Calix (CALX) 10-Q 27 Jul 21 2021 Q2 Quarterly report Financial data

Cover

Cover - shares	6 Months Ended
	Jul. 03, 2021	Jul. 19, 2021
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jul. 3, 2021
Document Transition Report	false
Entity File Number	001-34674
Entity Registrant Name	Calix, Inc
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	68-0438710
Entity Address, Address Line One	2777 Orchard Parkway
Entity Address, City or Town	San Jose
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	95131
City Area Code	408
Local Phone Number	514-3000
Title of 12(b) Security	Common Stock, par value $0.025 per share
Trading Symbol	CALX
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		63,496,164
Document Fiscal Period Focus	Q2
Document Fiscal Year Focus	2021
Amendment Flag	false
Entity Central Index Key	0001406666
Current Fiscal Year End Date	--12-31

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jul. 03, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 58,590	$ 80,807
Marketable securities	117,259	52,982
Accounts receivable, net	80,164	69,419
Inventory	77,136	52,268
Prepaid expenses and other current assets	17,449	11,414
Total current assets	350,598	266,890
Property and equipment, net	19,663	20,381
Right-of-use operating leases	10,983	11,741
Goodwill	116,175	116,175
Other assets	10,416	12,165
Total assets	507,835	427,352
Current liabilities:
Accounts payable	34,971	13,115
Accrued liabilities	58,627	68,736
Deferred revenue	23,951	19,189
Total current liabilities	117,549	101,040
Long-term portion of deferred revenue	21,307	19,904
Operating leases	11,920	12,946
Other long-term liabilities	11,421	13,137
Total liabilities	162,197	147,027
Commitments and contingencies (See Note 7)
Stockholders’ equity:
Preferred stock, $0.025 par value; 5,000 shares authorized; no shares issued and outstanding as of July 3, 2021 and December 31, 2020	0	0
Common stock, $0.025 par value; 100,000 shares authorized; 63,200 shares issued and outstanding as of July 3, 2021, and 62,122 shares issued and outstanding as of December 31, 2020	1,580	1,553
Additional paid-in capital	972,259	948,055
Accumulated other comprehensive loss	(182)	(191)
Accumulated deficit	(628,019)	(669,092)
Total stockholders’ equity	345,638	280,325
Total liabilities and stockholders’ equity	$ 507,835	$ 427,352

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Jul. 03, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 0.025	$ 0.025
Preferred stock, shares authorized (in shares)	5,000,000	5,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.025	$ 0.025
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares issued (in shares)	63,200,000	62,122,000
Common stock, shares outstanding (in shares)	63,200,000	62,122,000

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 03, 2021	Jun. 27, 2020	Jul. 03, 2021	Jun. 27, 2020
Revenue:
Revenue	$ 168,670	$ 119,023	$ 330,744	$ 220,705
Cost of revenue:
Cost of revenue	79,051	62,618	154,883	118,676
Gross profit	89,619	56,405	175,861	102,029
Operating expenses:
Sales and marketing	29,710	21,343	57,761	41,967
Research and development	25,716	20,921	50,080	41,592
General and administrative	13,664	11,193	26,689	21,862
Restructuring charges	0	6,286	0	6,286
Total operating expenses	69,090	59,743	134,530	111,707
Income (loss) from operations	20,529	(3,338)	41,331	(9,678)
Interest and other income (expense), net:
Interest expense, net	(119)	(617)	(244)	(907)
Other income (expense), net	255	(109)	343	(94)
Total interest and other income (expense), net	136	(726)	99	(1,001)
Income (loss) before provision for income taxes	20,665	(4,064)	41,430	(10,679)
Provision for income taxes	207	148	357	477
Net income (loss)	$ 20,458	$ (4,212)	$ 41,073	$ (11,156)
Net income (loss) per common share:
Basic (in dollars per share)	$ 0.32	$ (0.07)	$ 0.65	$ (0.20)
Diluted (in dollars per share)	$ 0.30	$ (0.07)	$ 0.61	$ (0.20)
Weighted-average number of shares used to compute net income (loss) per common share
Basic (in shares)	63,042	57,261	62,795	56,906
Diluted (in shares)	67,634	57,261	67,347	56,906
Net income (loss)
Other comprehensive loss, net of tax - foreign currency translation adjustments, net	$ 44	$ 3	$ 9	$ 249
Comprehensive income (loss)	20,502	(4,209)	41,082	(10,907)
Systems
Revenue:
Revenue	159,553	110,841	312,855	205,350
Cost of revenue:
Cost of revenue	72,673	56,721	142,336	107,429
Services
Revenue:
Revenue	9,117	8,182	17,889	15,355
Cost of revenue:
Cost of revenue	$ 6,378	$ 5,897	$ 12,547	$ 11,247

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Loss	Accumulated Deficit	Treasury Stock
Beginning Balance, shares at Dec. 31, 2019		56,448
Balance at beginning of period at Dec. 31, 2019	$ 154,028	$ 1,545	$ 895,899	$ (854)	$ (702,576)	$ (39,986)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	6,225		6,225
Issuance of common stock under equity incentive plans, net of forfeitures (in shares)		1,695
Issuance of common stock under equity incentive plans, net of forfeitures	10,320	$ 42	10,278
Net income (loss)	(11,156)				(11,156)
Other comprehensive income (loss)	(249)			(249)
Ending Balance, shares at Jun. 27, 2020		58,143
Balance at end of period at Jun. 27, 2020	159,168	$ 1,587	912,402	(1,103)	(713,732)	(39,986)
Beginning Balance, shares at Mar. 28, 2020		56,628
Balance at beginning of period at Mar. 28, 2020	150,915	$ 1,549	899,978	(1,106)	(709,520)	(39,986)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	3,241		3,241
Issuance of common stock under equity incentive plans, net of forfeitures (in shares)		1,515
Issuance of common stock under equity incentive plans, net of forfeitures	9,221	$ 38	9,183
Net income (loss)	(4,212)				(4,212)
Other comprehensive income (loss)	3			3
Ending Balance, shares at Jun. 27, 2020		58,143
Balance at end of period at Jun. 27, 2020	$ 159,168	$ 1,587	912,402	(1,103)	(713,732)	(39,986)
Beginning Balance, shares at Dec. 31, 2020	62,122	62,122
Balance at beginning of period at Dec. 31, 2020	$ 280,325	$ 1,553	948,055	(191)	(669,092)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	11,394		11,394
Issuance of common stock under equity incentive plans, net of forfeitures (in shares)		1,078
Issuance of common stock under equity incentive plans, net of forfeitures	12,837	$ 27	12,810
Net income (loss)	41,073				41,073
Other comprehensive income (loss)	$ 9			9
Ending Balance, shares at Jul. 03, 2021	63,200	63,200
Balance at end of period at Jul. 03, 2021	$ 345,638	$ 1,580	972,259	(182)	(628,019)	0
Beginning Balance, shares at Apr. 03, 2021		62,851
Balance at beginning of period at Apr. 03, 2021	314,715	$ 1,572	961,846	(226)	(648,477)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	6,223		6,223
Issuance of common stock under equity incentive plans, net of forfeitures (in shares)		349
Issuance of common stock under equity incentive plans, net of forfeitures	4,198	$ 8	4,190
Net income (loss)	20,458				20,458
Other comprehensive income (loss)	$ 44			44
Ending Balance, shares at Jul. 03, 2021	63,200	63,200
Balance at end of period at Jul. 03, 2021	$ 345,638	$ 1,580	$ 972,259	$ (182)	$ (628,019)	$ 0

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jul. 03, 2021	Jun. 27, 2020
Operating activities:
Net income (loss)	$ 41,073	$ (11,156)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Stock-based compensation	11,394	6,225
Depreciation and amortization	7,737	7,006
Asset retirements and write-downs	0	3,749
Changes in operating assets and liabilities:
Accounts receivable, net	(10,745)	(12,082)
Inventory	(24,868)	3,494
Prepaid expenses and other assets	(6,390)	1,175
Accounts payable	21,918	(671)
Accrued liabilities	(10,184)	7,868
Deferred revenue	6,164	(947)
Other long-term liabilities	(2,742)	(726)
Net cash provided by operating activities	33,357	3,935
Investing activities
Purchases of property and equipment	(3,928)	(4,480)
Purchases of marketable securities	(147,277)	0
Maturities of marketable securities	83,000	0
Net cash used in investing activities	(68,205)	(4,480)
Financing activities:
Proceeds from common stock issuances related to employee benefit plans	12,837	10,320
Payments related to financing arrangements	(212)	(1,529)
Proceeds from line of credit	0	30,000
Repayment of line of credit	0	(34,000)
Payments to originate the line of credit	0	(285)
Net cash provided by financing activities	12,625	4,506
Effect of exchange rate changes on cash and cash equivalents	6	(238)
Net increase (decrease) in cash and cash equivalents	(22,217)	3,723
Cash and cash equivalents at beginning of period	80,807	47,457
Cash and cash equivalents at end of period	$ 58,590	$ 51,180

