Document and Entity Information - USD ($) $ in Billions	12 Months Ended
Document and Entity Information - USD ($) $ in Billions	Dec. 28, 2019	Jan. 31, 2020	Dec. 29, 2018
Document and Entity Information [Abstract]
Title of 12(b) Security	Common Stock, $0.01 par value
Trading Symbol	IRBT
Security Exchange Name	NASDAQ
Entity Address, State or Province	MA
Entity Incorporation, State or Country Code	DE
Document Transition Report	false
Document Annual Report	true
Common Stock, Shares, Outstanding	28,352,390		27,788,272
Entity Registrant Name	iROBOT CORPORATION
Entity Central Index Key	0001159167
Document Type	10-K
Entity File Number	001-36414
Document Period End Date	Dec. 28, 2019
Amendment Flag	false
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--12-28
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float	$ 2.5
Entity Common Stock, Shares Outstanding		28,352,390
Entity Tax Identification Number	77-0259335
Entity Address, Address Line One	8 Crosby Drive
Entity Address, City or Town	Bedford
Entity Address, Postal Zip Code	01730
City Area Code	781
Local Phone Number	430-3000
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 28, 2019	Dec. 29, 2018
Current assets:
Cash and cash equivalents	$ 239,392	$ 130,373
Short term investments	17,032	31,605
Accounts receivable, net	146,161	162,166
Inventory	157,347	164,633
Other current assets	34,285	25,660
Total current assets	594,217	514,437
Property and equipment, net	75,988	57,026
Operating lease right-of-use assets	47,478	0
Deferred tax assets	41,791	36,979
Goodwill	118,732	118,896
Intangible assets, net	12,352	24,273
Other assets	30,195	15,350
Total assets	920,753	766,961
Current liabilities:
Accounts payable	116,185	136,742
Accrued expenses	81,768	71,259
Deferred revenue and customer advances	4,549	5,756
Total current liabilities	202,502	213,757
Operating lease liabilities	54,928	0
Deferred tax liabilities	912	4,005
Other long-term liabilities	10,342	13,877
Total long-term liabilities	66,182	17,882
Total liabilities	268,684	231,639
Commitments and contingencies (Note 15)
Preferred stock, 5,000 shares authorized and none outstanding	0	0
Common stock, $0.01 par value; 100,000 shares authorized; 28,352 and 27,788 shares issued and outstanding, respectively	284	278
Additional paid-in capital	196,455	172,771
Retained earnings	452,321	367,021
Accumulated other comprehensive income (loss)	3,009	(4,748)
Total stockholders’ equity	652,069	535,322
Total liabilities and stockholders’ equity	$ 920,753	$ 766,961

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 28, 2019	Dec. 29, 2018
Statement of Financial Position [Abstract]
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares outstanding	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	28,352,390	27,788,272
Common stock, shares outstanding	28,352,390	27,788,272

Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Revenue	$ 1,214,010	$ 1,092,584	$ 883,911
Cost of product revenue	658,362	518,612	438,114
Amortization of acquired intangible assets	11,721	18,544	12,638
Total cost of revenue	670,083	537,156	450,752
Gross profit	543,927	555,428	433,159
Operating expenses:
Research and development	141,607	140,629	113,149
Selling and marketing	231,548	210,411	162,110
General and administrative	83,103	97,501	84,771
Amortization of acquired intangible assets	1,051	1,065	439
Total operating expenses	457,309	449,606	360,469
Operating income	86,618	105,822	72,690
Other income, net	12,215	2,800	3,676
Income before income taxes	98,833	108,622	76,366
Income tax expense	13,533	20,630	25,402
Net income	$ 85,300	$ 87,992	$ 50,964
Net income per share:
Basic	$ 3.04	$ 3.18	$ 1.85
Diluted	$ 2.97	$ 3.07	$ 1.77
Number of shares used in per share calculations:
Basic	28,097	27,692	27,611
Diluted	28,735	28,640	28,753

Consolidated Statement of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 85,300	$ 87,992	$ 50,964
Other comprehensive income (loss):
Net foreign currency translation adjustments	(3,435)	(5,896)	1,994
Net unrealized gains (losses) on cash flow hedges, net of tax	12,363	(327)	490
Net gains on cash flow hedge reclassified into earnings, net of tax	(1,418)	(499)	(295)
Net unrealized gains (losses) on marketable securities, net of tax	247	(18)	(46)
Total comprehensive income	$ 93,057	$ 81,252	$ 53,107

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References + Details

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings (Accumulated Deficit)	Accumulated Other Comprehensive Income (Loss)
Beginning balance, shares at Dec. 31, 2016		27,238,000
Beginning balance at Dec. 31, 2016	$ 388,956	$ 272	$ 161,885	$ 226,950	$ (151)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under employee stock plans	367,267	367,000
Issuance of common stock under employee stock plans	$ 10,573	$ 4	10,569
Conversion of deferred compensation	15,000
Vesting of restricted stock units		376,000
Vesting of restricted stock units	$ 0	$ 4	(4)
Stock-based compensation	19,751		19,751
Stock withheld to cover tax withholdings requirements upon restricted stock vesting		(51,000)
Stock withheld to cover tax withholdings requirements upon restricted stock vesting	(2,983)	$ 1	(2,982)
Other comprehensive income	2,143				2,143
Directors' deferred compensation	65		65
Net income	50,964			50,964
Ending balance, shares at Dec. 30, 2017		27,945,000
Ending balance at Dec. 30, 2017	470,327	$ 279	190,067	277,989	1,992
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of a change in accounting principle related to adoption of ASC 606	$ 858		783	75
Issuance of common stock under employee stock plans	239,830	285,000
Issuance of common stock under employee stock plans	$ 10,366	$ 3	10,363
Vesting of restricted stock units		408,000
Vesting of restricted stock units	0	$ 4	(4)
Stock-based compensation	25,804		25,804
Stock withheld to cover tax withholdings requirements upon restricted stock vesting		(51,000)
Stock withheld to cover tax withholdings requirements upon restricted stock vesting	(3,532)	$ 0	(3,532)
Other comprehensive income	(6,740)				(6,740)
Directors' deferred compensation	$ 65		65
Stock repurchases	(798,794)
Stock repurchases	$ (50,000)	$ (8)	(49,992)
Net income	$ 87,992			87,992
Ending balance, shares at Dec. 29, 2018	27,788,272	27,788,000
Ending balance at Dec. 29, 2018	$ 535,322	$ 278	172,771	367,021	(4,748)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of a change in accounting principle related to adoption of ASC 606	$ 1,040			1,040
Issuance of common stock under employee stock plans	127,024	187,000
Issuance of common stock under employee stock plans	$ 7,147	$ 2	7,145
Vesting of restricted stock units		436,000
Vesting of restricted stock units	0	$ 5	(5)
Stock-based compensation	23,744		23,744
Stock withheld to cover tax withholdings requirements upon restricted stock vesting		59,000
Stock withheld to cover tax withholdings requirements upon restricted stock vesting	7,277	$ 1	7,276
Other comprehensive income	7,757				7,757
Directors' deferred compensation	76		76
Net income	$ 85,300			85,300
Ending balance, shares at Dec. 28, 2019	28,352,390	28,352,000
Ending balance at Dec. 28, 2019	$ 652,069	$ 284	$ 196,455	$ 452,321	$ 3,009

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Cash flows from operating activities:
Net income	$ 85,300	$ 87,992	$ 50,964
Adjustments to reconcile net income to net cash provided by operating activities, net of the effects of acquisitions:
Depreciation and amortization	37,159	36,574	25,499
Gain on sale of equity investment	(8,439)	0	0
Gain on business acquisition	0	0	(2,243)
Stock-based compensation	23,744	25,804	19,751
Deferred income taxes, net	(11,118)	(10,848)	(999)
Other	7,267	1,837	864
Changes in operating assets and liabilities — (use) source
Accounts receivable	13,064	(23,920)	(53,251)
Inventory	7,307	(58,546)	(1,470)
Other assets	(3,310)	(8,533)	(10,562)
Accounts payable	(20,536)	22,470	17,457
Accrued expenses and other liabilities	(386)	(1,145)	30,305
Net cash provided by operating activities	130,052	71,685	76,315
Cash flows from investing activities:
Additions of property and equipment	(35,337)	(32,422)	(23,371)
Change in other assets	(5,436)	(2,363)	(1,542)
Proceeds from sale of equity investments	9,787	856	1,267
Cash paid for business acquisitions, net of cash acquired	(2,817)	0	(148,765)
Purchases of investments	0	(6,438)	(10,578)
Sales and maturities of investments	12,880	14,000	13,066
Net cash used in investing activities	(20,923)	(26,367)	(169,923)
Cash flows from financing activities:
Proceeds from employee stock plans	7,147	10,366	10,573
Income tax withholding payment associated with restricted stock vesting	(7,277)	(3,532)	(2,983)
Stock repurchases	0	(50,000)	0
Net cash (used in) provided by financing activities	(130)	(43,166)	7,590
Effect of exchange rate changes on cash and cash equivalents	20	(414)	130
Net increase (decrease) in cash and cash equivalents	109,019	1,738	(85,888)
Cash and cash equivalents, at beginning of period	130,373	128,635	214,523
Cash and cash equivalents, at end of period	239,392	130,373	128,635
Supplemental disclosure of cash flow information
Cash paid for income taxes	$ 22,582	$ 39,517	$ 25,879

Summary of Significant Accounting Policies

12 Months Ended

Dec. 28, 2019

Accounting Policies [Abstract]

Summary of Significant Accounting Policies



2.	Summary of Significant Accounting Policies

Basis of Presentation and Foreign Currency Translation

The accompanying consolidated financial statements include those of iRobot and its subsidiaries, after elimination of all intercompany balances and transactions. iRobot has prepared the accompanying consolidated financial statements in conformity with accounting principles generally accepted in the United States of America ("GAAP"). In addition, certain prior year amounts have been reclassified to conform to the current year presentation.

For the Company's subsidiaries that transact in a functional currency other than the U.S. dollar, assets and liabilities are translated into U.S. dollars at period-end foreign exchange rates. Revenues and expenses are translated into U.S. dollars at the average foreign exchange rates for the period. Translation adjustments are excluded from the determination of net income and are recorded in accumulated other comprehensive income (loss), a separate component of stockholders' equity.

The Company operates and reports using a 52-53 week fiscal year ending on the Saturday closest to December 31. Accordingly, the Company’s fiscal quarters end on the Saturday that falls closest to the last day of the third month of each quarter.

Use of Estimates

The preparation of these financial statements in conformity with GAAP requires the Company to make estimates and assumptions that affect the reported amounts of assets and liabilities and revenue and expenses. These estimates and judgments, include but are not limited to, revenue recognition, including performance obligations, variable consideration and other obligations such as product returns and incentives; warranty costs; valuation of goodwill and acquired intangible assets; valuation of financial instruments; accounting for business combinations; evaluating loss contingencies; accounting for stock-based compensation including performance-based assessments; and accounting for income taxes and related valuation allowances. The Company bases these estimates and judgments on historical experience, market participant fair value considerations, projected future cash flows and various other factors that the Company believes are reasonable under the circumstances. Actual results may differ from the Company’s estimates.

Business Combinations

The Company accounts for transactions that represent business combinations under the acquisition method of accounting. The Company allocates the total consideration paid for each acquisition to the assets it acquires and liabilities it assumes based on their fair values as of the date of acquisition, including identifiable intangible assets. The Company bases the fair value of identifiable intangible assets acquired in a business combination on valuations that use information and assumptions determined by management and which consider management’s best estimates of inputs and assumptions that a market participant would use. While the Company uses its best estimates and assumptions as part of the purchase price allocation process to accurately value assets acquired and liabilities assumed at the business combination date, its estimates and assumptions are inherently uncertain and subject to refinement. As a result, during the measurement period, which is generally one year from the acquisition date, any adjustment to the assets acquired and liabilities assumed is recorded against goodwill in the period in which the amount is determined. Any adjustment identified subsequent to the measurement period is included in operating results in the period in which the amount is determined.

Cash and Cash Equivalents

The Company considers all highly liquid investments with maturity of three months or less at the time of purchase to be cash and cash equivalents. The Company invests its excess cash primarily in money market funds or demand deposit accounts of major financial institutions. Accordingly, its cash and cash equivalents are subject to minimal credit and market risk. At December 28, 2019 and December 29, 2018, cash and cash equivalents totaled $239.4 million and $130.4 million, respectively. These cash and 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. Investments consisted of the following (in thousands):



	December 28, 2019				December 29, 2018
	Cost		Fair Market Value		Cost		Fair Market Value
Corporate and government bonds	$	17,016	$	17,032	$	30,035	$	29,605
Convertible note	—		—		2,000		2,000
Total short term investments	$	17,016	$	17,032	$	32,035	$	31,605

As of December 28, 2019, the Company’s investments had maturity dates ranging from February 2020 to March 2021. The Company invests primarily in investment grade securities and limits the amount of investment in any single issuer.

Accounts receivable allowances

Allowance for product returns: The Company records an allowance for product returns based on specific terms and conditions included in the customer agreements or based on historical experience and the Company's expectation of future returns.

Allowance for other credits and incentives: The Company records an allowance related to customer incentives such as discounts, promotions, price protection and other support programs. The allowance is based on specific terms and conditions included in customer agreements, specific programs and historical experience.

Allowance for doubtful accounts: The Company records an allowance for doubtful accounts for the estimated amount of accounts receivable that may not be collected based on an assessment of the potential risk of loss associated with delinquent accounts. The allowance including the activity within the allowance was immaterial for fiscal years 2019, 2018 and 2017. The balance at December 28, 2019 was $1.0 million.

Activity related to accounts receivable allowances was as follows (in thousands):



	Fiscal Year Ended
	December 28, 2019			December 29, 2018			December 30, 2017
Allowance for product returns
Balance at beginning of period	$	53,920		$	42,693		$	27,673
Acquired balance	—			—			6,088
Provision	71,575			68,476			54,981
Deduction	(68,217		)	(56,164		)	(43,831		)
Other adjustments	(2,087		)	(1,085		)	(2,218		)
Balance at end of period	$	55,191		$	53,920		$	42,693

Allowance for other credits and incentives
Balance at beginning of period	$	97,737		$	61,359		$	23,658
Acquired balance	—			—			11,932
Adjustment related to adoption of ASC 606	—			1,192			—
Provision	287,891			198,371			110,605
Deduction	(247,775		)	(161,672		)	(81,269		)
Other adjustments	(3,807		)	(1,513		)	(3,567		)
Balance at end of period	$	134,046		$	97,737		$	61,359

Inventory

Inventory is stated at the lower of cost or net realizable value with cost being determined using the first-in, first-out method. The Company maintains a reserve for inventory items to provide for an estimated amount of excess or obsolete inventory.

Warranty

The Company typically provides a one-year or two-year warranty against defects in materials and workmanship and will either repair the goods, provide replacement products or refund amounts to the customer for defective product. The Company records estimated warranty costs based on historical experience, at the time revenue is recognized. Actual results could differ from these estimates, which could cause increases or decreases to the warranty reserves in future periods.

Property and Equipment

Property and equipment are recorded at cost and consist primarily of computer equipment, leasehold improvements, business applications software, tooling and machinery. Depreciation is computed using the straight-line method over the estimated useful lives as follows:



	Estimated Useful Life
Computer and equipment	2-5 years
Furniture and fixtures	5
Machinery and tooling	2-5
Business applications software	3-7
Leasehold improvements	Lesser of economic benefit period or term of lease

Expenditures for additions and betterments of property 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 recognized.

Goodwill and Other Long-Lived Assets

Goodwill represents the excess of the purchase price in a business combination over the fair value of the net tangible and intangible assets acquired. Goodwill is not amortized but rather is assessed for impairment at the reporting unit level annually during its fourth quarter of each fiscal year or more frequently if the Company believes indicators of impairment exist. Goodwill impairment, if any, is determined by comparing the reporting unit's fair value to its carrying value. An impairment loss is recognized in an amount equal to the excess of the reporting unit's carrying value over its fair value, up to the amount of goodwill allocated to the reporting unit.

Other long-lived assets consist principally of completed technology, tradename, customer relationships, reacquired distribution rights and non-competition agreements. Reacquired distribution rights are amortized on an accelerated basis while all other intangible assets are amortized over their respective estimated useful lives on a straight-line basis, consistent with the pattern in which the economic benefits are being utilized.

The Company periodically evaluates the recoverability of other long-lived 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.

The impairment assessment of goodwill and other long-lived assets involves significant estimates and assumptions, which may be unpredictable and inherently uncertain. These estimates and assumptions include identification of reporting units and asset groups, long-term growth rates, profitability, estimated useful lives, comparable market multiples, and discount rates. Any changes in these assumptions could impact the result of the impairment assessment. There was no impairment of goodwill or other long-lived assets during fiscal 2019, 2018 and 2017.

Other Assets

The Company holds non-marketable equity securities as part of its strategic investments portfolio. The Company classifies the majority of these securities as equity securities without readily determinable fair values and measures these investments at cost, less any impairment, adjusted for observable price changes. These investments are valued using significant unobservable inputs or data in an inactive market and the valuation requires the Company's judgment due to the absence of market prices and inherent lack of liquidity. The estimated fair value is based on quantitative and qualitative factors including, but not limited to, subsequent financing activities by the investee and projected discounted cash flows. At December 28, 2019 and December 29, 2018, other assets consisted primarily of equity securities without readily determinable fair values and an equity method investment totaling $21.0 million and $15.1 million, respectively. On October 17, 2019, the Company disposed of one of its non-marketable equity securities, resulting in a gain of $8.4 million which was recorded in other income, net. In January 2020, Teladoc Health, Inc. announced that it had entered into a definitive agreement to acquire InTouch Health, one of the Company's strategic investees, with an expected closing date of no later than June 30, 2020. The Company expects to record a gain in other income, net at closing.

Financial Instruments and Hedging Activities

The Company utilizes derivative instruments to hedge specific financial risks including foreign exchange risk. The Company does not engage in speculative hedging activity. In order to account for a derivative instrument as a hedge, specific criteria must be met, including: (i) ensuring at the inception of the hedge that formal documentation exists for both the hedging relationship and the entity’s risk management objective and strategy for undertaking the hedge and (ii) at the inception of the hedge and on an ongoing basis, the hedging relationship is expected to be highly effective in achieving offsetting changes in fair value attributed to the hedged risk during the period that the hedge is designated. Further, an assessment of effectiveness is required whenever financial statements or earnings are reported. Absent meeting these criteria, changes in fair value are recognized in other income, net, in the consolidated statements of income. Once the underlying forecasted transaction is realized, the gain or loss from the derivative designated as a hedge of the transaction is reclassified from accumulated other comprehensive income (loss) to the statement of income, in revenue or cost of revenue.

Fair Value Measurements

The Company accounts for certain assets and liabilities at fair value. The fair value is established based on a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value. These tiers include:

•Level 1 - observable inputs such as quoted prices for identical instruments in active markets;


•	Level 2 - inputs other than quoted prices in active markets that are either directly or indirectly observable; and


•	Level 3 - unobservable inputs in which little or no market data exists, therefore requiring an entity to develop its own assumptions.

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. The fair value of employee stock options is estimated at the grant date using the Black-Scholes option-pricing model. The fair value for time-based restricted stock units and performance-based restricted stock units is based on the closing share price of the Company's common stock on the date of grant. For performance-based restricted stock units, the compensation cost is recognized based on the number of units expected to vest upon the achievement of the performance conditions. The Company recognizes stock-based compensation as an expense on a straight-line basis, over the requisite service period. The Company accounts for forfeitures as they occur, rather than applying an estimated forfeiture rate.

Research and Development

Costs incurred in the research and development of the Company’s products are expensed as incurred.

Advertising Expense

The Company expenses advertising costs as they are incurred. During the years ended December 28, 2019, December 29, 2018 and December 30, 2017 advertising expense totaled $125.0 million, $114.0 million and $91.8 million, respectively, and are recorded within the selling and marketing expenses in its consolidated statements of income.

Income Taxes

Deferred tax assets and liabilities are determined based on the difference between the financial statement and tax basis using enacted tax rates in effect in the years in which those temporary differences are expected to be recovered or settled in each jurisdiction. A valuation allowance is provided if, based upon the weight of available evidence, it is more likely than not that the related benefits will not be realized. The Company regularly reviews the deferred tax assets for recoverability considering historical profitability, projected future taxable income, future reversals of existing taxable temporary differences, as well as feasible tax planning strategies in each jurisdiction. As of December 28, 2019, December 29, 2018 and December 30, 2017, the Company had a valuation allowance of $3.8 million, $1.1 million and $0.8 million, respectively, for certain deferred tax assets for which the Company believes do not meet the "more likely than not" criteria for recognition.

The Company reports a liability for unrecognized tax benefits resulting from uncertain tax positions taken or expected to be taken in a tax return. The Company recognizes interest and penalties, if any, related to unrecognized tax benefits in the income tax provision.

On December 22, 2017, the Tax Cuts and Jobs Act of 2017 (the "Act") was signed into law making significant changes to the Internal Revenue Code of 1986, as amended (the "Internal Revenue Code"). Effective for the Company’s 2018 tax year, the Act reduces the statutory federal corporate tax rate from 35% to 21% and implements certain additional provisions including the Global Intangible Low-Taxed Income inclusion and the Foreign-Derived Intangible Income deduction. Upon the enactment of the Act in December 2017, the Company recorded a one-time provisional income tax provision of $11.9 million in the fourth quarter of 2017 which included a provisional amount of $8.9 million related to the remeasurement of certain deferred tax assets and liabilities based on the tax rates at which they are expected to reverse in the future and $3.0 million related to the one-time transition tax on the mandatory deemed repatriation of foreign earnings. On December 22, 2017, the SEC staff issued Staff Accounting Bulletin No. 118 ("SAB 118") to address the application of U.S. GAAP in situations when a registrant does not have the necessary information available, prepared, or analyzed (including computations) in reasonable detail to complete the accounting for certain income tax effects of the Act. In accordance with SAB 118, during the fourth quarter of 2018, the Company finalized its analysis of the income tax effects of the Act and there were no material adjustments to the provisional amounts recorded.

Concentration of Credit Risk and Significant Customers

Financial instruments which potentially expose the Company to concentrations of credit risk consist of accounts receivable and cash and cash equivalents. Management believes its credit policies are prudent and reflect normal industry terms and business risk. At December 28, 2019 and December 29, 2018, two customers accounted for a total of 26.6% and 23.1% of the Company's accounts receivable balance, respectively. For the fiscal years ended December 28, 2019, December 29, 2018, and December 30, 2017, the Company generated 21.3%, 17.3% and 13.5%, respectively, of total revenue from one of its retailers (Amazon).

The Company maintains its cash in bank deposit accounts and money market funds at high quality financial institutions. The individual balances, at times, may exceed federally insured limits.

Net Income Per Share

Basic income per share is calculated using the Company's weighted-average outstanding common shares. Diluted income per share is calculated using the Company's weighted-average outstanding common shares including the dilutive effect of stock awards as determined under the treasury stock method. The following table presents the calculation of both basic and diluted net income per share:



	Fiscal Year Ended
	December 28, 2019		December 29, 2018		December 30, 2017
Net income	$	85,300	$	87,992	$	50,964
Weighted-average shares outstanding	28,097		27,692		27,611
Dilutive effect of employee stock plans	638		948		1,142
Diluted weighted-average shares outstanding	28,735		28,640		28,753
Basic income per share	$	3.04	$	3.18	$	1.85
Diluted income per share	$	2.97	$	3.07	$	1.77

Restricted stock units and stock options representing approximately 0.2 million, 0.0 million and 0.0 million shares of common stock for the fiscal years ended December 28, 2019, December 29, 2018 and December 30, 2017, respectively, were excluded from the computation of diluted earnings per share as their effect would have been antidilutive.

Recently Adopted Accounting Standards

In June 2018, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") No. 2018-07, "Compensation - Stock Compensation: Improvements to Nonemployee Share-Based Payment Accounting (Topic 718)." The amendments in ASU No. 2018-07 expand the scope of Topic 718 to include share-based payments issued to nonemployees for goods or services. The amendments in this ASU are effective for annual periods beginning after December 15, 2018 and interim periods within those annual periods, with early adoption permitted. The Company adopted this standard effective December 30, 2018 which did not have a material impact on the Company's consolidated financial statements and related disclosures.

In February 2016, the FASB issued ASU No. 2016-02 "Leases." This ASU and subsequently issued amendments require lessees to recognize the assets and liabilities on their balance sheet for the rights and obligations created by most leases and continue to recognize expenses on their income statements over the lease term. The standard also requires disclosures designed to give financial statement users information on the amount, timing and uncertainty of cash flows arising from leases. In July 2018, the FASB issued ASU No. 2018-11, "Leases (Topic 842): Targeted Improvements," which provide an alternative transition method that entities can elect when adopting the new standard. Under this alternative transition method, a company is permitted to use its effective date as the date of initial application without restating comparative period financial statements. The Company adopted the standard effective December 30, 2018 using the alternative transition method which resulted in the recognition of operating lease right-of-use assets and operating lease liabilities of approximately $52.8 million and $67.3 million, respectively. The Company's consolidated financial statements as of and for the year ended December 28, 2019 are presented under the new standard, while the comparative fiscal years presented are not adjusted and continue to be reported in accordance with the historical accounting policy. See Note 4, "Leases," for the required disclosures related to the impact of adopting this standard and a discussion of the Company's updated policies related to lease accounting.

Recently Issued Accounting Standards

In December 2019, the FASB issued ASU No. 2019-12, "Income Taxes - Simplifying the Accounting for Income Taxes." The ASU simplifies the accounting for income taxes by removing certain exceptions to the general principles as well as clarifying and amending existing guidance to improve consistent application. The amendments to this ASU are effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2020, with early adoption permitted. Depending on the amendment, adoption may be applied on the retrospective, modified retrospective or prospective basis. The Company intends to adopt the ASU effective January 3, 2021, and is currently evaluating the impact to the consolidated financial statements.

In August 2018, the FASB issued ASU No. 2018-15, "Intangibles - Goodwill and Other Internal-Use Software." The new standard aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software (and hosting arrangements that include an internal use software license). The amendments to this ASU are effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019, with early adoption permitted. Implementation should be applied either retrospectively or prospectively to all implementation costs incurred after the date of adoption. The Company intends to adopt the ASU using the prospective method effective December 29, 2019, and does not expect the new standard will have a material impact on its consolidated financial statements.

In August 2018, the FASB issued ASU No. 2018-13, "Fair Value Measurement: Disclosure Framework—Changes to the Disclosure Requirements for Fair Value Measurement." The amendment modifies disclosure requirements related to fair value measurement. The amendments to this ASU are effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019. Implementation on a prospective or retrospective basis varies by specific disclosure requirement. Early adoption is permitted. The standard also allows for early adoption of any removed or modified disclosures upon issuance of this ASU while delaying adoption of the additional disclosures until their effective date. The Company does not believe this amendment will have a material impact on its consolidated financial statements.

In June 2016, the FASB issued ASU No. 2016-13, "Measurement of Credit Losses on Financial Instruments," which amends the impairment model by requiring entities to use a forward-looking approach based on expected losses rather than incurred losses to estimate credit losses on certain types of financial instruments. This may result in the earlier recognition of allowances for losses. The guidance is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years, with early adoption permitted. The Company intends to adopt the ASU effective December 29, 2019. The Company does not believe the new standard will have a material impact on its consolidated financial statements.

From time to time, new accounting pronouncements are issued by FASB that are adopted by the Company as of the specified effective date. Unless otherwise discussed, the Company believes that recently issued standards, which are not yet effective, will not have a material impact on the Company’s consolidated financial statements upon adoption.

Revenue Recognition (Notes)

12 Months Ended

Dec. 28, 2019

Revenue Recognition and Deferred Revenue [Abstract]

Revenue Recognition, Policy [Policy Text Block]



3.	Revenue Recognition

The Company primarily derives its revenue from product sales. The Company sells products directly to consumers through on-line stores and indirectly through resellers and distributors. Revenue is recognized upon transfer of control of promised products or services to customers, generally as title and risk of loss pass, in an amount that reflects the consideration the Company expects to receive in exchange for those products or services. Revenue is recognized only to the extent that it is probable that a significant reversal of revenue will not occur. Taxes collected from customers, which are subsequently remitted to governmental authorities, are excluded from revenue. Shipping and handling expenses are considered fulfillment activities and are expensed as incurred.

The Company’s product portfolio includes various consumer robots, many of which are Wi-Fi connected. The consumer robots are generally highly dependent on, and interrelated with, the embedded software and cannot function without the software. As such, the consumer robots are accounted for as a single performance obligation, and the revenue is recognized at a point in time when the control is transferred to distributors, resellers or directly to end customers through online stores. For consumer robots with Wi-Fi capability ("connected robots"), each sale represents an arrangement with multiple promises consisting of the robot, an app, cloud services and potential future unspecified software upgrades. The Company has determined that the app, cloud services and potential future unspecified software upgrades represent one promised service to the customer to enhance the functionality and interaction with the robot (referred to collectively as "Cloud Services").

Prior to the adoption of ASU No. 2014-09, "Revenue from Contracts with Customers," ("ASC 606") on December 31, 2017, the beginning of fiscal year 2018, the revenue allocated to the Cloud Services was deferred and recognized on a straight-line basis over the expected life of the connected robot. On December 31, 2017, the Company adopted ASC 606 using the modified retrospective method applied to those contracts that were not completed as of the adoption date. Upon ASC 606, the Company concluded that, on a quantitative and qualitative basis, the Cloud Services did not constitute a material performance obligation for the then existing products and, as such, these services were not considered a separate performance obligation that required allocation of transaction price. Under the modified retrospective method, the Company recognized the cumulative effect of the adoption and recorded a net increase of $1.0 million to the beginning retained earnings as of December 31, 2017.

