Calix (CALX) 10-Q 25 Jul 19 2019 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 29, 2019	Jul. 19, 2019
Document and Entity Information [Abstract]
Entity Registrant Name	CALIX, INC
Entity Central Index Key	0001406666
Document Type	10-Q
Document Period End Date	Jun. 29, 2019
Amendment Flag	false
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q2
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Current Reporting Status	Yes
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		55,440,609

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 29, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 34,942	$ 49,646
Restricted cash	628	628
Accounts receivable, net	60,186	67,026
Inventory	45,360	50,151
Prepaid expenses and other current assets	7,094	7,306
Total current assets	148,210	174,757
Property and equipment, net	29,105	24,945
Right-of-use operating leases	16,422	0
Goodwill	116,175	116,175
Other assets	1,336	1,203
Total assets	311,248	317,080
Current liabilities:
Accounts payable	37,522	40,209
Accrued liabilities	47,657	57,869
Deferred revenue	18,528	15,600
Line of credit	25,000	30,000
Total current liabilities	128,707	143,678
Long-term portion of deferred revenue	17,792	17,496
Operating leases	15,045	0
Other long-term liabilities	2,498	3,972
Total liabilities	164,042	165,146
Commitments and contingencies (See Note 6)
Stockholders’ equity:
Preferred stock, $0.025 par value; 5,000 shares authorized; no shares issued and outstanding as of June 29, 2019 and December 31, 2018	0	0
Common stock, $0.025 par value; 100,000 shares authorized; 60,773 shares issued and 55,443 shares outstanding as of June 29, 2019, and 59,285 shares issued and 53,955 shares outstanding as of December 31, 2018	1,520	1,482
Additional paid-in capital	886,076	876,073
Accumulated other comprehensive loss	(710)	(753)
Accumulated deficit	(699,694)	(684,882)
Treasury stock, 5,330 shares as of June 29, 2019 and December 31, 2018	(39,986)	(39,986)
Total stockholders’ equity	147,206	151,934
Total liabilities and stockholders’ equity	$ 311,248	$ 317,080

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Jun. 29, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 0.025	$ 0.025
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value (in dollars per share)	$ 0.025	$ 0.025
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	60,773,000	59,285,000
Common stock, shares outstanding	55,443,000	53,955,000
Treasury stock, shares	5,330,000	5,330,000

Condensed Consolidated Statemen

Condensed Consolidated Statements of Comprehensive Loss (Unaudited) - USD ($) shares in Thousands, $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 29, 2019	Jun. 30, 2018	Jun. 29, 2019	Jun. 30, 2018
Revenue:
Revenue		$ 100,304	$ 111,702	$ 189,654	$ 211,105
Cost of revenue:
Cost of revenue		55,636	60,836	106,643	118,180
Gross profit		44,668	50,866	83,011	92,925
Operating expenses:
Research and development	[1]	20,700	22,101	40,030	47,637
Sales and marketing	[1]	19,734	20,527	39,073	40,428
General and administrative	[1]	9,165	10,371	17,952	19,466
Restructuring charges		0	793	0	6,133
Gain on sale of product line		0	0	0	(6,704)
Total operating expenses		49,599	53,792	97,055	106,960
Loss from operations		(4,931)	(2,926)	(14,044)	(14,035)
Interest and other expense, net:
Interest expense, net		(142)	(165)	(250)	(388)
Other income (expense), net		123	456	(268)	162
Total interest and other income (expense), net		(19)	291	(518)	(226)
Loss before provision for income taxes		(4,950)	(2,635)	(14,562)	(14,261)
Provision for income taxes		95	158	250	268
Net loss		$ (5,045)	$ (2,793)	$ (14,812)	$ (14,529)
Net loss per common share:
Basic and diluted (in dollars per share)		$ (0.09)	$ (0.05)	$ (0.27)	$ (0.28)
Weighted-average number of shares used to compute net loss per common share:
Basic and diluted (in shares)		54,624	52,290	54,339	51,952
Other comprehensive income, net of tax:
Other comprehensive income, net of tax - foreign currency translation adjustments, net		$ (223)	$ (507)	$ 43	$ (228)
Comprehensive loss		(5,268)	(3,300)	(14,769)	(14,757)
Systems
Revenue:
Revenue		92,833	102,563	175,193	195,854
Cost of revenue:
Cost of revenue	[1]	49,561	54,363	94,162	105,996
Services
Revenue:
Revenue		7,471	9,139	14,461	15,251
Cost of revenue:
Cost of revenue	[1]	$ 6,075	$ 6,473	$ 12,481	$ 12,184
[1]	Includes stock-based compensation as follows: Three and Six Months Ended June 29, 2019 and June 30, 2018; Cost of revenue: Products - $123, $141, $278, $253 ; Services - $93, $90, $192, $167; Research and development - $873, $814, $1,889, $1,797; Sales and marketing - $814, $785, $1,888, $1,635; General administrative - $666, $714, $1,467, $1,449;

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Loss (Unaudited) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 29, 2019	Jun. 30, 2018	Jun. 29, 2019	Jun. 30, 2018
Systems
Stock-based compensation	$ 123	$ 141	$ 278	$ 253
Services
Stock-based compensation	93	90	192	167
Research and development
Stock-based compensation	873	814	1,889	1,797
Sales and marketing
Stock-based compensation	814	785	1,888	1,635
General and administrative
Stock-based compensation	$ 666	$ 714	$ 1,467	$ 1,449