Company and Basis of Presentati

Company and Basis of Presentation	6 Months Ended
	Jul. 03, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Company and Basis of Presentation	Company and Basis of Presentation Company Calix, Inc. (together with its subsidiaries, “Calix” or the “Company”) was incorporated in August 1999 and is a Delaware corporation. The Company is the leading global provider of cloud and software platforms, systems and services that focus on the access network, the portion of the network that governs available bandwidth and determines the range and quality of services that can be offered to subscribers. These cloud and software platforms enable broadband service providers (“BSPs”) of all types and sizes to innovate and transform their businesses. The Company’s BSP customers are empowered to utilize real-time data and insights from Calix platforms to simplify their businesses and deliver experiences that excite their subscribers. These insights enable BSPs to grow their businesses through increased subscriber acquisition, loyalty and revenue, thereby increasing the value of their businesses and contributions to their communities. Basis of Presentation The accompanying unaudited condensed consolidated financial statements, including the accounts of Calix, Inc. and its wholly-owned subsidiaries, have been prepared in accordance with the requirements of the U.S. Securities and Exchange Commission (“SEC”) for interim reporting. As permitted under those rules, certain footnotes or other financial information that are normally required by U.S. generally accepted accounting principles (“GAAP”) can be condensed or omitted. In the opinion of management, the financial statements include all normal and recurring adjustments that are considered necessary for the fair presentation of the Company’s financial position and operating results. All intercompany balances and transactions have been eliminated in consolidation. The Condensed Consolidated Balance Sheet as of December 31, 2020 has been derived from the audited financial statements at that date. The results of the Company’s operations can vary during each quarter of the year. Therefore, the results and trends in these interim financial statements may not be the same as those for the full year or any future periods. The information included in this Quarterly Report on Form 10-Q should be read in conjunction with the audited financial statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2020. The Company’s fiscal year begins on January 1 st and ends on December 31 st . Quarterly periods are based on a 4-4-5 calendar with the first quarter ending on the Saturday closest to March 31 st . As a result, the Company had five more days in the six months ended July 3, 2021 than for the six months ended June 27, 2020. The preparation of financial statements in conformity with GAAP for interim financial reporting requires management to make estimates and assumptions that affect the amounts reported in the condensed consolidated financial statements and accompanying notes. Actual results could differ from those estimates. Risks and Uncertainties The Company is subject to risks and uncertainties as a result of the COVID-19 pandemic. The extent of the impact of the COVID-19 pandemic on the Company’s business is highly uncertain and difficult to predict, particularly as variants of the coronavirus continue to spread around the world. Although the availability of vaccines has increased, there are no assurances as to when the pandemic will be fully contained. In March 2020, the Company instituted office closures, travel restrictions and a work-from-anywhere policy for substantially all of its employees due to shelter-in-place mandates. In July 2021, the Company reopened its U.S. offices to fully-vaccinated employees who choose to work in the office and visitors and lifted certain travel restrictions. The spread of COVID-19 has had a prolonged impact on the Company’s supply chain operations due to restrictions, reduced capacity and limited availability from suppliers on whom the Company relies for sourcing components and materials and from third-party partners on whom the Company relies for manufacturing, warehousing and logistics services. Although demand for the Company’s products has been strong in the short-term as subscribers seek more bandwidth and better Wi-Fi, customers’ purchasing decisions over the long-term may be impacted by the pandemic and its impact on the economy, which could in turn impact the Company’s revenue and results of operations. Furthermore, the Company’s supply chain continues to face constraints primarily due to challenges in sourcing components and materials for the Company’s products. The prolonged impact of COVID-19 could exacerbate these constraints or cause further supply chain disruptions. As of the issuance date of these condensed consolidated financial statements, the extent to which the COVID-19 pandemic may materially impact the Company’s financial condition, liquidity or results of operations remains uncertain.

Significant Accounting Policies

Significant Accounting Policies	6 Months Ended
	Jul. 03, 2021
Accounting Policies [Abstract]
Significant Accounting Policies	Significant Accounting Policies The Company’s significant accounting policies are disclosed in its Annual Report on Form 10-K for the year ended December 31, 2020. The Company’s significant accounting policies did not change during the six months ended July 3, 2021. Newly Adopted Accounting Standard The Company did not adopt any new accounting standards during the six months ended July 3, 2021 that were significant to the Company. Recent Accounting Pronouncements Not Yet Adopted There have been no additional accounting pronouncements or changes in accounting pronouncements during the six months ended July 3, 2021 as compared to the recent accounting pronouncements described in the Company’s Annual Report on Form 10-K for the year ended December 31, 2020, that are significant or potentially significant to the Company.

Cash, Cash Equivalents, and Mar

Cash, Cash Equivalents, and Marketable Securities	6 Months Ended
	Jul. 03, 2021
Cash and Cash Equivalents [Abstract]
Cash, Cash Equivalents, and Marketable Securities	Cash, Cash Equivalents and Marketable Securities The Company has invested its excess cash primarily in money market funds and highly liquid marketable securities such as commercial paper, corporate debt securities and U.S. government securities. The Company considers all investments with maturities of three months or less when purchased to be cash equivalents. Marketable securities represent highly liquid commercial paper, U.S. government agency securities and U.S. government securities with maturities greater than 90 days at date of purchase. Cash equivalents are stated at amounts that approximate fair value based on quoted market prices. Marketable securities are recorded at their fair values. Marketable securities with maturities greater than one year are classified as current because management considers all marketable securities to be available for current operations. The Company’s investments have been classified and accounted for as available-for-sale. Such investments are recorded at fair value and unrealized holding gains and losses are reported as a separate component of accumulated other comprehensive loss in the stockholders’ equity until realized. Realized gains and losses on sales of marketable securities, if any, are determined on the specific identification method and are reclassified from accumulated other comprehensive loss to results of operations as other income (expense), net. Realized and unrealized gains and losses were de minimis for the period ended July 3, 2021. Cash, cash equivalents and marketable securities consisted of the following (in thousands): July 3, December 31, Cash and cash equivalents: Cash $ 17,777 $ 30,745 Commercial paper 21,399 — Money market funds 18,263 10,068 Corporate debt securities 1,151 — U.S. government securities — 39,994 Total cash and cash equivalents 58,590 80,807 Marketable securities: Commercial paper 114,150 — U.S. government agency securities 3,109 — U.S. government securities — 52,982 Total marketable securities 117,259 52,982 $ 175,849 $ 133,789 The carrying amounts of the Company’s money market funds approximate their fair values due to their nature, duration and short maturities.

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jul. 03, 2021
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value MeasurementsThe Company measures its cash equivalents and marketable securities at fair value on a recurring basis. Fair value is an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. The Company utilizes the following three-tier value hierarchy, which prioritizes the inputs used in measuring fair value: Level 1 – Observable inputs that reflect quoted prices (unadjusted) for identical assets or liabilities in active markets. Level 2 – Observable inputs other than quoted prices included in Level 1 for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active, and model-driven valuations in which all significant inputs and significant value drivers are observable in active markets. Level 3 – Unobservable inputs to the valuation derived from fair valuation techniques in which one or more significant inputs or significant value drivers are unobservable. The fair value hierarchy also requires the Company to maximize the use of observable inputs, when available, and to minimize the use of unobservable inputs when determining inputs and determining fair value. The following tables sets forth the Company’s financial assets measured at fair value on a recurring basis based on the three-tier fair value hierarchy (in thousands): As of July 3, 2021 Level 1 Level 2 Total Money market funds $ 18,263 $ — $ 18,263 Commercial paper — 135,549 135,549 U.S. government agency securities — 3,109 3,109 Corporate debt securities — 1,151 1,151 $ 18,263 $ 139,809 $ 158,072 As of December 31, 2020 Level 1 Money market funds $ 10,068 U.S. government securities 92,976 $ 103,044