During the third quarter of 2018, the Company launched Roomba i7 and i7+ which brought a new level of intelligence and automation to robotic vacuum cleaners with the ability to learn, map and adapt to a home's floor plan. The Company has concluded that beginning with this launch, the Cloud Services related to these new products are a material performance obligation. For contracts that contain multiple performance obligations, the transaction price is allocated to each performance obligation based on a relative standalone selling price ("SSP"). The SSP reflects the Company's best estimate of what the selling prices of elements would be if they were sold regularly on a standalone basis. Revenue allocated to the robots is recognized at a point in time when control is transferred. Revenue allocated to the Cloud Services is deferred and recognized on a straight-line basis over the estimated period the software upgrades and services are expected to be provided. For contracts with a duration of greater than one year, the transaction price allocated to performance obligations that are unsatisfied as of December 28, 2019 and December 29, 2018 are not material. The Company does not disclose the value of unsatisfied performance obligations for contracts with an original expected duration of one year or less.

The Company’s products generally carry a one-year or two-year limited warranty that promises customers that delivered products are as specified. The Company does not consider these assurance-type warranties as a separate performance obligation and therefore, the Company accounts for such warranties under ASC 460, "Guarantees."

The Company provides limited rights of returns for direct-to-consumer sales generated through its on-line stores and certain resellers and distributors. The Company records an allowance for product returns based on specific terms and conditions included in the customer agreements or based on historical experience and the Company's expectation of future returns. In addition, the Company may provide other credits or incentives which are accounted for as variable consideration when estimating the amount of revenue to recognize. Where appropriate, these estimates take into consideration relevant factors such as the Company’s historical experience, current contractual requirements, specific known market events and forecasted inventory level in the channels. Overall, these reserves reflect the Company’s best estimates, and the actual amounts of consideration ultimately received may differ from the Company’s estimates. Returns and credits are estimated at contract inception and updated at the end of each reporting period as additional information becomes available. As of December 28, 2019, the Company has reserves for product returns of $55.2 million and other credits and incentives of $134.0 million. As of December 29, 2018, the Company had reserves for product returns of $53.9 million and other credits and incentives of $97.7 million. Revenue recognized during the years ended December 28, 2019 and December 29, 2018 related to performance obligations satisfied in a prior period was not material.

Disaggregation of Revenue

The following table provides information about disaggregated revenue by geographical region (in thousands):



	December 28, 2019		December 29, 2018
United States	$	603,618	$	560,995
EMEA	357,760		311,659
Other	252,632		219,930
Total revenue	$	1,214,010	$	1,092,584

Contract Balances

The following table provides information about receivables and contract liabilities from contracts with customers (in thousands):



	December 28 2019		December 29, 2018
Accounts receivable, net	$	146,161	$	162,166
Contract liabilities	6,991		5,756

The Company invoices customers based upon contractual billing schedules, and accounts receivable are recorded when the right to consideration becomes unconditional. Contract liabilities primarily relate to prepayments received from customers in advance of product shipments. The change in the opening and closing balances of the Company’s contract assets and contract liabilities primarily results from the timing difference between the Company’s performance and the customer’s payment. During the years ended December 28, 2019 and December 29, 2018, the Company recognized $5.8 million and $6.7 million, respectively, of the contract liability balance as revenue upon transfer of the products to customers.

Practical Expedients and Exemptions

The Company generally expenses sales commissions when incurred because the amortization period is generally one year or less. These costs are recorded within sales and marketing expenses.

The Company does not assess whether a prepayment received represents a significant financing component as the period between when the payment is received and the transfer of the products to the customer is generally one year or less.

The Company does not disclose the value of unsatisfied performance obligations for contracts with an original expected duration of one year or less.

Leases (Notes)

12 Months Ended

Dec. 28, 2019

Leases [Abstract]

Lessee, Operating Leases [Text Block]



4.	Leases

The Company's leasing arrangements primarily consist of operating leases for its facilities which include corporate, sales and marketing and research and development offices. For leases with terms greater than 12 months, the Company records the related right-of-use asset and lease obligation at the present value of lease payments over the term. The Company's leases typically include rental escalation clauses, renewal options and/or termination options that are factored into the determination of lease payments when appropriate. The Company does not separate lease and nonlease components of contracts and excludes all variable lease payments from the measurement of right-of-use assets and lease liabilities. The Company's variable lease payments generally include usage based nonlease components. The Company's lease agreements do not contain any residual

value guarantees or restrictive covenants. Leases with an initial term of 12 months or less are not recorded on the balance sheet. Lease expense is recognized on a straight-line basis over the lease term.

The Company's existing leases do not provide a readily determinable implicit rate. Therefore, the Company estimates its incremental borrowing rate to discount the lease payments based on information available at December 30, 2018 (date of initial application) or the lease commencement date for new leases post adoption. At December 28, 2019, the Company's weighted average discount rate was 3.61%, while the weighted average remaining lease term was 9.21 years.

The components of lease expense were as follows (in thousands):



	December 28, 2019
Operating lease cost	$	8,777
Variable lease cost	4,096
Total lease cost	$	12,873

Rental expense under operating leases for fiscal years 2018 and 2017 amounted to $12.9 million and $8.9 million, respectively.

Supplemental cash flow information related to leases was as follows (in thousands):



	December 28, 2019
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$	9,540
Right-of-use assets obtained in exchange for lease obligations:
Operating leases	$	53,227

Maturities of operating lease liabilities were as follows as of December 28, 2019 (in thousands):




2020	$	8,936
2021	8,263
2022	7,592
2023	7,145
2024	6,308
Thereafter	34,957
Total minimum lease payments	$	73,201
Less: imputed interest	11,430
Present value of future minimum lease payments	$	61,771
Less: current portion of operating lease liabilities (Note 9)	6,843
Long-term lease liabilities	$	54,928

Financial Statement Impact of Adopting ASC 842

The Company adopted ASC 842 effective December 30, 2018 using the alternative transition method. Under this alternative transition method, a company is permitted to use its effective date as the date of initial application without restating comparative period financial statements. The Company elected the package of practical expedients permitted under the transition guidance, which allowed the Company to carryforward its historical assessments of (1) whether contracts are or contain leases, (2) lease classification and (3) initial direct costs. In addition, the Company elected the practical expedient to use hindsight in determining lease term. The adoption of the new standard resulted in the recognition of right-of-use assets and lease liabilities of approximately $52.8 million and $67.3 million, respectively. The standard did not materially impact the Company's consolidated income or cash flows.

Business Combinations (Notes)

12 Months Ended

Dec. 28, 2019

Business Combinations [Abstract]

Business Combinations



5.	Business Combinations

Acquisition of Robopolis

In October 2017, the Company closed the acquisition of its largest European distributor, Robopolis SAS, a French company ("Robopolis"). The acquisition will better enable the Company to maintain its leadership position and grow its business in several Western European countries through direct control of pre- and post-sales market activities including sales, marketing, branding, channel relationships and customer service. The purchase price was $169.4 million in cash, net of acquired cash of $38.0 million. The acquisition was a stock purchase. The results of operations for this acquisition have been included in the Company’s operating results since the acquisition date.

The following table summarizes the final allocation of the purchase price (in thousands):



Cash	$	37,981
Accounts receivable, net (1)	21,426
Inventory	36,304
Goodwill	80,419
Intangible assets	36,597
Other assets	2,456
Total assets	215,183

Accounts payable	(29,391		)
Accrued expenses	(3,376		)
Deferred tax liabilities	(10,864		)
Other liabilities	(2,138		)
Total liabilities assumed	(45,769		)
Net assets acquired	$	169,414

(1) The accounts receivable balance includes reserves for product returns, discounts and promotions assumed as part of the acquisition.

The following table reflects the fair value of the acquired identifiable intangible assets and related estimates of useful lives (in thousands):



	Useful Life	Fair Value
Reacquired distribution rights	2.25 years	$	29,296
Customer relationships	14 years	7,029
Non-competition agreements	3 years	272
Total		$	36,597

Acquisition of Sales On Demand Corporation

In April 2017, the Company closed its acquisition of the iRobot-related distribution business of Sales On Demand Corporation ("SODC") for $16.6 million in cash, equal to the book value of the acquired assets. The acquisition will better enable the Company to maintain its leadership position and accelerate the growth of its business in Japan through direct control of pre- and post-sales market activities including sales, marketing, branding, channel relationships and customer service. It also expands the Company's presence and customer outreach opportunities in Japan. The acquisition was a stock purchase. The results of operations for this acquisition have been included in the Company's operating results since the acquisition date.

During 2017, the Company finalized the purchase price allocation and made measurement period adjustments to the provisional amounts reported as the estimated fair values of assets acquired. These measurement period adjustments resulted in a $2.2 million non-taxable gain on business acquisition which represents the excess of the fair value of the net assets acquired over the purchase price. The gain on business acquisition was recorded within other income, net in the consolidated statements of income. The Company believes that the gain on business acquisition was due to the transaction not being subjected to a competitive bidding process and the purchase price being determined based on the net book value of the net assets acquired.

The following table summarizes the final allocation of the purchase price (in thousands):



Cash	$	125
Accounts receivable, net (1)	(5,496		)
Inventory	18,290
Other assets	2,065
Deferred tax assets, net	409
Goodwill	—
Intangible assets	8,640
Total assets acquired	24,033

Accrued expenses and other current liabilities	(4,450		)
Other liabilities	(691		)
Total liabilities assumed	(5,141		)
Net assets acquired	$	18,892
Gain on business acquisition	(2,243		)
Total purchase price	$	16,649

(1) The accounts receivable balance reflects reserves for product returns, discounts and promotions assumed as part of the acquisition.

The following table reflects the fair value of the acquired identifiable intangible assets and related estimates of useful lives (in thousands):

Pro Forma Results (Unaudited)

The following table shows unaudited pro forma results of operations as if the Company had acquired Robopolis on January 1, 2017 (in thousands, except per share amounts):



	Fiscal Year Ended
	December 30, 2017
Revenue	$	901,612
Net income	51,887
Net income per share:
Basic income per share	$	1.88
Diluted income per share	$	1.80

The Company has not furnished pro forma financial information relating to its acquisition of SODC in 2017 and an immaterial acquisition during the fiscal year 2019, because such information is not material, individually or in the aggregate, to its financial results. The unaudited pro forma results of operations are not necessarily indicative of the actual results that would have occurred had the transactions taken place at the beginning of the periods indicated.

Working Capital Facilities

12 Months Ended

Dec. 28, 2019

Debt Disclosure [Abstract]

Revolving Line of Credit



10.	Working Capital Facility

Credit Facility

In June 2018, the Company entered into an agreement with Bank of America, N.A., increasing the amount of its unsecured revolving line of credit from $75.0 million to $150.0 million and extending the term of the credit facility to June 2023. As of December 28, 2019, the Company had no outstanding borrowings under the revolving credit facility. The revolving line of credit is available to fund working capital and other corporate purposes. The interest on loans under the credit facility accrues, 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 or (3) the Eurodollar Rate plus 1.0%. In the event that LIBOR is discontinued as expected in 2021, the Company expects the interest rates for the debt following such event will be based on either alternate base rates or agreed upon replacement rates. While the Company does not expect a LIBOR discontinuation to affect its ability to borrow or maintain already outstanding borrowings, it could result in higher interest rates.

The credit facility contains customary terms and conditions for credit facilities of this type, including restrictions on the Company's ability to incur or guarantee 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 maximum ratio of indebtedness to Adjusted EBITDA and a minimum specified interest coverage ratio.

The 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 28, 2019, the Company was in compliance with all covenants under the revolving credit facility.

Lines of Credit

The Company has an unsecured letter of credit facility with Bank of America, N.A., available to fund letters of credit up to an aggregate outstanding amount of $5.0 million. As of December 28, 2019, the Company had letters of credit outstanding of $0.5 million under the letter of credit facility.

The Company has an unsecured guarantee line of credit with Mizuho, Bank Ltd., available to fund import tax payments up to an aggregate outstanding amount of 220.0 million Japanese Yen. As of December 28, 2019, the Company had no outstanding balance under the guarantee line of credit.

Derivative Instruments and Hedging Activities (Notes)

12 Months Ended

Dec. 28, 2019

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Derivative Instruments and Hedging Activities



11.	Derivative Instruments and Hedging Activities

The Company operates internationally and, in the normal course of business, is exposed to fluctuations in foreign currency exchange rates. The foreign currency exposures typically arise from transactions denominated in currencies other than the functional currency of the Company's operations, primarily the British Pound, Canadian Dollar, Euro and Japanese Yen. The Company uses derivative instruments that are designated in cash flow hedge relationships to reduce or eliminate the effects of foreign exchange rate change on sales. These contracts typically have maturities of thirty-seven months or less. At December 28, 2019 and December 29, 2018, the Company had outstanding cash flow hedges with a total notional value of $424.6 million and $366.7 million, respectively.

The Company also enters into economic hedges that are not designated as hedges from an accounting standpoint to reduce or eliminate the effects of foreign exchange rate changes typically related to short term trade receivables and payables. These contracts typically have maturities of ten months or less. At December 28, 2019 and December 29, 2018, the Company had outstanding economic hedges with a total notional value of $58.4 million and $56.0 million, respectively.

The fair values of derivative instruments are as follows (in thousands):



		Fair Value
	Classification	December 28, 2019		December 29, 2018
Derivatives not designated as hedging instruments:
Foreign currency forward contracts	Other current assets	$	1,855	$	551
Foreign currency forward contracts	Accrued expenses	297		—
Derivatives designated as cash flow hedges:
Foreign currency forward contracts	Other current assets	$	4,347	$	53
Foreign currency forward contracts	Other assets	9,112		172
Foreign currency forward contracts	Accrued expenses	47		335
Foreign currency forward contracts	Long-term liabilities	414		795

Gains (losses) associated with derivative instruments not designated as hedging instruments are as follows (in thousands):



		Fiscal year ended
	Classification	December 28, 2019		December 29, 2018
Gain (loss) recognized in income	Other income, net	$	89	$	1,568

The following tables reflect the effect of derivatives designated as cash flow hedging for the years ended (in thousands):



	Gain (loss) recognized in OCI on Derivative (1)
	Fiscal year ended
	December 28, 2019		December 29, 2018

Foreign currency forward contracts	$	16,483	$	(686	)


(1)	The amount represents the change in fair value of derivative contracts due to changes in spot rates.



	Gain (loss) recognized in earnings on cash flow hedging instruments
	December 28, 2019				December 29, 2018
	Revenue		Cost of revenue		Revenue		Cost of revenue
Consolidated statements of income in which the effects of cash flow hedging instruments are recorded	$	1,214,010	$	670,083	$	1,092,584	$	537,156

Gain or (loss) on cash flow hedging relationships:
Foreign currency forward contracts:
Amount of gain (loss) reclassified from AOCI into earnings	$	1,889	$	—	$	948	$	(386	)

Fair Value Measurements

12 Months Ended

Dec. 28, 2019

Fair Value Disclosures [Abstract]

Fair Value Measurements



12.	Fair Value Measurements

The Company’s financial assets and liabilities measured at fair value on a recurring basis were as follows (in thousands):



	Fair Value Measurements as of
	December 28, 2019
	Level 1		Level 2 (1)		Level 3 (2)
Assets:
Corporate and government bonds, $17,016 at cost (3)	$	—	$	17,032	$	—
Derivative instruments (Note 11)	—		15,314		—
Total assets measured at fair value	$	—	$	32,346	$	—

Liabilities:
Derivative instruments (Note 11)	$	—	$	758	$	—
Total liabilities measured at fair value	$	—	$	758	$	—

The Company’s financial assets and liabilities measured at fair value on a recurring basis were as follows (in thousands):



	Fair Value Measurements as of
	December 29, 2018
	Level 1		Level 2 (1)		Level 3 (2)
Assets:
Money market funds	$	3,730	$	—	$	—
Corporate and government bonds, $30,035 at cost	—		29,605		—
Convertible note	—		—		2,000
Derivative instruments (Note 11)	—		776		—
Total assets measured at fair value	$	3,730	$	30,381	$	2,000

Liabilities:
Derivative instruments (Note 11)	$	—	$	1,130	$	—
Total liabilities measured at fair value	$	—	$	1,130	$	—


(1)	Level 2 fair value estimates are based on observable inputs other than quoted prices in active markets for identical assets and liabilities, quoted prices for identical or similar assets or liabilities in inactive markets, or other inputs that

are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities.

