Summary of Significant Accounting Policies (Policies)	6 Months Ended
Jun. 30, 2026
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The condensed consolidated financial statements included herein have been prepared by Repligen Corporation (the “Company”, “Repligen”, “our” or “we”) in accordance with generally accepted accounting principles in the United States (“GAAP”) and pursuant to the rules and regulations of the United States (“U.S.”) Securities and Exchange Commission (“SEC”). Certain information and note disclosures normally included in the audited financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. The information included within this Quarterly Report on Form 10-Q should be read in conjunction with the audited consolidated financial statements and accompanying notes thereto included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2025, which was filed with the SEC on February 26, 2026 (“Form 10-K”). The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting periods. The business and economic uncertainty resulting from global geopolitical conflicts, supply chain challenges, foreign currency fluctuations and cost pressures on customers' purchasing patterns has made such estimates more difficult to calculate. Accordingly, actual results could differ from those estimates. In the opinion of the Company, the accompanying unaudited condensed consolidated financial statements include all adjustments, consisting of only normal, recurring adjustments necessary for a fair presentation of results of the interim periods presented. Results of the interim periods presented are not necessarily indicative of results to be expected for the entire year. The condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All significant intercompany accounts and transactions have been eliminated in consolidation. During the three and six months ended June 30, 2026, the Company made no material changes in the application of its significant accounting policies that were disclosed within Note 2, “Summary of Significant Accounting Policies” included in Part II, Item 8, “Financial Statements and Supplementary Data” to the Company's Form 10-K.
Reclassification	Reclassification Certain prior year amounts have been reclassified to conform with the current year presentation. Beginning in 2026, “Restructuring activities and other charges” is presented separately on the condensed consolidated statements of comprehensive income or loss. This reclassification has no impact on net income or loss.
Recent Accounting Guidance	Recent Accounting Guidance The Company considers the applicability and impact of all Accounting Standards Updates (“ASUs”) issued by the Financial Accounting Standards Board (“FASB”) and other recently issued guidance or rule decisions on its condensed consolidated financial statements. Updates not listed below were assessed and determined to be either not applicable or are expected to have minimal impact on the Company’s condensed consolidated financial position, results of operations or related disclosures. Recently Issued Accounting Guidance – Not Yet Adopted In November 2024, the FASB issued ASU 2024-03, “Income Statement - Reporting Comprehensive Income - Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses”, which requires disclosure of specific expense categories in the notes to the financial statements. This includes: (i) amounts of purchased inventory, employee compensation, depreciation, amortization and other related costs and expenses; (ii) an explanation of costs and expenses that are not disaggregated on a quantitative basis; and (iii) the definition and total amount of selling expenses. The amendment is effective for annual reporting periods beginning after December 15, 2026, with early adoption permitted, and interim reporting periods beginning after December 15, 2027. The amendment should be applied prospectively to financial reporting periods after the effective date or retrospectively to any or all prior periods presented in the financial statements. The Company is currently evaluating the impact that the adoption of this standard will have on its consolidated financial statements and related disclosures.
Concentrations of Credit Risk and Significant Customers	Concentrations of Credit Risk and Significant Customers Financial instruments that subject the Company to significant concentrations of credit risk primarily consist of cash and cash equivalents, marketable securities and accounts receivable. The Company's investment policy requires that it only invest in highly-rated securities and limits its exposure to any single-issuer to mitigate the risk of credit loss. The Company’s expected loss allowance methodology for accounts receivable is developed using historical collection experience, current and future economic and market conditions and a review of the current status of customers' trade accounts receivable. The Company’s expected loss allowance and changes in the allowance period over period have not been historically material. Concentration of credit risk with respect to accounts receivable is limited to customers to whom the Company makes significant sales. To control credit risk, the Company performs regular credit evaluations of its customers’ financial condition. There was no revenue from a specific customer that represented 10% or more of the Company's total revenue for the three and six months ended June 30, 2026 or 2025. One customer represented 10% of the Company’s total trade accounts receivable balance at June 30, 2026, and no customer represented 10% or more of the Company's total trade accounts receivable balance at December 31, 2025.