Balance Sheet Details

Balance Sheet Details	6 Months Ended
	Jul. 03, 2021
Balance Sheet Related Disclosures [Abstract]
Balance Sheet Details	Balance Sheet Details Accounts receivable, net consisted of the following (in thousands): July 3, December 31, Accounts receivable $ 80,971 $ 70,824 Allowance for doubtful accounts (807) (1,405) $ 80,164 $ 69,419 Inventory consisted of the following (in thousands): July 3, December 31, Raw materials $ 182 $ 34 Finished goods 76,954 52,234 $ 77,136 $ 52,268 Property and equipment, net consisted of the following (in thousands): July 3, December 31, Test equipment $ 37,133 $ 37,670 Software 14,905 16,093 Computer equipment 9,897 9,062 Furniture and fixtures 2,025 2,069 Leasehold improvements 1,466 1,345 Total 65,426 66,239 Accumulated depreciation and amortization (45,763) (45,858) $ 19,663 $ 20,381 Other long-term assets consisted of the following (in thousands): July 3, December 31, Intangible asset $ 8,201 $ 9,517 Other long-term assets 2,215 2,648 $ 10,416 $ 12,165 Intangible Asset Acquisition In March 2018, and as amended in December 2020, the Company entered into an agreement with a vendor to develop certain software product and related enhancements pursuant to which the Company is obligated to make revenue-share payments under the program, subject to aggregate fixed revenue-share payments of $15.8 million. The payments are based on a revenue-share rate applied to revenue from the developed-product and the corresponding hardware sales through March 2024. If the minimum revenue-share payments are not achieved by the end of that period, a true-up payment will be due. The Company had its first sale in August 2019, and as a result, the Company capitalized an intangible asset with a value of $13.2 million in the third quarter of 2019 and also recognized a liability of $13.2 million (a non-cash investing activity). The intangible asset has an estimated five-year useful life and is being amortized using the greater of the ratio of current gross revenue for the products to the total of current and anticipated future gross revenue for the products or the straight-line method. As of July 3, 2021, the liability, including accrued interest, was $14.0 million of which $3.4 million is included in accrued liabilities and $10.6 million in other long-term liabilities in the accompanying Condensed Consolidated Balance Sheet. As of December 31, 2020, the liability, including accrued interest, was $13.9 million of which $2.9 million was included in accrued liabilities and $11.0 million in other long-term liabilities. Accrued liabilities consisted of the following (in thousands): July 3, December 31, Compensation and related benefits $ 16,725 $ 23,740 Warranty and retrofit 9,911 9,208 Taxes payable 4,459 3,476 Professional and consulting fees 4,347 4,497 Component inventory held by suppliers 4,002 3,992 Current portion of revenue share obligations 3,417 2,925 Customer advances or rebates 3,359 8,374 Operating leases 3,005 2,994 Product returns 2,062 1,888 Operations 1,741 950 Freight 1,543 1,955 Other 4,056 4,737 $ 58,627 $ 68,736 Changes in the Company’s accrued warranty and retrofit liability were as follows (in thousands): Three Months Ended Six Months Ended July 3, June 27, July 3, June 27, Balance at beginning of period $ 9,650 $ 7,430 $ 9,208 $ 7,294 Provision for warranty and retrofit charged to cost of revenue 1,003 1,276 2,205 2,625 Utilization of reserve (742) (974) (1,502) (2,187) Balance at end of period $ 9,911 $ 7,732 $ 9,911 $ 7,732 Accrued Restructuring Charges Responding to trends caused by the COVID-19 pandemic, the Company initiated a restructuring plan in June 2020 to accelerate the Company’s All Platform future and to align with a work-from-anywhere culture. The Company incurred restructuring charges of approximately $6.3 million, consisting of facilities-related charges and severance and other termination-related benefits during 2020. As part of the Company’s shift to a work-from-anywhere culture, many of the Company’s employees elected to work remotely on a permanent basis. In light of this change, the Company evaluated its space needs and determined that a portion of the Company's leased office spaces in Richardson, Texas and San Jose, California would no longer be utilized. As a result, the right-of-use assets related to these leases were written down, resulting in a charge of $3.5 million during 2020. In addition, the Company wrote off assets with net book value of $0.3 million and accrued common areas maintenance fees and property taxes related to the unused office space totaling $1.4 million during 2020. The following table summarizes restructuring activities (in thousands): Facilities Severance and Related Benefits Total Balance as of December 31, 2020 $ 1,244 $ 132 $ 1,376 Cash payments (133) (132) (265) Balance as of July 3, 2021 $ 1,111 $ — $ 1,111

Credit Agreements

Credit Agreements	6 Months Ended
	Jul. 03, 2021
Line of Credit Facility [Abstract]
Credit Agreements	Credit Agreements Line of Credit The Company has a loan and security agreement with Bank of America, N.A. (“BofA Loan Agreement”). The BofA Loan Agreement provides for a revolving facility up to a principal amount of $35.0 million, including a $10.0 million sublimit for letters of credit. The BofA Loan Agreement matures, and all outstanding amounts become due and payable, in January 2023. The BofA Loan Agreement is secured by substantially all of the Company’s assets, including its intellectual property. Loans under the credit facility bear interest at a rate per annum equal to either LIBOR (customarily defined) plus an applicable margin between 1.5% to 2.0% or Prime Rate (customarily defined) plus an applicable margin between 0.5% to 1.0% (3.75% as of July 3, 2021), in each case largely based on a fixed charge coverage ratio measured at the end of each fiscal quarter. As of July 3, 2021, the Company had no outstanding borrowings and had full availability of borrowings up to $35.0 million.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jul. 03, 2021
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Lease Commitments The Company leases office space under non-cancelable operating leases. Certain of the Company’s operating leases contain renewal options and rent acceleration clauses. Future minimum payments under the non-cancelable operating leases consisted of the following as of July 3, 2021 (in thousands): Period Future Minimum Lease Payments Remainder of 2021 $ 1,905 2022 3,911 2023 4,053 2024 3,855 2025 3,342 Thereafter 158 Total future minimum lease payments 17,224 Less imputed interest (2,299) $ 14,925 As of July 3, 2021, the operating lease liability consisted of the following (in thousands): Accrued liabilities - current portion of operating leases $ 3,005 Operating leases 11,920 $ 14,925 The Company leases its headquarters office space in San Jose, California under a lease agreement that expires in December 2025. The future minimum lease payments under the lease are $10.7 million and are included in the table above. The weighted average discount rate for the Company's operating leases as of July 3, 2021 was 6.6%. The weighted average remaining lease term as of July 3, 2021 was 4.3 years. For the three and six months ended July 3, 2021, total rent expense of the Company was $0.9 million and $2.1 million, respectively. For the three and six months ended June 27, 2020, total rent expense of the Company was $1.1 million and $2.2 million, respectively. Cash paid within operating cash flows for operating leases was $2.0 million and $1.7 million for the six months ended July 3, 2021 and June 27, 2020, respectively. Purchase Commitments The Company’s suppliers, including contract manufacturers (“CMs”) and original design manufacturers (“ODMs”), place orders for certain component inventory in advance based upon the Company’s build forecasts in order to reduce manufacturing lead times and ensure adequate component supply. The components are used by the CMs and ODMs to build the products included in the build forecasts. The Company generally does not take ownership of the components held by CMs and ODMs. The Company places purchase orders with its CMs and ODMs in order to fulfill its monthly finished product inventory requirements. The Company incurs a liability when the CMs and ODMs convert the component inventory to a finished product and takes ownership of the finished goods inventory. In the event of termination of services with a manufacturing partner, the Company has purchased, and may be required to purchase in the future, certain of the remaining components inventory held by the CM or ODM as well as any outstanding orders pursuant to the contractual provisions with such CM or ODM. As of July 3, 2021, the Company had approximately $140.9 million of outstanding purchase commitments for inventories to be delivered by its suppliers, including CMs and ODMs, within one year. The Company has from time to time, and subject to certain conditions, reimbursed certain suppliers for component inventory purchases when this inventory has been rendered excess or obsolete, for example due to manufacturing and engineering change orders resulting from design changes, manufacturing discontinuation of products by its suppliers, or in cases where the Company has committed inventory levels that greatly exceed projected demand. The estimated excess and obsolete inventory liabilities related to such manufacturing and engineering change orders and other factors, which are included in accrued liabilities in the accompanying balance sheets, was $4.0 million for both of the periods ending July 3, 2021 and December 31, 2020, respectively. The Company records the related charges in cost of systems revenue in its Condensed Consolidated Statements of Comprehensive Income (Loss). Litigation From time to time, the Company is involved in various legal proceedings arising from the normal course of business activities. The Company is not currently a party to any legal proceedings that, if determined adversely to the Company, in management’s opinion, are currently expected to individually or in the aggregate have a material adverse effect on the Company’s business, operating results or financial condition taken as a whole.

