Organization and Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2022
Accounting Policies [Abstract]
Basis of Presentation and Principles of Consolidation	Basis of Presentation and Principles of Consolidation The accompanying unaudited condensed consolidated financial statements include the accounts of Arista Networks, Inc. and its wholly-owned subsidiaries and have been prepared in accordance with U.S. Generally Accepted Accounting Principles (“GAAP”) and the requirements of the U.S. Securities and Exchange Commission (the “SEC”) for interim reporting. As permitted under those rules, certain footnotes or other financial information that are normally required by GAAP can be condensed or omitted. In management’s opinion, the unaudited condensed consolidated financial statements have been prepared on the same basis as the audited consolidated financial statements and include all adjustments, which include only normal recurring adjustments, necessary for the fair presentation of our financial information. The results for the three and nine months ended September 30, 2022, are not necessarily indicative of the results expected for the full fiscal year. The condensed consolidated balance sheet as of December 31, 2021 has been derived from the audited consolidated financial statements at that date but does not include all of the information and notes required by GAAP for complete financial statements. All significant inter-company accounts and transactions have been eliminated. Our condensed consolidated financial statements and related financial information in this Quarterly Report on Form 10-Q should be read in conjunction with the audited consolidated financial statements and related footnotes included in our Annual Report on Form 10-K for the fiscal year ended December 31, 2021, filed with the SEC on February 15, 2022.
Use of Estimates	Use of Estimates The preparation of the accompanying consolidated financial statements in conformity with GAAP requires us to make estimates and assumptions that affect the amounts reported and disclosed in the consolidated financial statements and accompanying notes. Those estimates and assumptions include, but are not limited to, valuation of inventory and contract manufacturer/supplier liabilities, accounting for income taxes, including the recognition of deferred tax assets and liabilities, valuation allowance on deferred tax assets and reserves for uncertain tax positions, revenue recognition and deferred revenue, allowance for doubtful accounts, sales rebates and return reserves, valuation of goodwill and acquisition-related intangible assets, estimate of useful lives of long-lived assets including intangible assets, and the recognition and measurement of contingent liabilities. We evaluate our estimates and assumptions based on historical experience and other factors and adjust these estimates and assumptions when facts and circumstances dictate. Actual results could differ materially from these estimates.
Risks and Uncertainties	Risks and Uncertainties Global economic and business activities continue to face widespread macroeconomic uncertainties, including supply chain and labor shortages, inflation and monetary policy shifts, recession risks, the ongoing global coronavirus ("COVID-19") pandemic and potential disruptions from the Russia-Ukraine conflict and the U.S. trade war with China. Our contract manufacturers and suppliers have experienced workforce disruptions, delays in component sourcing, production and export of their products and component shortages and increased component costs, which have disrupted our supply chain and have impacted and will likely continue to impact our ability to supply products to our customers on a timely basis. While overall demand remains strong across our customers base, we believe ongoing supply disruptions combined with other supply chain related constraints could impact our ability to fulfill this increased demand and as a result could negatively impact our business in future periods. In addition, inflation pressure in our supply chain and scarcity of some materials needed to build our products have increased our cost of revenue and have impacted, and may continue to negatively impact our gross margin. Our operating cash flows have also been and may continue to be negatively impacted by increased component inventories on hand or at our contract manufacturers, awaiting supply of a limited number of scarce components necessary to build and ship the completed product. The extent of the impact on our operational and financial performance, including our ability to execute our business strategies and initiatives in the expected time frame, and the impact of any initiatives and programs we may undertake to address financial and operational challenges, will depend on future developments, the impact to our customers, partners, employees, contract manufacturers and supply chain, all of which continue to evolve and are unpredictable. Management continues to actively monitor the impact of these macroeconomic factors on the Company's financial condition, liquidity, operations, suppliers, industry, and workforce. As of the date of issuance of these condensed consolidated financial statements, the extent to which these factors may materially impact the Company's financial condition, liquidity, or results of operations is uncertain.
Recently Adopted Accounting Pronouncements	Recently Adopted Accounting Pronouncements In October 2021, the FASB issued ASU 2021-08, Business Combinations (Topic 805): Accounting for Contract Assets and Contract Liabilities from Contracts with Customers. ASU 2021-08 requires companies to recognize and measure contract assets and contract liabilities relating to contracts with customers that are acquired in a business combination in accordance with ASC 606. Under previous GAAP, an acquirer generally recognized assets acquired and liabilities assumed in a business combination, including contract assets and contract liabilities arising from revenue contracts with customers, at fair value on the acquisition date. ASU No. 2021-08 results in the acquirer recording acquired contract assets and liabilities on the same basis that would have been recorded by the acquiree before the acquisition under ASC Topic 606. The ASU is effective for fiscal years beginning after December 15, 2022, with early adoption permitted. The Company adopted this ASU as of January 1, 2022 on a prospective basis and the adoption impact was immaterial to the condensed consolidated financial statements. The standard did not impact acquired contract assets or liabilities from business combinations occurring prior to the adoption date.