Delcath Systems (DCTH) 10-Q 12 Nov 20 2020 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2020	Nov. 12, 2020
Cover [Abstract]
Entity Registrant Name	DELCATH SYSTEMS, INC.
Entity Central Index Key	0000872912
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Document Quarterly Report	true
Document Transition Report	false
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Incorporation, State or Country Code	DE
Entity Interactive Data Current	Yes
Entity File Number	001-16133
Entity Tax Identification Number	06-1245881
Entity Address, Address Line One	1633 Broadway
Entity Address Address Line2	Suite 22C
Entity Address City Or Town	New York
Entity Address State Or Province	NY
Entity Address Postal Zip Code	10019
City Area Code	212
Local Phone Number	489-2100
Entity Shell Company	false
Entity Current Reporting Status	Yes
Entity Common Stock, Shares Outstanding		4,116,754
Document Fiscal Year Focus	2020
Trading Symbol	DCTH
Title of 12(b) Security	Common stock
Document Fiscal Period Focus	Q3
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2020
Security Exchange Name	NASDAQ

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Current assets
Cash and cash equivalents	$ 10,899	$ 10,002
Restricted cash	181	181
Accounts receivables, net	103	21
Inventories	839	654
Prepaid expenses and other current assets	1,860	1,759
Total current assets	13,882	12,617
Property, plant and equipment, net	1,318	735
Deferred offering costs	268
Right-of-use assets	1,097	860
Total assets	16,565	14,212
Current liabilities
Accounts payable	1,502	4,533
Accrued expenses	6,085	6,947
Deferred revenue, current	501	482
Lease liabilities, current	556	664
Convertible notes payable, current	2,000
Warrant liability		3,368
Total current liabilities	10,644	15,994
Deferred revenue, non-current	2,103	2,378
Lease liabilities, non-current	542	197
Convertible notes payable, non-current		2,000
Total liabilities	13,289	20,569
Commitments and contingencies (Note 13)
Stockholders' equity (deficit)
Preferred stock, $.01 par value; 10,000,000 shares authorized; 21,473 and 41,517 shares issued and outstanding at September 30, 2020 and December 31, 2019, respectively	0	0
Common stock, $.01 par value; 1,000,000,000 shares authorized; 4,035,558 and 67,091 shares issued and outstanding at September 30, 2020 and December 31, 2019, respectively*	40	1
Additional paid-in capital	391,545	364,785
Accumulated deficit	(388,298)	(371,171)
Accumulated other comprehensive income	(11)	28
Total stockholders' equity (deficit)	3,276	(6,357)
Total liabilities and stockholders' equity (deficit)	$ 16,565	$ 14,212

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - $ / shares	Sep. 30, 2020	Dec. 31, 2019
Statement Of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, shares issued (in shares)	21,473	41,517
Preferred stock, shares outstanding (in shares)	21,473	41,517
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	1,000,000,000	1,000,000,000
Common stock, shares issued (in shares)	4,035,558	67,091
Common stock, shares outstanding (in shares)	4,035,558	67,091

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Cost of goods sold		$ (188)	$ (172)	$ (434)	$ (440)
Gross profit		278	208	705	623
Operating expenses:
Research and development expenses		3,260	1,778	8,457	6,789
Selling, general and administrative expenses		1,998	4,002	6,571	9,204
Total operating expenses		5,258	5,780	15,028	15,993
Operating loss		(4,980)	(5,572)	(14,323)	(15,370)
Change in fair value of the warrant liability, net			434	(2,832)	451
Loss on issuance of financial instrument			1,714		1,721
Interest expense		(44)	(671)	(154)	(4,735)
Other income		33	4	182	4
Net loss		(4,991)	(7,519)	(17,127)	(21,371)
Deemed dividend for triggering of warrant down round feature				(55)
Net loss attributable to common stockholders		(4,991)	(7,519)	(17,182)	(21,371)
Net loss		(4,991)	(7,519)	(17,127)	(21,371)
Other comprehensive (loss) income:
Foreign currency translation adjustments		(103)	89	(39)	39
Total other comprehensive loss		$ (5,094)	$ (7,430)	$ (17,166)	$ (21,332)
Common share data:
Basic loss per common share	[1]	$ (1.16)	$ (73.82)	$ (7.75)	$ (207.58)
Diluted loss per common share	[1]	$ (1.16)	$ (73.82)	$ (7.75)	$ (207.58)
Weighted average number of basic shares outstanding	[1]	4,288,593	101,862	2,217,611	102,956
Weighted average number of diluted shares outstanding	[1]	4,288,593	101,862	2,217,611	102,956
Product Revenue [Member]
Revenue		$ 340	$ 216	$ 778	$ 528
Other Revenue [Member]
Revenue		$ 126	$ 164	$ 361	$ 535
[1]	* reflects, one-for-seven hundred (1:700) reverse stock split effected on December 24, 2019.

