Document And Entity Information - USD ($)	6 Months Ended
	Dec. 31, 2020	Mar. 26, 2021	Jun. 30, 2020
Document Information Line Items
Entity Registrant Name	Dune Acquisition Corp
Document Type	10-K/A
Current Fiscal Year End Date	--12-31
Entity Public Float			$ 176,640,000
Amendment Flag	true
Amendment Description	References throughout this Amendment No. 2 to the Annual Report on Form 10-K to “we,” “us,” the “Company” or “our company” are to Dune Acquisition Corporation, unless the context otherwise indicates. This Amendment No. 2 (“Amendment No. 2”) to the Annual Report on Form 10-K/A amends Amendment No. 1 to the Annual Report on Form 10-K/A of Dune Acquisition Corporation, for the year ended December 31, 2020, as filed with the Securities and Exchange Commission (“SEC”) on June 21, 2021 (the “First Amended Filing”). The Company has re-evaluated the Company’s application of ASC 480-10-S99-3A to its accounting classification of the redeemable Class A common stock, par value $0.0001 per share (the “Public Shares”), issued as part of the units sold in the Company’s initial public offering (the “IPO”) on December 22, 2020. Historically, a portion of the Public Shares was classified as permanent equity to maintain stockholders’ equity greater than $5 million on the basis that the Company will not redeem its Public Shares in an amount that would cause its net tangible assets to be less than $5,000,001, as described in the Company’s amended and restated certificate of incorporation (the “Charter”). Pursuant to such re-evaluation, the Company’s management has determined that the Public Shares include certain provisions that require classification of all of the Public Shares as temporary equity regardless of the net tangible assets redemption limitation contained in the Charter. In addition, in connection with the change in presentation for the Public Shares, the Company determined it should restate its earnings per share calculation to allocate income and losses shared pro rata between the two classes of shares. This presentation contemplates the Company’s consummation of an initial business combination within the time period provided in the Charter as the most likely outcome, in which case, both classes of shares share pro rata in the income and losses of the Company. Therefore, on November 19, 2021, the Company’s management and the audit committee of the Company’s board of directors (the “Audit Committee”) concluded that the Company’s previously issued (i) audited balance sheet as of December 22, 2020 (the “Post IPO Balance Sheet”), as previously restated in the First Amended Filing, (ii) audited financial statements included in the First Amended Filing; (iii) unaudited interim financial statements included in the Company’s Quarterly Report on Form 10-Q for the quarterly period ended March 31, 2021, filed with the SEC on June 21, 2021; (iv) unaudited interim financial statements included in the Company’s Quarterly Report on Form 10-Q for the quarterly period ended June 30, 2021, filed with the SEC on August 16, 2021; and (v) unaudited interim financial statements included in the Company’s Quarterly Report on Form 10-Q for the quarterly period ended September 30, 2021, filed with the SEC on November 12, 2021 (the “Q3 Form 10-Q”) (the periods included in such Quarterly Reports, the “Affected Quarterly Periods”), should be restated to report all Public Shares as temporary equity and should no longer be relied upon. As such, the Company will restate its financial statements in this Form 10-K/A for the Post IPO Balance Sheet and the Company’s audited financial statements included in the First Amended Filing and the Affected Quarterly Periods in an Amendment No. 1 to the Company’s Q3 Form 10-Q, to be filed with the SEC (the “Q3 Form 10-Q/A”). The restatement does not have an impact on its cash position and cash held in the trust account established in connection with the IPO (the “Trust Account”). The Company’s management has concluded that a material weakness remains in the Company’s internal control over financial reporting and that the Company’s disclosure controls and procedures were not effective. The Company’s remediation plan with respect to such material weakness will be described in more detail in the Q3 Form 10-Q/A. We are filing this Amendment No. 2 to amend and restate the First Amended Filing with modification as necessary to reflect the restatements. The following items have been amended to reflect the restatements: Part I, Item 1A. Risk Factors Part II, Item 7, Management’s Discussion and Analysis of Financial Condition and Results of Operations Part II, Item 8. Financial Statements and Supplementary Data Part II, Item 9A Controls and Procedures In addition, the Company’s Chief Executive Officer and Chief Financial Officer have provided new certifications dated as of the date of this filing in connection with this Form 10-K/A (Exhibits 31.1, 31.2, 32.1 and 32.2). Except as described above, no other information included in the Annual Report on Form 10-K of Dune Acquisition Corp. as of and for the period ended December 31, 2020, as filed with the SEC on March 29, 2021 (the “Original Filing”) or the First Amended Filing is being amended or updated by this Amendment No. 2 and, other than as described herein, this Amendment No. 2 does not purport to reflect any information or events subsequent to the Original Filing or the First Amended Filing. This Amendment No. 2 continues to describe the conditions as of the date of the Original Filing or the First Amended Filing and, except as expressly contained herein, we have not updated, modified or supplemented the disclosures contained in the Original Filing or the First Amended Filing. Accordingly, this Amendment No. 2 should be read in conjunction with the Original Filing and the First Amended Filing and with our filings with the SEC subsequent to the Original Filing.
Entity Central Index Key	0001817232
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Non-accelerated Filer
Entity Well-known Seasoned Issuer	No
Document Period End Date	Dec. 31, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Shell Company	true
Entity Ex Transition Period	false
Document Transition Report	false
Entity File Number	001-39819
Entity Incorporation, State or Country Code	DE
Entity Interactive Data Current	Yes
Class A Common Stock
Document Information Line Items
Entity Common Stock, Shares Outstanding		17,250,000
Class B Common Stock
Document Information Line Items
Entity Common Stock, Shares Outstanding		4,312,500