General (Policies)	9 Months Ended
Sep. 30, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Risk And Uncertainties	Risks and Uncertainties Due to the global outbreak of SARS-CoV-2, a novel strain of coronavirus that causes Coronavirus disease (COVID-19), the Company experienced an impact on certain areas of its business. These effects included a slowing of patient recruitment in the FOCUS trial and a reduction in the pace at which we can monitor data at our clinical trial sites. The resulting delay in completing enrollment and additional time required to monitor data has caused our planned announcement for the top-line data from our FOCUS trial to shift to early 2021. We now plan to submit a New Drug Application (NDA) to the FDA in the first quarter of 2022 for the treatment of mOM. The ability to achieve this goal is contingent on our ability to monitor data at our clinical sites and therefore the timeline may shift as access to the clinical sites changes in response to the rapidly evolving situation. We have also experienced a decline in EU commercial product revenue and additional impacts to the business may arise that we are not aware of currently. The ultimate impact of the pandemic on the Company’s results of operations, financial position, liquidity, or capital resources cannot be reasonably estimated at this time.
Liquidity And Going Concern	Liquidity and Going Concern The accompanying interim condensed consolidated financial statements have been prepared on a going concern basis, which contemplates the realization of assets and the satisfaction of liabilities in the normal course of business. The Company has incurred losses since inception and expects to continue incurring losses for the next several years. These losses, among other factors, raise substantial doubt about the Company’s ability to continue as a going concern. The Company’s existence is dependent upon management’s ability to obtain additional funding sources or to enter into strategic alliances. There can be no assurance that the Company’s efforts will result in the resolution of the Company’s liquidity needs. The accompanying statements do not include any adjustments that might result should the Company be unable to continue as a going concern.
Basis of Presentation	Basis of Presentation These interim condensed consolidated financial statements are unaudited and were prepared by the Company in accordance with generally accepted accounting principles in the United States of America (GAAP) and with the SEC’s instructions to Form 10-Q and Article 10 of Regulation S-X. They include the accounts of all entities controlled by Delcath and all significant inter-company accounts and transactions have been eliminated in consolidation. All historical share and per share amounts have been retrospectively adjusted for the one-for-seven hundred reverse stock split effected on December 24, 2019. The preparation of interim condensed consolidated financial statements requires management to make assumptions and estimates that impact the amounts reported. These interim condensed consolidated financial statements reflect all adjustments, consisting of normal recurring accruals, necessary for a fair presentation of the Company’s results of operations, financial position and cash flows for the interim periods ended September 30, 2020 and 2019; however, certain information and footnote disclosures normally included in our Annual Report have been condensed or omitted as permitted by GAAP. It is important to note that the Company’s results of operations and cash flows for interim periods are not necessarily indicative of the results of operations and cash flows to be expected for a full fiscal year or any interim period.
Deferred Offering Costs	Deferred Offering Costs Deferred offering costs are expenses directly related to an at-the-market offering of the Company’s common stock (the “ATM Offering”) (see Note 9), which is pursuant to a prospectus supplement which is part of a shelf registration that was declared effective by the SEC on December 31, 2018 (the “Shelf Registration”). These costs consist of legal, accounting, printing, and filing fees that the Company has capitalized, including fees incurred by the independent registered public accounting firm directly related to the offerings. Deferred costs associated with the ATM Offering will be amortized to additional paid in capital on a pro-rata basis as the Company raises funds pursuant to the ATM Offering, with any remaining deferred offering costs charged to the results of operations at the end of the life of the Shelf Registration. As of September 30, 2020, the unamortized deferred offering costs were $268.0.
Reclassifications	Reclassifications Certain prior period balances have been reclassified in order to conform to current period presentation. These reclassifications have no effect on previously reported results of operations or loss per share.
Recently Adopted and Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements In December 2019, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2019-12, Simplifying the Accounting for Income Taxes. The list of changes is comprehensive; however, the changes will not significantly impact the Company due to the full valuation allowance that is recorded against the Company’s deferred tax assets. ASU 2019-12 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2020. Early adoption of ASU 2019-12 is permitted, including adoption in any interim period for public business entities for periods for which financial statements have not yet been issued. An entity that elects to early adopt the amendments in an interim period should reflect any adjustments as of the beginning of the annual period that includes that interim period. Additionally, an entity that elects early adoption must adopt all the amendments in the same period. The Company will adopt ASU 2019-12 in 2021.

