Significant Accounting Policies (Policies)	6 Months Ended
Significant Accounting Policies (Policies)	Jun. 27, 2020
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 at December 31, 2019 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, 2019. 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 less day in the six months ended June 27, 2020 than for the six months ended June 29, 2019. 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 recent 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. The Company has instituted office closures, travel restrictions and instituted a mandatory work-from-home policy for substantially all of its employees. The spread of COVID-19 has impacted the Company's supply chain operations through restrictions and shutdown of business activities by suppliers whom the Company relies on for sourcing components and materials and third-party partners whom the Company relies on for manufacturing, warehousing and logistics services. Although demand for the Company's products may remain strong in the short-term as subscribers seek more bandwidth and better WiFi, 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 challenges in sourcing components and materials to manufacture its products, and future outbreaks could 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 is uncertain.
Recent Accounting Pronouncements	Newly Adopted Accounting Standard The Company did not adopt any new accounting standards during the six months ended June 27, 2020 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 June 27, 2020, as compared to the recent accounting pronouncements described in the Company's Annual Report on Form 10-K for the year ended December 31, 2019, 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.