Summary of Significant Accounting Policies (Policies)	9 Months Ended
Summary of Significant Accounting Policies (Policies)	Oct. 02, 2022
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited Consolidated Financial Statements of the Company have been prepared in accordance with generally accepted accounting principles in the U.S. (“GAAP”) for interim financial information and with the general instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, certain footnotes or other financial information required by GAAP have been condensed or omitted. In the opinion of management, all adjustments considered necessary for a fair presentation (consisting of normal recurring accruals) have been included. The information at October 2, 2022, and for the three and nine months ended October 2, 2022 and October 3, 2021, is unaudited. For further information, refer to the Consolidated Financial Statements and notes thereto for the year ended January 2, 2022 included in Quidel’s 2021 Annual Report on Form 10-K. Operating results for any quarter are historically seasonal in nature and are not necessarily indicative of the results expected for the full year. The Company follows the concept of a fiscal year that ends on the Sunday nearest to the end of the month of December, and fiscal quarters that end on the Sunday nearest to the end of the months of March, June, and September. For 2022 and 2021, the Company’s fiscal year will end or has ended on January 1, 2023 and January 2, 2022, respectively. For 2022 and 2021, the Company’s third quarter ended on October 2, 2022 and October 3, 2021, respectively. The three and nine-month periods ended October 2, 2022 and October 3, 2021 each included 13 and 26 weeks, respectively.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses and the related disclosures of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.
Regulatory Accounting	Significant Accounting Policies During the nine months ended October 2, 2022, there have been no changes to the Company’s significant accounting policies as described in Quidel’s 2021 Annual Report on Form 10-K, except for the addition of certain policies related to the Combinations, which are discussed below.
Business Combinations Policy	Business Combinations The cost of an acquired business is assigned to the tangible and identifiable intangible assets acquired and liabilities assumed on the basis of the estimated fair values at the date of acquisition. We assess fair value, which is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date, using a variety of methods including, but not limited to, an income approach and a market approach, such as the estimation of future cash flows of the acquired business and current selling prices of similar assets. Fair value of the assets acquired and liabilities assumed, including intangible assets, in-process research and development (“IPR&D”), and contingent payments, are measured based on the assumptions and estimations with regards to variable factors such as the amount and timing of future cash flows for the asset or liability being measured, appropriate risk-adjusted discount rates, nonperformance risk, or other factors that market participants would consider. Upon acquisition, we determine the estimated economic lives of the acquired intangible assets for amortization purposes, which are based on the underlying expected cash flows of such assets. When applicable, adjustments to inventory are based on the fair market value of inventory and amortized into income based on the period in which the underlying inventory is sold. Goodwill is an asset representing the future economic benefits arising from other assets acquired in a business combination that is not individually identified and separately recognized. Actual results may vary from projected results and assumptions used in the fair value assessments.
Pension and Other Postretirement Plans, Pensions, Policy	Defined Benefit Plans and Other Post-Employment BenefitsIn connection with the Combinations, the Company assumed Ortho’s defined benefit plans in certain countries and a retiree healthcare reimbursement plan for certain U.S. employees. Defined benefit plans specify an amount of pension benefit that an employee will receive on retirement, usually dependent on factors such as age, years of service and compensation. The net obligation with respect to defined benefit plans is calculated separately for each plan by estimating the amount of the future benefits that employees have earned in return for their service in the current and prior periods. These benefits are then discounted to determine the present value of the obligations and are then adjusted for the impact of any unamortized prior service costs. The net obligation is then determined with reference to the fair value of the plan assets (if any). The discount rate used is the yield on bonds that are denominated in the currency in which the benefits will be paid and that have maturity dates approximating the terms of the obligations. The calculations are performed by qualified actuaries using the projected unit credit method.
Government Assistance	Government AssistanceIn connection with the Combinations, the Company acquired a previously established agreement between Ortho and the Biomedical Advanced Research and Development Authority (“BARDA”), a division of the U.S. Department of Health and Human Services, which provided funding for Ortho to build manufacturing space and production support equipment to increase COVID-19 assay production capacity, as well as to build a manufacturing facility to produce certain analyzers needed to support COVID-19 testing. Amounts received from BARDA under this grant are recorded as a reduction to the carrying value of the related assets. A portion of the grant is for purposes of reimbursement of certain general and administrative expenses related to the project, which will not be capitalized as part of the equipment constructed in connection with the project and will be recorded as a reduction to the related expense. The Company received $15.8 million during the nine months ended October 2, 2022, which was recorded as a reduction to the carrying value of the related assets.