				December 29,
		2014			2013				2012
		(In thousands)
	Current
	Federal	$	15,128		$	6,363			$	12,540
	State	129			1,124				473
	Foreign	91			41				(8		)
	Total current tax provision	15,348			7,528				13,005
	Deferred
	Federal	1,268			(2,026		)		(4,003		)
	State	(2,010		)	(728		)		(692		)
	Total deferred tax provision	(742		)	(2,754		)		(4,695		)
	Total income tax provision	$	14,606		$	4,774			$	8,310
	In certain jurisdictions, an immaterial provision has been made for deferred taxes on undistributed earnings of non-U.S. subsidiaries that the Company expects to distribute in 2015. In other jurisdictions, for the remaining undistributed earnings of non-U.S. subsidiaries, no provision has been made for deferred taxes as these earnings have been indefinitely reinvested. As of December 27, 2014, a deferred tax liability has not been established for approximately $0.6 million of cumulative undistributed earnings of non-U.S. subsidiaries, as the Company plans to keep these amounts permanently reinvested overseas. The amount of any unrecognized deferred tax liability on these undistributed earnings would be immaterial.
	The components of net deferred tax assets were as follows:
		December 27,			December 28,
		2014			2013
		(In thousands)
	Net deferred tax assets
	Current deferred tax assets
	Reserves and accruals	$	18,568		$	18,554
	Stock-based compensation	767			556
	Net operating loss carryforwards	2,470			2,470
	Foreign tax credits	148			105
	Valuation allowance	—			(1,100		)
	Total current deferred tax assets	21,953			20,585
	Non-current deferred tax assets
	Reserves and accruals	586			715
	Tax credits	5,927			5,737
	Property and equipment	178			1,308
	Stock-based compensation	5,011			4,957
	Net operating loss carryforwards	3,879			6,587
	Valuation allowance	—			(990		)
	Total non-current deferred tax assets	15,581			18,314
	Current deferred tax liabilities
	Prepaids	448			441
	Total current deferred tax liabilities	448			441
	Non-current deferred tax liabilities
	Intangible assets	7,172			8,219
	Total non-current deferred tax liabilities	7,172			8,219
	Total net deferred tax assets	$	29,914		$	30,239
	As of December 28, 2013, the Company maintained a valuation allowance of $2.1 million related to certain state tax attributes from the Evolution Robotics, Inc. acquisition. During the year ended December 27, 2014, this valuation allowance was released when realization of these state tax attributes became more likely than not.
	The table below summarizes activity relating to the valuation allowance:
	Fiscal Year Ended	Balance at			Additions			Additions Charged to Goodwill			Deductions	Balance
		beginning  of			Charged to							at End
		period			Costs and							of Period
					Expenses
		(In thousands)
	December 29, 2012	$	—		—			2,691			—	$	2,691
	December 28, 2013	$	2,691		—			—			601	$	2,090
	December 27, 2014	$	2,090		—			—			2,090	$	—
	The net deferred tax assets after valuation allowance as of December 27, 2014 and December 28, 2013 were $29.9 million and $30.2 million, respectively.
	The Company has federal and state net operating loss carryforwards of $34.5 million and $45.0 million as of December 27, 2014 and December 28, 2013, respectively, which expire from 2028 to 2032. The Company has federal and state research and development credit carryforwards of $9.1 million and $8.9 million as of December 27, 2014 and December 28, 2013, respectively, which expire from 2022 to 2029. The Company has state investment tax credit carryforwards of $0.7 million and $0.6 million as of December 27, 2014 and December 28, 2013, respectively, which expire from 2015 to 2024. Under the Internal Revenue Code, certain substantial changes in the Company’s ownership could result in an annual limitation on the amount of these tax carryforwards which can be utilized in future years. As of December 27, 2014, the Company has $34.5 million of net operating loss carryforwards and $2.2 million of federal and state research and development credits related to the acquisition of Evolution Robotics that are limited by Section 382 and Section 383, respectively, of the Internal Revenue Code. However, these limitations are not expected to cause any of these net operating loss carryforwards or federal and state research and development credits to expire unused.
	The reconciliation of the expected tax (benefit) expense (computed by applying the federal statutory rate to income before income taxes) to actual tax expense was as follows:
		Fiscal Year Ended
		December 27,			December 28,				December 29,
		2014			2013				2012
		(In thousands)
	Expected federal income tax	$	18,344		$	11,345			$	8,962
	Miscellaneous permanent items	691			405				338
State taxes (net of federal benefit)	1,058			867				497
Federal and state credits	(1,487		)	(3,909		)		(418		)
Change in valuation allowance	(2,090		)	—				—
Domestic production activities deduction	(1,562		)	(1,168		)		(1,100		)
Settlement of uncertain tax positions	(176		)	(2,696		)		—
Other	(172		)	(70		)		31
	$	14,606		$	4,774			$	8,310
A summary of the Company’s adjustments to its gross unrecognized tax benefits, inclusive of interest, in the current year is as follows:
	Fiscal Year Ended
	December 27, 2014
Balance at beginning of period	$	2,618
Increase for tax positions related to the current year	252
Decrease for tax positions related to prior years	(108		)
Decreases for settlements with applicable taxing authorities	(271		)
Decreases for lapses of statute of limitations	—
Balance at end of period	$	2,491
The Company accrues interest and, if applicable, penalties for any uncertain tax positions. Interest and penalties are classified as a component of income tax expense. As of December 27, 2014, December 28, 2013 and December 29, 2012, there were no material accrued interest or penalties. Over the next twelve months it is reasonably possible that the Company may recognize approximately $0.2 million of previously net unrecognized tax benefits related to U.S. federal, state and foreign tax audits and expiration of the statute of limitations. If all of our unrecognized tax benefits as of December 27, 2014 were to become recognizable in the future, we would record a $1.9 million benefit to the income tax provision, reflective of federal benefit on state items.
Included in the Company’s state tax credit carryforwards are unrecognized tax benefits related to stock-based compensation beginning from January 1, 2006 of $0.5 million and $0.5 million as of December 27, 2014 and December 28, 2013, respectively. Included in the Company's state net operating loss carryforwards are unrecognized tax benefits related to stock-based compensation beginning from January 1, 2006 of $0.7 million and $0 as of December 27, 2014 and December 28, 2013, respectively. These unrecognized tax benefits will be credited to additional paid-in capital when they reduce income taxes payable. Therefore, these amounts were not included in the Company’s gross or net deferred tax assets at December 27, 2014 and December 28, 2013.
The Company follows the with and without approach for direct and indirect effects of windfall tax deductions.

Commitments_and_Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 27, 2014
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies
	11	Commitments and Contingencies
	Legal
	From time to time and in the ordinary course of business, the Company is subject to various claims, charges and litigation. The outcome of litigation cannot be predicted with certainty and some lawsuits, claims or proceedings may be disposed of unfavorably to us, which could materially affect the Company's financial condition or results of operations.
	Lease Obligations
	The Company leases its facilities. Rental expense under operating leases for fiscal 2014, 2013 and 2012 amounted to $4.8 million, $5.3 million, and $4.4 million, respectively. Future minimum rental payments under operating leases were as follows as of December 27, 2014:
		Operating
		Leases
	2015	$	3,460
	2016	2,670
	2017	2,383
	2018	2,383
	2019	2,383
	Thereafter	794
	Total minimum lease payments	$	14,073
	Outstanding Purchase Orders
	At December 27, 2014, we had outstanding purchase orders aggregating approximately $78.1 million. The purchase orders, the majority of which are with our 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 any time 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 December 27, 2014 and December 28, 2013, respectively.
	Government Contract Contingencies
	Several of the Company’s prime contracts with the U.S. federal government do not contain a limitation of liability provision, creating a risk of responsibility for direct and consequential damages. Several subcontracts with prime contractors hold the prime contractor harmless against liability that stems from our work and do not contain a limitation of liability. These provisions could cause substantial liability for the Company. In addition, the Company is subject to audits by the U.S. federal government as part of routine audits of government contracts. As part of an audit, these agencies may review the Company’s performance on contracts, cost structures and compliance with applicable laws, regulations and standards. If any of its costs are found to be allocated improperly to a specific contract, the costs may not be reimbursed and any costs already reimbursed for such contract may have to be refunded. Accordingly, an audit could result in a material adjustment to our revenue and results of operations. Annually, the Company submits final indirect billing rates to DCMA based upon actual costs incurred throughout the year. These final billing rates are subject to audit by DCAA. As of December 27, 2014, fiscal years 2012 through 2014 are open for audit by DCAA.
	Warranty
	The Company provides warranties on most products and has established a reserve for warranty based on estimated warranty costs. The reserve is included as part of accrued expenses (Note 6) in the accompanying consolidated balance sheets.
	Activity related to the warranty accrual was as follows:
		Fiscal Year Ended
		December 27,			December 28,			December 29,
		2014			2013			2012
		(In thousands)
	Balance at beginning of period	$	6,497		$	6,057		$	10,306
	Provision (*)	6,410			1,744			(1,682		)
	Warranty usage(**)	(5,138		)	(1,304		)	(2,567		)
	Balance at end of period	$	7,769		$	6,497		$	6,057
	__________________________________
	(*)	During 2012, the Company recorded favorable adjustments relating to reductions in its international warranty accrual for our home robots business related to our sustained improvements in product quality, resulting in a net credit for its 2012 warranty provision.
	(**)	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 a nexus in new jurisdictions with respect to sales tax. The Company has recorded a liability for potential exposure in several 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.

Employee_Benefits

Employee Benefits	12 Months Ended
	Dec. 27, 2014
Employee Benefits [Abstract]
Employee Benefits
	12	Employee Benefits
	The Company sponsors a retirement plan under Section 401(k) of the Internal Revenue Code (the “Retirement Plan”). All Company employees, with the exception of temporary, contract and international employees are eligible to participate in the Retirement Plan after satisfying age and length of service requirements prescribed by the plan. Under the Retirement Plan, employees may make tax-deferred contributions, and the Company, at its sole discretion, and subject to the limits prescribed by the IRS, may make either a nonelective contribution on behalf of all eligible employees or a matching contribution on behalf of all plan participants.
	The Company elected to make a matching contribution of approximately $1.7 million, $1.5 million and $1.7 million for the plan years ended December 27, 2014, December 28, 2013 and December 29, 2012 (“Plan-Year 2014,” “Plan-Year 2013” and “Plan-Year 2012”), respectively. The employer contribution represents a matching contribution at a rate of 50% of each employee’s first six percent contribution. Accordingly, each employee participating during Plan-Year 2014, Plan-Year 2013 and Plan-Year 2012 is entitled up to a maximum of three percent of his or her eligible annual payroll. The employer matching contribution for Plan-Year 2014 is included in accrued compensation in the accompanying consolidated balance sheet.

Acquisition_of_Evolution_Robot

Acquisition of Evolution Robotics, Inc.	12 Months Ended
	Dec. 27, 2014
Business Combinations [Abstract]
Acquisition of Evolution Robotics, Inc.
	13	Acquisition of Evolution Robotics, Inc.
	On October 1, 2012, the Company acquired 100% of the equity of Evolution Robotics, Inc. (Evolution) for $74.8 million in cash, including the effect of working capital adjustments and cash received, with $8.88 million of the purchase price placed into an escrow account to settle certain claims for indemnification for breaches or inaccuracies in Evolution’s representations and warranties, covenants and agreements. As of December 27, 2014, all indemnification claims and escrow balances have been released. Evolution was the developer of Mint and Mint Plus automatic floor cleaning robots, based in Pasadena, California, and is included in the Company's home robots business unit.
	Pro Forma Disclosures (Unaudited)
	The following unaudited pro forma consolidated results of operations for fiscal 2012 assume that the acquisition of Evolution occurred as of January 2, 2011.
		Fiscal Year Ended
		29-Dec-12
		(In thousands)
	Revenue	$	445,469
	Net Income	8,723
	These pro forma amounts do not purport to be indicative of the results that would have actually been obtained if the acquisitions had occurred at the beginning of the periods presented or that may be obtained in the future.