Stockholders' Equity

Stockholders' Equity	6 Months Ended
	Jul. 03, 2021
Stockholders' Equity Note [Abstract]
Stockholders' Equity	Stockholders’ Equity 2019 Equity Incentive Award Plan Employees and consultants of the Company, its subsidiaries and affiliates, as well as members of the Company’s Board of Directors, are eligible to receive awards under the 2019 Equity Incentive Award Plan (“the 2019 Plan”). The 2019 Plan provides for the grant of stock options, including incentive stock options and nonqualified stock options, stock appreciation rights, restricted stock, restricted stock units, other stock or cash-based awards and dividend equivalents to eligible individuals. At the Company’s 2021 annual meeting of stockholders, the stockholders approved an increase in the number of shares of common stock issuable under the 2019 Plan by 3.8 million shares. As of July 3, 2021, there were 7.0 million shares available for issuance under the 2019 Plan. Stock Options During the three months ended July 3, 2021, stock option awards exercisable for up to an aggregate of 0.5 million shares of common stock were granted with a grant date weighted-average exercise price of $40.82 per share. During the six months ended July 3, 2021, stock option awards exercisable for up to an aggregate of 0.6 million shares of common stock were granted with a grant date weighted-average exercise price of $39.38 per share. These stock option awards vest 25% on the first anniversary of the vesting commencement date and on a quarterly basis thereafter over an additional three years. In February 2021, performance-based stock option awards exercisable for up to an aggregate of 0.7 million shares of common stock were granted to certain Company executives with a grant date exercise price of $36.74 per share. The actual number of shares earned is contingent upon achievement of annual corporate financial targets for bookings and non-GAAP net income for 2021 (collectively, the “2021 Performance Targets”) during the one-year performance period. These performance-based stock option awards will vest, subject to certification by the Compensation Committee of the Company’s Board of Directors upon the achievement of the 2021 Performance Targets, as to 25% of the shares of common stock earned on the one year anniversary of the date of grant, and as to the remaining 75% of the shares of common stock earned, in substantially equal quarterly installments over the subsequent 36 months, subject to the executive’s continuous service with the Company through the respective vesting dates. If the non-GAAP net income target is achieved below 80% of target or the bookings target is achieved below 90% of target, no shares would be awarded, and the performance-based stock option awards would be forfeited in full. If both targets are achieved at the minimum threshold of 80% of target for non-GAAP net income and 90% of target for bookings, then the shares are awarded at 50% of the granted shares, with an increasing percentage of shares awarded above the minimum thresholds up to 100% of the granted shares if both targets are achieved at 100% or more of target. The probability of meeting the performance conditions related to these performance-based stock option awards was assessed to be probable as of July 3, 2021, and stock-based compensation expense of $1.9 million was recognized for the three months ended July 3, 2021. For the six months ended July 3, 2021, stock-based compensation expense of $2.9 million was recognized. During the three months ended July 3, 2021, 0.1 million shares of common stock were issued pursuant to the exercise of stock options at a weighted-average exercise price of $7.38 per share. During the six months ended July 3, 2021, 0.6 million shares of common stock were issued pursuant to the exercise of stock options at a weighted-average exercise price of $9.17 per share. As of July 3, 2021, unrecognized stock-based compensation expense of $31.7 million related to stock options, net of estimated forfeitures, is expected to be recognized over a weighted-average period of 2.4 years. Employee Stock Purchase Plans The Company maintains two employee stock purchase plans - the Amended and Restated Employee Stock Purchase Plan (the “ESPP”) and the Amended and Restated 2017 Nonqualified Employee Stock Purchase Plan (the “NQ ESPP”). The ESPP allows eligible employees to purchase shares of the Company’s common stock through payroll deductions of up to 15% of their eligible compensation subject to certain Internal Revenue Code limitations. In addition, no participant may purchase more than 2,000 shares of common stock in each offering period. The offering periods under the ESPP are two six-month offering periods from August 15 th through February 14 th and February 15 th through August 14 th of each year. The price of common stock purchased under the ESPP is 85% of the lower of the fair market value of the common stock on the commencement date and the end date of each six-month offering period. At the Company’s 2021 annual meeting of stockholders, the stockholders approved an increase in the number of shares of common stock issuable under the ESPP by 1.3 million shares, which will go into effect for the six-month purchase period commencing August 15, 2021 and ending on February 14, 2022. The total shares authorized for issuance under the ESPP increased from 9.8 million shares to 11.1 million shares. As of July 3, 2021, there were 2.4 million shares available for issuance under the ESPP. During the six months ended July 3, 2021, 0.2 million shares were purchased under the ESPP. As of July 3, 2021, unrecognized stock-based compensation expense of $0.3 million related to the ESPP is expected to be recognized over a remaining service period of 0.1 years. The NQ ESPP allows eligible employees to purchase shares of the Company’s common stock through payroll deductions of up to 25% of their eligible compensation. Eligible employees have the right to (a) purchase the maximum number of whole shares of common stock that can be purchased with the elected payroll deductions during each offering period for which the employee is enrolled at a purchase price equal to the closing price of the Company’s common stock on the last day of such offering period and (b) receive an equal number of shares of the Company’s common stock that are subject to a risk of forfeiture in the event the employee terminates employment within the one year period immediately following the purchase date. The NQ ESPP provides two six-month offering periods from November 15 th through May 14 th and May 15 th through November 14 th of each year. At the Company’s 2021 annual meeting of stockholders, the stockholders approved an increase in the number of shares of common stock issuable under the NQ ESPP by 0.8 million shares. The maximum number of shares of common stock currently authorized for issuance under the NQ ESPP is 5.5 million shares, with a maximum of 0.5 million shares allocated per purchase period. As of July 3, 2021, there were 2.9 million shares available for issuance under the NQ ESPP, including the stockholder-approved 0.8 million share increase. During the three and six months ended July 3, 2021, 0.2 million shares were purchased and issued. As of July 3, 2021, unrecognized stock-based compensation expense of $6.0 million related to the NQ ESPP is expected to be recognized over a remaining weighted-average service period of 1.1 year. Stock-Based Compensation The following table summarizes stock-based compensation expense (in thousands): Three Months Ended Six Months Ended July 3, June 27, July 3, June 27, Cost of revenue: Products $ 186 $ 126 $ 348 $ 233 Services 157 90 307 205 Sales and marketing 1,723 1,002 3,170 1,958 Research and development 1,644 1,098 3,227 2,107 General and administrative 2,513 926 4,342 1,722 $ 6,223 $ 3,242 $ 11,394 $ 6,225

Revenue from Contracts with Cus

Revenue from Contracts with Customers	6 Months Ended
	Jul. 03, 2021
Revenue from Contract with Customer [Abstract]
Revenue from Contracts with Customers	Revenue from Contracts with Customers The Company derives revenue from contracts with customers primarily from the following and categorizes its revenue as follows: • Systems include revenue from the sale of access and premises systems, software platform licenses and cloud-based software subscriptions; and • Services include revenue from professional services, customer support, software- and cloud-based maintenance, extended warranty subscriptions, training and managed services. The following is a summary of revenue disaggregated by geographic region based upon the location of the customers (in thousands): Three Months Ended Six Months Ended July 3, 2021 June 27, 2020 July 3, 2021 June 27, 2020 United States $ 133,618 $ 108,198 $ 268,324 $ 196,248 Canada 7,444 2,868 13,950 6,431 Europe 9,844 2,110 13,259 6,231 Middle East 5,172 2,330 12,260 4,631 Caribbean 6,954 2,310 11,717 4,682 Other 5,638 1,207 11,234 2,482 $ 168,670 $ 119,023 $ 330,744 $ 220,705 Contract Asset The primary contract asset is revenue recognized on professional services contracts where the services are transferred to the customer over time, which has yet to be billed, and is classified within accounts receivable. Amounts are billed in accordance with the agreed-upon contractual terms. The balance as of December 31, 2020 was $2.3 million of which $0.7 million remained in the Company's Condensed Consolidated Balance Sheet as of July 3, 2021. The closing balance as of July 3, 2021 was $1.4 million of which the Company expects to bill 66% of the balance during the remainder of 2020. The decrease in the contract asset was driven by billings for past services and a reduction in expected cash collections on ongoing projects partially offset by additional unbilled work performed during the three months ended July 3, 2021. Contract Liability Deferred revenue consisted of the following (in thousands): July 3, December 31, Current: Products and services $ 19,399 $ 14,651 Extended warranty 4,552 4,538 23,951 19,189 Long-term: Products and services 2,729 1,879 Extended warranty 18,578 18,025 21,307 19,904 $ 45,258 $ 39,093 The increase in the deferred revenue balance for the three and six months ended July 3, 2021 is primarily driven by cash payments received or due in advance of satisfying the Company’s performance obligations offset by $6.8 million and $11.1 million of revenue recognized that was included in the deferred revenue balance at the beginning of each period, respectively. Revenue allocated to remaining performance obligations represent contract revenue that has not yet been recognized, which includes deferred revenue and amounts that will be invoiced and recognized as revenue in future periods. This amount was $92.0 million as of July 3, 2021, and the Company expects to recognize 36% of such revenue over the next 12 months and the remainder thereafter. Contract Costs The Company capitalizes certain sales commissions related primarily to multi-year subscriptions and extended warranty support for which the expected amortization period is greater than one year. As of July 3, 2021, the unamortized balance of deferred commissions was $2.3 million. For the three and six months ended July 3, 2021, the amount of amortization was $0.2 million and $0.3 million, respectively. There was no impairment loss in relation to the costs capitalized. Concentration of Customer Risk No company accounted for more than 10% of the Company's total revenue for the three and six months ended July 3, 2021. Lumen Technologies, Inc. (formerly CenturyLink, Inc.) represented 15% of total revenue for three and six months ended June 27, 2020. No other customers accounted for more than 10% of the Company’s total revenue for three and six months ended June 27, 2020. No customer represented more than 10% of the Company’s accounts receivable as of July 3, 2021 or December 31, 2020.