(2)

Level 3 fair value estimates are based on inputs that are generally unobservable and typically reflect management’s estimates of assumptions that market participants would use in pricing the asset or liability. The fair values are therefore determined using model-based techniques, including option pricing and discounted cash flow models. Unobservable inputs used in the models are significant to the fair values of the assets and liabilities.


(3)	As of December 28, 2019, the Company’s investments had maturity dates ranging from February 2020 to March 2021.

The following table provides a summary of changes in fair value of our Level 3 investment for the twelve months ended December 28, 2019 (in thousands):



Balance as of December 29, 2018	$	2,000
Conversion of convertible note	(2,000		)
Balance as of December 28, 2019	$	—

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Stock-Based Compensation

12 Months Ended

Dec. 28, 2019

Share-based Payment Arrangement [Abstract]

Stock-Based Compensation



14.	Stock-Based Compensation

The Company has awards and options outstanding under three stock incentive plans: the 2005 Stock Option and Incentive Plan (the "2005 Plan"), the 2015 Stock Option and Incentive Plan (the "2015 Plan") and the 2018 Stock Option and Incentive Plan (the "2018 Plan" and together with 2005 Plan and the 2015 Plan, the "Plans"). The 2018 Plan is the only one of the three plans under which new awards may currently be granted. Under the 2018 Plan, which became effective on May 23, 2018, 1,750,000 shares were initially reserved for issuance in the form of incentive stock options, non-qualified stock options, stock appreciation rights, restricted stock awards, restricted stock units, unrestricted stock awards, cash-based awards, and dividend equivalent rights. Stock awards returned to the Plans, with the exception of those issued under the 2005 Plan, as a result of their expiration, cancellation or termination are automatically made available for issuance under the 2018 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. As of December 28, 2019, there were 1,293,482 shares available for future grant under the 2018 Plan. The Company recognized $23.7 million, $25.8 million and $19.8 million of stock-based compensation expense during the fiscal years ended December 28, 2019, December 29, 2018, and December 30, 2017, respectively.

Stock-based compensation breaks down by expense classification as follows (in thousands):



	Fiscal Year Ended
	December 28, 2019		December 29, 2018		December 30, 2017
Cost of revenue	$	1,486	$	1,407	$	1,082
Research and development	9,186		7,494		5,009
Selling and marketing	3,323		2,842		2,571
General and administrative	9,749		14,061		11,089
Total	$	23,744	$	25,804	$	19,751

Stock Options

Options granted under the Plans are exercisable in full at any time subsequent to vesting, generally vest over four years, and expire five years or ten years from the date of grant or, if earlier, 90 days from employee termination. The exercise price of stock options is typically equal to the Company's closing stock price on the date of grant.

As of December 28, 2019, the unamortized compensation costs associated with stock options was $0.4 million with a weighted-average remaining recognition period of 0.61 years.

The following table summarizes stock option activity for fiscal years 2019, 2018 and 2017:



	Number of Shares		Weighted Average Exercise Price		Weighted Average Remaining Contractual Term	Aggregate Intrinsic Value(1)
Outstanding at December 31, 2016	1,088,174		$	32.27
Granted	10,975		57.33
Exercised	(367,267	)	28.79
Canceled	(18,928	)	36.72
Outstanding at December 30, 2017	712,954		$	34.34
Granted	—		—
Exercised	(239,830	)	33.40
Canceled	(10,863	)	46.20
Outstanding at December 29, 2018	462,261		$	34.55
Granted	—		—
Exercised	(127,024	)	32.95
Canceled	(12,329	)	37.03
Outstanding at December 28, 2019	322,908		$	35.08	2.47 years	$5.65 million
Vested and expected to vest at December 28, 2019	322,908		$	35.08	2.47 years	$5.65 million
Exercisable as of December 28, 2019	293,159		$	34.30	2.35 years	$5.32 million

_________________________


(1)	The aggregate intrinsic value on the table above represents the difference between the Company's closing stock price on December 28, 2019 of $50.20 and the exercise price of the underlying in-the-money option.

During fiscal years 2019, 2018, and 2017, the total intrinsic value of stock options exercised was $8.9 million, $14.9 million, and $21.8 million, respectively.

Time-based Restricted Stock Units

Time-based restricted stock units entitle the holder to a specific number of shares of common stock upon vesting, typically over a four year period. As of December 28, 2019, the unamortized compensation costs associated with restricted stock units was $49.2 million with a weighted-average remaining recognition period of 2.53 years.

The following table summarizes the time-based restricted stock unit activity for fiscal years 2019, 2018 and 2017:



	Number of Shares Underlying Restricted Stock		Weighted Average Grant Date Fair Value
Outstanding at December 31, 2016	935,179		$	35.07
Granted	396,164		72.63
Vested	(351,543	)	33.73
Forfeited	(41,347	)	39.52
Outstanding at December 30, 2017	938,453		$	51.24
Granted	307,614		81.55
Vested	(351,816	)	47.30
Forfeited	(38,362	)	60.62
Outstanding at December 29, 2018	855,889		$	63.32
Granted	407,325		79.91
Vested	(358,119	)	54.89
Forfeited	(85,863	)	76.85
Outstanding at December 28, 2019	819,232		$	73.83

The aggregate intrinsic value of outstanding time-based restricted stock units at December 28, 2019 was $42.8 million based on the Company's closing stock price on December 28, 2019 of $50.20, with a weighted average remaining contractual term of 1.52 years.

Performance-Based Restricted Stock Units

The Company grants performance-based restricted stock units ("PSUs") to certain of its employees. The PSUs have performance metrics based on financial performance of the Company measured at the end of a three year performance period. For the 2017 grant year, the performance metric for these awards is based on revenue, operating income and/or operating income percent, with a threshold requirement for a minimum amount of revenue growth. Starting in 2018, the Company has removed revenue as a performance metric in the PSU plan design and changed the payout metric from three-year cumulative operating income as a percentage of annual revenue to three-year cumulative operating income in dollars. The number of shares actually earned at the end of the three-year period will range from 0% to 200% of the target number of PSUs granted based on the Company’s performance against the performance conditions.

The unamortized fair value as of December 28, 2019 associated with performance based restricted stock units was $1.7 million with a weighted-average remaining recognition period of 1.04 years.

The following table summarizes the performance-based restricted stock unit activity for fiscal years 2019, 2018 and 2017:



	Number of Shares Underlying PSU		Weighted Average Grant Date Fair Value
Outstanding at December 31, 2016	163,911		$	35.03
Granted	105,650		57.33
Vested	(24,792	)	43.35
Forfeited	(2,708	)	39.71
Outstanding at December 30, 2017	242,061		$	43.97
Granted	91,538		68.41
Vested	(56,259	)	34.30
Forfeited	(3,221	)	45.71
Outstanding at December 29, 2018	274,119		$	54.10
Granted	70,827		122.20
Vested	(78,943	)	33.33
Forfeited	(49,772	)	78.29
Outstanding at December 28, 2019	216,231		$	78.42

The aggregate intrinsic value of outstanding PSUs was $11.3 million based on the Company's closing stock price on December 28, 2019 of $50.20 with a weighted average remaining contractual term of 1.04 years.

Employee Stock Purchase Plan

In May 2017, the Company’s stockholders approved the 2017 Employee Stock Purchase Plan ("ESPP"). Eligible employees may purchase the Company’s common stock through payroll deductions at a price equal to 85% of the lower of the fair market values of the stock as of the beginning or the end of six-month offering periods beginning November 15 and May 15 of each year. An employee’s payroll deductions under the ESPP are limited to 15% of the employee’s compensation, up to $4,000 each period, for the purchase of common stock not to exceed 1,000 shares per offering period. As of December 28, 2019, there were 570,962 shares reserved for future issuance under the ESPP. The Company recognized $1.1 million, $1.0 million, and $0.1 million of stock-based compensation expense during the fiscal years ended December 28, 2019, December 29, 2018, and December 30, 2017, respectively.

Commitments and Contingencies

12 Months Ended

Dec. 28, 2019

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies



15.	Commitments and Contingencies

Legal Proceedings

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 our financial condition or results of operations. For the following litigation matters, a liability is not probable or the amount cannot be reasonably estimated and therefore accruals have not been made.

On October 24, 2019, purported Company shareholder Miramar Firefighters’ Pension Fund filed a putative class action in the U.S. District Court for the Southern District of New York against the Company and certain of its directors and officers, captioned Miramar Firefighters’ Pension Fund v. iRobot Corporation, et al., No. 1:19-cv-09837. The complaint alleges violations of Sections 10(b) and 20(a) of the Securities Exchange Act of 1934, as amended (the "Exchange Act") and Rule 10b-5 thereunder based on allegedly false and misleading statements and omissions concerning the Company’s acquisitions of Sales on Demand Corporation and Robopolis SAS and the Company’s subsequent financial performance. The complaint seeks, among other things, unspecified compensatory damages, including interest, in connection with the Company’s allegedly inflated stock price, attorneys’ fees and costs, and unspecified equitable/injunctive relief. This case has been transferred to the U.S. District Court for the District of Massachusetts. A similar case captioned Campbell v. iRobot Corporation, et al., No. 1:19-cv-12483 was also filed in the U.S. District Court for the Southern District of New York and subsequently transferred to the

U.S. District Court for the District of Massachusetts. On January 24, 2020, the Court consolidated the Miramar and Campbell cases and appointed a lead plaintiff and lead plaintiff's Counsel.

On December 20, 2019, purported Company shareholders David Katz and Thomas Wightman, derivatively on behalf of iRobot Corporation, filed a complaint in the U.S. District Court for Southern District of New York against the Company and certain of its directors and officers, captioned David Katz and Thomas Wightman, on behalf of iRobot Corporation v. iRobot Corporation, et al., No. 1:19-cv-11692. The complaint alleges breaches of fiduciary duties, unjust enrichment, violations of Sections 10(b) and 20(a) of the Exchange Act and Rule 10b-5 thereunder based on allegedly false and misleading statements and omissions concerning the Company’s acquisitions of Sales on Demand Corporation and Robopolis SAS and the Company’s subsequent financial performance. The complaint seeks, among other things, unspecified compensatory damages, including interest, in connection with the Company’s allegedly inflated stock price, attorneys’ fees and costs, and unspecified equitable/injunctive relief. This case has been transferred to the U.S. District Court for the District of Massachusetts.

On January 9, 2020, purported Company shareholder Robert Truman, derivatively on behalf of iRobot Corporation, filed a complaint in the U.S. District Court for the District of Massachusetts against the Company and certain of its directors and officers, captioned Robert Truman, on behalf of iRobot Corporation v. iRobot Corporation, et al., No. 1:20-cv-10034. The complaint alleges breaches of fiduciary duties, unjust enrichment, abuse of control, gross mismanagement, waste of corporate assets, and violations of Sections 10(b), 14(a) and 20(a) of the Exchange Act and Rule 10b-5 thereunder based on allegedly false and misleading statements and omissions concerning the Company’s acquisitions of Sales on Demand Corporation and Robopolis SAS and the Company’s subsequent financial performance. The complaint seeks, among other things, unspecified compensatory damages, including interest, in connection with the Company’s allegedly inflated stock price, attorneys’ fees and costs, and unspecified equitable/injunctive relief.

On January 22, 2020, purported Company shareholder Alexa Ruhfass, derivatively on behalf of iRobot Corporation, filed a complaint in the U.S. District Court for the District of Massachusetts against the Company and certain of its directors and officers, captioned Alexa Ruhfass, on behalf of iRobot Corporation v. iRobot Corporation, et al., No. 1:20-cv-10133. The complaint alleges breaches of fiduciary duties, unjust enrichment, waste of corporate assets, and violations of Sections 14(a) and 20(a) of the Exchange Act and Rule 10b-5 thereunder based on allegedly false and misleading statements and omissions concerning the Company’s acquisitions of Sales on Demand Corporation and Robopolis SAS and the Company’s subsequent financial performance. The complaint seeks, among other things, unspecified compensatory damages, including interest, in connection with the Company’s allegedly inflated stock price, attorneys’ fees and costs, and unspecified equitable/injunctive relief.

On February 10, 2020, purported Company shareholder William Tasco, derivatively on behalf of iRobot Corporation, filed a complaint in the U.S. District Court for the District of Massachusetts against the Company and certain of its directors and officers, captioned William Tasco, derivatively on behalf of iRobot Corporation v. iRobot Corporation, et al., No. 1:20-cv-10253. The complaint alleges breaches of fiduciary duties, unjust enrichment, abuse of control, gross mismanagement, waste of corporate assets, and violations of Sections 10(b), 14(a) and 20(a) of the Exchange Act and Rule 10b-5 thereunder based on allegedly false and misleading statements and omissions concerning the Company’s acquisitions of Sales on Demand Corporation and Robopolis SAS and the Company’s subsequent financial performance. The complaint seeks, among other things, unspecified compensatory damages, including interest, in connection with the Company’s allegedly inflated stock price, attorneys’ fees and costs, and unspecified equitable/injunctive relief.

Outstanding Purchase Orders

At December 28, 2019, we had outstanding purchase orders aggregating approximately $124.4 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 28, 2019 and December 29, 2018, respectively.

Warranty

The Company provides warranties on most products and has established a reserve for warranty obligations based on estimated warranty costs. The reserve is included as part of accrued expenses (Note 9) in the accompanying consolidated balance sheets.

Activity related to the warranty accrual was as follows (in thousands):



	Fiscal Year Ended
	December 28, 2019			December 29, 2018			December 30, 2017
Balance at beginning of period	$	11,964		$	11,264		$	8,464
Liability assumed (1)	—			—			2,186
Provision	14,091			10,798			8,591
Warranty usage	(12,199		)	(10,098		)	(7,977		)
Balance at end of period	$	13,856		$	11,964		$	11,264

__________________________________

(1)

Warranty assumed as part of the acquisition of the iRobot-related distribution business of SODC.

Income Taxes

12 Months Ended

Dec. 28, 2019

Income Tax Disclosure [Abstract]

Income Taxes



17.	Income Taxes

Income (loss) before provision for income taxes was as follows (in thousands):



	Fiscal Year Ended
	December 28, 2019		December 29, 2018			December 30, 2017
Domestic	$	84,225	$	113,078		$	71,382
Foreign	14,608		(4,456		)	4,984
Income before income taxes	$	98,833	$	108,622		$	76,366

The components of income tax expense were as follows (in thousands):



	Fiscal Year Ended
	December 28, 2019			December 29, 2018			December 30, 2017
Current
Federal	$	13,366		$	17,627		$	17,555
State	5,004			3,676			1,691
Foreign	6,941			10,732			7,355
Total current income tax provision	$	25,311		$	32,035		$	26,601
Deferred
Federal	$	(9,345	)	$	(2,475	)	$	6,664
State	(1,783		)	(1,149		)	(2,470		)
Foreign	(650		)	(7,781		)	(5,393		)
Total deferred income tax provision	(11,778		)	(11,405		)	(1,199		)
Total income tax provision	$	13,533		$	20,630		$	25,402

On December 22, 2017, the Tax Cuts and Jobs Act of 2017 (the "Act") was signed into law making significant changes to the Internal Revenue Code. Effective for the Company's 2018 tax year, the Act reduces the statutory federal corporate tax rate from 35% to 21% and implements certain additional provisions including the Global Intangible Low-Taxed Income inclusion and the Foreign Derived Intangible Income deduction. Upon the enactment of the Act in December 2017, the Company recorded a one-time provisional income tax provision of $11.9 million in the fourth quarter of 2017 which included a provisional amount of $8.9 million related to the remeasurement of certain deferred tax assets and liabilities based on the tax rates at which they are expected to reverse in the future and $3.0 million related to the one-time transition tax on the mandatory deemed repatriation of foreign earnings. On December 22, 2017, the SEC staff issued Staff Accounting Bulletin No. 118 ("SAB 118") to address the application of U.S. GAAP in situations when a registrant does not have the necessary information available, prepared, or analyzed (including computations) in reasonable detail to complete the accounting for certain income tax effects of the Act. In accordance with SAB 118, during the fourth quarter of 2018, the Company finalized its analysis of the income tax effects of the Act and determined no material adjustments to the provisional amounts recorded were required.

The reconciliation of statutory federal income tax to actual tax expense is as follows (in thousands):



	Fiscal Year Ended
	December 28, 2019			December 29, 2018			December 30, 2017
Statutory federal income tax	$	20,755		$	22,812		$	26,728
State taxes (net of federal benefit)	3,999			4,312			2,089
Federal and state credits	(8,152		)	(5,638		)	(4,486		)
Domestic production activities deduction	—			—			(1,528		)
Excess tax benefits relating to stock-based compensation	(6,468		)	(6,529		)	(11,709		)
Tax Cuts and Jobs Act of 2017	—			2,127			11,861
Foreign-derived intangible income deduction	(4,180		)	(2,678		)	—
EMEA business restructuring	—			2,292			—
Executive compensation	2,081			745			1,354
Tax impact of foreign earnings	1,986			1,336			(636		)
Change in valuation allowance	2,678			348			800
Other	834			1,503			929
	$	13,533		$	20,630		$	25,402

The components of net deferred tax assets were as follows (in thousands):



	December 28, 2019			December 29, 2018
Deferred tax assets
Revenue reserves	$	21,355		$	17,420
Accruals and other liabilities	8,225			7,844
Operating lease liabilities	14,117			—
Tax credits and net operating loss carryforwards	8,814			7,781
Stock-based compensation	4,981			4,975
Other	5,068			4,087
Gross deferred tax assets	62,560			42,107
Valuation allowance	(3,826		)	(1,148		)
Total deferred tax assets	58,734			40,959
Deferred tax liabilities
Intangible assets	3,838			7,317
Operating lease right-of-use assets	13,249			—
Other	768			668
Total deferred tax liabilities	17,855			7,985
Net deferred tax assets	$	40,879		$	32,974

The Company intends to continue to invest all of its unremitted foreign earnings, as well as the capital in its foreign subsidiaries, indefinitely outside of the U.S. At December 28, 2019, the Company has unremitted foreign earnings and any unrecognized deferred tax liability on these unremitted earnings would be immaterial.

The Company has federal net operating loss carryforwards of $1.8 million as of December 28, 2019. The Company had foreign net operating loss carryforwards of $3.4 million as of December 29, 2018 that were fully utilized during tax year ended December 28, 2019. The Company has state research and development credit carryforwards of $13.1 million and $10.7 million as of December 28, 2019 and December 29, 2018, respectively, which expire from 2028 to 2034. Under the Internal Revenue Code and state law, 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 28, 2019, December 29, 2018 and December 30, 2017, the Company had a valuation allowance of $3.8 million, $1.1 million and $0.8 million, respectively, for state research

and development credit carryforwards and certain foreign deferred tax assets for which the Company believes do not meet the "more likely than not" criteria for recognition.

A summary of the Company’s adjustments to its gross unrecognized tax benefits in the current year is as follows (in thousands):



	Fiscal Year Ended
	December 28, 2019			December 29, 2018			December 30, 2017
Balance at beginning of period	$	7,119		$	4,590		$	5,146
Increase for tax positions related to the current year	770			2,891			580
Increase for tax positions related to acquisition	—			1,493			—
Increase (decrease) for tax positions related to prior years	(768		)	407			(523		)
Decrease for settlements with applicable taxing authorities	—			(2,262		)	—
Decrease for lapses of statute of limitations	—			—			(613		)
Balance at end of period	$	7,121		$	7,119		$	4,590

During the fourth quarter of 2018, the Company finalized the purchase accounting related to its acquisition of Robopolis and recorded a $1.5 million adjustment for uncertain pre-acquisition income tax positions in various taxing jurisdictions against goodwill. In addition, the Company recorded a charge of $2.3 million for estimated taxes associated with a restructuring of the EMEA business during fiscal 2018. The Company accrues interest and, if applicable, penalties for any uncertain tax positions as a component of income tax expense. As of December 28, 2019, December 29, 2018 and December 30, 2017 there were no material accrued interest or penalties.

The Company is subject to taxation in the United States (federal and state) and foreign jurisdictions. The statute of limitations for examinations by the Internal Revenue Service (the "IRS") and state tax authorities is closed for fiscal years prior to 2014. Federal and state carryforward attributes that were generated prior to fiscal 2014 may still be adjusted upon examination by the federal or state tax authorities if they either have been or will be used in a period for which the statute of limitations is still open. The Company is currently under examination by the IRS for the years 2014 and 2015. There are other ongoing audits in various other jurisdictions that are not material to the Company's financial statements. The Company regularly assesses the likelihood of adverse outcomes resulting from these examinations to determine the adequacy of its provision for income taxes. The Company continues to monitor the progress of ongoing discussions with tax authorities and the effect, if any, of the expected expiration of the statute of limitations in various taxing jurisdictions. The Company believes that an adequate provision has been made for any adjustments that may result from tax examinations. However, the outcome of tax audits cannot be predicted with certainty. If any issues addressed in the Company's tax audits are resolved in a manner not consistent with management's expectations, the Company could be required to adjust its provision for income taxes in the period such resolution occurs. Although the timing of resolution, settlement, and closure of audits is not certain, it is reasonably possible that certain U.S. federal and non-U.S. tax audits may be concluded within the next 12 months, which could increase or decrease the balance of the Company's gross unrecognized tax benefits. The Company does not expect a significant change in the amount of unrecognized tax benefits within the next 12 months. If all of the Company's unrecognized tax benefits as of December 28, 2019 were to become recognizable in the future, it would record a $7.4 million benefit, inclusive of interest, to the income tax provision.

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 28, 2019

Accounting Policies [Abstract]

Basis of Presentation

Basis of Presentation and Foreign Currency Translation

Fiscal Year-End

Use of Estimates

Business Combinations

Cash and Cash Equivalents

Short Term Investments



	December 28, 2019				December 29, 2018
	Cost		Fair Market Value		Cost		Fair Market Value
Corporate and government bonds	$	17,016	$	17,032	$	30,035	$	29,605
Convertible note	—		—		2,000		2,000
Total short term investments	$	17,016	$	17,032	$	32,035	$	31,605

Accounts receivable allowances

Inventory

Warranty

Property and Equipment



	Estimated Useful Life
Computer and equipment	2-5 years
Furniture and fixtures	5
Machinery and tooling	2-5
Business applications software	3-7
Leasehold improvements	Lesser of economic benefit period or term of lease

Goodwill and Other Long-Lived Assets

Other Assets

Financial Instruments and Hedging Activities

Fair Value Measurements

•Level 1 - observable inputs such as quoted prices for identical instruments in active markets;


•	Level 2 - inputs other than quoted prices in active markets that are either directly or indirectly observable; and

•

Level 3 - unobservable inputs in which little or no market data exists, therefore requiring an entity to develop its own assumptions.

Stock-Based Compensation

Research and Development

Costs incurred in the research and development of the Company’s products are expensed as incurred.

Advertising Expense

Income Taxes

Concentration of Credit Risk and Significant Customers

The Company maintains its cash in bank deposit accounts and money market funds at high quality financial institutions. The individual balances, at times, may exceed federally insured limits.

Net Income Per Share



	Fiscal Year Ended
	December 28, 2019		December 29, 2018		December 30, 2017
Net income	$	85,300	$	87,992	$	50,964
Weighted-average shares outstanding	28,097		27,692		27,611
Dilutive effect of employee stock plans	638		948		1,142
Diluted weighted-average shares outstanding	28,735		28,640		28,753
Basic income per share	$	3.04	$	3.18	$	1.85
Diluted income per share	$	2.97	$	3.07	$	1.77

Recent Accounting Pronouncements

Recently Adopted Accounting Standards

Recently Issued Accounting Standards

Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 28, 2019

Accounting Policies [Abstract]

Components of available for sale securities



	December 28, 2019				December 29, 2018
	Cost		Fair Market Value		Cost		Fair Market Value
Corporate and government bonds	$	17,016	$	17,032	$	30,035	$	29,605
Convertible note	—		—		2,000		2,000
Total short term investments	$	17,016	$	17,032	$	32,035	$	31,605

Activity related to accounts receivable allowances was as follows (in thousands):



	Fiscal Year Ended
	December 28, 2019			December 29, 2018			December 30, 2017
Allowance for product returns
Balance at beginning of period	$	53,920		$	42,693		$	27,673
Acquired balance	—			—			6,088
Provision	71,575			68,476			54,981
Deduction	(68,217		)	(56,164		)	(43,831		)
Other adjustments	(2,087		)	(1,085		)	(2,218		)
Balance at end of period	$	55,191		$	53,920		$	42,693

Allowance for other credits and incentives
Balance at beginning of period	$	97,737		$	61,359		$	23,658
Acquired balance	—			—			11,932
Adjustment related to adoption of ASC 606	—			1,192			—
Provision	287,891			198,371			110,605
Deduction	(247,775		)	(161,672		)	(81,269		)
Other adjustments	(3,807		)	(1,513		)	(3,567		)
Balance at end of period	$	134,046		$	97,737		$	61,359

Property and equipment

Depreciation is computed using the straight-line method over the estimated useful lives as follows:



	Estimated Useful Life
Computer and equipment	2-5 years
Furniture and fixtures	5
Machinery and tooling	2-5
Business applications software	3-7
Leasehold improvements	Lesser of economic benefit period or term of lease

Property and equipment consists of the following (in thousands):



	December 28, 2019		December 29, 2018
Computer and equipment	$	13,588	$	12,339
Furniture and fixtures	6,494		5,231
Machinery and tooling	79,213		60,281
Leasehold improvements	39,538		28,701
Business applications software	17,933		15,638
Subtotal	156,766		122,190
Less: accumulated depreciation	80,778		65,164
Property and equipment, net	$	75,988	$	57,026

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 28, 2019		December 29, 2018		December 30, 2017
Net income	$	85,300	$	87,992	$	50,964
Weighted-average shares outstanding	28,097		27,692		27,611
Dilutive effect of employee stock plans	638		948		1,142
Diluted weighted-average shares outstanding	28,735		28,640		28,753
Basic income per share	$	3.04	$	3.18	$	1.85
Diluted income per share	$	2.97	$	3.07	$	1.77

Business Combinations (Tables)

12 Months Ended

Dec. 28, 2019

Business Combinations [Abstract]

Schedule of allocation of purchase price

The following table summarizes the final allocation of the purchase price (in thousands):



Cash	$	125
Accounts receivable, net (1)	(5,496		)
Inventory	18,290
Other assets	2,065
Deferred tax assets, net	409
Goodwill	—
Intangible assets	8,640
Total assets acquired	24,033

Accrued expenses and other current liabilities	(4,450		)
Other liabilities	(691		)
Total liabilities assumed	(5,141		)
Net assets acquired	$	18,892
Gain on business acquisition	(2,243		)
Total purchase price	$	16,649

(1) The accounts receivable balance reflects reserves for product returns, discounts and promotions assumed as part of the acquisition.

The following table summarizes the final allocation of the purchase price (in thousands):



Cash	$	37,981
Accounts receivable, net (1)	21,426
Inventory	36,304
Goodwill	80,419
Intangible assets	36,597
Other assets	2,456
Total assets	215,183

Accounts payable	(29,391		)
Accrued expenses	(3,376		)
Deferred tax liabilities	(10,864		)
Other liabilities	(2,138		)
Total liabilities assumed	(45,769		)
Net assets acquired	$	169,414

Schedule of acquired intangible assets

The following table reflects the fair value of the acquired identifiable intangible assets and related estimates of useful lives (in thousands):

The following table reflects the fair value of the acquired identifiable intangible assets and related estimates of useful lives (in thousands):



	Useful Life	Fair Value
Reacquired distribution rights	2.25 years	$	29,296
Customer relationships	14 years	7,029
Non-competition agreements	3 years	272
Total		$	36,597

Schedule of pro forma results

Pro Forma Results (Unaudited)

The following table shows unaudited pro forma results of operations as if the Company had acquired Robopolis on January 1, 2017 (in thousands, except per share amounts):



	Fiscal Year Ended
	December 30, 2017
Revenue	$	901,612
Net income	51,887
Net income per share:
Basic income per share	$	1.88
Diluted income per share	$	1.80

Goodwill and other intangible assets (Tables)

12 Months Ended

Dec. 28, 2019

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of goodwill

The following table summarizes the activity in the carrying amount of goodwill for fiscal years 2019 and 2018 (in thousands):



Balance as of December 30, 2017	$	121,440
Purchase accounting adjustments	830
Effect of foreign currency translation	(3,374		)
Balance as of December 29, 2018	118,896
Acquisition	2,050
Effect of foreign currency translation	(2,214		)
Balance as of December 28, 2019	$	118,732

Other intangible assets

Intangible assets consisted of the following (in thousands):



	December 28, 2019						December 29, 2018
	Cost		Accumulated Amortization		Net		Cost		Accumulated Amortization		Net
Completed technology	$	28,100	$	24,605	$	3,495	$	26,900	$	21,607	$	5,293
Tradename	100		100		—		100		100		—
Customer relationships	11,095		2,302		8,793		11,291		1,365		9,926
Reacquired distribution rights	31,680		31,680		—		32,499		23,598		8,901
Non-competition agreements	256		192		64		263		110		153
Total	$	71,231	$	58,879	$	12,352	$	71,053	$	46,780	$	24,273

Estimated future amortization expense related to current intangible assets

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):



	Cost of Revenue		Operating Expenses		Total
2020	$	1,140	$	1,000	$	2,140
2021	1,140		781		1,921
2022	915		781		1,696
2023	240		781		1,021
2024	60		781		841
Thereafter	—		4,733		4,733
Total	$	3,495	$	8,857	$	12,352

Derivative Instruments and Hedging Activities (Tables)

12 Months Ended

Dec. 28, 2019

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Schedule of fair values of derivative instruments

The fair values of derivative instruments are as follows (in thousands):



		Fair Value
	Classification	December 28, 2019		December 29, 2018
Derivatives not designated as hedging instruments:
Foreign currency forward contracts	Other current assets	$	1,855	$	551
Foreign currency forward contracts	Accrued expenses	297		—
Derivatives designated as cash flow hedges:
Foreign currency forward contracts	Other current assets	$	4,347	$	53
Foreign currency forward contracts	Other assets	9,112		172
Foreign currency forward contracts	Accrued expenses	47		335
Foreign currency forward contracts	Long-term liabilities	414		795

Schedule of derivative instruments gain (loss)

Gains (losses) associated with derivative instruments not designated as hedging instruments are as follows (in thousands):



		Fiscal year ended
	Classification	December 28, 2019		December 29, 2018
Gain (loss) recognized in income	Other income, net	$	89	$	1,568

The following tables reflect the effect of derivatives designated as cash flow hedging for the years ended (in thousands):



	Gain (loss) recognized in OCI on Derivative (1)
	Fiscal year ended
	December 28, 2019		December 29, 2018

Foreign currency forward contracts	$	16,483	$	(686	)


(1)	The amount represents the change in fair value of derivative contracts due to changes in spot rates.



	Gain (loss) recognized in earnings on cash flow hedging instruments
	December 28, 2019				December 29, 2018
	Revenue		Cost of revenue		Revenue		Cost of revenue
Consolidated statements of income in which the effects of cash flow hedging instruments are recorded	$	1,214,010	$	670,083	$	1,092,584	$	537,156

Gain or (loss) on cash flow hedging relationships:
Foreign currency forward contracts:
Amount of gain (loss) reclassified from AOCI into earnings	$	1,889	$	—	$	948	$	(386	)

Fair Value Measurements (Tables)

12 Months Ended

Dec. 28, 2019

Fair Value Disclosures [Abstract]

Schedule of financial assets and liabilities measured at fair value on a recurring basis

The Company’s financial assets and liabilities measured at fair value on a recurring basis were as follows (in thousands):



	Fair Value Measurements as of
	December 28, 2019
	Level 1		Level 2 (1)		Level 3 (2)
Assets:
Corporate and government bonds, $17,016 at cost (3)	$	—	$	17,032	$	—
Derivative instruments (Note 11)	—		15,314		—
Total assets measured at fair value	$	—	$	32,346	$	—

Liabilities:
Derivative instruments (Note 11)	$	—	$	758	$	—
Total liabilities measured at fair value	$	—	$	758	$	—

The Company’s financial assets and liabilities measured at fair value on a recurring basis were as follows (in thousands):



	Fair Value Measurements as of
	December 29, 2018
	Level 1		Level 2 (1)		Level 3 (2)
Assets:
Money market funds	$	3,730	$	—	$	—
Corporate and government bonds, $30,035 at cost	—		29,605		—
Convertible note	—		—		2,000
Derivative instruments (Note 11)	—		776		—
Total assets measured at fair value	$	3,730	$	30,381	$	2,000

Liabilities:
Derivative instruments (Note 11)	$	—	$	1,130	$	—
Total liabilities measured at fair value	$	—	$	1,130	$	—


(1)	Level 2 fair value estimates are based on observable inputs other than quoted prices in active markets for identical assets and liabilities, quoted prices for identical or similar assets or liabilities in inactive markets, or other inputs that

are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities.

(2)


(3)	As of December 28, 2019, the Company’s investments had maturity dates ranging from February 2020 to March 2021.

Stock-Based Compensation (Tables)

12 Months Ended

Dec. 28, 2019

Share based compensation expense by classification [Line Items]

Share based compensation expense by classification [Table Text Block]

Stock-based compensation breaks down by expense classification as follows (in thousands):



	Fiscal Year Ended
	December 28, 2019		December 29, 2018		December 30, 2017
Cost of revenue	$	1,486	$	1,407	$	1,082
Research and development	9,186		7,494		5,009
Selling and marketing	3,323		2,842		2,571
General and administrative	9,749		14,061		11,089
Total	$	23,744	$	25,804	$	19,751

Summary of stock option plan activity

The following table summarizes stock option activity for fiscal years 2019, 2018 and 2017:



	Number of Shares		Weighted Average Exercise Price		Weighted Average Remaining Contractual Term	Aggregate Intrinsic Value(1)
Outstanding at December 31, 2016	1,088,174		$	32.27
Granted	10,975		57.33
Exercised	(367,267	)	28.79
Canceled	(18,928	)	36.72
Outstanding at December 30, 2017	712,954		$	34.34
Granted	—		—
Exercised	(239,830	)	33.40
Canceled	(10,863	)	46.20
Outstanding at December 29, 2018	462,261		$	34.55
Granted	—		—
Exercised	(127,024	)	32.95
Canceled	(12,329	)	37.03
Outstanding at December 28, 2019	322,908		$	35.08	2.47 years	$5.65 million
Vested and expected to vest at December 28, 2019	322,908		$	35.08	2.47 years	$5.65 million
Exercisable as of December 28, 2019	293,159		$	34.30	2.35 years	$5.32 million

_________________________

(1)

The aggregate intrinsic value on the table above represents the difference between the Company's closing stock price on December 28, 2019 of $50.20 and the exercise price of the underlying in-the-money option.

Activities relating to time based restricted stock units

The following table summarizes the time-based restricted stock unit activity for fiscal years 2019, 2018 and 2017:



	Number of Shares Underlying Restricted Stock		Weighted Average Grant Date Fair Value
Outstanding at December 31, 2016	935,179		$	35.07
Granted	396,164		72.63
Vested	(351,543	)	33.73
Forfeited	(41,347	)	39.52
Outstanding at December 30, 2017	938,453		$	51.24
Granted	307,614		81.55
Vested	(351,816	)	47.30
Forfeited	(38,362	)	60.62
Outstanding at December 29, 2018	855,889		$	63.32
Granted	407,325		79.91
Vested	(358,119	)	54.89
Forfeited	(85,863	)	76.85
Outstanding at December 28, 2019	819,232		$	73.83

Activities relating to performance based restricted stock units

The following table summarizes the performance-based restricted stock unit activity for fiscal years 2019, 2018 and 2017:



	Number of Shares Underlying PSU		Weighted Average Grant Date Fair Value
Outstanding at December 31, 2016	163,911		$	35.03
Granted	105,650		57.33
Vested	(24,792	)	43.35
Forfeited	(2,708	)	39.71
Outstanding at December 30, 2017	242,061		$	43.97
Granted	91,538		68.41
Vested	(56,259	)	34.30
Forfeited	(3,221	)	45.71
Outstanding at December 29, 2018	274,119		$	54.10
Granted	70,827		122.20
Vested	(78,943	)	33.33
Forfeited	(49,772	)	78.29
Outstanding at December 28, 2019	216,231		$	78.42

Schedule of Share-based Payment Award, Employee Stock Purchase Plan, Valuation Assumptions [Table Text Block]

Employee Stock Purchase Plan

Income Taxes (Tables)

12 Months Ended

Dec. 28, 2019

Income Tax Disclosure [Abstract]

Schedule of income (loss) before provision for income taxes

Income (loss) before provision for income taxes was as follows (in thousands):



	Fiscal Year Ended
	December 28, 2019		December 29, 2018			December 30, 2017
Domestic	$	84,225	$	113,078		$	71,382
Foreign	14,608		(4,456		)	4,984
Income before income taxes	$	98,833	$	108,622		$	76,366

Components of income tax expense

The components of income tax expense were as follows (in thousands):



	Fiscal Year Ended
	December 28, 2019			December 29, 2018			December 30, 2017
Current
Federal	$	13,366		$	17,627		$	17,555
State	5,004			3,676			1,691
Foreign	6,941			10,732			7,355
Total current income tax provision	$	25,311		$	32,035		$	26,601
Deferred
Federal	$	(9,345	)	$	(2,475	)	$	6,664
State	(1,783		)	(1,149		)	(2,470		)
Foreign	(650		)	(7,781		)	(5,393		)
Total deferred income tax provision	(11,778		)	(11,405		)	(1,199		)
Total income tax provision	$	13,533		$	20,630		$	25,402

Reconciliation of the expected tax (benefit) expense

The reconciliation of statutory federal income tax to actual tax expense is as follows (in thousands):



	Fiscal Year Ended
	December 28, 2019			December 29, 2018			December 30, 2017
Statutory federal income tax	$	20,755		$	22,812		$	26,728
State taxes (net of federal benefit)	3,999			4,312			2,089
Federal and state credits	(8,152		)	(5,638		)	(4,486		)
Domestic production activities deduction	—			—			(1,528		)
Excess tax benefits relating to stock-based compensation	(6,468		)	(6,529		)	(11,709		)
Tax Cuts and Jobs Act of 2017	—			2,127			11,861
Foreign-derived intangible income deduction	(4,180		)	(2,678		)	—
EMEA business restructuring	—			2,292			—
Executive compensation	2,081			745			1,354
Tax impact of foreign earnings	1,986			1,336			(636		)
Change in valuation allowance	2,678			348			800
Other	834			1,503			929
	$	13,533		$	20,630		$	25,402

Components of net deferred tax assets

The components of net deferred tax assets were as follows (in thousands):



	December 28, 2019			December 29, 2018
Deferred tax assets
Revenue reserves	$	21,355		$	17,420
Accruals and other liabilities	8,225			7,844
Operating lease liabilities	14,117			—
Tax credits and net operating loss carryforwards	8,814			7,781
Stock-based compensation	4,981			4,975
Other	5,068			4,087
Gross deferred tax assets	62,560			42,107
Valuation allowance	(3,826		)	(1,148		)
Total deferred tax assets	58,734			40,959
Deferred tax liabilities
Intangible assets	3,838			7,317
Operating lease right-of-use assets	13,249			—
Other	768			668
Total deferred tax liabilities	17,855			7,985
Net deferred tax assets	$	40,879		$	32,974

Schedule of adjustments to uncertain tax position

A summary of the Company’s adjustments to its gross unrecognized tax benefits in the current year is as follows (in thousands):



	Fiscal Year Ended
	December 28, 2019			December 29, 2018			December 30, 2017
Balance at beginning of period	$	7,119		$	4,590		$	5,146
Increase for tax positions related to the current year	770			2,891			580
Increase for tax positions related to acquisition	—			1,493			—
Increase (decrease) for tax positions related to prior years	(768		)	407			(523		)
Decrease for settlements with applicable taxing authorities	—			(2,262		)	—
Decrease for lapses of statute of limitations	—			—			(613		)
Balance at end of period	$	7,121		$	7,119		$	4,590

- Accounts Receivable Allowances (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Allowance for Doubtful Accounts, Premiums and Other Receivables	$ 1,000
Allowance for other credits and incentives [Member]
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	97,737	$ 61,359	$ 23,658
Acquired balance	0	0	11,932
Adjustment related to adoption of ASC 606	0	1,192	0
Provision	287,891	198,371	110,605
Deduction	(247,775)	(161,672)	(81,269)
Other adjustments	(3,807)	(1,513)	(3,567)
Balance at end of period	134,046	97,737	61,359
Allowance for product returns [Member]
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	53,920	42,693	27,673
Acquired balance	0	0	6,088
Provision	71,575	68,476	54,981
Deduction	(68,217)	(56,164)	(43,831)
Other adjustments	(2,087)	(1,085)	(2,218)
Balance at end of period	$ 55,191	$ 53,920	$ 42,693

- Property and Equipment (Details)	12 Months Ended
- Property and Equipment (Details)	Dec. 28, 2019
Leasehold improvements
Property, Plant and Equipment [Line Items]
Capital Leases and Leasehold Improvements Terms	Lesser of economic benefit period or term of lease
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	5 years
Minimum \| Computer and equipment
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	2 years
Minimum \| Machinery and tooling
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	2 years
Minimum \| Tooling
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	2 years
Minimum \| Business applications software
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	3 years
Maximum \| Computer and equipment
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	5 years
Maximum \| Machinery and tooling
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	5 years
Maximum \| Tooling
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	5 years
Maximum \| Business applications software
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	7 years

- Net Income Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 28, 2019	Sep. 28, 2019	Jun. 29, 2019	Mar. 30, 2019	Dec. 29, 2018	Sep. 29, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Basic and Diluted Net Income Per Share
Net income	$ 20,041	$ 35,532	$ 7,207	$ 22,520	$ 25,191	$ 31,929	$ 10,471	$ 20,401	$ 85,300	$ 87,992	$ 50,964
Weighted-average shares outstanding									28,097	27,692	27,611
Dilutive effect of employee stock plans									638	948	1,142
Diluted weighted-average shares outstanding									28,735	28,640	28,753
Basic									$ 3.04	$ 3.18	$ 1.85
Diluted	$ 0.70	$ 1.24	$ 0.25	$ 0.78	$ 0.88	$ 1.12	$ 0.37	$ 0.71	$ 2.97	$ 3.07	$ 1.77

- Definition

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

+ References

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+ Details

- Definition

The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

+ References

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+ Details

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References + Details

Summary of Significant Accounting Policies - Narrative (Details) - USD ($) $ in Thousands, shares in Millions	3 Months Ended	12 Months Ended
	Dec. 30, 2017	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017	Dec. 31, 2016
Accounting Policies [Line Items]
Document Period End Date		Dec. 28, 2019
Equity Securities without Readily Determinable Fair Value, Amount		$ 21,000	$ 15,100
Cash equivalents		239,400	130,400
Advertising Expense		125,000	114,000	$ 91,800
Valuation allowance	$ 800	$ 3,826	$ 1,148	$ 800
Tax Cuts and Jobs Act of 2017, income tax expense (benefit), transition tax fior accumulated foreign earnings	3,000
Tax Cuts and Jobs Act of 2017, income tax expense (benefit)	11,900
Tax Cuts and Jobs Act of 2017, income tax expense (benefit), remeasurement of certain deferred tax assets and liabilities	8,900
Antidilutive securities excluded from computation of earnings per share (in shares)		0.2	0.0	0.0
Customer Concentration Risk \| Accounts Receivable \| Two Customers [Member]
Accounting Policies [Line Items]
Concentration risk percentage		26.60%	23.10%
Customer Concentration Risk \| Revenue \| Amazon [Member]
Accounting Policies [Line Items]
Concentration risk percentage		21.30%	17.30%	13.50%
Allowance for product returns
Accounting Policies [Line Items]
Valuation allowances and reserves	$ 42,693	$ 55,191	$ 53,920	$ 42,693	$ 27,673