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - 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, 2017		51,509
Balance at beginning of period at Dec. 31, 2017	$ 144,963	$ 1,421	$ 851,054	$ (169)	$ (667,357)	$ (39,986)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	5,301		5,301
Exercise of stock options, shares		8
Exercise of stock options	51	$ 0	51
Issuance of vested performance restricted stock units and restricted stock units, net of taxes withheld, shares		749
Issuance of vested performance restricted stock units and restricted stock units, net of taxes withheld	(7)	$ 18	(25)
Stock issued under employee stock purchase plans, shares		786
Stock issued under employee stock purchase plans	3,836	$ 21	3,815
Net loss	(14,529)				(14,529)
Other comprehensive income	(228)			(228)
Ending Balance, shares at Jun. 30, 2018		53,052
Balance at end of period at Jun. 30, 2018	141,160	$ 1,460	860,196	(397)	(680,113)	(39,986)
Beginning Balance, shares at Mar. 31, 2018		51,717
Balance at beginning of period at Mar. 31, 2018	138,039	$ 1,426	853,809	110	(677,320)	(39,986)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	2,544		2,544
Exercise of stock options, shares		7
Exercise of stock options	43	$ 0	43
Issuance of vested performance restricted stock units and restricted stock units, net of taxes withheld, shares		521
Issuance of vested performance restricted stock units and restricted stock units, net of taxes withheld	(3)	$ 13	(16)
Stock issued under employee stock purchase plans, shares		807
Stock issued under employee stock purchase plans	3,837	$ 21	3,816
Net loss	(2,793)				(2,793)
Other comprehensive income	(507)			(507)
Ending Balance, shares at Jun. 30, 2018		53,052
Balance at end of period at Jun. 30, 2018	$ 141,160	$ 1,460	860,196	(397)	(680,113)	(39,986)
Beginning Balance, shares at Dec. 31, 2018	53,955	53,955
Balance at beginning of period at Dec. 31, 2018	$ 151,934	$ 1,482	876,073	(753)	(684,882)	(39,986)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	$ 5,714		5,714
Exercise of stock options, shares	100	55
Exercise of stock options	$ 326	$ 2	324
Issuance of vested performance restricted stock units and restricted stock units, net of taxes withheld, shares		501
Issuance of vested performance restricted stock units and restricted stock units, net of taxes withheld	(156)	$ 13	(169)
Stock issued under employee stock purchase plans, shares		932
Stock issued under employee stock purchase plans	4,157	$ 23	4,134
Net loss	(14,812)				(14,812)
Other comprehensive income	$ 43			43
Ending Balance, shares at Jun. 29, 2019	55,443	55,443
Balance at end of period at Jun. 29, 2019	$ 147,206	$ 1,520	886,076	(710)	(699,694)	(39,986)
Beginning Balance, shares at Mar. 30, 2019		54,164
Balance at beginning of period at Mar. 30, 2019	145,841	$ 1,488	879,475	(487)	(694,649)	(39,986)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	$ 2,569		2,569
Exercise of stock options, shares	7	6
Exercise of stock options	$ 35	$ 0	35
Issuance of vested performance restricted stock units and restricted stock units, net of taxes withheld, shares		334
Issuance of vested performance restricted stock units and restricted stock units, net of taxes withheld	(130)	$ 8	(138)
Stock issued under employee stock purchase plans, shares		939
Stock issued under employee stock purchase plans	4,159	$ 24	4,135
Net loss	(5,045)				(5,045)
Other comprehensive income	$ (223)			(223)
Ending Balance, shares at Jun. 29, 2019	55,443	55,443
Balance at end of period at Jun. 29, 2019	$ 147,206	$ 1,520	$ 886,076	$ (710)	$ (699,694)	$ (39,986)

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 29, 2019	Jun. 30, 2018
Operating activities:
Net loss	$ (14,812)	$ (14,529)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	5,714	5,301
Depreciation and amortization	4,644	4,942
Loss on retirement of property and equipment	138	247
Gain on sale of product line	0	(6,704)
Changes in operating assets and liabilities:
Accounts receivable, net	6,840	11,348
Inventory	4,791	9,524
Prepaid expenses and other assets	1,697	(1,066)
Accounts payable	(2,676)	(10,315)
Accrued liabilities	(10,314)	(2,589)
Deferred revenue	3,223	1,180
Other long-term liabilities	(2,496)	(17)
Net cash used in operating activities	(3,251)	(2,678)
Investing activities:
Purchases of property and equipment	(9,538)	(2,955)
Proceeds from sale of product line	0	10,350
Net cash provided by (used in) investing activities	(9,538)	7,395
Financing activities:
Proceeds from exercise of stock options	326	51
Proceeds from employee stock purchase plans	4,157	3,836
Taxes paid for awards vested under equity incentive plan	(156)	(7)
Payments related to financing arrangements	(1,267)	0
Proceeds from line of credit	89,000	288,064
Repayment of line of credit	(94,000)	(288,064)
Net cash provided by (used in) financing activities	(1,940)	3,880
Effect of exchange rate changes on cash, cash equivalents and restricted cash	25	(197)
Net increase (decrease) in cash, cash equivalents and restricted cash	(14,704)	8,400
Cash, cash equivalents and restricted cash at beginning of period	50,274	39,775
Cash, cash equivalents and restricted cash at end of period	$ 35,570	$ 48,175

Company and Basis of Presentati

Company and Basis of Presentation	6 Months Ended
	Jun. 29, 2019
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 a leading global provider of cloud and software platforms, systems and services required to deliver the unified access network and smart home and business services of tomorrow. The Company’s platforms and services help its customers build next generation networks by embracing a DevOps operating model, optimizing the subscriber experience by leveraging big data analytics and turn the complexity of the smart home and business into new revenue streams. The Company's cloud and software platforms, systems and services enable communication service providers (“CSPs”) to provide a wide range of revenue-generating services, from basic voice and data to advanced broadband services, over legacy and next-generation access networks. The Company focuses on CSP access networks, the portion of the network that governs available bandwidth and determines the range and quality of services that can be offered to subscribers. 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 at December 31, 2018 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, 2018 . 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, second and third quarters ending on the 13th Saturday of each fiscal period. As a result, the Company had one fewer day in the six months ended June 29, 2019 than in the six months ended June 30, 2018 . 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.

Significant Accounting Policies

Significant Accounting Policies	6 Months Ended
	Jun. 29, 2019
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, 2018 . The Company’s significant accounting policies did not change during the six months ended June 29, 2019 , except for those impacted by the newly adopted accounting standard below. Newly Adopted Accounting Standard Leases In February 2016, the FASB issued Accounting Standards Update No. 2016-02, Leases (Topic 842), which requires recognition of an asset and liability for lease arrangements longer than twelve months. The Company adopted the new standard effective January 1, 2019 using the effective date approach which eliminates the need to restate amounts presented prior to that date. The Company also elected the package of practical expedients but not the hindsight practical expedient. The adoption had a material impact on the Company's Condensed Consolidated Balance Sheets but did not impact the Company's Condensed Consolidated Statements of Comprehensive Loss or Cash Flows. Upon adoption on January 1, 2019, the Company recognized an operating lease right-of-use asset of $15.8 million and a lease liability of $16.7 million . Recent Accounting Pronouncements Not Yet Adopted There have been no recent accounting pronouncements or changes in accounting pronouncements during the six months ended June 29, 2019 , as compared to the recent accounting pronouncements described in the Company's Annual Report on Form 10-K for the year ended December 31, 2018, that are of significance or potential significance to the Company.