Goodwill_and_other_intangible_

Goodwill and other intangible assets	12 Months Ended
	Dec. 27, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and other intangible assets
	14	Goodwill and other intangible assets
	The carrying amount of the goodwill at December 27, 2014 is $48.8 million. $41.0 million resulted from the acquisition of Evolution Robotics, Inc. in October 2012 and was assigned to the home robots reporting unit. $7.7 million (net of a subsequent write-down of $0.2 million) resulted from the acquisition of Nekton Research, LLC completed in September 2008 and was assigned to the defense and security reporting unit. In conjunction with the reorganization completed as of the beginning of the fiscal year 2013, the defense and security reporting unit was divided into two reporting units: the defense and security reporting unit and the research reporting unit. As a result, the goodwill of $7.9 million was reassigned utilizing a relative fair value allocation approach. $7.7 million and $0.2 million were reassigned to the defense and security and research reporting units, respectively.
	During the second quarter of 2013, the Company decided to refocus its funded research activities. The Company considered this decision to be an impairment indicator, requiring an interim impairment test within the research reporting unit. The Company performed an impairment assessment using the income approach, and determined that goodwill was impaired. The Company recorded an impairment loss of $0.2 million within general and administrative expenses during the fiscal year ended December 28, 2013.
	In the fourth quarter of 2014, the Company completed its annual goodwill impairment test. The first step of the two-step impairment test, which involves comparing the fair values of the applicable reporting units with their aggregate carrying values, including goodwill, was completed, and the Company did not identify any additional goodwill impairment.
	Other intangible assets include the value assigned to completed technology, research contracts, and trade names. The estimated useful lives for all of these intangible assets are two to ten years. The intangible assets are being amortized on a straight-line basis, which is consistent with the pattern that the estimated economic benefits of the intangible assets are expected to be utilized.
	Intangible assets at December 27, 2014 and December 28, 2013 consisted of the following:
		December 27, 2014								December 28, 2013
		Cost		Accumulated		Impairment Loss		Net		Cost		Accumulated		Impairment Loss		Net
				Amortization								Amortization
		(In thousands)
	Completed technology	$	30,600	$	9,691	$	1,788	$	19,121	$	30,600	$	6,202	$	1,788	$	22,610
	Research contracts	100		100		—		—		100		100		—		—
	Tradename	800		775		—		25		800		742		—		58
	Total	$	31,500	$	10,566	$	1,788	$	19,146	$	31,500	$	7,044	$	1,788	$	22,668
	As part of the Company's decision during 2013 to refocus its funded research activities, the Company decided to no longer pursue certain research contracts in which completed technology acquired as part of the acquisition of Nekton Research, LLC was utilized. As a result, the Company performed an impairment assessment of the associated intangible asset using the income approach, and recorded an impairment loss of $1.8 million within general and administrative expenses during the fiscal year ended December 28, 2013.
	Amortization expense related to acquired intangible assets was $3.5 million, $3.8 million, and $1.2 million for the fiscal years ended December 27, 2014, December 28, 2013 and December 29, 2012, respectively. The estimated future amortization expense related to current intangible assets in each of the five succeeding fiscal years is expected to be as follows:
		(In thousands)
	2015	$	3,482
	2016	3,457
	2017	3,457
	2018	3,457
	2019	2,818
	Total	$	16,671

Restructuring_Charges

Restructuring Charges	12 Months Ended
	Dec. 27, 2014
Restructuring and Related Activities [Abstract]
Restructuring Charges
	15	Restructuring charges
	In 2013 and 2012, the Company incurred restructuring charges of $3.3 million, and $3.7 million, respectively. The restructuring charges incurred in 2013 primarily related to a $1.8 million write-down of an intangible asset, costs associated with the closing of its San Luis Obispo, California office and severance-related costs. The restructuring charges incurred in 2012 primarily consisted of cost reductions in its defense and security business unit, which resulted in workforce reductions and the write-off of certain inventory and fixed assets.
	The activity for the restructuring programs is presented below:
		Fiscal Year Ended
		27-Dec-14			28-Dec-13			December 29, 2012
		(In thousands)
	Balance at beginning of period	$	675		$	197		$	—
	Charges	—			3,296			3,679
	Utilization	(675		)	(2,818		)	(3,482		)
	Balance at end of period	$	—		$	675		$	197

Industry_Segment_Geographic_In

Industry Segment, Geographic Information and Significant Customers	12 Months Ended
	Dec. 27, 2014
Segment Reporting [Abstract]
Industry Segment, Geographic Information and Significant Customers
	16	Industry Segment, Geographic Information and Significant Customers
	The Company operates in two reportable segments, the home robots business unit and the defense and security robots business unit. The nature of products and types of customers for the two segments vary significantly. As such, the segments are managed separately.
	Home Robots
	The Company’s home robots business unit offers products 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. The Company’s home robots business unit includes mobile robots used in the maintenance of households.
	Defense and Security Robots
	The Company’s defense and security robots business unit offers products to the U.S. Department of Defense through a small U.S. government-focused sales force, and to other North American and international entities through small domestic and international sales teams, as well as through North American and international distributors. The Company’s defense and security robots are used to increase warfighters', law enforcement, security forces and first responders' safety and productivity.
	Other
	The Company’s other revenue and cost of revenue result from other smaller business units that do not meet the criteria of a reportable segment, as well as certain operational costs included in cost of revenue.
	The table below presents segment information about revenue, cost of revenue, gross margin and income before income taxes:
		Fiscal Year Ended
		December 27,			December 28,			December 29,
		2014			2013			2012
		(In thousands)
	Revenue:
	Home Robots	$	507,414		$	427,853		$	356,805
	Defense & Security Robots	45,502			50,003			70,948
	Other	3,930			9,545			8,491
	Total revenue	556,846			487,401			436,244
	Cost of revenue:
	Home Robots	251,095			217,011			174,756
	Defense & Security Robots	24,409			24,975			40,468
	Other	23,287			24,261			26,672
	Total cost of revenue	298,791			266,247			241,896
	Gross margin:
	Home Robots	256,319			210,842			182,049
	Defense & Security Robots	21,093			25,028			30,480
	Other	(19,357		)	(14,716		)	(18,181		)
	Total gross margin	258,055			221,154			194,348
	Research and development	69,408			63,649			57,066
	Selling and marketing	86,091			71,529			66,412
	General and administrative	49,439			53,358			45,698
	Other income (expense), net	(708		)	(203		)	435
	Income before income taxes	$	52,409		$	32,415		$	25,607
	As of December 27, 2014, goodwill of $41.0 million and purchased intangible assets, net of $19.1 million recorded in conjunction with the acquisition of Evolution Robotics, Inc. in October 2012 are directly associated with the home robots business unit. Goodwill of $7.7 million recorded in conjunction with the acquisition of Nekton in September 2008 is directly associated with the defense and security business unit. Other long lived assets are not directly attributable to individual business segments.
	Geographic Information
	For the fiscal years ended December 27, 2014, December 28, 2013 and December 29, 2012, sales to non-U.S. customers accounted for 60.9%, 59.5% and 57.3% of total revenue, respectively.
	Significant Customers
	For the fiscal years ended December 27, 2014, December 28, 2013 and December 29, 2012, U.S. federal government orders, contracts and subcontracts accounted for 4.3%, 6.2% and 15.1% of total revenue, respectively. For the fiscal years ended December 27, 2014, December 28, 2013 and December 29, 2012 approximately 75.7%, 75.3% and 75.4%, respectively, of our home robot product revenue resulted from sales to 15 customers. For the fiscal years ended December 27, 2014 and December 28, 2013, the Company generated an aggregate of 29.8% and 33.2%, respectively, of its total revenue from its home robots distributor in Japan (Sales on Demand Corporation) and a network of affiliated European distributors of the Company's home robots.

Quarterly_Information_Unaudite

Quarterly Information (Unaudited)	12 Months Ended
	Dec. 27, 2014
Quarterly Financial Information Disclosure [Abstract]
Quarterly Information (Unaudited)
	17	Quarterly Information (Unaudited)
		Fiscal Quarter Ended
		March 30,		June 29,		September 28,		December 28,		March 28,		June 28,		September 27,		December 27,
		2013		2013		2013		2013		2014		2014		2014		2014
		(In thousands, except per share amounts)
	Revenue	$	106,195	$	130,362	$	124,501	$	126,343	$	114,204	$	139,803	$	143,497	$	159,342
	Gross margin	46,558		61,605		54,061		58,930		51,710		62,121		67,889		76,335
	Net income (loss)	8,355		8,294		7,804		3,188		5,280		8,530		14,607		9,386
	Diluted earnings (loss) per share	$	0.29	$	0.28	$	0.26	$	0.11	$	0.18	$	0.28	$	0.48	$	0.31