General (Policies)

9 Months Ended

Sep. 30, 2020

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Risks and Uncertainties

Due to the global outbreak of SARS-CoV-2, a novel strain of coronavirus that causes Coronavirus disease (COVID-19), the Company experienced an impact on certain areas of its business. These effects included a slowing of patient recruitment in the FOCUS trial and a reduction in the pace at which we can monitor data at our clinical trial sites. The resulting delay in completing enrollment and additional time required to monitor data has caused our planned announcement for the top-line data from our FOCUS trial to shift to early 2021. We now plan to submit a New Drug Application (NDA) to the FDA in the first quarter of 2022 for the treatment of mOM. The ability to achieve this goal is contingent on our ability to monitor data at our clinical sites and therefore the timeline may shift as access to the clinical sites changes in response to the rapidly evolving situation. We have also experienced a decline in EU commercial product revenue and additional impacts to the business may arise that we are not aware of currently. The ultimate impact of the pandemic on the Company’s results of operations, financial position, liquidity, or capital resources cannot be reasonably estimated at this time.

Liquidity And Going Concern

Liquidity and Going Concern

The accompanying interim condensed consolidated financial statements have been prepared on a going concern basis, which contemplates the realization of assets and the satisfaction of liabilities in the normal course of business. The Company has incurred losses since inception and expects to continue incurring losses for the next several years. These losses, among other factors, raise substantial doubt about the Company’s ability to continue as a going concern.

The Company’s existence is dependent upon management’s ability to obtain additional funding sources or to enter into strategic alliances. There can be no assurance that the Company’s efforts will result in the resolution of the Company’s liquidity needs. The accompanying statements do not include any adjustments that might result should the Company be unable to continue as a going concern.

Basis of Presentation

These interim condensed consolidated financial statements are unaudited and were prepared by the Company in accordance with generally accepted accounting principles in the United States of America (GAAP) and with the SEC’s instructions to Form 10-Q and Article 10 of Regulation S-X. They include the accounts of all entities controlled by Delcath and all significant inter-company accounts and transactions have been eliminated in consolidation. All historical share and per share amounts have been retrospectively adjusted for the one-for-seven hundred reverse stock split effected on December 24, 2019.

The preparation of interim condensed consolidated financial statements requires management to make assumptions and estimates that impact the amounts reported. These interim condensed consolidated financial statements reflect all adjustments, consisting of normal recurring accruals, necessary for a fair presentation of the Company’s results of operations, financial position and cash flows for the interim periods ended September 30, 2020 and 2019; however, certain information and footnote disclosures normally included in our Annual Report have been condensed or omitted as permitted by GAAP. It is important to note that the Company’s results of operations and cash flows for interim periods are not necessarily indicative of the results of operations and cash flows to be expected for a full fiscal year or any interim period.

Deferred Offering Costs

Deferred offering costs are expenses directly related to an at-the-market offering of the Company’s common stock (the “ATM Offering”) (see Note 9), which is pursuant to a prospectus supplement which is part of a shelf registration that was declared effective by the SEC on December 31, 2018 (the “Shelf Registration”). These costs consist of legal, accounting, printing, and filing fees that the Company has capitalized, including fees incurred by the independent registered public accounting firm directly related to the offerings. Deferred costs associated with the ATM Offering will be amortized to additional paid in capital on a pro-rata basis as the Company raises funds pursuant to the ATM Offering, with any remaining deferred offering costs charged to the results of operations at the end of the life of the Shelf Registration. As of September 30, 2020, the unamortized deferred offering costs were $268.0.

Reclassifications

Certain prior period balances have been reclassified in order to conform to current period presentation. These reclassifications have no effect on previously reported results of operations or loss per share.

Recently Adopted and Issued Accounting Pronouncements

Recently Issued Accounting Pronouncements

In December 2019, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2019-12, Simplifying the Accounting for Income Taxes. The list of changes is comprehensive; however, the changes will not significantly impact the Company due to the full valuation allowance that is recorded against the Company’s deferred tax assets. ASU 2019-12 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2020. Early adoption of ASU 2019-12 is permitted, including adoption in any interim period for public business entities for periods for which financial statements have not yet been issued. An entity that elects to early adopt the amendments in an interim period should reflect any adjustments as of the beginning of the annual period that includes that interim period. Additionally, an entity that elects early adoption must adopt all the amendments in the same period. The Company will adopt ASU 2019-12 in 2021.