Income Taxes

Income Taxes	6 Months Ended
	Jul. 03, 2021
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The following table presents the provision for income taxes from operations and the effective tax rates for the periods indicated (in thousands, except percentages): Three Months Ended Six Months Ended July 3, June 27, July 3, June 27, Provision for income taxes $ 207 $ 148 $ 357 $ 477 Effective tax rate 1.0 % (3.6) % 0.9 % (4.5) % The effective tax rate for the three months ended July 3, 2021 was determined using an estimated annual effective tax rate adjusted for discrete items, if any, that occurred during the respective periods. Deferred tax assets are recognized if realization of such assets is more likely than not. The Company has established and continues to maintain a full valuation allowance against its net deferred tax assets, with the exception of certain foreign deferred tax assets, as the Company does not believe that realization of those assets is more likely than not. The Company’s effective tax rate may be subject to fluctuation during the year as new information is obtained, which may affect the assumptions used to estimate the annual effective tax rate, including factors such as the mix of forecasted pre-tax earnings in the various jurisdictions in which it operates, valuation allowances against deferred tax assets, the recognition or de-recognition of tax benefits related to uncertain tax positions and changes in or the interpretation of tax laws in jurisdictions where it conducts business. While the Company has reported U.S. pre-tax income for the first half of 2021, the Company has not yet been able to establish a sustained level of profitability in the U.S. or other sufficient significant positive evidence to conclude that its U.S. deferred tax assets are more likely than not to be realized. Therefore, the Company continues to maintain a valuation allowance against most of its U.S. deferred tax assets. At some point, if the Company establishes a sustained level of profitability and projects continued profitability, the Company may reverse a significant portion of its valuation allowance recorded against U.S. deferred tax assets, resulting in a non-recurring non-cash income tax benefit.

Net Income (Loss) Per Common Sh

Net Income (Loss) Per Common Share	6 Months Ended
	Jul. 03, 2021
Earnings Per Share [Abstract]
Net Income (Loss) Per Common Share	Net Income (Loss) Per Common Share The following table sets forth the computation of basic and diluted net income (loss) per common share for the periods indicated (in thousands, except per share data): Three Months Ended Six Months Ended July 3, June 27, July 3, June 27, Numerator: Net income (loss) $ 20,458 $ (4,212) $ 41,073 $ (11,156) Denominator: Weighted-average common shares outstanding used to compute basic net income (loss) per share 63,042 57,261 62,795 56,906 Effect of dilutive common stock equivalents 4,592 — 4,552 — Weighted-average common shares outstanding used to compute diluted net income (loss) per share 67,634 57,261 67,347 56,906 Net income (loss) per common share: Basic net income (loss) per common share $ 0.32 $ (0.07) $ 0.65 $ (0.20) Diluted net income (loss) per common share $ 0.30 $ (0.07) $ 0.61 $ (0.20) Potentially dilutive shares, weighted average 1,096 6,996 752 6,789 Potentially dilutive shares have been excluded from the computation of diluted net income (loss) per common share when their effect is antidilutive. These antidilutive shares were primarily from stock options. For each of the periods presented where the Company reported a net loss, the effect of all potentially dilutive securities would be antidilutive, and as a result diluted net loss per common share is the same as basic net loss per common share.

Significant Accounting Polici_2

Significant Accounting Policies (Policies)	6 Months Ended
	Jul. 03, 2021
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements, including the accounts of Calix, Inc. and its wholly-owned subsidiaries, have been prepared in accordance with the requirements of the U.S. Securities and Exchange Commission (“SEC”) for interim reporting. As permitted under those rules, certain footnotes or other financial information that are normally required by U.S. generally accepted accounting principles (“GAAP”) can be condensed or omitted. In the opinion of management, the financial statements include all normal and recurring adjustments that are considered necessary for the fair presentation of the Company’s financial position and operating results. All intercompany balances and transactions have been eliminated in consolidation. The Condensed Consolidated Balance Sheet as of December 31, 2020 has been derived from the audited financial statements at that date. The results of the Company’s operations can vary during each quarter of the year. Therefore, the results and trends in these interim financial statements may not be the same as those for the full year or any future periods. The information included in this Quarterly Report on Form 10-Q should be read in conjunction with the audited financial statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2020. The Company’s fiscal year begins on January 1 st and ends on December 31 st . Quarterly periods are based on a 4-4-5 calendar with the first quarter ending on the Saturday closest to March 31 st . As a result, the Company had five more days in the six months ended July 3, 2021 than for the six months ended June 27, 2020. The preparation of financial statements in conformity with GAAP for interim financial reporting requires management to make estimates and assumptions that affect the amounts reported in the condensed consolidated financial statements and accompanying notes. Actual results could differ from those estimates.
Risks and Uncertainties	Risks and Uncertainties The Company is subject to risks and uncertainties as a result of the COVID-19 pandemic. The extent of the impact of the COVID-19 pandemic on the Company’s business is highly uncertain and difficult to predict, particularly as variants of the coronavirus continue to spread around the world. Although the availability of vaccines has increased, there are no assurances as to when the pandemic will be fully contained. In March 2020, the Company instituted office closures, travel restrictions and a work-from-anywhere policy for substantially all of its employees due to shelter-in-place mandates. In July 2021, the Company reopened its U.S. offices to fully-vaccinated employees who choose to work in the office and visitors and lifted certain travel restrictions. The spread of COVID-19 has had a prolonged impact on the Company’s supply chain operations due to restrictions, reduced capacity and limited availability from suppliers on whom the Company relies for sourcing components and materials and from third-party partners on whom the Company relies for manufacturing, warehousing and logistics services. Although demand for the Company’s products has been strong in the short-term as subscribers seek more bandwidth and better Wi-Fi, customers’ purchasing decisions over the long-term may be impacted by the pandemic and its impact on the economy, which could in turn impact the Company’s revenue and results of operations. Furthermore, the Company’s supply chain continues to face constraints primarily due to challenges in sourcing components and materials for the Company’s products. The prolonged impact of COVID-19 could exacerbate these constraints or cause further supply chain disruptions. As of the issuance date of these condensed consolidated financial statements, the extent to which the COVID-19 pandemic may materially impact the Company’s financial condition, liquidity or results of operations remains uncertain.
Newly Adopted Accounting Standard and Recent Accounting Pronouncements Not Yet Adopted	Newly Adopted Accounting Standard The Company did not adopt any new accounting standards during the six months ended July 3, 2021 that were significant to the Company. Recent Accounting Pronouncements Not Yet Adopted There have been no additional accounting pronouncements or changes in accounting pronouncements during the six months ended July 3, 2021 as compared to the recent accounting pronouncements described in the Company’s Annual Report on Form 10-K for the year ended December 31, 2020, that are significant or potentially significant to the Company.
Revenue Recognition	The Company derives revenue from contracts with customers primarily from the following and categorizes its revenue as follows: • Systems include revenue from the sale of access and premises systems, software platform licenses and cloud-based software subscriptions; and • Services include revenue from professional services, customer support, software- and cloud-based maintenance, extended warranty subscriptions, training and managed services.

