Business and Summary of Significant Accounting Policies	9 Months Ended
Business and Summary of Significant Accounting Policies	Sep. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Business and Summary of Significant Accounting Policies	Business and Summary of Significant Accounting Policies Business Description Tenable Holdings, Inc. (the “Company,” “we,” "us," or “our”) is a provider of Cyber Exposure solutions, which is a discipline for managing, measuring and comparing cybersecurity risk in the digital era. Our enterprise software platform enables broad visibility into an organization’s cyber exposure across the modern attack surface and deep insights that help organizations translate technical data into business insights to understand and reduce their cybersecurity risk. Basis of Presentation The accompanying consolidated financial statements include the accounts of Tenable Holdings, Inc. and our wholly owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation. The consolidated financial statements have been prepared in conformity with United States generally accepted accounting principles (“GAAP”) for interim financial information. The consolidated statements are unaudited and should be read in conjunction with the consolidated financial statements and related notes included in our 2019 Annual Report on Form 10-K ("10-K") filed with the Securities and Exchange Commission on February 28, 2020. The consolidated financial statements have been prepared on a basis consistent with the audited annual consolidated financial statements included in the 10-K and, in the opinion of management, include all adjustments of a normal recurring nature necessary to fairly state our financial position, our results of operations, and cash flows. The results for the nine months ended September 30, 2020 are not necessarily indicative of the operating results expected for the year ending December 31, 2020 or any other future period. Use of Estimates The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. These estimates include, but are not limited to, the determination of the estimated economic life of perpetual licenses for revenue recognition, the estimated period of benefit for deferred commissions, the useful lives of long-lived assets, the fair value of acquired intangible assets, the valuation of stock-based compensation, including the estimated underlying fair value of our common stock prior to our IPO, the incremental borrowing rate for operating leases, and the valuation of deferred tax assets. We base these estimates on historical experience and on various other assumptions that we believe to be reasonable. Actual results could differ significantly from these estimates. Significant Accounting Policies Our significant accounting policies are described in our 10-K. During the nine months ended September 30, 2020, there were no material changes to our significant accounting policies other than those described below. Recently Adopted Accounting Pronouncements We adopted Accounting Standards Update ("ASU") No. 2016-13 — Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, effective January 1, 2020 using the modified retrospective approach. The adoption of this guidance did not have a material impact on our condensed consolidated financial statements. The new standard replaces the previous incurred loss impairment methodology with a methodology that reflects current expected credit losses for financial assets, including trade receivables, which are not measured at fair value, through net income. Under the new standard, our allowance for doubtful accounts reflects our best estimate of expected future credit losses based on various factors, including our historical collection experience, age of accounts receivable balances, current conditions, reasonable and supportable forecasts of future economic conditions, as well as other factors that may impact our ability to collect our accounts receivable. However, given the uncertainty caused by the COVID-19 pandemic and other factors, these estimates may change and future credit losses may differ from our estimates. Additionally, the new standard requires us to evaluate impairments of available-for-sale debt securities due to credit-related and non-credit-related factors, including market risk, and if it is more-likely-than-not that we would have to sell the security before the recovery of the amortized cost basis. Identified credit-related impairments would be recognized as a charge in the statement of operations.