Summary of Significant Accounting Policies (Policies)

6 Months Ended

Jun. 30, 2026

The condensed consolidated financial statements included herein have been prepared by Repligen Corporation (the “Company”, “Repligen”, “our” or “we”) in accordance with generally accepted accounting principles in the United States (“GAAP”) and pursuant to the rules and regulations of the United States (“U.S.”) Securities and Exchange Commission (“SEC”). Certain information and note disclosures normally included in the audited financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. The information included within this Quarterly Report on Form 10-Q should be read in conjunction with the audited consolidated financial statements and accompanying notes thereto included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2025, which was filed with the SEC on February 26, 2026 (“Form 10-K”).

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting periods. The business and economic uncertainty resulting from global geopolitical conflicts, supply chain challenges, foreign currency fluctuations and cost pressures on customers' purchasing patterns has made such estimates more difficult to calculate. Accordingly, actual results could differ from those estimates.

In the opinion of the Company, the accompanying unaudited condensed consolidated financial statements include all adjustments, consisting of only normal, recurring adjustments necessary for a fair presentation of results of the interim periods presented. Results of the interim periods presented are not necessarily indicative of results to be expected for the entire year. The condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All significant intercompany accounts and transactions have been eliminated in consolidation.

During the three and six months ended June 30, 2026, the Company made no material changes in the application of its significant accounting policies that were disclosed within Note 2, “Summary of Significant Accounting Policies” included in Part II, Item 8, “Financial Statements and Supplementary Data” to the Company's Form 10-K.

Reclassification

Certain prior year amounts have been reclassified to conform with the current year presentation. Beginning in 2026, “Restructuring activities and other charges” is presented separately on the condensed consolidated statements of comprehensive income or loss. This reclassification has no impact on net income or loss.

Recent Accounting Guidance

The Company considers the applicability and impact of all Accounting Standards Updates (“ASUs”) issued by the Financial Accounting Standards Board (“FASB”) and other recently issued guidance or rule decisions on its condensed consolidated financial statements. Updates not listed below were assessed and determined to be either not applicable or are expected to have minimal impact on the Company’s condensed consolidated financial position, results of operations or related disclosures.

Recently Issued Accounting Guidance – Not Yet Adopted

In November 2024, the FASB issued ASU 2024-03, “Income Statement - Reporting Comprehensive Income - Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses”, which requires disclosure of specific expense categories in the notes to the financial statements. This includes: (i) amounts of purchased inventory, employee compensation, depreciation, amortization and other related costs and expenses; (ii) an explanation of costs and expenses that are not disaggregated on a quantitative basis; and (iii) the definition and total amount of selling expenses. The amendment is effective for annual reporting periods beginning after December 15, 2026, with early adoption permitted, and interim reporting periods beginning after December 15, 2027. The amendment should be applied prospectively to financial reporting periods after the effective date or retrospectively to any or all prior periods presented in the financial statements. The Company is currently evaluating the impact that the adoption of this standard will have on its consolidated financial statements and related disclosures.

Concentrations of Credit Risk and Significant Customers

Financial instruments that subject the Company to significant concentrations of credit risk primarily consist of cash and cash equivalents, marketable securities and accounts receivable. The Company's investment policy requires that it only invest in highly-rated securities and limits its exposure to any single-issuer to mitigate the risk of credit loss.

The Company’s expected loss allowance methodology for accounts receivable is developed using historical collection experience, current and future economic and market conditions and a review of the current status of customers' trade accounts receivable. The Company’s expected loss allowance and changes in the allowance period over period have not been historically material. Concentration of credit risk with respect to accounts receivable is limited to customers to whom the Company makes significant sales. To control credit risk, the Company performs regular credit evaluations of its customers’ financial condition.

There was no revenue from a specific customer that represented 10% or more of the Company's total revenue for the three and six months ended June 30, 2026 or 2025.

One customer represented 10% of the Company’s total trade accounts receivable balance at June 30, 2026, and no customer represented 10% or more of the Company's total trade accounts receivable balance at December 31, 2025.