Basis of Presentation	6 Months Ended
Mar. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	1. Basis of Presentation The unaudited consolidated financial statements of Brooks Automation, Inc. and its subsidiaries (“Brooks”, or the “Company”) included herein have been prepared in accordance with accounting principles generally accepted in the United States ("GAAP"). All intercompany accounts and transactions have been eliminated in consolidation. In the opinion of management, all material adjustments, which are of a normal and recurring nature and necessary for a fair statement of the financial position and results of operations and cash flows for the periods presented, have been reflected in the accompanying unaudited consolidated financial statements. The results of operations for the interim periods are not necessarily indicative of the results of operations to be expected for the full fiscal year. Discontinued Operations In the fourth quarter of fiscal year 2018, the Company entered into a definitive agreement to sell its semiconductor cryogenics business to Edwards Vacuum LLC (a member of the Atlas Copco Group), (the “Disposition”). The Company determined that the cryogenics business met the “held for sale” criteria and the “discontinued operations” criteria in accordance with Financial Accounting Standard Boards (“FASB”) Accounting Standards Codification (“ASC”) 205, Presentation of Financial Statements, (“FASB ASC 205”) as of September 30, 2018. The Consolidated Balance Sheets and Consolidated Statements of Operations, and the notes to the Consolidated Financial Statements were restated for all periods presented to reflect the discontinuation of the cryogenics business, in accordance with FASB ASC 205. The discussion in the notes to these Consolidated Financial Statements, unless otherwise noted, relate solely to the Company's continuing operations. Please refer to Note 3, “Discontinued Operations” for further information. Certain information and footnote disclosures normally included in the Company’s annual consolidated financial statements have been condensed or omitted and, accordingly, the accompanying financial information should be read in conjunction with the audited consolidated financial statements and notes thereto contained in the Company’s Annual Report on Form 10‑K filed with the United States Securities and Exchange Commission (the “SEC”) for the fiscal year ended September 30, 2018 (the "2018 Annual Report on Form 10‑K"). The accompanying Consolidated Balance Sheet as of September 30, 2018 was derived from the audited annual consolidated financial statements as of the period then ended. Revision of Prior Period Financial Statements During the three months ended March 31, 2019, the Company identified a misclassification related to the presentation of the product and service revenue and the cost of product and service revenue related to GENEWIZ in the Company's Consolidated Statements of Operations for the three months ended December 31, 2018. The total revenue and cost of revenue related to GENEWIZ for the three months ended December 31, 2018 were included in the product revenue and cost of revenue line items instead of the service revenue and cost of revenue line items in the Consolidated Statements of Operations in the Form 10-Q for the quarter ended December 31, 2018. GENEWIZ was acquired during the three months ended December 31, 2018 and therefore the misclassifiation did not impact any other historical periods. The misclassification had no impact on total revenue or the total cost of revenue, gross profit, operating income (loss), net income (loss), as well as basic and diluted net income (loss) per share during any of the periods presented. Additionally, the misclassification had no impact on the Company's consolidated balance sheets and consolidated statements of cash flows during any of the prior periods. The Company considered the guidance in Accounting Standard Codification (ASC) Topic 250, “Accounting Changes and Error Corrections,” ASC Topic 250-10-S99-1, “Assessing Materiality,” and ASC Topic 250-10-S99-2, “Considering the Effects of Prior Year Misstatements when Quantifying Misstatements in Current Year Financial Statements" in evaluating whether the Company’s previously issued consolidated financial statements were materially misstated. The Company concluded this misclassification was not material individually or in the aggregate to the financial statements presented for the three months ended December 31, 2018, and therefore, amendments of the previously filed Form 10-Q for the three months ended December 31, 2018 was not required. The revision for this correction to the three months ended December 31, 2018 is reflected in the reported revenue and cost of revenue classification for the six months ended March 31, 2019 in this report and will be corrected in any future filings containing such financial information for the three months ended December 31, 2018. The following table summarizes the effects of the misclassification to the three months ended December 31, 2018:

1. Basis of Presentation

The unaudited consolidated financial statements of Brooks Automation, Inc. and its subsidiaries (“Brooks”, or the “Company”) included herein have been prepared in accordance with accounting principles generally accepted in the United States ("GAAP"). All intercompany accounts and transactions have been eliminated in consolidation. In the opinion of management, all material adjustments, which are of a normal and recurring nature and necessary for a fair statement of the financial position and results of operations and cash flows for the periods presented, have been reflected in the accompanying unaudited consolidated financial statements. The results of operations for the interim periods are not necessarily indicative of the results of operations to be expected for the full fiscal year.

Discontinued Operations

In the fourth quarter of fiscal year 2018, the Company entered into a definitive agreement to sell its semiconductor cryogenics business to Edwards Vacuum LLC (a member of the Atlas Copco Group), (the “Disposition”). The Company determined that the cryogenics business met the “held for sale” criteria and the “discontinued operations” criteria in accordance with Financial Accounting Standard Boards (“FASB”) Accounting Standards Codification (“ASC”) 205, Presentation of Financial Statements, (“FASB ASC 205”) as of September 30, 2018. The Consolidated Balance Sheets and Consolidated Statements of Operations, and the notes to the Consolidated Financial Statements were restated for all periods presented to reflect the discontinuation of the cryogenics business, in accordance with FASB ASC 205. The discussion in the notes to these Consolidated Financial Statements, unless otherwise noted, relate solely to the Company's continuing operations. Please refer to Note 3, “Discontinued Operations” for further information.

Certain information and footnote disclosures normally included in the Company’s annual consolidated financial statements have been condensed or omitted and, accordingly, the accompanying financial information should be read in conjunction with the audited consolidated financial statements and notes thereto contained in the Company’s Annual Report on Form 10‑K filed with the United States Securities and Exchange Commission (the “SEC”) for the fiscal year ended September 30, 2018 (the "2018 Annual Report on Form 10‑K"). The accompanying Consolidated Balance Sheet as of September 30, 2018 was derived from the audited annual consolidated financial statements as of the period then ended.

Revision of Prior Period Financial Statements

During the three months ended March 31, 2019, the Company identified a misclassification related to the presentation of the product and service revenue and the cost of product and service revenue related to GENEWIZ in the Company's Consolidated Statements of Operations for the three months ended December 31, 2018. The total revenue and cost of revenue related to GENEWIZ for the three months ended December 31, 2018 were included in the product revenue and cost of revenue line items instead of the service revenue and cost of revenue line items in the Consolidated Statements of Operations in the Form 10-Q for the quarter ended December 31, 2018. GENEWIZ was acquired during the three months ended December 31, 2018 and therefore the misclassifiation did not impact any other historical periods. The misclassification had no impact on total revenue or the total cost of revenue, gross profit, operating income (loss), net income (loss), as well as basic and diluted net income (loss) per share during any of the periods presented. Additionally, the misclassification had no impact on the Company's consolidated balance sheets and consolidated statements of cash flows during any of the prior periods. The Company considered the guidance in Accounting Standard Codification (ASC) Topic 250, “Accounting Changes and Error Corrections,” ASC Topic 250-10-S99-1, “Assessing Materiality,” and ASC Topic 250-10-S99-2, “Considering the Effects of Prior Year Misstatements when Quantifying Misstatements in Current Year Financial Statements" in evaluating whether the Company’s previously issued consolidated financial statements were materially misstated. The Company concluded this misclassification was not material individually or in the aggregate to the financial statements presented for the three months ended December 31, 2018, and therefore, amendments of the previously filed Form 10-Q for the three months ended December 31, 2018 was not required. The revision for this correction to the three months ended December 31, 2018 is reflected in the reported revenue and cost of revenue classification for the six months ended March 31, 2019 in this report and will be corrected in any future filings containing such financial information for the three months ended December 31, 2018.

The following table summarizes the effects of the misclassification to the three months ended December 31, 2018: