Operations	12 Months Ended
Operations	Sep. 26, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Operations	Operations Hologic, Inc. (the “Company” or “Hologic”) develops, manufactures and supplies premium diagnostics products, medical imaging systems, and surgical products with an emphasis on women's health and well-being through early detection and treatment. Until December 30, 2019, the Company's product portfolio included light-based aesthetic and medical treatment systems sold by its former Medical Aesthetics business. The Company completed the sale of its Medical Aesthetics segment on December 30, 2019 (the first day of the second quarter of fiscal 2020). During the second, third and fourth quarters of fiscal 2020, the Company operated in four segments: Diagnostics, Breast Health, GYN Surgical and Skeletal Health. COVID-19 Considerations The pandemic caused by the spread of the novel strain of coronavirus disease 2019 ("COVID-19") has created significant volatility, uncertainty and economic disruption in the markets the Company sells its products into, primarily the U.S., Europe and Asia-Pacific. In the second, third and fourth quarters of fiscal 2020, the spread of COVID-19 has negatively impacted business and healthcare activity globally. As healthcare systems respond to the increasing demands of managing COVID-19 and the resulting economic uncertainties, governments around the world have imposed measures designed to reduce the transmission of COVID-19, and individuals are responding to the fears of contracting COVID-19. In particular, elective procedures and exams have been and continue to be delayed or cancelled, there has been a significant reduction in physician office visits, and hospitals have postponed or cancelled capital purchases as well as limited or eliminated services, however in the second half of the third quarter of fiscal 2020, the Company started to see a recovery of elective procedures and exams, which continued into the fourth quarter. The reductions in testing and procedures have had, and the Company believes will continue to have, a negative impact on the Company's operating results and cash flows. However, the impact of the Company's commercial release of its COVID-19 assays more than offset these negative impacts, as the Company generated significant revenue from the sales of these assays in the third and fourth quarters of fiscal 2020. The negative effects of COVID-19 and the associated economic disruptions were felt primarily beginning in the second half of March in many of the Company's end-markets and earlier in Asia, primarily China, and the impact to the Company's legacy products in the third fiscal quarter was significant. The impact to its legacy products was less severe in the fourth quarter. While the Company's results of operations and cash flows in the third and fourth quarter of fiscal 2020 were positively impacted by the sale of its COVID-19 assays, the COVID-19 pandemic could have an adverse impact on its operating results, cash flows and financial condition in the future. The factors that could create such adverse impact include: the severity and duration of the COVID-19 pandemic; continued demand for COVID-19 testing; competition from existing and new COVID-19 testing technologies and products; the COVID-19 pandemic’s impact on the U.S. and international healthcare system, the U.S. economy and worldwide economy; and the timing, scope and effectiveness of U.S. and international governmental responses to the COVID-19 pandemic and associated economic disruptions. In addition to adversely affecting demand for the Company's products, other than its COVID-19 assays, COVID-19 and associated economic disruptions could continue to have an adverse impact on the Company's supply chains and distribution systems, including as a result of impacts associated with preventive and precautionary measures that it, other businesses and governments have taken and will take. A reduction or interruption in any of the Company's manufacturing processes could have a material adverse effect on its business. The Company believes that the uncertainty surrounding global financial markets and deteriorating worldwide macroeconomic conditions resulting from the pandemic have caused and may continue to cause the purchasers of medical equipment to decrease their medical equipment purchasing and procurement activities. Additionally, the pandemic has caused and may further cause constrictions in world credit markets that have caused and could cause its customers to experience increased difficulty in paying their existing obligations to the Company or in securing the financing necessary to purchase the Company's products. Economic uncertainty has resulted and may continue to result in cost-conscious consumers focusing on acute care rather than wellness, which may also continue to adversely affect demand for the Company's products (other than the Company's COVID-19 assays). As the Company assessed the potential longer term economic and capital market uncertainties resulting from the COVID-19 pandemic, at the end of March 2020 the Company suspended its accounts receivable securitization program and borrowed $750.0 million under its revolver. The Company used $250.0 million of these proceeds to pay off all amounts then owed under its accounts receivable securitization agreement and retained the balance as cash reserve. As of the end of fiscal 2020, the Company repaid $500.0 million of the $750.0 million borrowed under its revolver. As of September 26, 2020 the Company had an additional $1.25 billion available under its revolver and $701.0 million of cash on hand. In response to the negative impact of COVID-19 on the Company's business, in April 2020 the Company initiated cost-cutting measures, which included not only reducing discretionary and variable spend, such as travel, marketing programs and the use of contractors, consultants and temporary help, but the Company also implemented employee furloughs, salary cuts primarily in the U.S., reduced hours and in certain instances employee terminations. Further, in April 2020, the Company had shut down certain manufacturing facilities temporarily and implemented reduced work-week schedules in response to lower near-term demand for many of its products. As of the end of the third quarter of fiscal 2020, substantially all of the Company's employee cost-cutting measures ceased, and the majority of the impacted manufacturing facilities are back to pre-COVID levels. The Company has also taken measures to ensure the safety of its employees and to comply with governmental orders. These measures could require that the Company's employees continue to work remotely or otherwise refrain from reporting to their normal workplace for extended periods of time, which in turn could result in a decrease in its commercial and marketing activities.