Cash, Cash Equivalents and Rest

Cash, Cash Equivalents and Restricted Cash	6 Months Ended
	Jun. 29, 2019
Cash and Cash Equivalents [Abstract]
Cash, Cash Equivalents and Restricted Cash	Cash, Cash Equivalents and Restricted Cash Cash, cash equivalents and restricted cash consisted of the following (in thousands): June 29, December 31, Cash and cash equivalents: Cash $ 34,928 $ 45,806 Money market funds 14 3,840 Total cash and cash equivalents 34,942 49,646 Restricted cash 628 628 $ 35,570 $ 50,274 The carrying amounts of the Company’s money market funds approximate their fair values due to their nature, duration and short maturities.

Balance Sheet Details

Balance Sheet Details	6 Months Ended
	Jun. 29, 2019
Balance Sheet Related Disclosures [Abstract]
Balance Sheet Details	Balance Sheet Details Accounts receivable, net consisted of the following (in thousands): June 29, December 31, Accounts receivable $ 60,583 $ 67,396 Allowance for doubtful accounts (397 ) (370 ) $ 60,186 $ 67,026 Inventory consisted of the following (in thousands): June 29, December 31, Raw materials $ 6,207 $ 10,815 Finished goods 39,153 39,336 $ 45,360 $ 50,151 Property and equipment, net consisted of the following (in thousands): June 29, December 31, Test equipment $ 37,683 $ 39,148 Computer equipment and software 38,185 34,697 Furniture and fixtures 2,331 1,976 Leasehold improvements 1,758 3,559 Total 79,957 79,380 Accumulated depreciation and amortization (50,852 ) (54,435 ) $ 29,105 $ 24,945 Accrued liabilities consisted of the following (in thousands): June 29, December 31, Compensation and related benefits $ 14,076 $ 19,811 Warranty and retrofit 7,910 8,547 Customer rebates/prepayments 4,906 6,103 Accrued professional and consulting fees 5,910 6,060 Operating leases 2,381 — Current portion of equipment financing arrangements 1,720 1,778 Non-income related taxes 1,503 1,288 Freight 1,021 1,187 Insurance 776 917 Excess and obsolete inventory at suppliers 654 2,667 Product return reserve 885 880 Accrued other 5,915 8,631 $ 47,657 $ 57,869 Warranty and Retrofit The Company provides a standard warranty for its hardware products. Hardware generally has a one -, three - or five -year standard warranty from the date of shipment. Under certain circumstances, the Company also provides fixes on specifically identified performance failures for products that are outside of the standard warranty period and recognizes estimated costs related to retrofit activities upon identification of such product failures. The Company accrues for potential warranty and retrofit claims based on the Company’s historical product failure rates and historical costs incurred in correcting product failures along with other relevant information related to any specifically identified product failures. The Company’s warranty and retrofit accruals are based on estimates of losses that are probable based on information available. The adequacy of the accrual is reviewed on a periodic basis and adjusted, if necessary, based on additional information as it becomes available. Changes in the Company’s warranty and retrofit accrual are as follows (in thousands): Three Months Ended Six Months Ended June 29, June 30, June 29, June 30, Balance at beginning of period $ 8,166 $ 8,097 $ 8,547 $ 8,708 Provision for warranty and retrofit charged to cost of revenue 860 1,560 1,567 3,029 Utilization of reserve (1,116 ) (1,469 ) (2,204 ) (3,549 ) Balance at end of period $ 7,910 $ 8,188 $ 7,910 $ 8,188

Credit Agreements

Credit Agreements	6 Months Ended
	Jun. 29, 2019
Line of Credit Facility [Abstract]
Credit Agreements	Credit Agreements Line of Credit On August 7, 2017, the Company entered into a loan and security agreement (the “Loan Agreement”) with Silicon Valley Bank (“SVB”). The Loan Agreement provides for a senior secured revolving credit facility with SVB, pursuant to which SVB agreed to make revolving advances available to the Company in a principal amount of up to $30.0 million based on a customary accounts receivable borrowing base, subject to certain exceptions for accounts originating outside the United States and certain specific accounts, which could reduce the amount available to the Company under the credit facility. The credit facility includes affirmative and negative covenants applicable to the Company and its subsidiaries. Furthermore, the Loan Agreement requires the Company to maintain a liquidity ratio at minimum levels set forth in more detail in the Loan Agreement. The credit facility also includes events of default, the occurrence and continuation of which would provide SVB with the right to demand immediate repayment of any principal and unpaid interest under the credit facility, and to exercise remedies against the Company and the collateral securing the loans under the credit facility. In February 2019, the Company entered into a third amendment to the Loan Agreement to reduce the required minimum level of the Adjusted Quick Ratio ("AQR") for the first half of 2019 and the required minimum Adjusted EBITDA for the first fiscal quarter of 2019 to accommodate the increased costs and use of cash that the Company anticipated for the first half of 2019 related to activities to mitigate the impact of the U.S. tariffs. As of June 29, 2019 , the Company was in compliance with these requirements. As of June 29, 2019 , the Company had borrowings outstanding of $25.0 million under the line of credit. In May 2019, the Company entered into a five -month, irrevocable standby letter of credit for $5.0 million , which reduces the borrowing capacity of the line to $25.0 million . The Company's interest rate on the line of credit was 7.0% as of June 29, 2019 and 6.5% as of June 30, 2018 . Financing Arrangements During 2018, the Company entered into financing arrangements to purchase lab and test equipment for approximately $5.1 million . Each agreement is to be paid over 36 months with a weighted average interest rate of 6.2% . As of June 29, 2019 , there was $3.8 million outstanding under these financing arrangements, which is included in accrued liabilities and other long-term liabilities in the accompanying Condensed Consolidated Balance Sheet. During 2017 and 2019, t he Company entered into financing arrangements for consulting services for up to $4.2 million in connection with the Company’s enterprise resource planning (“ERP”) implementation. The current amounts due under this agreement are to be paid over a weighted average term of 2.5 years with a weighted average interest rate of 6.9% . As of June 29, 2019 , there was $1.1 million outstanding under this arrangement, which is included in accrued liabilities and other long-term liabilities in the accompanying Condensed Consolidated Balance Sheet.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 29, 2019
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 June 29, 2019 (in thousands): Period Minimum Future Lease Payments Remainder of 2019 $ 1,687 2020 3,661 2021 3,447 2022 3,298 2023 3,362 Thereafter 6,100 Total future minimum lease payments 21,555 Less imputed interest (4,129 ) $ 17,426 Operating lease liability consisted of the following (in thousands): June 29, Accrued liabilities - current portion of operating leases $ 2,381 Operating leases 15,045 $ 17,426 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 $15.1 million and are included in the table above. The above table also includes future minimum lease payments for the Company's other office facilities, which expire at various dates through 2025. In August 2018, the Company entered into a new office lease agreement for 22,000 square feet in Petaluma, California. The lease commenced in February 2019 for a term of 64 months . The future minimum lease payments of $2.7 million are included in the table above. The Company recorded a right-of-use operating lease asset and operating lease liability of $2.2 million in the first quarter of 2019. The Company’s previous lease in Petaluma, California expired in March 2019. In July 2019, the Company entered into a new office lease agreement for 9,000 square feet in Plymouth, Minnesota. The lease will commence in December 2019 for a term of 64 months . T he aggregate lease commitment is $0.8 million and is not included in the table above. The weighted average discount rate for the Company's operating leases as of June 29, 2019 was 7.0% . The weighted average remaining lease term as of June 29, 2019 was 5.5 years . For the three and six months ended June 29, 2019 , total rent expense of the Company was $1.3 million and $2.5 million , respectively. For the three and six months ended June 30, 2018 , total rent expense of the Company was $0.7 million and $1.5 million , respectively. Cash paid within operating cash flows for operating leases was $1.2 million and $2.0 million for three and six months ended June 29, 2019 , respectively. Purchase Commitments The Company’s 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 inventory when transferred to the designated shipping warehouse. 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 June 29, 2019 , the Company had approximately $51.7 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 its 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 parts by its suppliers, or in cases where inventory levels 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, were $0.7 million and $2.7 million as of June 29, 2019 and December 31, 2018 , respectively. The Company records the related charges in cost of systems revenue in its Condensed Consolidated Statements of Comprehensive Loss. In March 2018, the Company entered into an agreement with a vendor for engineering services pursuant to which the Company will be obligated to make future minimum payments of $15.8 million through 2022. Payments are expected to begin in 2020. 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
	Jun. 29, 2019
Stockholders' Equity Note [Abstract]
Stockholders' Equity	Stockholders’ Equity 2019 Equity Incentive Award Plan At the annual meeting of stockholders of the Company in May 2019, the stockholders approved the 2019 Equity Incentive Award Plan (the “2019 Plan”). The 2019 Plan supersedes and replaces the 2010 Equity Incentive Award Plan (the “2010 Plan”) and preceding plans. No further awards will be granted under the 2010 Plan; however, the terms and conditions of the 2010 Plan will continue to govern any outstanding awards granted under the 2010 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 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 (“RSUs”), other stock or cash-based awards and dividend equivalents to eligible individuals. The number of shares available for issuance under the 2019 Plan includes an initial reserve of 1.7 million shares of common stock, any shares of common stock that are available for issuance under the 2010 Plan as of the effective date of the 2019 Plan and any shares of common stock subject to issued and outstanding awards under the 2010 Plan that expire, are cancelled or otherwise terminate following the effective date of the 2019 Plan. As of June 29, 2019 , there were 2.6 million shares available for issuance under the 2019 Plan. Stock Options During the six months ended June 29, 2019 , performance-based stock option awards exercisable for up to an aggregate of 2.0 million shares of common stock were granted to Company executives with a grant date fair value of $8.03 per share. These performance-based stock option awards contain a one -year performance period and a subsequent three -year service period. The actual number of shares earned is contingent upon achievement of both annual and quarterly corporate financial targets for revenue, non-GAAP gross margin and non-GAAP net income per share for 2019 (collectively, the “2019 Performance Targets”). These performance-based stock option awards would vest, subject to certification by the Compensation Committee of the Company’s Board of Directors, of the achievement of the 2019 Performance Targets, as to 25% of the shares of common stock earned on the date of such certification, 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. No shares are awarded unless all of the 2019 Performance Targets are met. If all of the 2019 Performance targets are met, each executive receives 100% of their target shares. Furthermore, each executive may receive a number of shares above their target shares for achievement of at least 125% above the non-GAAP net income per share target, up to a maximum of 200% of the target shares for achievement above 125% of the net income per share target. The probability of meeting the performance conditions related to these performance-based stock option awards was assessed to be unlikely as of June 29, 2019 , and therefore no stock-based compensation expense was recognized for the three and six months ended June 29, 2019 . During the three months ended June 29, 2019 , seven thousand shares of common stock were issued pursuant to the exercise of stock options at a weighted-average exercise price of $5.42 per share. During the six months ended June 29, 2019 , 0.1 million shares of common stock were issued pursuant to the exercise of stock options at a weighted-average exercise price of $5.90 per share. As of June 29, 2019 , unrecognized stock-based compensation expense of $3.4 million related to stock options, net of estimated forfeitures, is expected to be recognized over a weighted-average period of 2.7 years. Restricted Stock Units During the three and six months ended June 29, 2019 , RSUs of 0.2 million were granted with a grant date fair value of $6.62 per share. During the three months ended June 29, 2019 , RSUs of 0.4 million vested. During the six months ended June 29, 2019 , RSUs of 0.5 million vested. As of June 29, 2019 , unrecognized stock-based compensation expense of $2.6 million related to RSUs, net of estimated forfeitures, was expected to be recognized over a weighted-average period of 1.1 years. Performance Restricted Stock Units (“PRSUs”) During the six months ended June 29, 2019 , no PRSUs were granted. During the six months ended June 29, 2019 , PRSUs of 0.1 million vested. As of June 29, 2019 , all PRSUs have been fully vested and expensed. 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 “Nonqualified ESPP”). The ESPP allows eligible employees to purchase shares of the Company’s common stock through payroll deductions of up to 15% of their annual 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 six -month periods commencing on May 15 and November 15 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 annual meeting of stockholders of the Company in May 2019, the stockholders approved an increase in the number of shares of common stock issuable under the ESPP by 2.5 million shares. The increase in shares for the ESPP will go into effect for the purchase period commencing November 15, 2019, and the total shares authorized for issuance under the ESPP increases from 7.3 million shares to 9.8 million shares. As of June 29, 2019 , there were 1.1 million shares available for issuance under the ESPP. During the three and six months ended June 29, 2019 , 0.5 million shares were purchased under the ESPP. As of June 29, 2019 , unrecognized stock-based compensation expense of $0.6 million related to the ESPP is expected to be recognized over a remaining service period of 0.4 years. The Nonqualified ESPP allows eligible employees to purchase shares of the Company’s common stock through payroll deductions of up to 25% of their annual 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 Nonqualified ESPP provides two six -month offering periods, currently from December 21 through June 20 and June 21 through December 20 of each year. At the annual meeting of stockholders of the Company on May 16, 2018, the stockholders approved an amendment of certain terms and an increase in the number of shares of common stock issuable under the Nonqualified ESPP by 2.5 million shares. The maximum number of shares of common stock currently authorized for issuance under the Nonqualified ESPP is 3.5 million shares, with a maximum of 0.5 million shares allocated per purchase period. During the three and six months ended June 29, 2019 , 0.5 million shares were purchased and issued. As of June 29, 2019 , there were 2.0 million shares available for issuance under the Nonqualified ESPP. As of June 29, 2019 , unrecognized stock-based compensation expense of $3.1 million related to the Nonqualified ESPP is expected to be recognized over a remaining weighted-average service period of 1.2 years.

Revenue from Contracts with Cus

Revenue from Contracts with Customers	6 Months Ended
	Jun. 29, 2019
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. • 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 June 29, 2019 June 30, 2018 June 29, 2019 June 30, 2018 United States $ 85,837 $ 92,691 $ 161,622 $ 182,080 Middle East 5,949 7,993 9,700 11,143 Canada 3,317 2,254 6,732 4,540 Europe 2,471 3,744 4,910 4,971 Caribbean 501 1,537 2,767 2,674 Other 2,229 3,483 3,923 5,697 $ 100,304 $ 111,702 $ 189,654 $ 211,105 Contract Asset The primary contract asset is revenue recognized on professional services contracts where the services are transferred to the customer over time, less any progress billings and advanced payments, and is classified within accounts receivable. Amounts are billed in accordance with the agreed-upon contractual terms. The balance at December 31, 2018 was $5.9 million of which $2.4 million remained in the Company's Condensed Consolidated Balance Sheet at June 29, 2019 . The closing balance at June 29, 2019 was $5.3 million of which the Company expects to bill 58% of the balance during the remainder of 2019. The decrease in the contract asset was driven by the timing of professional services contracts with a major customer. Contract Liability Deferred revenue consisted of the following (in thousands): June 29, December 31, Current: Products and services $ 14,470 $ 11,600 Extended warranty 4,058 4,000 18,528 15,600 Long-term: Products and services 634 440 Extended warranty 17,158 17,056 17,792 17,496 $ 36,320 $ 33,096 The increase in the deferred revenue balance for the three and six months ended June 29, 2019 is primarily driven by cash payments received or due in advance of satisfying the Company's performance obligations, offset by $6.7 million and $10.2 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 for contracts greater than one year, which includes deferred revenue and amounts that will be invoiced and recognized as revenue in future periods. This amount was $52.5 million as of June 29, 2019 , and the Company expects to recognize 32% of such revenue over the next 12 months and the remainder thereafter. Contract Costs The Company capitalizes certain sales commissions related primarily to support, software maintenance, extended warranty and Calix Cloud products for which the expected amortization period is greater than one year. As of June 29, 2019 , the unamortized balance of deferred commissions was $0.7 million . For the three and six months ended June 29, 2019 , the amount of amortization was less than $0.1 million , and there was no impairment loss in relation to the costs capitalized. Concentration of Customer Risk The Company had one customer that accounted for more than 10% of its total revenue for the three and six months ended June 29, 2019 and June 30, 2018 . The one customer represented 17% and 15% of the Company’s total revenue for the three and six months ended June 29, 2019 , respectively. The one customer also represented 21% and 17% of the Company’s total revenue for the three and six months ended June 30, 2018, respectively. That one customer also represented more than 10% of the Company’s accounts receivable as of June 29, 2019 and June 30, 2018 .

Income Taxes

Income Taxes	6 Months Ended
	Jun. 29, 2019
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The following table presents the provision for income taxes from continuing operations and the effective tax rates for the periods indicated (in thousands, except percentages): Three Months Ended Six Months Ended June 29, June 30, June 29, June 30, Provision for income taxes $ 95 $ 158 $ 250 $ 268 Effective tax rate (1.9 )% (6.0 )% (1.7 )% (1.9 )% The effective tax rate for the three and six months ended June 29, 2019 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 .

Net Loss Per Common Share

Net Loss Per Common Share	6 Months Ended
	Jun. 29, 2019
Earnings Per Share [Abstract]
Net Loss Per Common Share	Net Loss Per Common Share The following table sets forth the computation of basic and diluted net loss per common share for the periods indicated (in thousands, except per share data): Three Months Ended Six Months Ended June 29, June 30, June 29, June 30, Numerator: Net loss $ (5,045 ) $ (2,793 ) $ (14,812 ) $ (14,529 ) Denominator: Weighted-average common shares outstanding used to compute basic and diluted net loss per share 54,624 52,290 54,339 51,952 Basic and diluted net loss per common share $ (0.09 ) $ (0.05 ) $ (0.27 ) $ (0.28 ) Potentially dilutive shares, weighted average 7,191 5,751 6,832 6,271 Potentially dilutive shares have been excluded from the computation of diluted net loss per common share when their effect is antidilutive. These antidilutive shares were primarily from stock options, restricted stock units and performance restricted stock units. 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
	Jun. 29, 2019
Accounting Policies [Abstract]
Recent Accounting Pronouncements	Newly Adopted Accounting Standard Leases In February 2016, the FASB issued Accounting Standards Update No. 2016-02, Leases (Topic 842), which requires recognition of an asset and liability for lease arrangements longer than twelve months. The Company adopted the new standard effective January 1, 2019 using the effective date approach which eliminates the need to restate amounts presented prior to that date. The Company also elected the package of practical expedients but not the hindsight practical expedient. The adoption had a material impact on the Company's Condensed Consolidated Balance Sheets but did not impact the Company's Condensed Consolidated Statements of Comprehensive Loss or Cash Flows. Upon adoption on January 1, 2019, the Company recognized an operating lease right-of-use asset of $15.8 million and a lease liability of $16.7 million . Recent Accounting Pronouncements Not Yet Adopted There have been no recent accounting pronouncements or changes in accounting pronouncements during the six months ended June 29, 2019 , as compared to the recent accounting pronouncements described in the Company's Annual Report on Form 10-K for the year ended December 31, 2018, that are of significance or potential significance 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. • Services include revenue from professional services, customer support, software- and cloud-based maintenance, extended warranty subscriptions, training and managed services.

Cash, Cash Equivalents and Re_2

Cash, Cash Equivalents and Restricted Cash (Tables)	6 Months Ended
	Jun. 29, 2019
Cash and Cash Equivalents [Abstract]
Summary of cash and cash equivalents	Cash, cash equivalents and restricted cash consisted of the following (in thousands): June 29, December 31, Cash and cash equivalents: Cash $ 34,928 $ 45,806 Money market funds 14 3,840 Total cash and cash equivalents 34,942 49,646 Restricted cash 628 628 $ 35,570 $ 50,274

Balance Sheet Details (Tables)

Balance Sheet Details (Tables)	6 Months Ended
	Jun. 29, 2019
Balance Sheet Related Disclosures [Abstract]
Summary of accounts receivable, net	Accounts receivable, net consisted of the following (in thousands): June 29, December 31, Accounts receivable $ 60,583 $ 67,396 Allowance for doubtful accounts (397 ) (370 ) $ 60,186 $ 67,026
Summary of inventory	Inventory consisted of the following (in thousands): June 29, December 31, Raw materials $ 6,207 $ 10,815 Finished goods 39,153 39,336 $ 45,360 $ 50,151
Summary of property and equipment, net	Property and equipment, net consisted of the following (in thousands): June 29, December 31, Test equipment $ 37,683 $ 39,148 Computer equipment and software 38,185 34,697 Furniture and fixtures 2,331 1,976 Leasehold improvements 1,758 3,559 Total 79,957 79,380 Accumulated depreciation and amortization (50,852 ) (54,435 ) $ 29,105 $ 24,945
Summary of accrued liabilities	Accrued liabilities consisted of the following (in thousands): June 29, December 31, Compensation and related benefits $ 14,076 $ 19,811 Warranty and retrofit 7,910 8,547 Customer rebates/prepayments 4,906 6,103 Accrued professional and consulting fees 5,910 6,060 Operating leases 2,381 — Current portion of equipment financing arrangements 1,720 1,778 Non-income related taxes 1,503 1,288 Freight 1,021 1,187 Insurance 776 917 Excess and obsolete inventory at suppliers 654 2,667 Product return reserve 885 880 Accrued other 5,915 8,631 $ 47,657 $ 57,869
Product warranty activities	Changes in the Company’s warranty and retrofit accrual are as follows (in thousands): Three Months Ended Six Months Ended June 29, June 30, June 29, June 30, Balance at beginning of period $ 8,166 $ 8,097 $ 8,547 $ 8,708 Provision for warranty and retrofit charged to cost of revenue 860 1,560 1,567 3,029 Utilization of reserve (1,116 ) (1,469 ) (2,204 ) (3,549 ) Balance at end of period $ 7,910 $ 8,188 $ 7,910 $ 8,188

Commitments and Contingencies (

Commitments and Contingencies (Tables)	6 Months Ended
	Jun. 29, 2019
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 June 29, 2019 (in thousands): Period Minimum Future Lease Payments Remainder of 2019 $ 1,687 2020 3,661 2021 3,447 2022 3,298 2023 3,362 Thereafter 6,100 Total future minimum lease payments 21,555 Less imputed interest (4,129 ) $ 17,426
Lessee, operating leases	Operating lease liability consisted of the following (in thousands): June 29, Accrued liabilities - current portion of operating leases $ 2,381 Operating leases 15,045 $ 17,426

Revenue from Contracts with C_2

Revenue from Contracts with Customers (Tables)	6 Months Ended
	Jun. 29, 2019
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 June 29, 2019 June 30, 2018 June 29, 2019 June 30, 2018 United States $ 85,837 $ 92,691 $ 161,622 $ 182,080 Middle East 5,949 7,993 9,700 11,143 Canada 3,317 2,254 6,732 4,540 Europe 2,471 3,744 4,910 4,971 Caribbean 501 1,537 2,767 2,674 Other 2,229 3,483 3,923 5,697 $ 100,304 $ 111,702 $ 189,654 $ 211,105
Deferred Revenue, by Arrangement, Disclosure	Deferred revenue consisted of the following (in thousands): June 29, December 31, Current: Products and services $ 14,470 $ 11,600 Extended warranty 4,058 4,000 18,528 15,600 Long-term: Products and services 634 440 Extended warranty 17,158 17,056 17,792 17,496 $ 36,320 $ 33,096

Income Taxes (Tables)

Income Taxes (Tables)	6 Months Ended
	Jun. 29, 2019
Income Tax Disclosure [Abstract]
Schedule of income taxes	The following table presents the provision for income taxes from continuing operations and the effective tax rates for the periods indicated (in thousands, except percentages): Three Months Ended Six Months Ended June 29, June 30, June 29, June 30, Provision for income taxes $ 95 $ 158 $ 250 $ 268 Effective tax rate (1.9 )% (6.0 )% (1.7 )% (1.9 )%

Net Loss Per Common Share (Tabl

Net Loss Per Common Share (Tables)	6 Months Ended
	Jun. 29, 2019
Earnings Per Share [Abstract]
Schedule of net income (loss) per share	The following table sets forth the computation of basic and diluted net loss per common share for the periods indicated (in thousands, except per share data): Three Months Ended Six Months Ended June 29, June 30, June 29, June 30, Numerator: Net loss $ (5,045 ) $ (2,793 ) $ (14,812 ) $ (14,529 ) Denominator: Weighted-average common shares outstanding used to compute basic and diluted net loss per share 54,624 52,290 54,339 51,952 Basic and diluted net loss per common share $ (0.09 ) $ (0.05 ) $ (0.27 ) $ (0.28 ) Potentially dilutive shares, weighted average 7,191 5,751 6,832 6,271

Significant Accounting Polici_3

Significant Accounting Policies (Details) - USD ($) $ in Thousands	Jun. 29, 2019	Jan. 01, 2019	Dec. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease right-of-use assets	$ 16,422		$ 0
Operating lease liability	$ 17,426
Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease right-of-use assets		$ 15,800
Operating lease liability		$ 16,700

Cash, Cash Equivalents and Re_3

Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Jun. 29, 2019	Dec. 31, 2018	Jun. 30, 2018	Dec. 31, 2017
Cash and Cash Equivalents [Line Items]
Total cash and cash equivalents	$ 34,942	$ 49,646
Restricted cash	628	628
Total cash	35,570	50,274	$ 48,175	$ 39,775
Cash
Cash and Cash Equivalents [Line Items]
Total cash and cash equivalents	34,928	45,806
Money market funds
Cash and Cash Equivalents [Line Items]
Total cash and cash equivalents	$ 14	$ 3,840

Balance Sheet Details - Account

Balance Sheet Details - Accounts Receivable (Details) - USD ($) $ in Thousands	Jun. 29, 2019	Dec. 31, 2018
Summary of accounts receivable, net
Accounts receivable	$ 60,583	$ 67,396
Allowance for doubtful accounts	(397)	(370)
Accounts receivable, net	$ 60,186	$ 67,026

Balance Sheet Details - Invento

Balance Sheet Details - Inventory (Details) - USD ($) $ in Thousands	Jun. 29, 2019	Dec. 31, 2018
Summary of inventory, net
Raw materials	$ 6,207	$ 10,815
Finished goods	39,153	39,336
Total inventory	$ 45,360	$ 50,151

Balance Sheet Details - Propert

Balance Sheet Details - Property and Equipment, net (Details) - USD ($) $ in Thousands	Jun. 29, 2019	Dec. 31, 2018
Summary of property and equipment, net
Property and equipment, gross	$ 79,957	$ 79,380
Accumulated depreciation and amortization	(50,852)	(54,435)
Property and equipment, net	29,105	24,945
Test equipment
Summary of property and equipment, net
Property and equipment, gross	37,683	39,148
Computer equipment and software
Summary of property and equipment, net
Property and equipment, gross	38,185	34,697
Furniture and fixtures
Summary of property and equipment, net
Property and equipment, gross	2,331	1,976
Leasehold improvements
Summary of property and equipment, net
Property and equipment, gross	$ 1,758	$ 3,559

Balance Sheet Details - Accrued

Balance Sheet Details - Accrued Liabilities (Details) - USD ($) $ in Thousands	Jun. 29, 2019	Dec. 31, 2018
Summary of accrued liabilities
Compensation and related benefits	$ 14,076	$ 19,811
Warranty and retrofit	7,910	8,547
Customer rebates/prepayments	4,906	6,103
Accrued professional and consulting fees	5,910	6,060
Operating leases	2,381	0
Current portion of equipment financing arrangements	1,720	1,778
Non-income related taxes	1,503	1,288
Freight	1,021	1,187
Insurance	776	917
Excess and obsolete inventory at suppliers	654	2,667
Product return reserve	885	880
Accrued other	5,915	8,631
Total accrued liabilities	$ 47,657	$ 57,869

Balance Sheet Details - Warrant

Balance Sheet Details - Warranty Reserve (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 29, 2019	Jun. 30, 2018	Jun. 29, 2019	Jun. 30, 2018
Other Commitments [Line Items]
Warranty period			3 years
Movement in Standard Product Warranty Accrual [Roll Forward]
Balance at beginning of period	$ 8,166	$ 8,097	$ 8,547	$ 8,708
Provision for warranty and retrofit charged to cost of revenue	860	1,560	1,567	3,029
Utilization of reserve	(1,116)	(1,469)	(2,204)	(3,549)
Balance at end of period	$ 7,910	$ 8,188	$ 7,910	$ 8,188
Minimum
Other Commitments [Line Items]
Warranty period			1 year
Maximum
Other Commitments [Line Items]
Warranty period			5 years

Credit Agreements (Details)

Credit Agreements (Details) - USD ($)	1 Months Ended	12 Months Ended
	May 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jun. 29, 2019	Jun. 30, 2018	Aug. 07, 2017
Debt Instrument [Line Items]
Line of credit		$ 30,000,000		$ 25,000,000
Letter of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity				$ 25,000,000
Debt instrument, term	5 months
Face amount	$ 5,000,000
Silicon Valley Bank | Letter of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity						$ 30,000,000
Interest rate				7.00%	6.50%
Research And Development Equipment
Debt Instrument [Line Items]
Purchase obligation		$ 5,100,000
Purchase obligation, term		36 months
Weighted average interest rate		6.20%
Amount outstanding				$ 3,800,000
Consulting Services
Debt Instrument [Line Items]
Purchase obligation			$ 4,200,000
Purchase obligation, term			2 years 6 months
Weighted average interest rate			6.90%
Amount outstanding				$ 1,100,000

Commitments and Contingencies -

Commitments and Contingencies - Textual (Details) ft² in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 29, 2019USD ($)	Jun. 30, 2018USD ($)	Jun. 29, 2019USD ($)	Jun. 30, 2018USD ($)	Jul. 31, 2019USD ($)ft²	Dec. 31, 2018USD ($)	Aug. 31, 2018USD ($)ft²
Commitments and Contingencies [Line Items]
Right-of-use operating leases	$ 16,422		$ 16,422			$ 0
Operating lease liability	17,426		17,426
Rent expense	1,300	$ 700	2,500	$ 1,500
Operating lease, payments	1,200		2,000
Outstanding purchase commitments	51,700		51,700
Accrued customer rebates/prepayments	654		654			$ 2,667
San Jose, California
Commitments and Contingencies [Line Items]
Future minimum payments due	15,100		15,100
Petaluma, CA
Commitments and Contingencies [Line Items]
Future minimum payments due							$ 2,700
Area of office | ft²							22
Term of contract							64 months
Right-of-use operating leases	2,200		2,200
Operating lease liability	2,200		2,200
Engineering Services
Commitments and Contingencies [Line Items]
Other commitment	$ 15,800		$ 15,800
Subsequent Event | Plymouth, MN
Commitments and Contingencies [Line Items]
Future minimum payments due					$ 800
Area of office | ft²					9
Term of contract					64 months

Commitments and Contingencies_2

Commitments and Contingencies - Operating Leases (Details) $ in Thousands	Jun. 29, 2019USD ($)
Commitments and Contingencies Disclosure [Abstract]
Remainder of 2019	$ 1,687
2020	3,661
2021	3,447
2022	3,298
2023	3,362
Thereafter	6,100
Total future minimum lease payments	21,555
Less imputed interest	(4,129)
Operating lease liability	$ 17,426
Weighted average operating discount rate used to determine the operating lease liability (percent)	7.00%
Weighted average remaining lease term for operating lease	5 years 5 months 18 days

Commitments and Contingencies_3

Commitments and Contingencies - Operating Lease Liability (Details) - USD ($) $ in Thousands	Jun. 29, 2019	Dec. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Accrued liabilities - current portion of operating leases	$ 2,381	$ 0
Operating leases	15,045	$ 0
Operating lease liability	$ 17,426

Stockholders' Equity (Details)