Cash, Cash Equivalents and Rest

Cash, Cash Equivalents and Restricted Cash (Tables)	6 Months Ended
	Jul. 03, 2021
Cash and Cash Equivalents [Abstract]
Summary of cash and cash equivalents	Cash, cash equivalents and marketable securities consisted of the following (in thousands): July 3, December 31, Cash and cash equivalents: Cash $ 17,777 $ 30,745 Commercial paper 21,399 — Money market funds 18,263 10,068 Corporate debt securities 1,151 — U.S. government securities — 39,994 Total cash and cash equivalents 58,590 80,807 Marketable securities: Commercial paper 114,150 — U.S. government agency securities 3,109 — U.S. government securities — 52,982 Total marketable securities 117,259 52,982 $ 175,849 $ 133,789

Fair Value Measures and Disclos

Fair Value Measures and Disclosures (Tables)	6 Months Ended
	Jul. 03, 2021
Fair Value Disclosures [Abstract]
Fair value, assets measured on recurring basis	The following tables sets forth the Company’s financial assets measured at fair value on a recurring basis based on the three-tier fair value hierarchy (in thousands): As of July 3, 2021 Level 1 Level 2 Total Money market funds $ 18,263 $ — $ 18,263 Commercial paper — 135,549 135,549 U.S. government agency securities — 3,109 3,109 Corporate debt securities — 1,151 1,151 $ 18,263 $ 139,809 $ 158,072 As of December 31, 2020 Level 1 Money market funds $ 10,068 U.S. government securities 92,976 $ 103,044

Balance Sheet Details (Tables)

Balance Sheet Details (Tables)	6 Months Ended
	Jul. 03, 2021
Balance Sheet Related Disclosures [Abstract]
Summary of accounts receivable, net	Accounts receivable, net consisted of the following (in thousands): July 3, December 31, Accounts receivable $ 80,971 $ 70,824 Allowance for doubtful accounts (807) (1,405) $ 80,164 $ 69,419
Summary of inventory	Inventory consisted of the following (in thousands): July 3, December 31, Raw materials $ 182 $ 34 Finished goods 76,954 52,234 $ 77,136 $ 52,268
Summary of property and equipment, net	Property and equipment, net consisted of the following (in thousands): July 3, December 31, Test equipment $ 37,133 $ 37,670 Software 14,905 16,093 Computer equipment 9,897 9,062 Furniture and fixtures 2,025 2,069 Leasehold improvements 1,466 1,345 Total 65,426 66,239 Accumulated depreciation and amortization (45,763) (45,858) $ 19,663 $ 20,381
Schedule of other long-term assets	Other long-term assets consisted of the following (in thousands): July 3, December 31, Intangible asset $ 8,201 $ 9,517 Other long-term assets 2,215 2,648 $ 10,416 $ 12,165
Summary of accrued liabilities	Accrued liabilities consisted of the following (in thousands): July 3, December 31, Compensation and related benefits $ 16,725 $ 23,740 Warranty and retrofit 9,911 9,208 Taxes payable 4,459 3,476 Professional and consulting fees 4,347 4,497 Component inventory held by suppliers 4,002 3,992 Current portion of revenue share obligations 3,417 2,925 Customer advances or rebates 3,359 8,374 Operating leases 3,005 2,994 Product returns 2,062 1,888 Operations 1,741 950 Freight 1,543 1,955 Other 4,056 4,737 $ 58,627 $ 68,736
Product warranty activities	Changes in the Company’s accrued warranty and retrofit liability were as follows (in thousands): Three Months Ended Six Months Ended July 3, June 27, July 3, June 27, Balance at beginning of period $ 9,650 $ 7,430 $ 9,208 $ 7,294 Provision for warranty and retrofit charged to cost of revenue 1,003 1,276 2,205 2,625 Utilization of reserve (742) (974) (1,502) (2,187) Balance at end of period $ 9,911 $ 7,732 $ 9,911 $ 7,732
Restructuring and related costs	The following table summarizes restructuring activities (in thousands): Facilities Severance and Related Benefits Total Balance as of December 31, 2020 $ 1,244 $ 132 $ 1,376 Cash payments (133) (132) (265) Balance as of July 3, 2021 $ 1,111 $ — $ 1,111

Commitments and Contingencies (

Commitments and Contingencies (Tables)	6 Months Ended
	Jul. 03, 2021
Commitments and Contingencies Disclosure [Abstract]
Schedule of future minimum rental payments for operating leases	Future minimum payments under the non-cancelable operating leases consisted of the following as of July 3, 2021 (in thousands): Period Future Minimum Lease Payments Remainder of 2021 $ 1,905 2022 3,911 2023 4,053 2024 3,855 2025 3,342 Thereafter 158 Total future minimum lease payments 17,224 Less imputed interest (2,299) $ 14,925
Lessee, operating lease liability	As of July 3, 2021, the operating lease liability consisted of the following (in thousands): Accrued liabilities - current portion of operating leases $ 3,005 Operating leases 11,920 $ 14,925

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	6 Months Ended
	Jul. 03, 2021
Stockholders' Equity Note [Abstract]
Disclosure of share-based compensation arrangements by share-based payment award	The following table summarizes stock-based compensation expense (in thousands): Three Months Ended Six Months Ended July 3, June 27, July 3, June 27, Cost of revenue: Products $ 186 $ 126 $ 348 $ 233 Services 157 90 307 205 Sales and marketing 1,723 1,002 3,170 1,958 Research and development 1,644 1,098 3,227 2,107 General and administrative 2,513 926 4,342 1,722 $ 6,223 $ 3,242 $ 11,394 $ 6,225

Revenue from Contracts with C_2

Revenue from Contracts with Customers (Tables)	6 Months Ended
	Jul. 03, 2021
Revenue from Contract with Customer [Abstract]
Revenue from external customers by geographic areas	The following is a summary of revenue disaggregated by geographic region based upon the location of the customers (in thousands): Three Months Ended Six Months Ended July 3, 2021 June 27, 2020 July 3, 2021 June 27, 2020 United States $ 133,618 $ 108,198 $ 268,324 $ 196,248 Canada 7,444 2,868 13,950 6,431 Europe 9,844 2,110 13,259 6,231 Middle East 5,172 2,330 12,260 4,631 Caribbean 6,954 2,310 11,717 4,682 Other 5,638 1,207 11,234 2,482 $ 168,670 $ 119,023 $ 330,744 $ 220,705
Deferred revenue, by arrangement, disclosure	Deferred revenue consisted of the following (in thousands): July 3, December 31, Current: Products and services $ 19,399 $ 14,651 Extended warranty 4,552 4,538 23,951 19,189 Long-term: Products and services 2,729 1,879 Extended warranty 18,578 18,025 21,307 19,904 $ 45,258 $ 39,093

Income Taxes (Tables)

Income Taxes (Tables)	6 Months Ended
	Jul. 03, 2021
Income Tax Disclosure [Abstract]
Schedule of income taxes	The following table presents the provision for income taxes from operations and the effective tax rates for the periods indicated (in thousands, except percentages): Three Months Ended Six Months Ended July 3, June 27, July 3, June 27, Provision for income taxes $ 207 $ 148 $ 357 $ 477 Effective tax rate 1.0 % (3.6) % 0.9 % (4.5) %

Net Income (Loss) Per Common _2

Net Income (Loss) Per Common Share (Tables)	6 Months Ended
	Jul. 03, 2021
Earnings Per Share [Abstract]
Schedule of net income (loss) per share	The following table sets forth the computation of basic and diluted net income (loss) per common share for the periods indicated (in thousands, except per share data): Three Months Ended Six Months Ended July 3, June 27, July 3, June 27, Numerator: Net income (loss) $ 20,458 $ (4,212) $ 41,073 $ (11,156) Denominator: Weighted-average common shares outstanding used to compute basic net income (loss) per share 63,042 57,261 62,795 56,906 Effect of dilutive common stock equivalents 4,592 — 4,552 — Weighted-average common shares outstanding used to compute diluted net income (loss) per share 67,634 57,261 67,347 56,906 Net income (loss) per common share: Basic net income (loss) per common share $ 0.32 $ (0.07) $ 0.65 $ (0.20) Diluted net income (loss) per common share $ 0.30 $ (0.07) $ 0.61 $ (0.20) Potentially dilutive shares, weighted average 1,096 6,996 752 6,789

Cash, Cash Equivalents, and M_2

Cash, Cash Equivalents, and Marketable Securities - (Details) - USD ($) $ in Thousands	Jul. 03, 2021	Dec. 31, 2020
Cash and Cash Equivalents [Line Items]
Total cash and cash equivalents	$ 58,590	$ 80,807
Marketable securities	117,259	52,982
Cash, Cash Equivalents, and Marketable Securities	175,849	133,789
Commercial paper
Cash and Cash Equivalents [Line Items]
Marketable securities	114,150	0
U.S. government agency securities
Cash and Cash Equivalents [Line Items]
Marketable securities	3,109	0
U.S. government securities
Cash and Cash Equivalents [Line Items]
Marketable securities	0	52,982
Cash
Cash and Cash Equivalents [Line Items]
Total cash and cash equivalents	17,777	30,745
Commercial paper
Cash and Cash Equivalents [Line Items]
Total cash and cash equivalents	21,399	0
Money market funds
Cash and Cash Equivalents [Line Items]
Total cash and cash equivalents	18,263	10,068
Corporate debt securities
Cash and Cash Equivalents [Line Items]
Total cash and cash equivalents	1,151	0
U.S. government agency securities
Cash and Cash Equivalents [Line Items]
Total cash and cash equivalents	$ 0	$ 39,994