Revenue Recognition Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 28, 2019	Sep. 28, 2019	Jun. 29, 2019	Mar. 30, 2019	Dec. 29, 2018	Sep. 29, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Disaggregation of Revenue [Line Items]
Revenues	$ 426,778	$ 289,399	$ 260,172	$ 237,661	$ 384,665	$ 264,534	$ 226,317	$ 217,068	$ 1,214,010	$ 1,092,584	$ 883,911
UNITED STATES
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax									603,618	560,995
EMEA [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax									357,760	311,659
All Other Regions [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax									$ 252,632	$ 219,930

Leases (Details) - USD ($) $ in Thousands	12 Months Ended
Leases (Details) - USD ($) $ in Thousands	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Leases [Abstract]
Operating Lease, Payments	$ 9,540
Operating Lease, Weighted Average Discount Rate, Percent	3.61%
Operating Lease, Weighted Average Remaining Lease Term	9 years 2 months 15 days
Operating Lease, Cost	$ 8,777
Variable Lease, Cost	4,096
Operating Leases, Rent Expense, Net	12,873	$ 12,900	$ 8,900
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	$ 53,227

Leases Maturity of Operating Lease Liability (Details) - USD ($) $ in Thousands	Dec. 28, 2019	Dec. 29, 2018
Leases [Abstract]
Lessee, Operating Lease, Liability, Payments, Due Next Twelve Months	$ 8,936
Lessee, Operating Lease, Liability, Payments, Due Year Two	8,263
Lessee, Operating Lease, Liability, Payments, Due Year Three	7,592
Lessee, Operating Lease, Liability, Payments, Due Year Four	7,145
Lessee, Operating Lease, Liability, Payments, Due Year Five	6,308
Lessee, Operating Lease, Liability, Payments, Due after Year Five	34,957
Lessee, Operating Lease, Liability, Payments, Due	73,201
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	11,430
Operating Lease, Liability	61,771
Current portion of operating lease liabilities	6,843	$ 0
Operating Lease, Liability, Noncurrent	$ 54,928	$ 0

Business Combinations - Robopolis Acquisition (Details) - USD ($) $ in Thousands		12 Months Ended
	Oct. 02, 2017	Dec. 29, 2018	Dec. 28, 2019	Dec. 30, 2017
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Goodwill		$ 118,896	$ 118,732	$ 121,440
Goodwill, Purchase Accounting Adjustments		$ 830
Robopolis
Business Acquisition [Line Items]
Payments to acquire business net of cash acquired	$ 169,400
Cash acquired from acquisition	38,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Cash	37,981
Accounts receivable, net (1)	21,426
Inventory	36,304
Goodwill	80,419
Intangible assets	36,597
Other assets	2,456
Total assets	215,183
Accounts payable	(29,391)
Accrued expenses	(3,376)
Deferred tax liabilities	(10,864)
Other liabilities	(2,138)
Total liabilities assumed	45,769
Net assets acquired	169,414
Intangible assets acquired, fair value	$ 36,597
Reacquired distribution rights \| Robopolis
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Intangible assets, useful life	2 years 3 months
Intangible assets acquired, fair value	$ 29,296
Customer relationships \| Robopolis
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Intangible assets, useful life	14 years
Intangible assets acquired, fair value	$ 7,029
Non-competition agreements \| Robopolis
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Intangible assets, useful life	3 years
Intangible assets acquired, fair value	$ 272

Business Combinations - Sales On Demand Corporation Acquisition (Details) - USD ($) $ in Thousands			12 Months Ended
	Oct. 02, 2017	Apr. 03, 2017	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Goodwill			$ 118,732	$ 118,896	$ 121,440
Gain on business acquisition			$ 0	0	$ 2,243
Sales On Demand Corporation
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross				16,649
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Cash		$ 125
Accounts receivable, net (1)		(5,496)
Inventory		18,290
Deferred tax assets, net		409
Goodwill		0
Intangible assets		8,640
Total assets		24,033
Accrued expenses and other current liabilities		(4,450)
Other liabilities		(691)
Total liabilities assumed		(5,141)
Net assets acquired		18,892
Gain on business acquisition				$ 2,243
Intangible assets acquired, fair value		8,640
Other assets		$ 2,065
Sales On Demand Corporation \| Customer relationships
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Intangible assets, useful life		13 years
Intangible assets acquired, fair value		$ 4,490
Sales On Demand Corporation \| Reacquired distribution rights
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Intangible assets, useful life		9 months
Intangible assets acquired, fair value		$ 4,150
Robopolis
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross	$ 169,400
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Cash	37,981
Accounts receivable, net (1)	21,426
Inventory	36,304
Goodwill	80,419
Intangible assets	36,597
Total assets	215,183
Other liabilities	(2,138)
Total liabilities assumed	(45,769)
Net assets acquired	169,414
Intangible assets acquired, fair value	36,597
Other assets	$ 2,456
Robopolis \| Customer relationships
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Intangible assets, useful life	14 years
Intangible assets acquired, fair value	$ 7,029
Robopolis \| Reacquired distribution rights
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Intangible assets, useful life	2 years 3 months
Intangible assets acquired, fair value	$ 29,296

Business Combinations - Pro Forma (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 28, 2019	Sep. 28, 2019	Jun. 29, 2019	Mar. 30, 2019	Dec. 29, 2018	Sep. 29, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Business Combinations [Abstract]
Revenue	$ 426,778	$ 289,399	$ 260,172	$ 237,661	$ 384,665	$ 264,534	$ 226,317	$ 217,068	$ 1,214,010	$ 1,092,584	$ 883,911
Revenue											901,612
Net income	$ 20,041	$ 35,532	$ 7,207	$ 22,520	$ 25,191	$ 31,929	$ 10,471	$ 20,401	$ 85,300	$ 87,992	50,964
Net income											$ 51,887
Basic									$ 3.04	$ 3.18	$ 1.85
Basic income per share (in dollars per share)											1.88
Diluted	$ 0.70	$ 1.24	$ 0.25	$ 0.78	$ 0.88	$ 1.12	$ 0.37	$ 0.71	$ 2.97	$ 3.07	1.77
Diluted income per share (in dollars per share)											$ 1.80

- Definition

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References + Details

Property and Equipment 1 (Details) - USD ($) $ in Thousands	12 Months Ended
Property and Equipment 1 (Details) - USD ($) $ in Thousands	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Property, Plant and Equipment [Line Items]
Subtotal	$ 156,766	$ 122,190
Less: accumulated depreciation	80,778	65,164
Property and equipment, net	75,988	57,026
Capitalized Computer Software, Net	6,800	4,700
Depreciation	24,400	17,000	$ 12,300
Capitalized Computer Software, Amortization	1,500	1,200	$ 1,500
Computer and equipment
Property, Plant and Equipment [Line Items]
Subtotal	13,588	12,339
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Subtotal	6,494	5,231
Machinery and tooling
Property, Plant and Equipment [Line Items]
Subtotal	79,213	60,281
Leasehold improvements
Property, Plant and Equipment [Line Items]
Subtotal	39,538	28,701
Business applications software
Property, Plant and Equipment [Line Items]
Subtotal	$ 17,933	$ 15,638

Goodwill and other intangible assets - Goodwill (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill, Acquired During Period	$ 2,050
Goodwill [Roll Forward]
Goodwill	118,896	$ 121,440
Acquisition		830
Effect of foreign currency translation	(2,214)	(3,374)
Goodwill	$ 118,732	$ 118,896

Goodwill and other intangible assets - Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 28, 2019	Dec. 29, 2018
Finite-Lived Intangible Assets, Net [Abstract]
Cost	$ 71,231	$ 71,053
Accumulated Amortization	58,879	46,780
Net	12,352	24,273
Completed technology
Finite-Lived Intangible Assets, Net [Abstract]
Cost	28,100	26,900
Accumulated Amortization	24,605	21,607
Net	3,495	5,293
Tradename
Finite-Lived Intangible Assets, Net [Abstract]
Cost	100	100
Accumulated Amortization	100	100
Net	0	0
Customer relationships
Finite-Lived Intangible Assets, Net [Abstract]
Cost	11,095	11,291
Accumulated Amortization	2,302	1,365
Net	8,793	9,926
Reacquired distribution rights
Finite-Lived Intangible Assets, Net [Abstract]
Cost	31,680	32,499
Accumulated Amortization	31,680	23,598
Net	0	8,901
Non-competition agreements
Finite-Lived Intangible Assets, Net [Abstract]
Cost	256	263
Accumulated Amortization	192	110
Net	$ 64	$ 153

Goodwill and other intangible assets - Future Amortization Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months	$ 2,140
Finite-Lived Intangible Assets, Amortization Expense, Year Two	1,921
Finite-Lived Intangible Assets, Amortization Expense, Year Three	1,696
Finite-Lived Intangible Assets, Amortization Expense, Year Four	1,021
Finite-Lived Intangible Assets, Amortization Expense, Year Five	841
Finite-Lived Intangible Assets, Amortization Expense, after Year Five	4,733
Finite-lived intangible assets, future amortization total	12,352
Amortization of intangible assets	12,800	$ 19,600	$ 13,100
Cost of revenue
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months	1,140
Finite-Lived Intangible Assets, Amortization Expense, Year Two	1,140
Finite-Lived Intangible Assets, Amortization Expense, Year Three	915
Finite-Lived Intangible Assets, Amortization Expense, Year Four	240
Finite-Lived Intangible Assets, Amortization Expense, Year Five	60
Finite-Lived Intangible Assets, Amortization Expense, after Year Five	0
Finite-lived intangible assets, future amortization total	3,495
Operating Expense [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months	1,000
Finite-Lived Intangible Assets, Amortization Expense, Year Two	781
Finite-Lived Intangible Assets, Amortization Expense, Year Three	781
Finite-Lived Intangible Assets, Amortization Expense, Year Four	781
Finite-Lived Intangible Assets, Amortization Expense, Year Five	781
Finite-Lived Intangible Assets, Amortization Expense, after Year Five	4,733
Finite-lived intangible assets, future amortization total	$ 8,857

Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 28, 2019	Dec. 29, 2018
Components of accrued expenses
Accrued warranty	$ 13,856	$ 11,964
Accrued other compensation	13,331	10,518
Accrued bonus	12,541	21,226
Accrued sales and other indirect taxes payable	12,440	11,397
Accrued direct fulfillment costs	10,582	5,372
Current portion of operating lease liabilities	6,843	0
Accrued federal and state income taxes	3,378	1,936
Accrued other	8,797	8,846
Accrued expenses, total	$ 81,768	$ 71,259

Working Capital Facilities (Details) $ in Thousands, ¥ in Millions	12 Months Ended
	Dec. 28, 2019 USD ($)	Dec. 28, 2019 JPY (¥)	Dec. 30, 2017 USD ($)
Debt Disclosure [Abstract]
Letters of Credit Outstanding, Amount	$ 500
Revolving Line of Credit (Textual) [Abstract]
Maximum amount available for borrowing under credit facility	$ 150,000		$ 75,000
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%	1.00%
Interest Rate Above the Federal Fund Rate Under Condition Two	0.50%	0.50%
Interest rate above the LIBOR rate plus under condition two	1.00%	1.00%
Line of Credit Facility, Amount Outstanding	$ 0
Letter of credit facility, maximum borrowing	$ 5,000
Line of credit, maximum amount \| ¥		¥ 220.0

Derivative Instruments and Hedging Activities - Fair Value of Derivatives (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018
Derivatives not designated as hedging instruments:
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	$ 58,400	$ 56,000
Foreign currency forward contracts \| Derivatives not designated as hedging instruments: \| Other current assets
Derivative, Fair Value, Net [Abstract]
Derivative Asset	1,855	551
Foreign currency forward contracts \| Derivatives not designated as hedging instruments: \| Accrued expenses
Derivative, Fair Value, Net [Abstract]
Derivative Liability	297	0
Cash flow hedge \| Derivatives designated as cash flow hedges:
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	424,600	366,700
Cash flow hedge \| Foreign currency forward contracts \| Derivatives designated as cash flow hedges: \| Other current assets
Derivative, Fair Value, Net [Abstract]
Derivative Asset	4,347	53
Cash flow hedge \| Foreign currency forward contracts \| Derivatives designated as cash flow hedges: \| Other assets
Derivative, Fair Value, Net [Abstract]
Derivative Asset	9,112	172
Cash flow hedge \| Foreign currency forward contracts \| Derivatives designated as cash flow hedges: \| Accrued expenses
Derivative, Fair Value, Net [Abstract]
Derivative Liability	47	335
Cash flow hedge \| Foreign currency forward contracts \| Derivatives designated as cash flow hedges: \| Other Noncurrent Liabilities [Member]
Derivative, Fair Value, Net [Abstract]
Derivative Liability	$ 414	$ 795
Maximum \| Derivatives not designated as hedging instruments:
Derivatives, Fair Value [Line Items]
Derivative, Term of Contract	10 months
Maximum \| Cash flow hedge \| Derivatives designated as cash flow hedges:
Derivatives, Fair Value [Line Items]
Derivative, Term of Contract	37 months

Derivative Instruments and Hedging Activities - Gain (Loss) on Derivatives (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 28, 2019	Sep. 28, 2019	Jun. 29, 2019	Mar. 30, 2019	Dec. 29, 2018	Sep. 29, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Revenue	$ 426,778	$ 289,399	$ 260,172	$ 237,661	$ 384,665	$ 264,534	$ 226,317	$ 217,068	$ 1,214,010	$ 1,092,584	$ 883,911
Cost of Goods and Services Sold									670,083	537,156	$ 450,752
Other income, net
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recognized in income									89	1,568
Foreign currency forward contracts \| Cash flow hedge
Derivative Instruments, Gain (Loss) [Line Items]
Effective portion, Gain (loss) recognized in OCI on Derivative									16,483	(686)
Foreign currency forward contracts \| Revenue \| Cash flow hedge
Derivative Instruments, Gain (Loss) [Line Items]
Effective portion, Gain (loss) reclassified from accumulated OCI into income									1,889	948
Foreign currency forward contracts \| Cost of revenue \| Cash flow hedge
Derivative Instruments, Gain (Loss) [Line Items]
Effective portion, Gain (loss) reclassified from accumulated OCI into income									$ 0	$ (386)
Derivatives designated as cash flow hedges: \| Maximum \| Cash flow hedge
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Term of Contract									37 months

Fair Value Measurements (Details) - USD ($) $ in Thousands	12 Months Ended
Fair Value Measurements (Details) - USD ($) $ in Thousands	Dec. 28, 2019	Dec. 29, 2018
Assets:
Convertible note	$ 0	$ 2,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	(2,000)
Recurring \| Level 1
Assets:
Corporate and government bonds, $17,016 at cost (3)	0	0
Convertible note		0
Derivative instruments (Note 11)	0	0
Total assets measured at fair value	0	3,730
Liabilities:
Derivative instruments (Note 11)	0	0
Total liabilities measured at fair value	0	0
Recurring \| Level 1 \| Money market funds
Assets:
Money market funds		3,730
Recurring \| Level 2
Assets:
Corporate and government bonds, $17,016 at cost (3)	17,032	29,605
Convertible note		0
Derivative instruments (Note 11)	15,314	776
Total assets measured at fair value	32,346	30,381
Liabilities:
Derivative instruments (Note 11)	758	1,130
Total liabilities measured at fair value	758	1,130
Recurring \| Level 2 \| Money market funds
Assets:
Money market funds		0
Recurring \| Level 3 (2)
Assets:
Corporate and government bonds, $17,016 at cost (3)	0	0
Convertible note		2,000
Derivative instruments (Note 11)	0	0
Total assets measured at fair value	0	2,000
Liabilities:
Derivative instruments (Note 11)	0	0
Total liabilities measured at fair value	$ 0	0
Recurring \| Level 3 (2) \| Money market funds
Assets:
Money market funds		$ 0

Stockholders' Equity (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 29, 2018 USD ($) $ / shares shares	Dec. 28, 2019 vote $ / shares shares	Feb. 27, 2018 USD ($)
Equity [Abstract]
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, par value (in dollars per share) \| $ / shares	$ 0.01	$ 0.01
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, votes per share \| vote		1
Stock repurchase program, authorized amount \| $			$ 50,000
Stock repurchases (in shares)	798,794
Stock repurchases \| $	$ 50,000

Stock-Based Compensation - Stock Options Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
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	0	0	10,975
Document Period End Date	Dec. 28, 2019
Compensation not yet recognized, options	$ 400
Summary of stock option plan activity
Number of Shares, Beginning Balance	462,261	712,954	1,088,174
Number of Shares, Exercised	(127,024)	(239,830)	(367,267)
Number of Shares, Canceled	(12,329)	(10,863)	(18,928)
Number of Shares, Ending Balance	322,908	462,261	712,954
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Weighted Average Exercise Price, Beginning Balance (in dollars per share)	$ 34.55	$ 34.34	$ 32.27
Weighted Average Exercise Price, Granted (in dollars per share)	0	0	57.33
Weighted Average Exercise Price, Exercised (in dollars per share)	32.95	33.40	28.79
Weighted Average Exercise Price, Canceled (in dollars per share)	37.03	46.20	36.72
Weighted Average Exercise Price, Ending Balance (in dollars per share)	$ 35.08	$ 34.55	$ 34.34
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Number of Shares, Vested and expected to vest	322,908
Number of Shares, Exercisable	293,159
Weighted Average Exercise Price, Vested and expected to vest (in dollars per share)	$ 35.08
Weighted Average Exercise Price, Exercisable (in dollars per share)	$ 34.30
Weighted Average Remaining Contractual Term, Vested and expected to vest	2 years 5 months 19 days
Weighted Average Remaining Contractual Term, Ending Balance	2 years 5 months 19 days
Weighted Average Remaining Contractual Term, Exercisable	2 years 4 months 6 days
Aggregate Intrinsic Value, Ending Balance	$ 5,650
Aggregate Intrinsic Value, Vested and expected to vest	5,650
Aggregate Intrinsic Value, Exercisable	$ 5,320
Share price (in dollars per share)	$ 50.20
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average remaining recognition period	7 months 9 days
Employee Stock Option \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	4 years
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period	5 years
Employee Stock Option \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period	10 years
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Terms of Award	four year
Weighted average remaining recognition period	2 years 6 months 10 days

Stock-Based Compensation - RSUs and PSUs (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Share price (in dollars per share)	$ 50.20
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost not yet recognized	$ 49.2
Weighted average remaining recognition period	2 years 6 months 10 days
Activities relating to restricted stock awards
Number of Shares Underlying Restricted Stock, Beginning Balance	855,889	938,453	935,179
Number of Shares Underlying Restricted Stock, Granted	407,325	307,614	396,164
Number of Shares Underlying Restricted Stock, Vested	(358,119)	(351,816)	(351,543)
Number of Shares Underlying Restricted Stock, Forfeited	(85,863)	(38,362)	(41,347)
Number of Shares Underlying Restricted Stock, Ending Balance	819,232	855,889	938,453
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Weighted Average Grant Date Fair Value, Beginning Balance (in dollars per share)	$ 63.32	$ 51.24	$ 35.07
Weighted Average Grant Date Fair Value, Granted (in dollars per share)	79.91	81.55	72.63
Weighted Average Grant Date Fair Value, Vested (in dollars per share)	54.89	47.30	33.73
Weighted Average Grant Date Fair Value, Forfeited (in dollars per share)	76.85	60.62	39.52
Weighted Average Grant Date Fair Value, Ending Balance (in dollars per share)	$ 73.83	$ 63.32	$ 51.24
Outstanding, aggregate intrinsic value	$ 42.8
Outstanding, weighted average remaining contractual term	1 year 6 months 7 days
Share-based Compensation Arrangement by Share-based Payment Award, Terms of Award	four year
Performance Based Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost not yet recognized	$ 1.7
Weighted average remaining recognition period	1 year 14 days
Activities relating to restricted stock awards
Number of Shares Underlying Restricted Stock, Beginning Balance	274,119	242,061	163,911
Number of Shares Underlying Restricted Stock, Granted	70,827	91,538	105,650
Number of Shares Underlying Restricted Stock, Vested	(78,943)	(56,259)	(24,792)
Number of Shares Underlying Restricted Stock, Forfeited	(49,772)	(3,221)	(2,708)
Number of Shares Underlying Restricted Stock, Ending Balance	216,231	274,119	242,061
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Weighted Average Grant Date Fair Value, Beginning Balance (in dollars per share)	$ 54.10	$ 43.97	$ 35.03
Weighted Average Grant Date Fair Value, Granted (in dollars per share)	122.20	68.41	57.33
Weighted Average Grant Date Fair Value, Vested (in dollars per share)	33.33	34.30	43.35
Weighted Average Grant Date Fair Value, Forfeited (in dollars per share)	78.29	45.71	39.71
Weighted Average Grant Date Fair Value, Ending Balance (in dollars per share)	$ 78.42	$ 54.10	$ 43.97
Outstanding, aggregate intrinsic value	$ 11.3
Outstanding, weighted average remaining contractual term	1 year 14 days
Share-based Compensation Arrangement by Share-based Payment Award, Terms of Award	three year
Performance Based Restricted Stock Units \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights percentage	0.00%
Performance Based Restricted Stock Units \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights percentage	200.00%

Stock-Based Compensation - ESPP (Details) - USD ($)	1 Months Ended	12 Months Ended
Stock-Based Compensation - ESPP (Details) - USD ($)	May 31, 2017	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017	May 23, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Capital shares reserved for future issuance					1,750,000
Maximum percentage of salary	15.00%
Maximum dollar amount	$ 4,000
Maximum number of shares per employee	1,000
Number of shares available for grant		1,293,482
Purchase price of common stock percent	85.00%
Employee Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available for grant		570,962
Share-based Payment Arrangement, Expensed and Capitalized, Amount		$ 1,100,000	$ 1,000,000.0	$ 100,000

Commitments and Contingencies (Details 1) - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Activity related to the warranty accrual
Balance at beginning of period	$ 11,964	$ 11,264	$ 8,464
Liability assumed	0	0	2,186
Provision	14,091	10,798	8,591
Warranty usage	(12,199)	(10,098)	(7,977)
Balance at end of period	$ 13,856	$ 11,964	$ 11,264

Income Taxes - Income (Loss) Before Provision For Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Income Tax Disclosure [Abstract]
Domestic	$ 84,225	$ 113,078	$ 71,382
Foreign	14,608	(4,456)	4,984
Income before income taxes	$ 98,833	$ 108,622	$ 76,366

Income Taxes - Components of Income Tax Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Current
Federal	$ 13,366	$ 17,627	$ 17,555
State	5,004	3,676	1,691
Foreign	6,941	10,732	7,355
Total current income tax provision	25,311	32,035	26,601
Deferred
Federal	(9,345)	(2,475)	6,664
State	(1,783)	(1,149)	(2,470)
Foreign	(650)	(7,781)	(5,393)
Total deferred income tax provision	(11,778)	(11,405)	(1,199)
Total income tax provision	$ 13,533	$ 20,630	$ 25,402

Income Taxes - Effective Income Tax Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Reconciliation of the expected tax (benefit) expense
Statutory federal income tax	$ 20,755	$ 22,812	$ 26,728
State taxes (net of federal benefit)	3,999	4,312	2,089
Federal and state credits	(8,152)	(5,638)	(4,486)
Domestic production activities deduction	0	0	(1,528)
Excess tax benefits relating to stock-based compensation	(6,468)	(6,529)	(11,709)
Tax Cuts and Jobs Act of 2017	0	2,127	11,861
Foreign-derived intangible income deduction	(4,180)	(2,678)	0
EMEA business restructuring	0	2,292	0
Executive compensation	2,081	745	1,354
Tax impact of foreign earnings	1,986	1,336	(636)
Change in valuation allowance	2,678	348	800
Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions	(768)		(523)
Other	834	1,503	929
Total expected tax (benefits) expenses	$ 13,533	$ 20,630	$ 25,402

Income Taxes - Net Deferred Tax Assets (Details) - USD ($) $ in Thousands	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Deferred tax assets
Revenue reserves	$ 21,355	$ 17,420
Accruals and other liabilities	8,225	7,844
Operating lease liabilities	14,117	0
Tax credits and net operating loss carryforwards	8,814	7,781
Stock-based compensation	4,981	4,975
Other	5,068	4,087
Gross deferred tax assets	62,560	42,107
Valuation allowance	(3,826)	(1,148)	$ (800)
Total deferred tax assets	58,734	40,959
Deferred tax liabilities
Intangible assets	3,838	7,317
Operating lease right-of-use assets	13,249	0
Other	768	668
Total deferred tax liabilities	17,855	7,985
Net deferred tax assets	$ 40,879	$ 32,974

Income Taxes - Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Company's adjustments to its uncertain tax position
Balance at beginning of period	$ 7,119	$ 4,590	$ 5,146
Increase for tax positions related to the current year	770	2,891	580
Increase for tax positions related to acquisition	0	1,493	0
Increase (decrease) for tax positions related to prior years	(768)		(523)
Increase for tax positions related to prior years		407
Decrease for settlements with applicable taxing authorities	0	(2,262)	0
Decrease for lapses of statute of limitations	0	0	(613)
Balance at end of period	$ 7,121	$ 7,119	$ 4,590

Income Taxes - Narrative (Details) - USD ($)	3 Months Ended
Income Taxes - Narrative (Details) - USD ($)	Dec. 30, 2017	Dec. 28, 2019	Dec. 29, 2018
Tax Credit Carryforward [Line Items]
Tax Cuts and Jobs Act of 2017, income tax expense (benefit)	$ 11,900,000
Tax Cuts and Jobs Act of 2017, income tax expense (benefit), remeasurement of certain deferred tax assets and liabilities	8,900,000
Tax Cuts and Jobs Act of 2017, income tax expense (benefit), transition tax fior accumulated foreign earnings	3,000,000.0
Operating loss carryforwards		$ 1,800,000	$ 3,400,000
Valuation allowance	800,000	3,826,000	1,148,000
Income tax penalties and interest accrued	$ 0	0	0
Unrecognized tax benefits that would impact effective tax rate		7,400,000
State and Local Jurisdiction
Tax Credit Carryforward [Line Items]
Tax credit carryforward		$ 13,100,000	$ 10,700,000

Industry Segment, Geographic Information and Significant Customers (Details Textual) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 28, 2019	Sep. 28, 2019	Jun. 29, 2019	Mar. 30, 2019	Dec. 29, 2018	Sep. 29, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Revenues from External Customers and Long-Lived Assets [Line Items]
Document Period End Date									Dec. 28, 2019
Revenue	$ 426,778	$ 289,399	$ 260,172	$ 237,661	$ 384,665	$ 264,534	$ 226,317	$ 217,068	$ 1,214,010	$ 1,092,584	$ 883,911
Customer Concentration Risk \| Revenue \| Amazon [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk percentage									21.30%	17.30%	13.50%
Non-US [Member] \| Geographic Concentration Risk \| Revenue
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk percentage									50.30%	48.70%	48.80%
Domestic Destination [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									$ 603,618	$ 560,995	$ 452,563
Geographic Distribution, Foreign [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									$ 610,392	$ 531,589	$ 431,348

Quarterly Information (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 28, 2019	Sep. 28, 2019	Jun. 29, 2019	Mar. 30, 2019	Dec. 29, 2018	Sep. 29, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Quarterly Financial Information Disclosure [Abstract]
Revenue	$ 426,778	$ 289,399	$ 260,172	$ 237,661	$ 384,665	$ 264,534	$ 226,317	$ 217,068	$ 1,214,010	$ 1,092,584	$ 883,911
Details of Quarterly Information (Unaudited)
Gross profit	169,370	136,841	118,170	119,546	186,511	135,206	117,926	115,785	543,927	555,428	433,159
Net income	$ 20,041	$ 35,532	$ 7,207	$ 22,520	$ 25,191	$ 31,929	$ 10,471	$ 20,401	$ 85,300	$ 87,992	$ 50,964
Diluted	$ 0.70	$ 1.24	$ 0.25	$ 0.78	$ 0.88	$ 1.12	$ 0.37	$ 0.71	$ 2.97	$ 3.07	$ 1.77

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References + Details

Revenue Recognition Significant Judgments (Details) - USD ($) $ in Millions	Dec. 28, 2019	Dec. 29, 2018
Revenue Recognition and Deferred Revenue [Abstract]
Refund liability, product returns	$ 55.2	$ 53.9
Refund liability, other credits and incentives	$ 134.0	$ 97.7

Inventory (Details) - USD ($) $ in Thousands	Dec. 28, 2019	Dec. 29, 2018
Inventory
Raw materials	$ 2,825	$ 2,992
Finished goods	154,522	161,641
Total	$ 157,347	$ 164,633

Employee Benefits (Details) - USD ($) $ in Millions	12 Months Ended
Employee Benefits (Details) - USD ($) $ in Millions	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Retirement Benefits [Abstract]
Defined Contribution Plan, Cost	$ 2.9	$ 2.8	$ 2.4
Defined Contribution Plan, Employer Matching Contribution, Percent of Match	50.00%
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay	6.00%
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent	3.00%

- Short Term Investments (Details) - USD ($) $ in Thousands	Dec. 28, 2019	Dec. 29, 2018
Components of available for sale securities
Total short term investments	$ 17,016	$ 32,035
Total short term investments, Fair Market Value	17,032	31,605
Corporate and government bonds
Components of available for sale securities
Total short term investments	17,016	30,035
Total short term investments, Fair Market Value	17,032	29,605
Convertible note
Components of available for sale securities
Total short term investments	0	2,000
Total short term investments, Fair Market Value	$ 0	$ 2,000

Summary of Significant Accounting Policies Income taxes (Details) - USD ($) $ in Thousands	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Income taxes [Abstract]
Valuation allowance	$ 3,826	$ 1,148	$ 800

Stock-Based Compensation - Narrative (Details) $ in Thousands	12 Months Ended
	Dec. 28, 2019 USD ($) plan shares	Dec. 29, 2018 USD ($)	Dec. 30, 2017 USD ($)	May 23, 2018 shares
Number of plans \| plan	3
Capital shares reserved for future issuance				1,750,000
Number of shares available for grant	1,293,482
Share-based Payment Arrangement, Expense \| $	$ 23,744	$ 25,804	$ 19,751

Useful Life

Fair Value

Customer relationships

Reacquired distribution rights