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 27, 2014
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. In addition, certain prior year amounts have been reclassified to conform with the current year presentation. iRobot has prepared the accompanying consolidated financial statements in conformity with accounting principles generally accepted in the United States of America.
Reorganization [Policy Text Block]	Reorganization
	In fiscal year 2012, the Company initiated a reorganization that resulted in, among other things, the centralization of all of the Company's engineering and operations activities. This reorganization was completed at the beginning of fiscal year 2013. In conjunction with this reorganization, the Company reviewed the financial statement classification of its costs and expenses. As a result of this review, the Company decided to classify certain expenses differently than had been classified and presented in prior periods to provide a more clear understanding of the Company's financial performance. As part of this review, the Company also evaluated the impact of the reorganization on its segment reporting and determined that certain modifications were necessary to present the segment information as now viewed by the Company's chief operating decision maker. Although the classification of certain expenses on the income statement changed in fiscal year 2013 as compared to prior periods, the Company recast the financial results of prior periods in a manner consistent with the fiscal year 2014 and 2013 presentation for comparability purposes. The reclassified amounts reflected in the consolidated statement of income for the year ended December 29, 2012 included herein conforms to the fiscal year 2014 and 2013 presentation. This reclassification of costs and expenses did not impact previously reported net income or earnings per share as the changes only impacted the categorization of costs within the consolidated statements of income for the periods in question. Consequently, the classification changes did not impact previously presented consolidated balance sheets, statements of cash flow or statements of stockholders' equity.
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, 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 will end on the Saturday that falls closest to the last day of the third month of each quarter.
Cash and Cash Equivalents	Cash and Cash Equivalents
	The Company considers all highly liquid investments with an original or remaining maturity of three months or less at the time of purchase to be cash equivalents. The Company invests its excess cash primarily in money market funds or savings accounts of major financial institutions. Accordingly, its cash equivalents are subject to minimal credit and market risk. At December 27, 2014 and December 28, 2013, cash equivalents were comprised of money market funds totaling $109.8 million and $101.4 million, respectively. These cash equivalents are carried at cost, which approximates fair value.
Short Term Investments	Short Term Investments
	The Company’s investments are classified as available-for-sale and are recorded at fair value with any unrealized gain or loss recorded as an element of stockholders’ equity. The fair value of investments is determined based on quoted market prices at the reporting date for those instruments. As of December 27, 2014 and December 28, 2013, investments consisted of:
		December 27,							December 28,
		2014							2013
		Cost			Fair				Cost			Fair
					Market Value							Market Value
		(In thousands)
	Corporate and government bonds	$	36,659		$	36,166			$	22,134		$	21,954
	Total short term investments	$	36,659		$	36,166			$	22,134		$	21,954
	As of December 27, 2014, the Company’s investments had maturity dates ranging from July 2015 to March 2018. The Company invests primarily in investment grade securities and limits the amount of investment in any single issuer.
Revenue Recognition	Revenue Recognition
	The Company derives its revenue from product sales and, to a lesser extent, 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, provided that collection is determined to be reasonably assured and no significant obligations remain. Sales to domestic and Canadian resellers of home 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. 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. The estimates for rights of return are directly based on specific terms and conditions included in the reseller 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 reseller 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 reseller agreement is modified. 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. The estimates and reserve for rebates and price protection are based on specific programs, expected usage and historical experience. Actual results could differ from these estimates.
	Under cost-plus-fixed-fee (CPFF) type contracts, the Company recognizes revenue based on costs incurred plus a pro rata portion of the total fixed fee. Costs incurred include labor and material that are 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 provisional rates currently in effect, 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 December 27, 2014, fiscal years 2012 through 2014 are open for audit by DCAA. In the situation where the Company’s anticipated actual billing rates will be lower than the provisional rates currently in effect, the Company records a cumulative revenue adjustment in the period in which the rate differential is identified. Revenue on firm fixed price (FFP) contracts is recognized using the percentage-of-completion method. For government product FFP contracts, revenue is recognized as the product is shipped or in accordance with the contract terms. Costs and estimated gross margins on contracts are recorded as revenue as work is performed based on the percentage that incurred costs compare to estimated total costs utilizing the most recent estimates of costs and funding. Changes in job performance, job conditions, and estimated profitability, including those arising from final contract settlements and government audits, may result in revisions to costs and income and are recognized in the period in which the revisions are determined. Since many contracts extend over a long period of time, revisions in cost and funding estimates during the progress of work have the effect of adjusting earnings applicable to past performance in the current period. When the current contract estimate indicates a loss, a provision is made for the total anticipated loss in the current period. Revenue earned in excess of billings, if any, is recorded as unbilled revenue. Billings in excess of revenue earned, if any, are recorded as deferred revenue.
Allowance for Doubtful Accounts	Allowance for Doubtful Accounts
	The Company maintains an allowance for doubtful accounts to provide for the estimated amount of accounts receivable that may not be collected. The allowance is based upon an assessment of customer creditworthiness, historical payment experience and the age of outstanding receivables.
	Activity related to the allowance for doubtful accounts was as follows:
		Fiscal Year Ended
		December 27,			December 28,				December 29,
		2014			2013				2012
		(In thousands)
	Balance at beginning of period	$	67		$	111			$	87
	Provision	—			—				37
	Deduction(*)	—			(44		)		(13		)
	Balance at end of period	$	67		$	67			$	111
	_____________________
	(*)	Deductions related to allowance for doubtful accounts represent amounts written off against the allowance, less recoveries.
Inventory	Inventory
	Inventory is stated at the lower of cost or net realizable value with cost being determined using the first-in, first-out (FIFO) method. The Company maintains a reserve for inventory items to provide for an estimated amount of excess or obsolete inventory.
	Activity related to the inventory reserve was as follows:
		Fiscal Year Ended
		December 27,			December 28,				December 29,
		2014			2013				2012
		(In thousands)
	Balance at beginning of period	$	5,280		$	6,608			$	2,568
	Provision	1,045			1,571				5,101
	Deduction(*)	(1,074		)	(2,899		)		(1,061		)
	Balance at end of period	$	5,251		$	5,280			$	6,608
	___________________________
	(*)	Deductions related to inventory reserve accounts represent amounts written off against the reserve.
Schedule of Valuation and Qualifying Accounts Disclosure [Text Block]	The table below summarizes activity relating to the valuation allowance:
	Fiscal Year Ended	Balance at			Additions			Additions Charged to Goodwill			Deductions		Balance
		beginning  of			Charged to								at End
		period			Costs and								of Period
					Expenses
		(In thousands)
	December 29, 2012	$	—		—			2,691			—		$	2,691
	December 28, 2013	$	2,691		—			—			601		$	2,090
	December 27, 2014	$	2,090		—			—			2,090		$	—
Property and Equipment	Property and Equipment
	Property and equipment are recorded at cost and consist primarily of computer equipment, leasehold improvements, business applications software and machinery. Depreciation is computed using the straight-line method over the estimated useful lives as follows:
		Estimated
		Useful Life
	Computer and research equipment	3 years
	Furniture	5
	Machinery	5-Feb
	Tooling	5-Feb
	Business applications software	7-May
	Capital leases and leasehold improvements	Lesser of economic benefit period or term of lease
	Expenditures for additions, renewals and betterments of plant and equipment are capitalized. Expenditures for repairs and maintenance are charged to expense as incurred. As assets are retired or sold, the related cost and accumulated depreciation are removed from the accounts and any resulting gain or loss is credited or charged to operations.
Long-Lived Assets, including Purchased Intangible Assets	Long-Lived Assets, including Purchased Intangible Assets
	The Company periodically evaluates the recoverability of long-lived assets, including other purchased intangible assets whenever events and changes in circumstances, such as reductions in demand or significant economic slowdowns in the industry, indicate that the carrying amount of an asset may not be fully recoverable. When indicators of impairment are present, the carrying values of the asset group are evaluated in relation to the future undiscounted cash flows of the underlying business. The net book value of the underlying asset is adjusted to fair value if the sum of the expected discounted cash flows is less than book value. Fair values are based on estimates of market prices and assumptions concerning the amount and timing of estimated future cash flows and assumed discount rates, reflecting varying degrees of perceived risk.
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.
Research and Development	Research and Development
	Costs incurred in the research and development of the Company’s products, classified as cost of revenue and research and development, are expensed as incurred.
Internal Use Software	Internal Use Software
	The Company capitalizes costs associated with the development and implementation of software for internal use. At December 27, 2014 and December 28, 2013, the Company had $8.2 million and $8.2 million, respectively, of costs related to enterprise-wide software included in fixed assets. Capitalized costs are being amortized over the assets’ estimated useful lives. The Company has recorded $0.8 million, $0.9 million and $1.0 million of amortization expense for the years ended December 27, 2014, December 28, 2013 and December 29, 2012, respectively.
Concentration of Credit Risk and Significant Customers	Concentration of Credit Risk and Significant Customers
	Financial instruments which potentially expose the Company to concentrations of credit risk consist of accounts receivable. Management believes its credit policies are prudent and reflect normal industry terms and business risk. At December 27, 2014, two customers accounted for a total of 32% of the Company's accounts receivable balance, each of which was greater than 10% of the balance and each of whom secured their balance with guaranteed letters of credit. At December 28, 2013, two customers accounted for a total of 37% of the Company’s accounts receivable balance, each of which was greater than 10% of the balance and each of whom secured their balance with guaranteed letters of credit. For the years ended December 27, 2014, December 28, 2013 and December 29, 2012, revenue from U.S. federal government orders, contracts and subcontracts, represented 4.3%, 6.2% and 15.1% of total revenue, respectively. For the fiscal years ended December 27, 2014, December 28, 2013 and December 29, 2012, the Company generated an aggregate of 29.8%, 33.2% and 30.6%, respectively, of total revenue from its home robots distributor in Japan and a network of affiliated European distributors of its home robots.
	The Company maintains its cash in bank deposit accounts at high quality financial institutions. The individual balances, at times, may exceed federally insured limits.
	Geographic Information
	For the fiscal years ended December 27, 2014, December 28, 2013 and December 29, 2012, sales to non-U.S. customers accounted for 60.9%, 59.5% and 57.3% of total revenue, respectively.
	Significant Customers
	For the fiscal years ended December 27, 2014, December 28, 2013 and December 29, 2012, U.S. federal government orders, contracts and subcontracts accounted for 4.3%, 6.2% and 15.1% of total revenue, respectively. For the fiscal years ended December 27, 2014, December 28, 2013 and December 29, 2012 approximately 75.7%, 75.3% and 75.4%, respectively, of our home robot product revenue resulted from sales to 15 customers. For the fiscal years ended December 27, 2014 and December 28, 2013, the Company generated an aggregate of 29.8% and 33.2%, respectively, of its total revenue from its home robots distributor in Japan (Sales on Demand Corporation) and a network of affiliated European distributors of the Company's home robots.
Stock-Based Compensation	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 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, net of estimated forfeitures.
Advertising Expense	Advertising Expense
	The Company expenses advertising costs as they are incurred. During the years ended December 27, 2014, December 28, 2013 and December 29, 2012 advertising expense totaled $46.1 million, $38.2 million and $34.9 million, respectively.
Net Income Per Share	Net Income Per Share
	The following table presents the calculation of both basic and diluted net income per share:
		Fiscal Year Ended
		December 27,			December 28,				December 29,
		2014			2013				2012
	Net income	$	37,803		$	27,641			$	17,297
	Weighted-average shares outstanding	29,485			28,495				27,577
	Dilutive effect of employee stock options and restricted shares	725			859				724
	Diluted weighted average shares outstanding	30,210			29,354				28,301
	Basic income per share	$	1.28		$	0.97			$	0.63
	Diluted income per share	$	1.25		$	0.94			$	0.61
	Potentially dilutive securities representing approximately 0.2 million, 0.7 million and 0.8 million shares of common stock for the fiscal years ended December 27, 2014, December 28, 2013 and December 29, 2012, 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 federal and state tax authorities is closed for fiscal years prior to 2011. Federal and state carryforward attributes that were generated prior to fiscal year 2011 may still be adjusted upon examination by the Internal Revenue Service (IRS) 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.
	As of December 28, 2013, the Company maintained a valuation allowance of $2.1 million related to certain state tax attributes from the Evolution Robotics, Inc. acquisition. During the year ended December 27, 2014, this valuation allowance was released when the realization of these state tax attributes became more likely than not.
Comprehensive Income	Comprehensive Income
	Accumulated other comprehensive income includes unrealized gains and losses on certain investments. The differences between net income and comprehensive income were related to unrealized gains (losses) on investments, net of tax.
Fair Value Measurements	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
	The Company’s financial assets measured at fair value on a recurring basis at December 27, 2014, were as follows:
		Fair Value Measurements as of
		December 27, 2014
	Description	Level 1			Level 2				Level 3
		(In thousands)
	Assets:
	Money market funds	$	109,843		$	—			$	—
	Corporate and government bonds	—			36,166				—
	Total assets measured at fair value	$	109,843		$	36,166			$	—
	The Company’s financial assets measured at fair value on a recurring basis at December 28, 2013, were as follows:
		Fair Value Measurements as of
		December 28, 2013
	Description	Level 1			Level 2				Level 3
		(In thousands)
	Assets:
	Money market funds	$	101,441		$	—			$	—
	Corporate and government bonds	—			21,954				—
	Total assets measured at fair value	$	101,441		$	21,954			$	—
	In each table above, the bond investments are valued based on observable market values as of the Company’s reporting date and are included in Level 2. The bond investments are recorded at fair value and marked-to-market at the end of each reporting period and realized and unrealized gains and losses are included in comprehensive income for that period. The fair value of the Company’s bond investments are included in short term investments in its consolidated balance sheets.
	Non-financial Assets
	The Company's non-financial assets, which include goodwill, intangible assets, and property and equipment are not required to be measured at fair value on a recurring basis. However, the Company evaluates the non-financial assets for impairment if a trigger event occurs, or when an annual impairment test is performed. If the asset is determined to be impaired, the asset is required to be recorded at fair value.
Fair Value, Assets Measured on Recurring Basis [Table Text Block]	The Company’s financial assets measured at fair value on a recurring basis at December 27, 2014, were as follows:
		Fair Value Measurements as of
		December 27, 2014
	Description	Level 1			Level 2				Level 3
		(In thousands)
	Assets:
	Money market funds	$	109,843		$	—			$	—
	Corporate and government bonds	—			36,166				—
	Total assets measured at fair value	$	109,843		$	36,166			$	—
	The Company’s financial assets measured at fair value on a recurring basis at December 28, 2013, were as follows:
		Fair Value Measurements as of
		December 28, 2013
	Description	Level 1			Level 2				Level 3
		(In thousands)
	Assets:
	Money market funds	$	101,441		$	—			$	—
	Corporate and government bonds	—			21,954				—
	Total assets measured at fair value	$	101,441		$	21,954			$	—
Recent Accounting Pronouncements	Recent Accounting Pronouncements
	In August 2014, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2014-15, “Presentation of Financial Statements - Going Concern.” ASU No. 2014-15 requires management of public and private companies to evaluate whether there is substantial doubt about the entity’s ability to continue as a going concern and, if so, disclose that fact. Management will also be required to evaluate and disclose whether its plans alleviate that doubt. The new standard is effective for annual periods ending after December 15, 2016, and interim periods within annual periods beginning after December 15, 2016. The Company does not believe that the impact of this amendment will be material to the Company’s consolidated financial statements.
	In June 2014, the FASB issued ASU No. 2014-12, “Accounting for Share-Based Payments When the Terms of an Award Provide That a Performance Target Could Be Achieved after the Requisite Service Period.” ASU No. 2014-12 requires a reporting entity to treat a performance target that affects vesting and that could be achieved after the requisite service period as a performance condition. It is effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2015. Early adoption is permitted. The Company is currently assessing the potential impact of ASU No. 2014-12 on its 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 that reporting period. Early application is not permitted. The Company is currently assessing the potential impact of ASU No. 2014-09 on its consolidated financial statements.
	On April 10, 2014, the FASB issued ASU No. 2014-08 “Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity.” ASU No. 2014-08 changes the criteria for reporting discontinued operations and modifies related disclosure requirements. The new guidance is effective on a prospective basis for fiscal years beginning after December 15, 2014, and interim periods within annual periods beginning on or after December 15, 2015. Early adoption is permitted for new disposals (or new classifications as held for sale) that have not been reported in financial statements previously issued or available for issuance. The Company is currently assessing the future impact of ASU No. 2014-08 on its consolidated financial statements.
	In July 2013, the FASB issued ASU 2013-11 “Presentation of an Unrecognized Tax Benefit when a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Exists”, related to the presentation of an unrecognized tax benefit when a net operating loss carryforward, a similar tax loss, or a tax credit carryforward exists.  This guidance clarifies prior guidance and eliminates diversity in practice on the presentation of unrecognized tax benefits when certain situations exist at the reporting date.  This guidance is effective for annual reporting periods beginning on or after December 15, 2013 and subsequent interim periods.  The impact of this amendment on the Company's consolidated financial statements was not material.
	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 the impact of recently issued standards, which are not yet effective, will not have a material impact on its consolidated financial statements upon adoption.