Fair Value Measures and Discl_2

Fair Value Measures and Disclosures (Details) - USD ($) $ in Thousands	Jul. 03, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
U.S. government agency securities	$ 117,259	$ 52,982
U.S. government agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
U.S. government agency securities	3,109	0
Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	158,072
Fair Value, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	18,263	103,044
Fair Value, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	139,809
Fair Value, Recurring | U.S. government agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
U.S. government agency securities	3,109
Fair Value, Recurring | U.S. government agency securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
U.S. government agency securities	0	92,976
Fair Value, Recurring | U.S. government agency securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
U.S. government agency securities	3,109
Fair Value, Recurring | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
U.S. government agency securities	1,151
Fair Value, Recurring | Corporate debt securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
U.S. government agency securities	0
Fair Value, Recurring | Corporate debt securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
U.S. government agency securities	1,151
Fair Value, Recurring | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds	18,263
Fair Value, Recurring | Money market funds | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds	18,263	$ 10,068
Fair Value, Recurring | Money market funds | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds	0
Fair Value, Recurring | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds	135,549
Fair Value, Recurring | Commercial paper | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds	0
Fair Value, Recurring | Commercial paper | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds	$ 135,549

Balance Sheet Details - Account

Balance Sheet Details - Accounts Receivable (Details) - USD ($) $ in Thousands	Jul. 03, 2021	Dec. 31, 2020
Summary of accounts receivable, net
Accounts receivable	$ 80,971	$ 70,824
Allowance for doubtful accounts	(807)	(1,405)
Accounts receivable, net	$ 80,164	$ 69,419

Balance Sheet Details - Invento

Balance Sheet Details - Inventory (Details) - USD ($) $ in Thousands	Jul. 03, 2021	Dec. 31, 2020
Summary of inventory, net
Raw materials	$ 182	$ 34
Finished goods	76,954	52,234
Total inventory	$ 77,136	$ 52,268

Balance Sheet Details - Propert

Balance Sheet Details - Property and Equipment, net (Details) - USD ($) $ in Thousands	Jul. 03, 2021	Dec. 31, 2020
Summary of property and equipment, net
Property and equipment, gross	$ 65,426	$ 66,239
Accumulated depreciation and amortization	(45,763)	(45,858)
Property and equipment, net	19,663	20,381
Test equipment
Summary of property and equipment, net
Property and equipment, gross	37,133	37,670
Software
Summary of property and equipment, net
Property and equipment, gross	14,905	16,093
Computer equipment
Summary of property and equipment, net
Property and equipment, gross	9,897	9,062
Furniture and fixtures
Summary of property and equipment, net
Property and equipment, gross	2,025	2,069
Leasehold improvements
Summary of property and equipment, net
Property and equipment, gross	$ 1,466	$ 1,345

Balance Sheet Details - Loss on

Balance Sheet Details - Loss on Asset Retirement (Details) - USD ($) $ in Thousands	6 Months Ended
	Jul. 03, 2021	Dec. 31, 2020	Sep. 28, 2019	Mar. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Intangible asset	$ 8,201	$ 9,517
Other long-term assets	2,215	2,648
Other assets, noncurrent	10,416	12,165
Accrued liabilities	58,627	68,736
Other long-term liabilities	11,421	13,137
Licensed Software
Finite-Lived Intangible Assets [Line Items]
Royalty payment commitment				$ 15,800
Intangible asset			$ 13,200
Other Liabilities	$ 14,000	13,900	$ 13,200
Useful life	5 years
Accrued liabilities	$ 3,400	2,900
Other long-term liabilities	$ 10,600	$ 11,000

Balance Sheet Details - Accrued

Balance Sheet Details - Accrued Liabilities (Details) - USD ($) $ in Thousands	Jul. 03, 2021	Dec. 31, 2020
Summary of accrued liabilities
Compensation and related benefits	$ 16,725	$ 23,740
Warranty and retrofit	9,911	9,208
Taxes payable	4,459	3,476
Professional and consulting fees	4,347	4,497
Component inventory held by suppliers	4,002	3,992
Current portion of revenue share obligations	3,417	2,925
Customer advances or rebates	3,359	8,374
Operating leases	3,005	2,994
Product returns	2,062	1,888
Operations	1,741	950
Freight	1,543	1,955
Other	4,056	4,737
Total accrued liabilities	$ 58,627	$ 68,736

Balance Sheet Details - Warrant

Balance Sheet Details - Warranty Reserve (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 03, 2021	Jun. 27, 2020	Jul. 03, 2021	Jun. 27, 2020
Movement in Standard Product Warranty Accrual [Roll Forward]
Balance at beginning of period	$ 9,650	$ 7,430	$ 9,208	$ 7,294
Provision for warranty and retrofit charged to cost of revenue	1,003	1,276	2,205	2,625
Utilization of reserve	(742)	(974)	(1,502)	(2,187)
Balance at end of period	$ 9,911	$ 7,732	$ 9,911	$ 7,732

Balance Sheet Details - Restruc

Balance Sheet Details - Restructuring (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jul. 03, 2021	Jun. 27, 2020	Jul. 03, 2021	Jun. 27, 2020	Dec. 31, 2020
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 0	$ 6,286	$ 0	$ 6,286
Restructuring Reserve [Roll Forward]
Balance as of December 31, 2020			1,376
Cash payments			(265)
Balance as of July 3, 2021	1,111		1,111		$ 1,376
All Platform Future And Work-From-Anywhere Culture Alignment
Restructuring Cost and Reserve [Line Items]
Restructuring charges					6,300
Asset, write-off					300
Accrued common areas maintenance fees and property taxes, write-off					1,400
Facilities
Restructuring Reserve [Roll Forward]
Balance as of December 31, 2020			1,244
Cash payments			(133)
Balance as of July 3, 2021	1,111		1,111		1,244
Facilities | Richardson, Texas and San Jose, California
Restructuring Cost and Reserve [Line Items]
Restructuring charges					3,500
Severance and Related Benefits
Restructuring Reserve [Roll Forward]
Balance as of December 31, 2020			132
Cash payments			(132)
Balance as of July 3, 2021	$ 0		$ 0		$ 132

Credit Agreements - Line of Cre

Credit Agreements - Line of Credit (Details) - Bank Of America	6 Months Ended
	Jul. 03, 2021USD ($)
Revolving Credit Facility
Debt Instrument [Line Items]
Revolving credit facility, maximum capacity	$ 35,000,000
Outstanding borrowings	0
Line of credit, amount available	35,000,000
Letter of Credit
Debt Instrument [Line Items]
Revolving credit facility, maximum capacity	$ 10,000,000
London Interbank Offered Rate (LIBOR) | Revolving Credit Facility
Debt Instrument [Line Items]
Interest rate	3.75%
London Interbank Offered Rate (LIBOR) | Minimum | Revolving Credit Facility
Debt Instrument [Line Items]
Basis spread on variable rate	1.50%
London Interbank Offered Rate (LIBOR) | Maximum | Revolving Credit Facility
Debt Instrument [Line Items]
Basis spread on variable rate	2.00%
Prime Rate | Minimum | Revolving Credit Facility
Debt Instrument [Line Items]
Basis spread on variable rate	0.50%
Prime Rate | Maximum | Revolving Credit Facility
Debt Instrument [Line Items]
Basis spread on variable rate	1.00%

Commitments and Contingencies -

Commitments and Contingencies - Textual (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 03, 2021	Jun. 27, 2020	Jul. 03, 2021	Jun. 27, 2020	Dec. 31, 2020
Commitments and Contingencies [Line Items]
Total future minimum lease payments	$ 17,224		$ 17,224
Weighted average operating discount rate used to determine the operating lease liability (percent)	6.60%		6.60%
Weighted average remaining lease term for operating lease	4 years 3 months 18 days		4 years 3 months 18 days
Rent expense	$ 900	$ 1,100	$ 2,100	$ 2,200
Operating lease, payments			2,000	$ 1,700
Outstanding purchase commitments	140,900		140,900
Accrued customer rebates/prepayments	4,002		4,002		$ 3,992
San Jose, California
Commitments and Contingencies [Line Items]
Total future minimum lease payments	$ 10,700		$ 10,700

Commitments and Contingencies_2

Commitments and Contingencies - Operating Leases (Details) $ in Thousands	Jul. 03, 2021USD ($)
Commitments and Contingencies Disclosure [Abstract]
Remainder of 2021	$ 1,905
2022	3,911
2023	4,053
2024	3,855
2025	3,342
Thereafter	158
Total future minimum lease payments	17,224
Less imputed interest	(2,299)
Operating lease liability	$ 14,925

Commitments and Contingencies_3

Commitments and Contingencies - Operating Lease Liability (Details) - USD ($) $ in Thousands	Jul. 03, 2021	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Accrued liabilities - current portion of operating leases	$ 3,005	$ 2,994
Operating leases	11,920	$ 12,946
Operating lease liability	$ 14,925
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:AccruedLiabilitiesCurrent

Stockholders' Equity - 2019 Equ

Stockholders' Equity - 2019 Equity Incentive Award Plan (Details) - 2019 Equity Incentive Award Plan shares in Millions	Jul. 03, 2021shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for issuance, additional shares (in shares)	3.8
Shares available for future grant (in shares)	7

Stockholders' Equity - Stock Op

Stockholders' Equity - Stock Options (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended	6 Months Ended
	Feb. 28, 2021	Jul. 03, 2021	Jul. 03, 2021	Jun. 27, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted (in shares)		500,000	600,000
Weighted-average grant date fair value (in dollars per share)		$ 40.82	$ 39.38
Stock-based compensation			$ 11,394	$ 6,225
Stock options exercised (in shares)		100,000	600,000
Weighted-average exercise price per share, stock options (in dollars per share)		$ 7.38	$ 9.17
Recognition period			2 years 4 months 24 days
2021 Performance Targets | Performance Based Stock Options | Executive Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted (in shares)	700,000
Weighted-average grant date fair value (in dollars per share)	$ 36.74
Award performance period	1 year
Net income per share, target achievement performance threshold, percent	80.00%
Bookings, target achievement performance threshold, percent	90.00%
Number of shares granted if no-GAAP income below 80% and bookings below 90% of target (in shares)	0
Shares award weighting percent	50.00%
Target achievement threshold for shares award sliding scale	100.00%
Stock-based compensation		$ 1,900	$ 2,900
2021 Performance Targets | Performance Based Stock Options | Period One | Executive Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights, percentage	25.00%
2021 Performance Targets | Performance Based Stock Options | Period Two | Executive Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights, percentage	75.00%
Award vesting period	36 months
2021 Performance Targets | Stock Options | Period One
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights, percentage			25.00%
2021 Performance Targets | Stock Options | Period Two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period			3 years

Stockholders' Equity - Employee

Stockholders' Equity - Employee Stock Purchase Plans (Details) $ in Millions	Jul. 03, 2021USD ($)periodPlanshares	Jul. 03, 2021USD ($)periodPlanshares	Jul. 03, 2021USD ($)periodPlanshares	Jul. 02, 2021shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of employee stock purchase plans | Plan	2	2	2
Recognition period			2 years 4 months 24 days
Unrecognized stock-based compensation expense, stock options | $	$ 31.7	$ 31.7	$ 31.7
2017 Nonqualified Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of additional shares authorized (in shares)	800,000
Number of shares authorized (in shares)	5,500,000	5,500,000	5,500,000
Shares available for future grant (in shares)	2,900,000	2,900,000	2,900,000
Shares purchased under ESPP (in shares)			200,000
Recognition period			1 year 1 month 6 days
Maximum contribution percent (up to 25%)	25.00%	25.00%	25.00%
Employee termination period following purchase date to receive shares subject to risk of forfeiture			1 year
Number of offering periods | period	2	2	2
Offering period			6 months
Number of shares authorized per purchase period (in shares)	500,000	500,000	500,000
Unrecognized stock-based compensation expense, stock options | $	$ 6	$ 6	$ 6
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
ESPP, maximum employee payroll deduction percentage	15.00%	15.00%	15.00%
ESPP, maximum number of shares per employee (in shares)			2,000
Offering period			6 months
ESPP, discounted purchase price percentage			85.00%
Number of additional shares authorized (in shares)	1,300,000
Number of shares authorized (in shares)	11,100,000	11,100,000	11,100,000	9,800,000
Shares available for future grant (in shares)	2,400,000	2,400,000	2,400,000
Shares purchased under ESPP (in shares)		200,000
Unrecognized stock-based compensation expense | $	$ 0.3	$ 0.3	$ 0.3
Recognition period			1 month 6 days
Offering period			6 months

Stockholders' Equity - Stock-Ba

Stockholders' Equity - Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 03, 2021	Jun. 27, 2020	Jul. 03, 2021	Jun. 27, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	$ 6,223	$ 3,242	$ 11,394	$ 6,225
Products
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	186	126	348	233
Services
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	157	90	307	205
Sales and marketing
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	1,723	1,002	3,170	1,958
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	1,644	1,098	3,227	2,107
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	$ 2,513	$ 926	$ 4,342	$ 1,722

Revenue from Contracts with C_3

Revenue from Contracts with Customers - Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 03, 2021	Jun. 27, 2020	Jul. 03, 2021	Jun. 27, 2020
Disaggregation of Revenue [Line Items]
Total revenues	$ 168,670	$ 119,023	$ 330,744	$ 220,705
United States
Disaggregation of Revenue [Line Items]
Total revenues	133,618	108,198	268,324	196,248
Canada
Disaggregation of Revenue [Line Items]
Total revenues	7,444	2,868	13,950	6,431
Europe
Disaggregation of Revenue [Line Items]
Total revenues	9,844	2,110	13,259	6,231
Middle East
Disaggregation of Revenue [Line Items]
Total revenues	5,172	2,330	12,260	4,631
Caribbean
Disaggregation of Revenue [Line Items]
Total revenues	6,954	2,310	11,717	4,682
Other
Disaggregation of Revenue [Line Items]
Total revenues	$ 5,638	$ 1,207	$ 11,234	$ 2,482

Revenue from Contracts with C_4

Revenue from Contracts with Customers - Contract Asset and Liability (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jul. 03, 2021	Jul. 03, 2021	Dec. 31, 2020
Disaggregation of Revenue [Line Items]
Contract with customer, asset	$ 1,400	$ 1,400	$ 2,300
Contract with customer, asset, prior period, not recognized	$ 700	$ 700
Contract with customer, asset, expected to be billed remainder of year, percent	66.00%	66.00%
Deferred revenue, current	$ 23,951	$ 23,951	19,189
Deferred revenue, current	21,307	21,307	19,904
Deferred revenue	45,258	45,258	39,093
Contract with customer, liability, revenue recognized	6,800	11,100
Products and services
Disaggregation of Revenue [Line Items]
Deferred revenue, current	19,399	19,399	14,651
Deferred revenue, current	2,729	2,729	1,879
Extended warranty
Disaggregation of Revenue [Line Items]
Deferred revenue, current	4,552	4,552	4,538
Deferred revenue, current	$ 18,578	$ 18,578	$ 18,025

Revenue from Contracts with C_5

Revenue from Contracts with Customers - Contract Costs (Details)	3 Months Ended	6 Months Ended
	Jul. 03, 2021USD ($)	Jul. 03, 2021USD ($)
Revenue from Contract with Customer [Abstract]
Capitalized contract cost, gross	$ 2,300,000	$ 2,300,000
Capitalized contract cost, amortization	200,000	300,000
Capitalized contract cost, impairment	$ 0	$ 0

Revenue from Contracts with C_6

Revenue from Contracts with Customers - Performance Obligations (Details) $ in Millions	Jul. 03, 2021USD ($)
Revenue from Contract with Customer [Abstract]
Remaining performance obligation, amount	$ 92
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-07-04
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation, percentage	36.00%
Performance obligations expected to be satisfied, expected timing	1 year

Revenue from Contracts with C_7

Revenue from Contracts with Customers - Concentration Risk (Details)	3 Months Ended	6 Months Ended
	Jun. 27, 2020	Jun. 27, 2020
Lumen Technologies, Inc. | Customer Concentration Risk | Revenue
Concentration Risk [Line Items]
Concentration risk, percentage	15.00%	15.00%

Income Taxes - (Details)

Income Taxes - (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 03, 2021	Jun. 27, 2020	Jul. 03, 2021	Jun. 27, 2020
Income Tax Disclosure [Abstract]
Provision for income taxes	$ 207	$ 148	$ 357	$ 477
Effective tax rate	1.00%	(3.60%)	0.90%	(4.50%)

Net Income (Loss) Per Common _3

Net Income (Loss) Per Common Share - (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 03, 2021	Jun. 27, 2020	Jul. 03, 2021	Jun. 27, 2020
Numerator:
Net income (loss)	$ 20,458	$ (4,212)	$ 41,073	$ (11,156)
Denominator:
Weighted-average common shares outstanding used to compute basic net income (loss) per share (in shares)	63,042	57,261	62,795	56,906
Effect of dilutive common stock equivalents (in shares)	4,592	0	4,552	0
Weighted-average common shares outstanding used to compute diluted net income (loss) per share (in shares)	67,634	57,261	67,347	56,906
Basic net income (loss) per common share (in dollars per share)	$ 0.32	$ (0.07)	$ 0.65	$ (0.20)
Diluted net income (loss) per common share (in dollars per share)	$ 0.30	$ (0.07)	$ 0.61	$ (0.20)
Potentially dilutive shares, weighted average (in shares)	1,096	6,996	752	6,789