Stockholders' Equity (Details) $ / shares in Units, $ in Millions	May 16, 2018shares	May 17, 2017periodshares	May 31, 2019shares	Jun. 29, 2019USD ($)Plan$ / sharesshares	Jun. 29, 2019USD ($)Plan$ / sharesshares	Nov. 15, 2019shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted (in shares)				2,000,000
Weighted-average grant date fair value (in dollars per share) | $ / shares				$ 8.03
Stock options exercised (in shares)				7,000	100,000
Weighted-average exercise price per share, stock options (in dollars per share) | $ / shares				$ 5.42	$ 5.90
Unrecognized stock-based compensation expense, stock options | $				$ 3.4	$ 3.4
Weighted-average amortization period					2 years 8 months 12 days
Number of employee stock purchase plans | Plan				2	2
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award performance period					1 year
Award subsequent performance period					3 years
Percent of shares received upon meeting targets					100.00%
Net income per share, target achievement performance threshold, percent					125.00%
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards granted (in shares)				200,000	200,000
Grant date fair value (in dollars per share) | $ / shares				$ 6.62	$ 6.62
Weighted-average amortization period					12 months 24 days
Awards vested (in shares)				400,000	500,000
Unrecognized stock-based compensation expense | $				$ 2.6	$ 2.6
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for issuance (in shares)				1,098,065	1,098,065
Weighted-average amortization period					4 months 24 days
Unrecognized stock-based compensation expense | $				$ 0.6	$ 0.6
ESPP, maximum employee payroll deduction percentage				15.00%	15.00%
ESPP, maximum number of shares per employee (in shares)					2,000
ESPP, discounted purchase price percentage					85.00%
Offering period					6 months
Number of additional shares authorized (in shares)			2,500,000
Shares purchased under ESPP (in shares)				500,000	500,000
Number of shares authorized (in shares)				7,300,000	7,300,000
Performance Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards granted (in shares)					0
Awards vested (in shares)				100,000
2019 Equity Incentive Award Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for issuance (in shares)			1,700,000	2,600,000	2,600,000
2017 Nonqualified Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for issuance (in shares)				2,000,000	2,000,000
Unrecognized stock-based compensation expense, stock options | $				$ 3.1	$ 3.1
Weighted-average amortization period					1 year 2 months
Maximum contribution percent (up to 25%)		25.00%
Number of offering periods | period		2
Offering period		6 months
Number of additional shares authorized (in shares)	2,500,000
Shares purchased under ESPP (in shares)				500,000	500,000
Number of shares authorized (in shares)		3,500,000
Number of shares authorized per purchase period (in shares)		500,000
Period One | Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights, percentage					25.00%
Period Two | Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights, percentage					75.00%
Award vesting period					36 months
Forecast | Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized (in shares)						9,800,000
Maximum | Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percent of shares received upon meeting targets					200.00%

Revenue from Contracts with C_3

Revenue from Contracts with Customers - Contract Costs (Details)	3 Months Ended	6 Months Ended
	Jun. 29, 2019USD ($)	Jun. 29, 2019USD ($)
Revenue from Contract with Customer [Abstract]
Capitalized contract cost, gross	$ 700,000	$ 700,000
Capitalized contract cost, amortization	$ 100,000	100,000
Capitalized contract cost, impairment		$ 0

Revenue from Contracts with C_4

Revenue from Contracts with Customers - Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 29, 2019	Jun. 30, 2018	Jun. 29, 2019	Jun. 30, 2018
Disaggregation of Revenue [Line Items]
Total revenues	$ 100,304	$ 111,702	$ 189,654	$ 211,105
United States
Disaggregation of Revenue [Line Items]
Total revenues	85,837	92,691	161,622	182,080
Middle East
Disaggregation of Revenue [Line Items]
Total revenues	5,949	7,993	9,700	11,143
Canada
Disaggregation of Revenue [Line Items]
Total revenues	3,317	2,254	6,732	4,540
Europe
Disaggregation of Revenue [Line Items]
Total revenues	2,471	3,744	4,910	4,971
Caribbean
Disaggregation of Revenue [Line Items]
Total revenues	501	1,537	2,767	2,674
Other
Disaggregation of Revenue [Line Items]
Total revenues	$ 2,229	$ 3,483	$ 3,923	$ 5,697

Revenue from Contracts with C_5

Revenue from Contracts with Customers - Contract Asset and Liability (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 29, 2019	Jun. 29, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Contract with customer, asset	$ 5,300	$ 5,300	$ 5,900
Contract with customer, asset, prior period, not recognized	$ 2,400	$ 2,400
Contract with customer, asset, expected to be billed remainder of year, percent	58.00%	58.00%
Deferred revenue, current	$ 18,528	$ 18,528	15,600
Deferred revenue, current	17,792	17,792	17,496
Deferred revenue	36,320	36,320	33,096
Contract with customer, liability, revenue recognized	6,700	10,200
Products and services
Disaggregation of Revenue [Line Items]
Deferred revenue, current	14,470	14,470	11,600
Deferred revenue, current	634	634	440
Extended warranty
Disaggregation of Revenue [Line Items]
Deferred revenue, current	4,058	4,058	4,000
Deferred revenue, current	$ 17,158	$ 17,158	$ 17,056

Revenue from Contracts with C_6

Revenue from Contracts with Customers - Performance Obligations (Details) $ in Millions	Jun. 29, 2019USD ($)
Revenue from Contract with Customer [Abstract]
Remaining performance obligation, amount	$ 52.5
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation, percentage	32.00%
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. 29, 2019	Jun. 30, 2018	Jun. 29, 2019	Jun. 30, 2018
Largest One Customer | Customer Concentration Risk | Sales Revenue, Net
Concentration Risk [Line Items]
Concentration risk, percentage	17.00%	21.00%	15.00%	17.00%

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 29, 2019	Jun. 30, 2018	Jun. 29, 2019	Jun. 30, 2018
Income Tax Disclosure [Abstract]
Provision for income taxes	$ 95	$ 158	$ 250	$ 268
Effective tax rate	(1.90%)	(6.00%)	(1.70%)	(1.90%)

Net Loss Per Common Share (Deta

Net Loss Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 29, 2019	Jun. 30, 2018	Jun. 29, 2019	Jun. 30, 2018
Numerator:
Net loss	$ (5,045)	$ (2,793)	$ (14,812)	$ (14,529)
Denominator:
Weighted-average common shares outstanding used to compute basic and diluted net loss per share (in shares)	54,624	52,290	54,339	51,952
Basic and diluted net loss per common share (in dollars per share)	$ (0.09)	$ (0.05)	$ (0.27)	$ (0.28)
Potentially dilutive shares, weighted average (in shares)	7,191	5,751	6,832	6,271

Uncategorized Items - calx-2019

Label	Element	Value
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	$ 1,773,000
Retained Earnings [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	$ 1,773,000