Summary_of_Significant_Account2

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 27, 2014
Valuation and Qualifying Accounts Disclosure [Line Items]
Components of available for sale securities	The fair value of investments is determined based on quoted market prices at the reporting date for those instruments. As of December 27, 2014 and December 28, 2013, investments consisted of:
		December 27,							December 28,
		2014							2013
		Cost			Fair				Cost			Fair
					Market Value							Market Value
		(In thousands)
	Corporate and government bonds	$	36,659		$	36,166			$	22,134		$	21,954
	Total short term investments	$	36,659		$	36,166			$	22,134		$	21,954
Activity related to allowance for doubtful accounts	Activity related to the allowance for doubtful accounts was as follows:
		Fiscal Year Ended
		December 27,			December 28,				December 29,
		2014			2013				2012
		(In thousands)
	Balance at beginning of period	$	67		$	111			$	87
	Provision	—			—				37
	Deduction(*)	—			(44		)		(13		)
	Balance at end of period	$	67		$	67			$	111
	_____________________
	(*)	Deductions related to allowance for doubtful accounts represent amounts written off against the allowance, less recoveries.
Activity related to Inventory reserve	The table below summarizes activity relating to the valuation allowance:
	Fiscal Year Ended	Balance at			Additions			Additions Charged to Goodwill			Deductions		Balance
		beginning  of			Charged to								at End
		period			Costs and								of Period
					Expenses
		(In thousands)
	December 29, 2012	$	—		—			2,691			—		$	2,691
	December 28, 2013	$	2,691		—			—			601		$	2,090
	December 27, 2014	$	2,090		—			—			2,090		$	—
Property and equipment	Depreciation is computed using the straight-line method over the estimated useful lives as follows:
		Estimated
		Useful Life
	Computer and research equipment	3 years
	Furniture	5
	Machinery	5-Feb
	Tooling	5-Feb
	Business applications software	7-May
	Capital leases and leasehold improvements	Lesser of economic benefit period or term of lease
	Property and equipment consists of the following at:
		December 27,			December 28,
		2014			2013
		(In thousands)
	Computer and equipment	$	15,173		$	13,715
	Furniture	2,297			1,845
	Machinery	5,307			3,705
	Tooling	18,614			12,228
	Leasehold improvements	20,833			15,983
	Business applications software	8,214			8,162
		70,438			55,638
	Less: accumulated depreciation	39,141			31,977
		$	31,297		$	23,661
Basic and diluted net income per share	The following table presents the calculation of both basic and diluted net income per share:
		Fiscal Year Ended
		December 27,			December 28,				December 29,
		2014			2013				2012
	Net income	$	37,803		$	27,641			$	17,297
	Weighted-average shares outstanding	29,485			28,495				27,577
	Dilutive effect of employee stock options and restricted shares	725			859				724
	Diluted weighted average shares outstanding	30,210			29,354				28,301
	Basic income per share	$	1.28		$	0.97			$	0.63
	Diluted income per share	$	1.25		$	0.94			$	0.61
Inventory Valuation Reserve [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Activity related to Inventory reserve	Activity related to the inventory reserve was as follows:
		Fiscal Year Ended
		December 27,			December 28,				December 29,
		2014			2013				2012
		(In thousands)
	Balance at beginning of period	$	5,280		$	6,608			$	2,568
	Provision	1,045			1,571				5,101
	Deduction(*)	(1,074		)	(2,899		)		(1,061		)
	Balance at end of period	$	5,251		$	5,280			$	6,608
	___________________________
	(*)	Deductions related to inventory reserve accounts represent amounts written off against the reserve.

Inventory_Tables

Inventory (Tables)	12 Months Ended
	Dec. 27, 2014
Inventory Disclosure [Abstract]
Inventory	Inventory consists of the following at:
		December 27,		December 28,
		2014		2013
		(In thousands)
	Raw materials	$	9,455	$	8,520
	Work in process	—		—
	Finished goods	38,402		37,587
		$	47,857	$	46,107

Property_and_Equipment_Tables

Property and Equipment (Tables)	12 Months Ended
	Dec. 27, 2014
Property, Plant and Equipment [Abstract]
Property and equipment	Depreciation is computed using the straight-line method over the estimated useful lives as follows:
		Estimated
		Useful Life
	Computer and research equipment	3 years
	Furniture	5
	Machinery	5-Feb
	Tooling	5-Feb
	Business applications software	7-May
	Capital leases and leasehold improvements	Lesser of economic benefit period or term of lease
	Property and equipment consists of the following at:
		December 27,		December 28,
		2014		2013
		(In thousands)
	Computer and equipment	$	15,173	$	13,715
	Furniture	2,297		1,845
	Machinery	5,307		3,705
	Tooling	18,614		12,228
	Leasehold improvements	20,833		15,983
	Business applications software	8,214		8,162
		70,438		55,638
	Less: accumulated depreciation	39,141		31,977
		$	31,297	$	23,661

Accrued_Expenses_Tables

Accrued Expenses (Tables)	12 Months Ended
	Dec. 27, 2014
Accrued Liabilities, Current [Abstract]
Components of accrued expenses	Accrued expenses consist of the following at:
		December 27,		December 28,
		2014		2013
		(In thousands)
	Accrued warranty	$	7,769	$	6,497
	Accrued direct fulfillment costs	1,346		1,362
	Accrued sales tax	867		831
	Accrued customer deposits	702		103
	Accrued rent	701		726
	Accrued sales commissions	531		539
	Accrued contractors	217		509
	Accrued other	6,568		4,313
		$	18,701	$	14,880
	Accrued compensation consists of the following at:
		December 27,		December 28,
		2014		2013
		(In thousands)
	Accrued bonus	$	8,455	$	13,002
	Accrued other compensation	7,780		6,604
		$	16,235	$	19,606

Stock_Options_Plans_and_StockB1

Stock Options Plans and Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 27, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Activities relating to restricted stock awards	The table below summarizes activity relating to restricted stock units:
		Number of		Weighted Average
		Shares Underlying		Grant Date Fair
		Restricted Stock		Value
	Outstanding at December 31, 2011	607,505		$	22.77
	Granted	685,529		24.62
	Vested	(204,053	)	21.24
	Forfeited	(147,951	)	25.07
	Outstanding at December 29, 2012	941,030		$	24.09
	Granted	521,056		25.87
	Vested	(348,141	)	22.57
	Forfeited	(186,291	)	24.91
	Outstanding at December 28, 2013	927,654		$	25.5
	Granted	372,159		38.25
	Vested	(318,367	)	25.38
	Forfeited	(71,591	)	28.42
	Outstanding at December 27, 2014	909,855		$	30.53
Summary of stock option plan activity	The table below summarizes stock option plan activity:
		Number of		Weighted Average			Weighted  Average	Aggregate
		Shares		Exercise Price			Remaining	Intrinsic
							Contractual Term	Value(1)
	Outstanding at December 31, 2011	2,561,292		$	17.17
	Granted	547,948		19.7
	Exercised	(390,956	)	11.07
	Canceled	(214,617	)	21.91
	Outstanding at December 29, 2012	2,503,667		$	18.27
	Granted	293,325		24.6
	Exercised	(840,951	)	16.21
	Canceled	(185,666	)	22.16
	Outstanding at December 28, 2013	1,770,375		$	19.89
	Granted	233,181		37.1
	Exercised	(486,252	)	18.39
	Canceled	(43,984	)	27.17
	Outstanding at December 27, 2014	1,473,320		$	22.89		3.87 years	$18.2 million
	Vested and expected to vest at December 27, 2014	1,419,559		$	22.61		3.79 years	$17.8 million
	Exercisable as of December 27, 2014	917,340		$	19.32		2.82 years	$14.2 million
	Weighted average fair value of options granted during the fiscal year ended December 27, 2014			$	15.87
	Options available for future grant at December 27, 2014	4,762,446
	_________________________
	-1	The aggregate intrinsic value on the table was calculated based upon the positive difference between the closing market value of the Company’s stock on December 27, 2014 of $34.81 and the exercise price of the underlying option.
Summary of information about stock options outstanding	The following table summarizes information about stock options outstanding at December 27, 2014:
			Options Outstanding						Options Exercisable
	Range of Exercise Prices		Number		Weighted Average	Weighted  Average			Number	Weighted Average
			Outstanding		Remaining	Exercise Price			Exercisable	Exercise Price
					Contractual Life
	$  3.54 - $ 7.76		156,380		3.68 years	$	6.08		134,520	$	6.29
	8.10 - 14.13		100,551		1.1	13.36			100,551	13.36
	14.52 - 14.52		164,442		2.26	14.52			164,442	14.52
	14.54 - 22.20		182,584		3.63	19.17			113,901	19.54
	22.86 - 22.86		194,508		5.09	22.86			79,614	22.86
	24.00 - 25.99		199,546		2.66	24.75			153,876	24.46
	26.59 - 33.48		264,971		4.3	31.19			156,756	31.05
	33.72 - 35.96		121,445		6.1	35.01			13,680	34.34
	37.08 - 37.08		34,500		6.84	37.08			—	—
	43.35 -  43.35		54,393		6.19	43.35			—	—
	$ 3.54 -  $43.35		1,473,320		3.87 years	$	22.89		917,340	$	19.32
Activities relating to restricted stock units	The table below summarizes activity relating to restricted stock units:
		Number of		Weighted Average
		Shares Underlying		Grant Date Fair
		Restricted Stock		Value
	Outstanding at December 31, 2011	607,505		$	22.77
	Granted	685,529		24.62
	Vested	(204,053	)	21.24
	Forfeited	(147,951	)	25.07
	Outstanding at December 29, 2012	941,030		$	24.09
	Granted	521,056		25.87
	Vested	(348,141	)	22.57
	Forfeited	(186,291	)	24.91
	Outstanding at December 28, 2013	927,654		$	25.5
	Granted	372,159		38.25
	Vested	(318,367	)	25.38
	Forfeited	(71,591	)	28.42
	Outstanding at December 27, 2014	909,855		$	30.53
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Activities relating to restricted stock awards
Activities relating to restricted stock units

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	Dec. 27, 2014
Valuation and Qualifying Accounts Disclosure [Line Items]
Components of income tax expense	The components of income tax expense were as follows:
		Fiscal Year Ended
		December 27,			December 28,				December 29,
		2014			2013				2012
		(In thousands)
	Current
	Federal	$	15,128		$	6,363			$	12,540
	State	129			1,124				473
	Foreign	91			41				(8		)
	Total current tax provision	15,348			7,528				13,005
	Deferred
	Federal	1,268			(2,026		)		(4,003		)
	State	(2,010		)	(728		)		(692		)
	Total deferred tax provision	(742		)	(2,754		)		(4,695		)
	Total income tax provision	$	14,606		$	4,774			$	8,310
Components of net deferred tax assets	The components of net deferred tax assets were as follows:
		December 27,			December 28,
		2014			2013
		(In thousands)
	Net deferred tax assets
	Current deferred tax assets
	Reserves and accruals	$	18,568		$	18,554
	Stock-based compensation	767			556
	Net operating loss carryforwards	2,470			2,470
	Foreign tax credits	148			105
	Valuation allowance	—			(1,100		)
	Total current deferred tax assets	21,953			20,585
	Non-current deferred tax assets
	Reserves and accruals	586			715
	Tax credits	5,927			5,737
	Property and equipment	178			1,308
	Stock-based compensation	5,011			4,957
	Net operating loss carryforwards	3,879			6,587
	Valuation allowance	—			(990		)
	Total non-current deferred tax assets	15,581			18,314
	Current deferred tax liabilities
	Prepaids	448			441
	Total current deferred tax liabilities	448			441
	Non-current deferred tax liabilities
	Intangible assets	7,172			8,219
	Total non-current deferred tax liabilities	7,172			8,219
	Total net deferred tax assets	$	29,914		$	30,239
Valuation allowance deferred tax assets	The table below summarizes activity relating to the valuation allowance:
	Fiscal Year Ended	Balance at			Additions			Additions Charged to Goodwill			Deductions	Balance
		beginning  of			Charged to							at End
		period			Costs and							of Period
					Expenses
		(In thousands)
	December 29, 2012	$	—		—			2,691			—	$	2,691
	December 28, 2013	$	2,691		—			—			601	$	2,090
	December 27, 2014	$	2,090		—			—			2,090	$	—
Reconciliation of the expected tax (benefit) expense	The reconciliation of the expected tax (benefit) expense (computed by applying the federal statutory rate to income before income taxes) to actual tax expense was as follows:
		Fiscal Year Ended
		December 27,			December 28,				December 29,
		2014			2013				2012
		(In thousands)
	Expected federal income tax	$	18,344		$	11,345			$	8,962
	Miscellaneous permanent items	691			405				338
	State taxes (net of federal benefit)	1,058			867				497
	Federal and state credits	(1,487		)	(3,909		)		(418		)
	Change in valuation allowance	(2,090		)	—				—
	Domestic production activities deduction	(1,562		)	(1,168		)		(1,100		)
	Settlement of uncertain tax positions	(176		)	(2,696		)		—
	Other	(172		)	(70		)		31
		$	14,606		$	4,774			$	8,310
Schedule of adjustments to uncertain tax position	A summary of the Company’s adjustments to its gross unrecognized tax benefits, inclusive of interest, in the current year is as follows:
		Fiscal Year Ended
		December 27, 2014
	Balance at beginning of period	$	2,618
	Increase for tax positions related to the current year	252
	Decrease for tax positions related to prior years	(108		)
	Decreases for settlements with applicable taxing authorities	(271		)
	Decreases for lapses of statute of limitations	—
	Balance at end of period	$	2,491

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 27, 2014
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 December 27, 2014:
		Operating
		Leases
	2015	$	3,460
	2016	2,670
	2017	2,383
	2018	2,383
	2019	2,383
	Thereafter	794
	Total minimum lease payments	$	14,073
Activity related to the warranty accrual	Activity related to the warranty accrual was as follows:
		Fiscal Year Ended
		December 27,			December 28,			December 29,
		2014			2013			2012
		(In thousands)
	Balance at beginning of period	$	6,497		$	6,057		$	10,306
	Provision (*)	6,410			1,744			(1,682		)
	Warranty usage(**)	(5,138		)	(1,304		)	(2,567		)
	Balance at end of period	$	7,769		$	6,497		$	6,057
	__________________________________
	(*)	During 2012, the Company recorded favorable adjustments relating to reductions in its international warranty accrual for our home robots business related to our sustained improvements in product quality, resulting in a net credit for its 2012 warranty provision.
	(**)	Warranty usage includes costs incurred for warranty obligations.

Acquisition_of_Evolution_Robot1

Acquisition of Evolution Robotics, Inc. Acquisition of Evolution Robotics, Inc. (Tables)	12 Months Ended
	Dec. 27, 2014
Business Combinations [Abstract]
Schedule of proforma consolidated results of operations	The following unaudited pro forma consolidated results of operations for fiscal 2012 assume that the acquisition of Evolution occurred as of January 2, 2011.
		Fiscal Year Ended
		29-Dec-12
		(In thousands)
	Revenue	$	445,469
	Net Income	8,723

Goodwill_and_other_intangible_1

Goodwill and other intangible assets (Tables)	12 Months Ended
	Dec. 27, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Other intangible assets
		December 27, 2014								December 28, 2013
		Cost		Accumulated		Impairment Loss		Net		Cost		Accumulated		Impairment Loss		Net
				Amortization								Amortization
		(In thousands)
	Completed technology	$	30,600	$	9,691	$	1,788	$	19,121	$	30,600	$	6,202	$	1,788	$	22,610
	Research contracts	100		100		—		—		100		100		—		—
	Tradename	800		775		—		25		800		742		—		58
	Total	$	31,500	$	10,566	$	1,788	$	19,146	$	31,500	$	7,044	$	1,788	$	22,668
Estimated future amortization expense related to current intangible assets
		(In thousands)
	2015	$	3,482
	2016	3,457
	2017	3,457
	2018	3,457
	2019	2,818
	Total	$	16,671

Restructuring_Charges_Restruct

Restructuring Charges Restructuring Charges (Tables)	12 Months Ended
	Dec. 27, 2014
Restructuring and Related Activities [Abstract]
Restructuring reserve roll forward	The activity for the restructuring programs is presented below:
		Fiscal Year Ended
		27-Dec-14			28-Dec-13			December 29, 2012
		(In thousands)
	Balance at beginning of period	$	675		$	197		$	—
	Charges	—			3,296			3,679
	Utilization	(675		)	(2,818		)	(3,482		)
	Balance at end of period	$	—		$	675		$	197

Industry_Segment_Geographic_In1

Industry Segment, Geographic Information and Significant Customers (Tables)	12 Months Ended
	Dec. 27, 2014
Segment Reporting [Abstract]
Concentration Risk Disclosure [Text Block]	Concentration of Credit Risk and Significant Customers
	Financial instruments which potentially expose the Company to concentrations of credit risk consist of accounts receivable. Management believes its credit policies are prudent and reflect normal industry terms and business risk. At December 27, 2014, two customers accounted for a total of 32% of the Company's accounts receivable balance, each of which was greater than 10% of the balance and each of whom secured their balance with guaranteed letters of credit. At December 28, 2013, two customers accounted for a total of 37% of the Company’s accounts receivable balance, each of which was greater than 10% of the balance and each of whom secured their balance with guaranteed letters of credit. For the years ended December 27, 2014, December 28, 2013 and December 29, 2012, revenue from U.S. federal government orders, contracts and subcontracts, represented 4.3%, 6.2% and 15.1% of total revenue, respectively. For the fiscal years ended December 27, 2014, December 28, 2013 and December 29, 2012, the Company generated an aggregate of 29.8%, 33.2% and 30.6%, respectively, of total revenue from its home robots distributor in Japan and a network of affiliated European distributors of its home robots.
	The Company maintains its cash in bank deposit accounts at high quality financial institutions. The individual balances, at times, may exceed federally insured limits.
	Geographic Information
	For the fiscal years ended December 27, 2014, December 28, 2013 and December 29, 2012, sales to non-U.S. customers accounted for 60.9%, 59.5% and 57.3% of total revenue, respectively.
	Significant Customers
	For the fiscal years ended December 27, 2014, December 28, 2013 and December 29, 2012, U.S. federal government orders, contracts and subcontracts accounted for 4.3%, 6.2% and 15.1% of total revenue, respectively. For the fiscal years ended December 27, 2014, December 28, 2013 and December 29, 2012 approximately 75.7%, 75.3% and 75.4%, respectively, of our home robot product revenue resulted from sales to 15 customers. For the fiscal years ended December 27, 2014 and December 28, 2013, the Company generated an aggregate of 29.8% and 33.2%, respectively, of its total revenue from its home robots distributor in Japan (Sales on Demand Corporation) and a network of affiliated European distributors of the Company's home robots.
Segment information about revenue, cost of revenue, gross margin and income before income taxes	The Company’s other revenue and cost of revenue result from other smaller business units that do not meet the criteria of a

Quarterly_Information_Unaudite1

Quarterly Information (Unaudited) (Tables)	12 Months Ended
	Dec. 27, 2014
Quarterly Financial Information Disclosure [Abstract]
Details of Quarterly Information (Unaudited)
		Fiscal Quarter Ended
		March 30,		June 29,		September 28,		December 28,		March 28,		June 28,		September 27,		December 27,
		2013		2013		2013		2013		2014		2014		2014		2014
		(In thousands, except per share amounts)
	Revenue	$	106,195	$	130,362	$	124,501	$	126,343	$	114,204	$	139,803	$	143,497	$	159,342
	Gross margin	46,558		61,605		54,061		58,930		51,710		62,121		67,889		76,335
	Net income (loss)	8,355		8,294		7,804		3,188		5,280		8,530		14,607		9,386
	Diluted earnings (loss) per share	$	0.29	$	0.28	$	0.26	$	0.11	$	0.18	$	0.28	$	0.48	$	0.31

Summary_of_Significant_Account3

Summary of Significant Accounting Policies (Details) (USD $)	Dec. 27, 2014	Dec. 28, 2013
In Thousands, unless otherwise specified
Components of available for sale securities
Total short term investments, Cost	$36,659	$22,134
Total short term investments, Fair Market Value	36,166	21,954
Bonds [Member]
Components of available for sale securities
Total short term investments, Cost	36,659	22,134
Total short term investments, Fair Market Value	$36,166	$21,954

Summary_of_Significant_Account4

Summary of Significant Accounting Policies (Details 1) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 27, 2014		Dec. 28, 2013		Dec. 29, 2012
Allowance for Doubtful Accounts Receivable [Roll Forward]
Balance at beginning of period	$67		$111		$87
Provision	0		0		37
Deduction	0	[1]	-44	[1]	-13	[1]
Balance at end of period	$67		$67		$111
[1]	Deductions related to allowance for doubtful accounts represent amounts written off against the allowance, less recoveries.

Summary_of_Significant_Account5

Summary of Significant Accounting Policies (Details 2) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Inventory Valuation Allowance [Roll Forward]
Balance at beginning of period	$5,280	$6,608	$2,568
Valuation Allowances and Reserves, Charged to Cost and Expense	1,045	1,571	5,101
Valuation Allowances and Reserves, Deductions	2,090	601	0
Balance at end of period	$5,251	$5,280	$6,608

Summary_of_Significant_Account6

Summary of Significant Accounting Policies (Details 3)	12 Months Ended
	Dec. 27, 2014
Computer and research equipment [Member]
Property Plant And Equipment [Line Items]
Estimated useful life	3 years
Furniture [Member]
Property Plant And Equipment [Line Items]
Estimated useful life	5 years
Capital leases and leasehold improvements [Member]
Property Plant And Equipment [Line Items]
Capital leases and leasehold improvements	Lesser of economic benefit period or term of lease
Minimum [Member] | Machinery [Member]
Property Plant And Equipment [Line Items]
Estimated useful life	2 years
Minimum [Member] | Tooling [Member]
Property Plant And Equipment [Line Items]
Estimated useful life	2 years
Minimum [Member] | Software and Software Development Costs [Member]
Property Plant And Equipment [Line Items]
Estimated useful life	5 years
Maximum [Member] | Machinery [Member]
Property Plant And Equipment [Line Items]
Estimated useful life	5 years
Maximum [Member] | Tooling [Member]
Property Plant And Equipment [Line Items]
Estimated useful life	5 years
Maximum [Member] | Software and Software Development Costs [Member]
Property Plant And Equipment [Line Items]
Estimated useful life	7 years

Summary_of_Significant_Account7

Summary of Significant Accounting Policies (Details 4) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 27, 2014	Sep. 27, 2014	Jun. 28, 2014	Mar. 29, 2014	Dec. 28, 2013	Sep. 28, 2013	Jun. 29, 2013	Mar. 30, 2013	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Basic and Diluted Net Income Per Share
Net income, as reported	$9,386	$14,607	$8,530	$5,280	$3,188	$7,804	$8,294	$8,355	$37,803	$27,641	$17,297
Weighted-average shares outstanding									29,485	28,495	27,577
Dilutive effect of employee stock options and restricted shares									725	859	724
Diluted weighted average shares outstanding									30,210	29,354	28,301
Basic income per share									$1.28	$0.97	$0.63
Diluted earnings (loss) per share	$0.31	$0.48	$0.28	$0.18	$0.11	$0.26	$0.28	$0.29	$1.25	$0.94	$0.61

Summary_of_Significant_Account8

Summary of Significant Accounting Policies (Details 5) (Fair Value, Measurements, Recurring [Member], USD $)	Dec. 27, 2014	Dec. 28, 2013
In Thousands, unless otherwise specified
Level 1 [Member]
Asset
Total assets measured at fair value	$109,843	$101,441
Level 1 [Member] | Money Market Funds [Member]
Asset
Total assets measured at fair value	109,843	101,441
Level 2 [Member]
Asset
Total assets measured at fair value	36,166	21,954
Level 2 [Member] | Bonds [Member]
Asset
Total assets measured at fair value	$36,166	$21,954

Summary_of_Significant_Account9

Summary of Significant Accounting Policies (Details Textual) (USD $)	12 Months Ended
Share data in Millions, unless otherwise specified	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012	Dec. 31, 2011
	customer	customer
Revenues from External Customers and Long-Lived Assets [Line Items]
Capitalized Computer Software, Gross	$8,200,000	$8,200,000
Summary of Significant Accounting Policies (Additional Textual) [Abstract]
Number of customers with accounts receivable balance greater than 10% of total receivables	2	2
Percentage of receivables held by two customers	32.00%	37.00%
Minimum percentage help by each customer with an accounts receivable balance greater than 10% of the total accounts receivable balance	10.00%	10.00%
Advertising cost	46,100,000	38,200,000	34,900,000
Potentially diluted shares of common stock	0.2	0.7	0.8
Deferred Tax Assets, Valuation Allowance	$0	$2,090,000	$2,691,000	$0
Government Contracts Concentration Risk [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration Risk, Percentage	4.30%	6.20%	15.10%
Customer Concentration Risk [Member] | Government Contracts Concentration Risk [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration Risk, Percentage	4.30%	6.20%	15.10%
Customer Concentration Risk [Member] | International distributors of home robots products [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration Risk, Percentage	29.80%	33.20%	30.60%

Recovered_Sheet1

Summary of Significant Accounting Policies (Details Texutal - Property Plant And Equipment) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Property Plant And Equipment [Line Items]
Capitalized Computer Software, Gross	$8.20	$8.20
Maximum [Member]
Property Plant And Equipment [Line Items]
Operating and Reporting Period	371 days
Minimum [Member]
Property Plant And Equipment [Line Items]
Operating and Reporting Period	364 days
Software and Software Development Costs [Member]
Property Plant And Equipment [Line Items]
Amortization Expense	$0.80	$0.90	$1

Recovered_Sheet2

Summary of Significant Accounting Policies Cash and cash equivalents (Details) (USD $)	Dec. 27, 2014	Dec. 28, 2013
In Millions, unless otherwise specified
Cash and Cash Equivalents [Abstract]
Cash Equivalents, at Carrying Value	$109.80	$101.40

Recovered_Sheet3

Summary of Significant Accounting Policies Inventory valuation (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 27, 2014		Dec. 28, 2013		Dec. 29, 2012
Valuation and Qualifying Accounts Disclosure [Line Items]
Valuation Allowances and Reserves, Deductions	$2,090		$601		$0
Inventory Valuation Reserve [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Valuation Allowances and Reserves, Deductions	$1,074	[1]	$2,899	[1]	$1,061	[1]
[1]	Deductions related to inventory reserve accounts represent amounts written off against the reserve.

Inventory_Details

Inventory (Details) (USD $)	Dec. 27, 2014	Dec. 28, 2013
In Thousands, unless otherwise specified
Inventory
Inventory, Raw Materials, Net of Reserves	$9,455	$8,520
Work in process	0	0
Finished goods	38,402	37,587
Total	$47,857	$46,107

Property_and_Equipment_Details

Property and Equipment (Details) (USD $)	12 Months Ended
	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Property and Equipment
Property, Plant and Equipment, Gross	$70,438,000	$55,638,000
Less: accumulated depreciation	39,141,000	31,977,000
Property, Plant and Equipment, Net, Total	31,297,000	23,661,000
Depreciation And Amortization [Abstract]
Depreciation	9,200,000	8,100,000	9,900,000
Computer and equipment [Member]
Property and Equipment
Property, Plant and Equipment, Gross	15,173,000	13,715,000
Furniture [Member]
Property and Equipment
Property, Plant and Equipment, Gross	2,297,000	1,845,000
Machinery [Member]
Property and Equipment
Property, Plant and Equipment, Gross	5,307,000	3,705,000
Tooling [Member]
Property and Equipment
Property, Plant and Equipment, Gross	18,614,000	12,228,000
Leasehold improvements [Member]
Property and Equipment
Property, Plant and Equipment, Gross	20,833,000	15,983,000
Software and Software Development Costs [Member]
Property and Equipment
Property, Plant and Equipment, Gross	$8,214,000	$8,162,000

Other_Assets_Details

Other Assets (Details) (USD $)	Dec. 27, 2014	Dec. 28, 2013
In Thousands, unless otherwise specified
Schedule of Cost-method Investments [Line Items]
Other Assets, Noncurrent	$10,751	$10,501

Accrued_Expenses_Details

Accrued Expenses (Details) (USD $)	Dec. 27, 2014	Dec. 28, 2013
In Thousands, unless otherwise specified
Accrued Liabilities, Current [Abstract]
Accrued Bonuses	$8,455	$13,002
Components of accrued expenses
Accrued warranty	7,769	6,497
Accrued direct fulfillment costs	1,346	1,362
Accrued Sales Tax	867	831
Customer Deposits, Current	702	103
Accrued rent	701	726
Accrued sales commissions	531	539
Accrued contractors, current	217	509
Accrued other	6,568	4,313
Accrued expenses, total	18,701	14,880
Accrued Employee Benefits, Current	7,780	6,604
Employee-related Liabilities, Current	$16,235	$19,606

Revolving_Line_of_Credit_Detai

Revolving Line of Credit (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 27, 2014
Revolving Line of Credit (Textual) [Abstract]
Maximum amount available for borrowing under credit facility	$75
Interest on loans under the credit facility	at either (1) LIBOR plus a margin, currently equal to 1.0%, based on the Company's ratio of indebtedness to Adjusted EBITDA (the "Eurodollar Rate"), or (2) the lender's base rate.
Interest rate above the LIBOR Daily Floating Rate or the Prime Rate of Lender under condition one	1.00%
Interest Rate Above the Federal Fund Rate Under Condition Two	0.50%
Interest rate above the LIBOR rate plus under condition two	1.00%
Termination date for all outstanding amount and credit facility	20-Dec-18

Common_Stock_Stock_repurchase_

Common Stock Stock repurchase (Details) (USD $)	12 Months Ended
	Dec. 27, 2014
Stock repurchase [Abstract]
Stock Repurchase Program, Authorized Amount	$50,000,000
Stock Repurchase Program Commencement Date	1-May-14
Stock Repurchase Program Expiration Date	30-Apr-15
Stock Repurchased and Retired During Period, Shares	55,973
Stock Repurchased During Period, Value	$1,678,000

Stock_Options_Plans_and_StockB2

Stock Options Plans and Stock-Based Compensation (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Fair value of each option grant computed on the grant date
Risk-free interest rate, minimum	1.65%	0.90%	0.63%
Risk-free interest rate, maximum	1.69%	1.77%	0.90%
Expected volatility, minimum	52.80%	54.00%	63.00%
Expected volatility, maximum	56.00%	58.00%	64.00%
Minimum [Member]
Fair value of each option grant computed on the grant date
Expected life	3 years 10 months 27 days	4 years 0 months 10 days	4 years 1 month 13 days
Maximum [Member]
Fair value of each option grant computed on the grant date
Expected life	3 years 11 months 15 days	4 years 2 months 15 days	4 years 2 months 4 days
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock Based Compensation Expense Expects to Recognize in Year One	2.9
Stock Based Compensation Expense Expects to Recognize in Year Two	2.2
Stock Based Compensation Expense Expects to Recognize in Year Three	1.1
Stock Based Compensation Expense Expects to Recognize in Year Four	0.4

Stock_Options_Plans_and_StockB3

Stock Options Plans and Stock-Based Compensation (Details 1) (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 27, 2014		Dec. 28, 2013	Dec. 29, 2012
Summary of stock option plan activity
Number of Shares, Beginning Balance	1,770,375		2,503,667	2,561,292
Weighted Average Exercise Price, Beginning Balance	$19.89		$18.27	$17.17
Number of Shares, Granted	233,181		293,325	547,948
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price	$37.10		$24.60	$19.70
Number of Shares, Exercised	-486,252		-840,951	-390,956
Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price	$18.39		$16.21	$11.07
Number of Shares, Canceled	-43,984		-185,666	-214,617
Number of Shares, Ending Balance	1,473,320		1,770,375	2,503,667
Weighted Average Exercise Price, Ending Balance	$22.89		$19.89	$18.27
Weighted Average Remaining Contractual Term, Ending Balance	3 years 10 months 15 days
Aggregate Intrinsic Value, Ending Balance	$18.20	[1]
Number of Shares, Vested and expected to vest	1,419,559
Weighted Average Exercise Price, Vested and expected to vest	$22.61
Weighted Average Remaining Contractual Term, Vested and expected to vest	3 years 9 months 15 days
Aggregate Intrinsic Value, Vested and expected to vest	17.8	[1]
Number of Shares, Exercisable	917,340
Weighted Average Exercise Price, Exercisable	$19.32
Weighted Average Remaining Contractual Term, Exercisable	2 years 9 months 24 days
Aggregate Intrinsic Value, Exercisable	$14.20	[1]
Share based compensation arrangement shares available for grant	4,762,446
Share-based Compensation Arrangements by Share-based Payment Award, Options, Forfeitures in Period, Weighted Average Exercise Price	$27.17		$22.16	$21.91
[1]	The aggregate intrinsic value on the table was calculated based upon the positive difference between the closing market value of the Company’s stock on December 27, 2014 of $34.81 and the exercise price of the underlying option.

Stock_Options_Plans_and_StockB4

Stock Options Plans and Stock-Based Compensation (Details 2) (USD $)	0 Months Ended	12 Months Ended
	Oct. 02, 2012	Dec. 27, 2014
Summary of information about stock options outstanding
Range of Exercise Price, Minimum	$2.55	$3.54
Range of Exercise Price, Maximum	$4.81	$43.35
Number Outstanding		1,473,320
Options Outstanding Weighted Average Remaining Contractual Life		3 years 10 months 15 days
Weighted Average Exercise Price		$22.89
Number Exercisable		917,340
Weighted Average Exercise Price		$19.32
Range of Exercise Prices One [Member]
Summary of information about stock options outstanding
Range of Exercise Price, Minimum		$3.54
Range of Exercise Price, Maximum		$7.76
Number Outstanding		156,380
Options Outstanding Weighted Average Remaining Contractual Life		3 years 8 months 5 days
Weighted Average Exercise Price		$6.08
Number Exercisable		134,520
Weighted Average Exercise Price		$6.29
Range of Exercise Prices Two [Member]
Summary of information about stock options outstanding
Range of Exercise Price, Minimum		$8.10
Range of Exercise Price, Maximum		$14.13
Number Outstanding		100,551
Options Outstanding Weighted Average Remaining Contractual Life		1 year 1 month 5 days
Weighted Average Exercise Price		$13.36
Number Exercisable		100,551
Weighted Average Exercise Price		$13.36
Range of Exercise Prices Three [Member]
Summary of information about stock options outstanding
Range of Exercise Price, Minimum		$14.52
Range of Exercise Price, Maximum		$14.52
Number Outstanding		164,442
Options Outstanding Weighted Average Remaining Contractual Life		2 years 3 months 5 days
Weighted Average Exercise Price		$14.52
Number Exercisable		164,442
Weighted Average Exercise Price		$14.52
Range of Exercise Prices Four [Member]
Summary of information about stock options outstanding
Range of Exercise Price, Minimum		$14.54
Range of Exercise Price, Maximum		$22.20
Number Outstanding		182,584
Options Outstanding Weighted Average Remaining Contractual Life		3 years 7 months 17 days
Weighted Average Exercise Price		$19.17
Number Exercisable		113,901
Weighted Average Exercise Price		$19.54
Range of Exercise Prices Five [Member]
Summary of information about stock options outstanding
Range of Exercise Price, Minimum		$22.86
Range of Exercise Price, Maximum		$22.86
Number Outstanding		194,508
Options Outstanding Weighted Average Remaining Contractual Life		5 years 1 month 3 days
Weighted Average Exercise Price		$22.86
Number Exercisable		79,614
Weighted Average Exercise Price		$22.86
Range of Exercise Prices Six [Member]
Summary of information about stock options outstanding
Range of Exercise Price, Minimum		$24
Range of Exercise Price, Maximum		$25.99
Number Outstanding		199,546
Options Outstanding Weighted Average Remaining Contractual Life		2 years 7 months 28 days
Weighted Average Exercise Price		$24.75
Number Exercisable		153,876
Weighted Average Exercise Price		$24.46
Range of Exercise Prices Seven [Member]
Summary of information about stock options outstanding
Range of Exercise Price, Minimum		$26.59
Range of Exercise Price, Maximum		$33.48
Number Outstanding		264,971
Options Outstanding Weighted Average Remaining Contractual Life		4 years 3 months 17 days
Weighted Average Exercise Price		$31.19
Number Exercisable		156,756
Weighted Average Exercise Price		$31.05
Range of Exercise Prices Eight [Member]
Summary of information about stock options outstanding
Range of Exercise Price, Minimum		$33.72
Range of Exercise Price, Maximum		$35.96
Number Outstanding		121,445
Options Outstanding Weighted Average Remaining Contractual Life		6 years 1 month 5 days
Weighted Average Exercise Price		$35.01
Number Exercisable		13,680
Weighted Average Exercise Price		$34.34
Range of Exercise Prices Nine [Member]
Summary of information about stock options outstanding
Range of Exercise Price, Minimum		$37.08
Range of Exercise Price, Maximum		$37.08
Number Outstanding		34,500
Options Outstanding Weighted Average Remaining Contractual Life		6 years 10 months 3 days
Weighted Average Exercise Price		$37.08
Number Exercisable		0
Weighted Average Exercise Price		$0
Range of Exercise Prices Ten [Member]
Summary of information about stock options outstanding
Range of Exercise Price, Minimum		$43.35
Range of Exercise Price, Maximum		$43.35
Number Outstanding		54,393
Options Outstanding Weighted Average Remaining Contractual Life		6 years 2 months 10 days
Weighted Average Exercise Price		$43.35
Number Exercisable		0
Weighted Average Exercise Price		$0

Stock_Options_Plans_and_Stock_

Stock Options Plans and Stock Based Compensation (Details 4) (Restricted Stock Units [Member], USD $)	12 Months Ended
	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Restricted Stock Units [Member]
Activities relating to restricted stock units
Number of Shares Underlying Restricted Stock, Beginning Balance	927,654	941,030	607,505
Weighted Average Grant Date Fair Value, Beginning Balance	$25.50	$24.09	$22.77
Number of Shares Underlying Restricted Stock, Granted	372,159	521,056	685,529
Weighted Average Grant Date Fair Value, Granted	$38.25	$25.87	$24.62
Number of Shares Underlying Restricted Stock, Vested	-318,367	-348,141	-204,053
Weighted Average Grant Date Fair Value, Vested	$25.38	$22.57	$21.24
Number of Shares Underlying Restricted Stock, Forfeited	-71,591	-186,291	-147,951
Number of Shares Underlying Restricted Stock, Ending Balance	909,855	927,654	941,030
Weighted Average Grant Date Fair Value, Ending Balance	$30.53	$25.50	$24.09
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value	$28.42	$24.91	$25.07

Stock_Options_Plans_and_Stock_1

Stock Options Plans and Stock Based Compensation (Details Textual) (USD $)	0 Months Ended		12 Months Ended
In Millions, except Share data, unless otherwise specified	Oct. 02, 2012	Oct. 10, 2005	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Effective date for stock options plan		10-Oct-05
Increase in number of shares reserved and available for issuance in different forms				4.50%
Share based compensation arrangement shares available for grant			4,762,446
Unamortized fair value stock options granted			$6.60
Weighted average fair value of each stock option granted			$15.87	$11.17	$13.23
Closing market value of stock			$34.81
Total intrinsic value of stock options exercised			10.5	12.1	6.2
Weighted average exercise price, exercisable			$19.32
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Lower Range Limit	$2.55		$3.54
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Upper Range Limit	$4.81		$43.35
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation expense for stock options and restricted stock units granted subsequent to initial S-1 filing			9.7
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Share-based Awards Other than Options			20.1	17.5	17.9
Stock-based compensation expense Expects to recognize in year one related to restricted stock units			8.3
Stock-based compensation expense Expects to recognize in year two related to restricted stock units			6.4
Stock-based compensation expense Expects to recognize in year three related to restricted stock units			4
Stock-based compensation expense Expects to recognize in year four related to restricted stock units			1.4
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation expense for stock options and restricted stock units granted subsequent to initial S-1 filing			4.1
Weighted average remaining recognition period			2 years 5 months 20 days
Stock-based compensation expense Expects to recognize in year one related to restricted stock units			2.9
Stock-based compensation expense Expects to recognize in year two related to restricted stock units			2.2
Stock-based compensation expense Expects to recognize in year three related to restricted stock units			1.1
Stock-based compensation expense Expects to recognize in year four related to restricted stock units			$0.40
Employee Stock Option [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period for options			5 years
Minimum expiration period for options			10 years
Employee Stock Option [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period for options			1 year
Minimum expiration period for options			7 years
Two Thousand Five Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for issuance in different forms		1,583,682
Share based compensation arrangement shares available for grant			4,762,446
Employee Termination [Member] | Employee Stock Option [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Minimum expiration period for options			90 days
Employee Termination [Member] | Employee Stock Option [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Minimum expiration period for options			60 days
Evolution Robotics, Inc. (ER) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross	114,248

Income_Taxes_Details

Income Taxes (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Current
Federal	$15,128	$6,363	$12,540
State	129	1,124	473
Foreign	91	41	-8
Total current tax provision	15,348	7,528	13,005
Deferred
Federal	1,268	-2,026	-4,003
State	-2,010	-728	-692
Deferred Income Tax Expense (Benefit)	-742	-2,754	-4,695
Total income tax provision	$14,606	$4,774	$8,310

Income_Taxes_Details_1

Income Taxes (Details 1) (USD $)	Dec. 27, 2014	Dec. 28, 2013
In Thousands, unless otherwise specified
Current deferred tax assets
Deferred Tax Assets, Reserves and Accruals, current	$18,568	$18,554
Stock-based compensation	767	556
Net operating loss carryforwards	2,470	2,470
Foreign tax credits	148	105
Valuation allowance	0	-1,100
Total current deferred tax assets	21,953	20,585
Non-current deferred tax assets
Reserves and accruals	586	715
Tax credits	5,927	5,737
Property and equipment	178	1,308
Stock-based compensation	5,011	4,957
Net operating loss carryforwards	3,879	6,587
Valuation allowance	0	-990
Total non-current deferred tax assets	15,581	18,314
Current deferred tax liabilities
Deferred Tax Liabilities, Prepaid Expenses	448	441
Total current deferred tax liabilities	448	441
Non-current deferred tax liabilities
Intangible assets	7,172	8,219
Total non-current deferred tax liabilities	7,172	8,219
Total net deferred tax assets	$29,914	$30,239

Income_Taxes_Details_2

Income Taxes (Details 2) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	$2,090	$2,691	$0
Valuation Allowances and Reserves, Charged to Cost and Expense	1,045	1,571	5,101
Valuation Allowances and Reserves, Charged to Other Accounts	0		2,691
Valuation Allowances and Reserves, Deductions	2,090	601	0
Balance at End of Period	$0	$2,090	$2,691

Income_Taxes_Details_3

Income Taxes (Details 3) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Reconciliation of the expected tax (benefit) expense
Expected federal income tax	$18,344	$11,345	$8,962
Effective Income Tax Rate Reconciliation, Other Adjustments, Amount	691	405	338
State taxes (net of federal benefit)	1,058	867	497
Federal and state credits	-1,487	-3,909	-418
Valuation Allowances and Reserves, Adjustments	-2,090	0	0
Effective Income Tax Rate Reconciliation, Deduction, Qualified Production Activity, Amount	-1,562	-1,168	-1,100
Other	-172	-70	31
Effective Income Tax Rate Reconciliation, Tax Settlement, Amount	-176	-2,696	0
Total expected tax (benefits) expenses	$14,606	$4,774	$8,310

Income_Taxes_Details_4

Income Taxes (Details 4) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 27, 2014
Company's adjustments to its uncertain tax position
Balance at beginning of period	$2,618
Increase for tax positions related to the current year	252
Increase for tax positions related to prior years	-108
Decreases for settlements with applicable taxing authorities	-271
Balance at end of period	$2,491

Income_Taxes_Details_Textual

Income Taxes (Details Textual) (USD $)	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012	Dec. 31, 2011
Income Taxes (Textual) [Abstract]
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued	$0	$0	$0
Deferred tax liability not established for undistributed earnings of non-US subsidiaries	600,000
Net deferred tax assets	29,914,000	30,239,000
Operating Loss Carryforwards	34,500,000	45,000,000
Decrease in unrecognised tax benefits due to settlement of federal tax audit	200,000
Unrecognized Tax Benefit to the income tax provision if it become recognizable	1,900,000
Unrecognized Tax Benefit, related to stock-based compensation, state NOLs	700,000	0
Unrecognized Tax Benefits	500,000	500,000
Deferred Tax Assets, Valuation Allowance	0	2,090,000	2,691,000	0
Evolution Robotics, Inc. (ER) [Member]
Income Taxes (Textual) [Abstract]
Operating Loss Carryforwards	34,500,000
Research Tax Credit Carryforward [Member]
Income Taxes (Textual) [Abstract]
Tax Credit Carryforward, Amount	9,100,000	8,900,000
Research Tax Credit Carryforward [Member] | Evolution Robotics, Inc. (ER) [Member]
Income Taxes (Textual) [Abstract]
Tax Credit Carryforward, Amount	2,200,000
Investment Tax Credit Carryforward [Member]
Income Taxes (Textual) [Abstract]
Tax Credit Carryforward, Amount	$700,000	$600,000

Commitments_and_Contingencies_1

Commitments and Contingencies (Details) (USD $)	Dec. 27, 2014
In Thousands, unless otherwise specified
Summary of future minimum rental payments under operating leases
2013	$3,460
2014	2,670
2015	2,383
2016	2,383
2017	2,383
Thereafter	794
Total minimum lease payments	$14,073

Commitments_and_Contingencies_2

Commitments and Contingencies (Details 1) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 27, 2014		Dec. 28, 2013		Dec. 29, 2012
Activity related to the warranty accrual
Balance at beginning of period	$6,497		$6,057		$10,306
Provision	6,410	[1]	1,744	[1]	1,682	[1]
Warranty usage	-5,138	[2]	-1,304	[2]	-2,567	[2]
Balance at end of period	$7,769		$6,497		$6,057
[1]	During 2012, the Company recorded favorable adjustments relating to reductions in its international warranty accrual for our home robots business related to our sustained improvements in product quality, resulting in a net credit for its 2012 warranty provision.
[2]	Warranty usage includes costs incurred for warranty obligations.

Commitments_and_Contingencies_3

Commitments and Contingencies (Details Textual) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Commitments and Contingencies (Textual) [Abstract]
Rental expense under operating leases	$4.80	$5.30	$4.40
Contractual Obligation	$78.10

Employee_Benefits_Details

Employee Benefits (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Defined Benefit Plan Disclosure [Line Items]
Defined Contribution Plan, Cost Recognized	$1.70	$1.50	$1.70
Employee Benefits (Textual) [Abstract]
Employer contribution to retirement plan	The employer contribution represents a matching contribution at a rate of 50% of each employee’s first six percent contribution. Accordingly, each employee participating during Plan-Year 2014, is entitled up to a maximum of three percent of his or her eligible annual payroll.
Rate of contribution made by the employer	50.00%
Employee rate at which matching contribution made by employer	6.00%
Maximum rate entitled to each employee under all the plans	3.00%

Acquisition_of_Evolution_Robot2

Acquisition of Evolution Robotics, Inc. Acquisition of Evolution Robotics, Inc. (Details 1) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 29, 2012
Business Acquisition, Pro Forma Information [Abstract]
Revenue	$445,469
Net Income	$8,723

Acquisition_of_Evolution_Robot3

Acquisition of Evolution Robotics, Inc. Acquisition of Evolution Robotics, Inc. (Details Textual) (Evolution Robotics, Inc. (ER) [Member], USD $)	0 Months Ended
In Millions, unless otherwise specified	Oct. 02, 2012
Evolution Robotics, Inc. (ER) [Member]
Business Acquisition [Line Items]
Ownership percentage acquired	100.00%
Total acquisition date fair value of the consideration transferred	$74.80
Amount of purchase price placed into an escrow account to settle certain claims for indemnification for breaches	$8.88

Goodwill_and_other_intangible_2

Goodwill and other intangible assets (Details) (USD $)	Dec. 27, 2014	Dec. 28, 2013
In Thousands, unless otherwise specified
Finite-Lived Intangible Assets, Net [Abstract]
Intangible assets cost	$31,500	$31,500
Intangible assets accumulated amortization	10,566	7,044
Finite-lived intangible assets, accumulated impairment loss	1,788	1,788
Total	19,146	22,668
Completed technology [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Intangible assets cost	30,600	30,600
Intangible assets accumulated amortization	9,691	6,202
Finite-lived intangible assets, accumulated impairment loss	1,788	1,788
Total	19,121	22,610
Research contracts [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Intangible assets cost	100	100
Intangible assets accumulated amortization	100	100
Finite-lived intangible assets, accumulated impairment loss	0	0
Total	0	0
Tradename [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Intangible assets cost	800	800
Intangible assets accumulated amortization	775	742
Finite-lived intangible assets, accumulated impairment loss	0	0
Total	$25	$58

Goodwill_and_other_intangible_3

Goodwill and other intangible assets (Details 1) (USD $)	12 Months Ended
	Dec. 28, 2013	Dec. 27, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Impairment of Intangible Assets, Finite-lived	$1,800,000
Finite-Lived Intangible Assets, Future Amortization Expense [Abstract]
2013		3,482,000
2014		3,457,000
2015		3,457,000
2016		3,457,000
2017		2,818,000
Total		$16,671,000

Goodwill_and_other_intangible_4

Goodwill and other intangible assets (Details Textual) (USD $)	12 Months Ended
	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Business Acquisition [Line Items]
Impairment of Intangible Assets, Finite-lived		$1,800,000
Goodwill, Impairment Loss		200,000
Goodwill	48,751,000	48,751,000
Amortization expense related to acquisition of intangible assets	3,500,000	3,800,000	1,200,000
Goodwill, Impaired, Accumulated Impairment Loss	200,000
Evolution Robotics, Inc. (ER) [Member]
Business Acquisition [Line Items]
Goodwill	41,000,000
Nekton Research LLC [Member]
Business Acquisition [Line Items]
Goodwill	7,709,000
Goodwill, Gross	7,909,000
Minimum [Member]
Business Acquisition [Line Items]
Estimated useful lives for intangible assets	2 years
Maximum [Member]
Business Acquisition [Line Items]
Estimated useful lives for intangible assets	10 years
Defense & Security Robots [Member] | Nekton Research LLC [Member]
Business Acquisition [Line Items]
Goodwill, Gross	7,709,000
Research Reporting Unit [Member] | Nekton Research LLC [Member]
Business Acquisition [Line Items]
Goodwill, Gross	$200,000

Restructuring_Charges_Restruct1

Restructuring Charges Restructuring Charges (Details) (USD $)	12 Months Ended
	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Restructuring Reserve [Roll Forward]
Balance at beginning of period	$675,000	$197,000	$0
Charges	0	3,296,000	3,679,000
Utilization	-675,000	-2,818,000	-3,482,000
Balance at end of period	0	675,000	197,000
Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges incurred		3,300,000	3,700,000
Restructuring Reserve [Roll Forward]
Charges		$1,800,000

Industry_Segment_Geographic_In2

Industry Segment Geographic Information and Significant Customers (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 27, 2014	Sep. 27, 2014	Jun. 28, 2014	Mar. 29, 2014	Dec. 28, 2013	Sep. 28, 2013	Jun. 29, 2013	Mar. 30, 2013	Dec. 27, 2014		Dec. 28, 2013		Dec. 29, 2012
Revenue:
Total revenue	$159,342	$143,497	$139,803	$114,204	$126,343	$124,501	$130,362	$106,195	$556,846		$487,401		$436,244
Cost of revenue:
Total cost of revenue									298,791		266,247		241,896
Gross margin:
Gross margin	76,335	67,889	62,121	51,710	58,930	54,061	61,605	46,558	258,055		221,154		194,348
Research and development									69,408	[1]	63,649	[1]	57,066	[1]
Selling and marketing									86,091	[1]	71,529	[1]	66,412	[1]
General and administrative									49,439	[1]	53,358	[1]	45,698	[1]
Other income (expense), net									-708		-203		435
Income before income taxes									52,409		32,415		25,607
Home Robots [Member]
Revenue:
Total revenue									507,414		427,853		356,805
Cost of revenue:
Total cost of revenue									251,095		217,011		174,756
Gross margin:
Gross margin									256,319		210,842		182,049
Defense & Security Robots [Member]
Revenue:
Total revenue									45,502		50,003		70,948
Cost of revenue:
Total cost of revenue									24,409		24,975		40,468
Gross margin:
Gross margin									21,093		25,028		30,480
Other Segments [Member]
Revenue:
Total revenue									3,930		9,545		8,491
Cost of revenue:
Total cost of revenue									23,287		24,261		26,672
Gross margin:
Gross margin									($19,357)		($14,716)		($18,181)
[1]	Stock-based compensation recorded in fiscal 2014, 2013 and 2012 breaks down by expense classification as follows: Fiscal Year Ended December 27, 2014 December 28, 2013 December 29, 2012 (In thousands)Cost of revenue$865 $700 $889Research and development3,359 2,700 1,904Selling and marketing1,296 1,246 808General and administrative8,258 8,763 7,382

Industry_Segment_Geographic_In3

Industry Segment, Geographic Information and Significant Customers (Details Textual) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Industry Segment Geographic Information and Significant Customers (Textual) [Abstract]
Number of reportable segments	2
Goodwill	48,751	48,751
Intangible assets, net	19,146	22,668
Number of customer generating major revenues	15
Evolution Robotics, Inc. (ER) [Member]
Industry Segment Geographic Information and Significant Customers (Textual) [Abstract]
Goodwill	41,000
Government Contracts Concentration Risk [Member]
Industry Segment Geographic Information and Significant Customers (Textual) [Abstract]
Concentration Risk, Percentage	4.30%	6.20%	15.10%
Foreign [Member] | Customers [member]
Industry Segment Geographic Information and Significant Customers (Textual) [Abstract]
Concentration Risk, Percentage	60.90%	59.50%	57.30%
Home Robots [Member] | Evolution Robotics, Inc. (ER) [Member]
Industry Segment Geographic Information and Significant Customers (Textual) [Abstract]
Goodwill	41,000
Intangible assets, net	19,100
Home Robots [Member] | Customers [member]
Industry Segment Geographic Information and Significant Customers (Textual) [Abstract]
Concentration Risk, Percentage	75.70%	75.30%	75.40%
Home Robots [Member] | Major Distributor [Domain]
Industry Segment Geographic Information and Significant Customers (Textual) [Abstract]
Concentration Risk, Percentage	29.80%	33.20%
Defense & Security Robots [Member] | Business Acquisition Nekton [Member]
Industry Segment Geographic Information and Significant Customers (Textual) [Abstract]
Goodwill	7,700

Quarterly_Information_Unaudite2

Quarterly Information (Unaudited) (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 27, 2014	Sep. 27, 2014	Jun. 28, 2014	Mar. 29, 2014	Dec. 28, 2013	Sep. 28, 2013	Jun. 29, 2013	Mar. 30, 2013	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Details of Quarterly Information (Unaudited)
Revenue	$159,342	$143,497	$139,803	$114,204	$126,343	$124,501	$130,362	$106,195	$556,846	$487,401	$436,244
Gross margin	76,335	67,889	62,121	51,710	58,930	54,061	61,605	46,558	258,055	221,154	194,348
Net income (loss)	$9,386	$14,607	$8,530	$5,280	$3,188	$7,804	$8,294	$8,355	$37,803	$27,641	$17,297
Diluted earnings (loss) per share	$0.31	$0.48	$0.28	$0.18	$0.11	$0.26	$0.28	$0.29	$1.25	$0.94	$0.61