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) (Parenthetical)	Dec. 24, 2019
Income Statement [Abstract]
Reverse stock split	1:700
Reverse stock split ratio	0.00142

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Stockholders' Equity (Deficit) (Unaudited) - USD ($) $ in Thousands	Total	Common Stock [Member]	Preferred Stock [Member]	Additional Paid in Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Income [Member]
Balance at Dec. 31, 2018	$ (14,939)			$ 329,065	$ (344,054)	$ 50
Balance (in shares) at Dec. 31, 2018		14,715	101
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Compensation expense for issuance of stock options	54			54
Compensation expense for issuance of restricted stock	4			4
Compensation expense for issuance of restricted stock (in shares)		20
Issuance of Series D Preferred Stock	150			150
Issuance of Series D Preferred Stock (in shares)			15
Conversion of Series D Preferred Stock to Debt	(1,160)			(1,160)
Conversion of Series D Preferred Stock to Debt (in shares)			(116)
Exercise of pre-funded warrants (in shares)		5,885
Net loss	(7,894)				(7,894)
Total comprehensive income (loss)	7					7
Balance at Mar. 31, 2019	(23,778)			328,113	(351,948)	57
Balance (in shares) at Mar. 31, 2019		20,620
Balance at Dec. 31, 2018	(14,939)			329,065	(344,054)	50
Balance (in shares) at Dec. 31, 2018		14,715	101
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(21,371)
Balance at Sep. 30, 2019	(18,825)			364,750	(383,664)	89
Balance (in shares) at Sep. 30, 2019		26,110	42,082
Balance at Mar. 31, 2019	(23,778)			328,113	(351,948)	57
Balance (in shares) at Mar. 31, 2019		20,620
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Compensation expense for issuance of stock options	75			75
Exercise of pre-funded warrants (in shares)		5,399
Exercise of warrants into common stock	13			13
Exercise of warrants into common stock (in shares)		91
Net loss	(5,959)				(5,959)
Total comprehensive income (loss)	(80)					(80)
Balance at Jun. 30, 2019	(29,729)			328,201	(357,907)	(23)
Balance (in shares) at Jun. 30, 2019		26,110
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Compensation expense for issuance of stock options	70			70
Issuance of Series E Preferred Stock	29,575			42,915	(13,340)
Issuance Of Series E Preferred Stock, Shares			32,572
Issuance of Series E-1 Preferred Stock	9,510			14,408	(4,898)
Issuance Of Series E1 Preferred Stock, Shares			9,510
Fair value of warrants issued	(20,844)			(20,844)
Net loss	(7,519)				(7,519)
Total comprehensive income (loss)	112					112
Balance at Sep. 30, 2019	(18,825)			364,750	(383,664)	89
Balance (in shares) at Sep. 30, 2019		26,110	42,082
Balance at Dec. 31, 2019	(6,357)	$ 1		364,785	(371,171)	28
Balance (in shares) at Dec. 31, 2019		67,091	41,517
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Compensation expense for issuance of stock options	25			25
Compensation expense for issuance of restricted stock	30			30
Compensation expense for issuance of restricted stock (in shares)		2,717
Conversion of Preferred stock into common stock (in shares)		2,915	(70)
Fractional rounding related to reverse stock split (in shares)		50
Registration of Series E and Series E-1 Preferred stock and related warrants	(106)			(106)
Fair value of warrants reclassified from liability to equity	6,199			6,199
Net loss	(7,861)				(7,861)
Total comprehensive income (loss)	65					65
Balance at Mar. 31, 2020	(8,005)	$ 1		370,933	(379,032)	93
Balance (in shares) at Mar. 31, 2020		72,773	41,447
Balance at Dec. 31, 2019	$ (6,357)	$ 1		364,785	(371,171)	28
Balance (in shares) at Dec. 31, 2019		67,091	41,517
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Conversion of Preferred stock into common stock (in shares)	2,000,224
Exercise of pre-funded warrants (in shares)	6,000
Net loss	$ (17,127)
Balance at Sep. 30, 2020	3,276	$ 40		391,545	(388,298)	(11)
Balance (in shares) at Sep. 30, 2020		4,035,558	21,473
Balance at Mar. 31, 2020	(8,005)	$ 1		370,933	(379,032)	93
Balance (in shares) at Mar. 31, 2020		72,773	41,447
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Compensation expense for issuance of restricted stock	606	$ 1		605
Compensation expense for issuance of restricted stock (in shares)		70,259
Conversion of Preferred stock into common stock	(1)	$ 15		(16)
Conversion of Preferred stock into common stock (in shares)		1,549,609	(15,497)
Exercise of pre-funded warrants (in shares)		6,000
Public Offering - issuance of common stock and warrants	19,378	$ 18		19,360
Public Offering - issuance of common stock and warrants (in shares)		1,823,000
Net loss	(4,275)				(4,275)
Total comprehensive income (loss)	(1)					(1)
Balance at Jun. 30, 2020	7,702	$ 35		390,882	(383,307)	92
Balance (in shares) at Jun. 30, 2020		3,521,641	25,950
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Conversion of Preferred stock into common stock		$ 4		(4)
Conversion of Preferred stock into common stock (in shares)		447,700	(4,477)
Exercise of warrants into common stock	602	$ 1		601
Exercise of warrants into common stock (in shares)		60,117
ATM Offering	66			66
ATM Offering, Shares		6,100
Net loss	(4,991)				(4,991)
Total comprehensive income (loss)	(103)					(103)
Balance at Sep. 30, 2020	$ 3,276	$ 40		$ 391,545	$ (388,298)	$ (11)
Balance (in shares) at Sep. 30, 2020		4,035,558	21,473

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Stockholders' Equity (Deficit) (Unaudited) (Parenthetical)	Dec. 24, 2019
Statement Of Stockholders Equity [Abstract]
Reverse stock split	1:700
Reverse stock split ratio	0.00142

Condensed Consolidated Statem_5

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Cash flows from operating activities:
Net loss	$ (17,127)	$ (21,371)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock option compensation expense	25	199
Restricted stock compensation expense	406	4
Depreciation expense	125	168
Amortization of right of use assets	492	1,535
Warrant liability fair value adjustment	2,832	(451)
Non-cash interest income	0	(23)
Equitization of expenses	0	1,474
Loss on issuance of financial instruments	0	1,715
Interest expense accrued related to convertible notes	120	33
Debt discount amortization	0	4,467
Changes in assets and liabilities:
(Increase) decrease in prepaid expenses and other assets	(100)	43
(Increase) decrease in accounts receivable	(82)	564
(Increase) decrease in inventories	(185)	85
Increase in deferred offering costs	(268)	0
Decrease in accounts payable and accrued expenses	(3,784)	(4,289)
Decrease in deferred revenue	(256)	(360)
Decrease in operating lease liabilities	(466)	(1,488)
Decrease in other liabilities	0	(627)
Net cash used in operating activities	(18,268)	(18,322)
Cash flows from investing activities:
Purchase of property, plant, and equipment	(708)	(2)
Net cash used in investing activities	(708)	(2)
Cash flows from financing activities:
Principal payments on financing leases	(26)	(49)
Net proceeds from the issuance of debt	0	3,719
Net payments related to reverse stock split	(106)	0
Net proceeds from Public Offering	19,377	0
Net proceeds from the exercise of warrants	601	0
Net cash provided by financing activities	19,912	30,330
Foreign currency effects on cash	(39)	(69)
Net increase in total cash	897	11,937
Total Cash:
Beginning of period	10,183	3,578
Interest expense	7	4
End of period	11,080	15,515
Supplemental Disclosure of Non-Cash Investing and Financing Activities:
Conversions of Preferred Stock into common stock	20	0
Reclassification of 2019 warrants from liability to equity	6,199	0
Exchange of 2019 warrants	0	13
Fair value of warrants issued	0	20,844
Adoption of ASC 842 lease standard	0	1,652
Right of use assets obtained in exchange for lease obligations	729	874
At-the-Market Offering [Member]
Cash flows from financing activities:
Gross proceeds from ATM Offering	70	0
Issuance costs related to ATM Offering	(4)	0
Series E Preferred Stock [Member]
Cash flows from financing activities:
Net proceeds from sale of Series D Preferred Stock	0	26,510
Series D Preferred Stock [Member]
Cash flows from financing activities:
Net proceeds from sale of Series D Preferred Stock	0	150
Supplemental Disclosure of Non-Cash Investing and Financing Activities:
Conversion of Series D Preferred Stock to debt	$ 0	$ 1,160

General

General	9 Months Ended
	Sep. 30, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
General	(1) General The unaudited interim condensed consolidated financial statements of Delcath Systems, Inc. (“Delcath” or the “Company”) as of and for the three and nine months ended September 30, 2020 and 2019 should be read in conjunction with the consolidated financial statements included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2019 (the “Annual Report”), which was filed with the Securities Exchange Commission (the “SEC”) on March 25, 2020 and may also be found on the Company’s website (www.delcath.com). In these notes to the condensed consolidated financial statements the terms “us”, “we” or “our” refer to Delcath and its consolidated subsidiaries. Description of Business Delcath Systems, Inc. is an interventional oncology company focused on the treatment of primary and metastatic liver cancers. Delcath’s proprietary technology enables the administration of high-dose chemotherapy to the liver while controlling systemic exposure and associated side effects. In the United States, the HEPZATO™ KIT (melphalan hydrochloride for injection/hepatic delivery system), or HEPZATO™, is currently the focus of a Phase 3 pivotal trial. HEPZATO is a combination drug device product regulated as a drug product by the United States Food and Drug Administration, or the FDA. In Europe, the device is commercially available as a stand-alone device without drug under the trade name Delcath CHEMOSAT® Hepatic Delivery System for Melphalan (“CHEMOSAT”), where it has been used at major medical centers to treat a wide range of cancers of the liver. Our clinical development program (“CDP”) for HEPZATO is comprised of the FOCUS Clinical Trial for Patients with Hepatic Dominant Ocular Melanoma (the “FOCUS Trial”), a global registration clinical trial in metastatic ocular melanoma, or mOM, and the ALIGN Trial, a global Phase 3 clinical trial for intrahepatic cholangiocarcinoma, or ICC (the “ALIGN Trial”). The FOCUS trial initiated treatment on the final enrolled patient on October 2, 2020. Presently, we have paused our work on the ALIGN trial while we reevaluate the trial design and are focusing our efforts on the FOCUS trial conclusion and subsequent NDA filing. We are currently reviewing the incidence, unmet need, available efficacy data and development requirements for a broad set of liver cancers in order to select a portfolio of follow-on indications which will maximize the value of the HEPZATO platform. Whether we continue the ALIGN trial will be dependent on the relative value of the ICC indication versus other alternative indications. In addition, our CDP also includes a registry for CHEMOSAT commercial cases performed in Europe and sponsorship of select investigator-initiated trials, or IITs. 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 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. Significant Accounting Policies There have been no material changes to our significant accounting policies as set forth in Note 3 Summary of Significant Accounting Policies to the consolidated financial statements included in the Company’s Annual Report, except for the following: 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 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.

Cash, Cash Equivalents and Rest

Cash, Cash Equivalents and Restricted Cash	9 Months Ended
	Sep. 30, 2020
Cash And Cash Equivalents [Abstract]
Cash, Cash Equivalents and Restricted Cash	(2) Cash, Cash Equivalents and Restricted Cash Cash and cash equivalents that are restricted as to withdrawal or use under the terms of certain contractual agreements are recorded in Restricted Cash Cash, cash equivalents, and r estricted cash balances were as follows: September 30, December 31, (in thousands) 2020 2019 Cash and cash equivalents $ 10,899 $ 10,002 Letters of credit 131 131 Security for credit cards 50 50 Total cash, cash equivalents and restricted cash shown in the statements of cash flows $ 11,080 $ 10,183

Inventories

Inventories	9 Months Ended
	Sep. 30, 2020
Inventory Disclosure [Abstract]
Inventories	(3) Inventories Inventories consist of the following: September 30, December 31, (in thousands) 2020 2019 Raw materials $ 376 $ 375 Work-in-process 463 279 Total inventories $ 839 $ 654

Prepaid Expenses and Other Curr

Prepaid Expenses and Other Current Assets	9 Months Ended
	Sep. 30, 2020
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]
Prepaid Expenses And Other Current Assets	(4) Prepaid Expenses and Other Current Assets Prepaid expenses and other current assets consist of the following: September 30, December 31, (in thousands) 2020 2019 Clinical trial expenses $ 1,497 $ 725 Insurance premiums 63 589 Other 1 300 445 Total prepaid expenses and other current assets $ 1,860 $ 1,759 1 Other consists of various prepaid expenses and other current assets, with no individual item accounting for more than 5% of prepaid expenses and other current assets at September 30, 2020 and December 31, 2019.

Property, Plant, and Equipment

Property, Plant, and Equipment	9 Months Ended
	Sep. 30, 2020
Property Plant And Equipment [Abstract]
Property, Plant, and Equipment	(5) Property, Plant, and Equipment Property, plant, and equipment consist of the following: September 30, December 31, Estimated (in thousands) 2020 2019 Useful Life Buildings and land $ 1,109 $ 589 30 years - Buildings Enterprise hardware and software 1,805 1,739 3 years Leaseholds 1,808 1,695 Lesser of lease term or estimated useful life Equipment 1,045 1,025 7 years Furniture 203 198 5 years Property, plant, and equipment, gross 5,970 5,246 Accumulated depreciation (4,652 ) (4,511 ) Property, plant and equipment, net $ 1,318 $ 735 On July 31, 2020, the Company exercised its option to purchase its 95-97 Park Road office location in Queensbury, NY for $460.3, pursuant to the terms of the lease agreement dated September 17, 2018, as amended on January 29, 2019 and further amended on July 31, 2020. Depreciation expense for the three and nine months ended September 30, 2020 was approximately $32.7 and $124.7 as compared to approximately $45.8 and $168.0 for the same periods in 2019.

Accrued Expenses

Accrued Expenses	9 Months Ended
	Sep. 30, 2020
Payables And Accruals [Abstract]
Accrued Expenses	(6) Accrued Expenses Accrued expenses consist of the following: September 30, December 31, (in thousands) 2020 2019 Clinical expenses $ 2,919 $ 2,497 Compensation, excluding taxes 2,499 3,525 Other 1 667 925 Total accrued expenses $ 6,085 $ 6,947 1 Other consists of various accrued expenses, with no individual item accounting for more than 5% of current liabilities at September 30, 2020 and December 31, 2019.

Leases

Leases	9 Months Ended
	Sep. 30, 2020
Leases [Abstract]
Leases	(7) Leases The Company recognizes right-of-use (“ROU”) assets and lease liabilities when it obtains the right to control an asset under a leasing arrangement with an initial term greater than twelve months. The Company leases its facilities under non-cancellable operating and financing leases. The Company evaluates the nature of each lease at the inception of an arrangement to determine whether it is an operating or financing lease and recognizes the ROU asset and lease liabilities based on the present value of future minimum lease payments over the expected lease term. The Company’s leases do not generally contain an implicit interest rate and therefore the Company uses the incremental borrowing rate it would expect to pay to borrow on a similar collateralized basis over a similar term in order to determine the present value of its lease payments. The following table summarizes the Company’s operating and financing leases as of and for the nine months ended September 30, 2020: (in thousands) US Ireland Total Lease cost Operating lease cost $ 353 $ 156 $ 509 Financing lease cost 27 — 27 Sublease income — (162 ) (162 ) Total $ 380 $ (6 ) $ 374 Other information Operating cash flows out from operating leases (353 ) (156 ) (509 ) Operating cash flows in from operating leases - 162 162 Operating cash flows out from financing leases (26 ) — (26 ) Right-of-use assets exchanged for new operating lease liabilities 729 — 729 Weighted average remaining lease term 2.4 0.8 Weighted average discount rate - operating leases 8 % 8 % Remaining maturities of the Company’s operating leases, excluding short-term leases, are as follows: (in thousands) US Ireland Total Year ended December 31, 2020 $ 118 $ 55 $ 173 Year ended December 31, 2021 416 128 544 Year ended December 31, 2022 406 - 406 Year ended December 31, 2023 68 - 68 Total 1,008 183 1,191 Less present value discount (86 ) (7 ) (93 ) Operating lease liabilities included in the condensed consolidated balance sheets at September 30, 2020 $ 922 $ 176 $ 1,098

Outstanding Debt

Outstanding Debt	9 Months Ended
	Sep. 30, 2020
Debt Disclosure [Abstract]
Outstanding Debt	(8) Outstanding Debt On June 6, 2019, the Company entered into an agreement with two institutional investors, pursuant to which the investors agreed to transfer and surrender to the Company for cancellation, warrants to purchase 5,605 shares of the Company’s common stock (the “Series D Warrants”) and warrants to purchase 0.1 million shares of the Company’s common stock (the “Pre-Funded Series D Warrants”). Under the terms of the Purchase Agreement, the Company agreed to sell and issue to the investors 8% Senior Secured Promissory Notes in an aggregate principal amount of $2,000 and with a July 16, 2021 maturity date, in full payment and satisfaction of the purchase price for the Series D Warrants and Pre-Funded Series D Warrants. This agreement was effective on July 15, 2019, upon the closing of the Company’s July 2019 Private Placement discussed in Note 9 herein and discussed further in Notes 10 and 11 to the Company’s audited consolidated financial statements contained in its Annual Report. Following the closing of the July 2019 Private Placement, the Company entered into an agreement under which the 8% Senior Secured Promissory Notes became convertible into shares of Series E Preferred Stock and Warrants (the “Unit”) at the price of $1,500 per Unit. The principal is recognized in Convertible notes payable, on the condensed consolidated balance sheet.

Stockholders' Equity

Stockholders' Equity	9 Months Ended
	Sep. 30, 2020
Stockholders Equity Note [Abstract]
Stockholders' Equity	(9) Stockholders’ Equity Preferred Stock Series E and Series E-1 Preferred Stock On July 11, 2019, the Company entered into a securities purchase agreement with certain accredited investors pursuant to which Delcath sold to investors an aggregate of 20,000 shares of our Series E convertible preferred stock, par value $0.01 per share, or the “Series E Preferred Stock”, at a price of $1,000 per share and a warrant, or a “2019 E Warrant”, to purchase a number of shares of common stock equal to the number of shares of common stock issuable upon conversion of the Series E Preferred Stock purchased by the investor, or the “July 2019 Private Placement”. In connection with the July 2019 Private Placement, the Company exchanged $11,800 of debt, interest and Series D Warrants for 11,500 shares of Series E Preferred Stock and related 2019 E Warrants, $100 in accounts payables for 149 shares of Series E Preferred Stock and related 2019 E Warrants and issued 923 shares of Series E Preferred Stock and related 2019 E Warrants to certain investors in exchange for a waiver of rights under exchange agreements signed in December 2018 and March 2019, or the “Debt Exchange”. On August 19, 2019, the Company entered into a securities purchase agreement with certain accredited investors pursuant to which Delcath sold to investors an aggregate of 9,510 shares of Series E-1 convertible preferred stock, par value $0.01 per share, or the Series E-1 Preferred Stock, at a price of $1,000 per share and a warrant, or a “2019 E-1 Warrant”, and together with the 2019 E Warrant, the “2019 Warrants”, to purchase a number of shares of common stock of the Company equal to the number of shares of common stock issuable upon conversion of the Series E-1 Preferred Stock purchased by the investor, or the “August 2019 Private Placement”, and, collectively with the July 2019 Private Placement, the “Private Placements”. Each share of Series E Preferred Stock and Series E-1 Preferred Stock, or, collectively, the “Preferred Stock”, is convertible at any time at the option of the holder into the number of shares of common stock determined by dividing the current conversion price. At December 31, 2019, the conversion price was $23.04 and was subsequently adjusted to $10.00 upon the pricing of a $21,996 public offering of the Company’s common stock and warrants on May 5, 2020, as discussed further below. As a result of the price adjustment, the excess of the fair value of the common stock that will be received on conversion, measured on the price reset date, exceeded the original proceeds allocated to the Preferred Stock by $12,000. The holders of the Preferred Stock are entitled to receive dividends on shares of Preferred Stock equal (on an “as converted” basis) to and in the same form as dividends paid on shares of the common stock. Any such dividends that are not paid to the holders of the Preferred Stock will increase the stated value. No other dividends will be paid on shares of Preferred Stock. Each 2019 Warrant had an exercise price equal to $23.04 per share at December 31, 2019. The exercise price was subsequently adjusted to $10.00 per share upon the pricing of a $21,996 offering on May 5, 2020, as discussed further below, which resulted in the recognition of a $54.5 deemed dividend. The 2019 Warrants are exercisable until 5:00 p.m. (NYC time) on December 24, 2024. As of September 30, 2020, there were 21,473 shares of Preferred Stock outstanding and 1,826,579 2019 Warrants outstanding. Public Offering On May 5, 2020, the Company closed a public offering of 1,823,000 shares of common stock, 377,000 pre-funded warrants and Series F warrants to purchase 2,224,900 shares of common stock at an exercise price of $10.00 per share (the “Public Offering”). Delcath received gross proceeds of approximately $21,996 from the offering, before deducting the underwriting discount and estimated offering expenses. As a result of the Public Offering, the Preferred Stock conversion price was adjusted to $10.00 per share and the exercise price of the 2019 Warrants was adjusted to $10.00 per share and neither instrument is subject to further price resets. At-the-Market Offering On August 18, 2020, the Company entered into a sales agreement with Cantor Fitzgerald & Co. (“Cantor Fitzgerald”), pursuant to which the Company may offer and sell, from time to time, through Cantor Fitzgerald, as sales agent or principal, shares of the Company’s common stock, (the “Placement Shares”), having an aggregate offering price of up to $10,000 (the “ATM Offering”). The Company has no obligation to sell any Placement Shares under the sales agreement. Subject to the terms and conditions of the sales agreement, Cantor Fitzgerald will use commercially reasonable efforts, consistent with its normal trading and sales practices, applicable state and federal law, rules and regulations and the rules of the Nasdaq Stock Market, to sell Placement Shares from time to time based upon the Company’s instructions, including any price, time or size limits specified by the Company. The Company will pay Cantor Fitzgerald a commission of 3.0% of the aggregate gross proceeds from each sale of Placement Shares, reimburse Cantor Fitzgerald’s legal fees and disbursements up to $50.0 and provide Cantor Fitzgerald with customary indemnification and contribution rights. The sales agreement may be terminated by Cantor Fitzgerald or the Company upon notice to the other party as provided in the sales agreement, or by Cantor Fitzgerald at any time in certain circumstances, including the occurrence of a material and adverse change in the Company’s business or financial condition that makes it impractical or inadvisable to market the Placement Shares or to enforce contracts for the sale of the Placement Shares. In connection with the ATM Offering, in consideration for a fee equal to 1.05% of the gross sales price per share sold in the ATM Offering, ROTH Capital Advisors, LLC (“Roth”) waived, solely with respect to the ATM Offering, (i) Roth’s right, pursuant to certain engagement letters dated August 14, 2019 and January 13, 2020 between Roth and the Company, to act as placement agent or underwriter with respect to offerings of the Company’s securities and to receive a minimum of 35% of the fees paid to the agents or underwriters for such offerings and (ii) the lock-up provision included in a certain Underwriting Agreement dated May 1, 2020 between Roth and the Company requiring the prior written consent of Roth for any offer or sale of the Company’s common stock by the Company during the 90-day period following the date of the Underwriting Agreement. Rosalind Master Fund L.P. and Rosalind Opportunities Fund I L.P. (together, “Rosalind”) waived, solely with respect to the ATM Offering, Rosalind’s right, pursuant to that certain Support and Conversion Agreement dated March 11, 2020 between Rosalind and the Company, as amended, to participate in any offer or sale of the Company’s common stock by the Company occurring within a two-year period. On August 18, 2020, the Company and the holders of a requisite number of shares of the Company’s Series E Convertible Preferred Stock and Series E-1 Convertible Preferred Stock and related warrants (the “Holders”) entered into an Amendment to those certain Securities Purchase Agreements, dated July 11, 2020 and August 15, 2019, among the Company and the parties signatory thereto, for the purpose of clarifying that offerings of the Company’s common stock in “at the market” transactions are excluded from the rights of the holders set forth therein. Through September 30, 2020, the Company sold 6,100 shares of common stock for aggregate gross proceeds of $70.5 pursuant to the ATM Offering. Other Common Stock Issuances During the nine months ended September 30, 2020 the Company issued 2,000,224 shares of the Company’s common stock pursuant to conversions of Preferred Stock. During the nine months ended September 30, 2020, the Company issued 6,000 shares of common stock associated with the exercise of pre-funded warrants and 60,117 shares of common stock associated with other warrants. During the nine months ended September 30, 2020, the Company issued 72,976 shares of common stock as compensation. 2020 Omnibus Equity Incentive Plan On September 30, 2020 (the “Effective Date”), the Company’s 2020 Omnibus Equity Incentive Plan (the “2020 Plan”) was adopted by the Company’s Board of Directors. If subsequently approved by the Company’s stockholders, the 2020 Plan will continue in effect until the tenth anniversary of the Effective Date, or until earlier terminated by the Board. The 2020 Plan will be administered by the Board of Directors or a committee designated by the Board of Directors. The 2020 Plan provides for the grant of incentive stock options, non-qualified stock options, stock appreciation rights, restricted stock awards, restricted stock unit awards, performance awards, as well as other stock-based awards or cash awards that are deemed to be consistent with the purposes of the plan to Company employees, directors and consultants. There are 675,000 shares of common stock reserved under the 2020 Plan, of which all remained available to be issued as of September 30, 2020 (see Note 14 – Subsequent Events – Option Grants for details of awards granted on October 1, 2020). Upon stockholder approval of the 2020 Plan, no further grants of awards will be made under the 2019 Equity Incentive Plan. Share-Based Compensation The Company’s 2019 Equity Incentive Plan (the “Plan”) allows for grants in the form of incentive stock options, nonqualified stock options, stock units, stock awards, stock appreciation rights, and other stock-based awards. All of the Company’s officers, directors, employees, consultants, and advisors are eligible to receive grants under the Plan. The maximum number of shares reserved for issuance under the Plan is 2,142. Options to purchase shares of common stock are granted at exercise prices not less than 100% of fair value on the dates of grant. As of September 30, 2020, the Plan had approximately 1,643 shares available for grant. The following is a summary of stock option activity under the Plan for the nine months ended September 30, 2020: Number of Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term (Years) Aggregate Intrinsic Value Outstanding at December 31, 2019 1,640 $ 196.70 9.1 $ — Granted — Exercised — Cancelled/Forfeited (1,141 ) Outstanding at September 30, 2020 499 $ 196.70 8.4 $ — Exercisable at September 30, 2020 499 $ 196.70 8.4 $ — At September 30, 2020, there was no unrecognized compensation expense related to non-vested share-based compensation awards under the Plan. The following is a summary of share-based compensation expense in the statement of operations for the three and nine months ended September 30, 2020 Three months ended September 30, Nine months ended September 30, (in thousands) 2020 2019 2020 2019 Selling, general and administrative $ — $ 54 $ 655 $ 160 Research and development — 16 5 43 Total $ — $ 70 $ 660 $ 203 Warrants The following is a summary of warrant activity for the nine months ended September 30, 2020: Warrants Exercise Share Weighted Average Exercise Price Weighted Average Remaining (Years) Outstanding at December 31, 2019 1,826,608 $7.00 - $23.04 $ 23.04 5.0 Issued 2,601,900 10.00 Exercised (66,117 ) 9.09 Expired (18 ) 7.00 Outstanding at September 30, 2020 4,362,373 $0.01- $10.00 $ 9.15 4.5 As of September 30, 2020, warrants to purchase 371,000 shares of common stock were pre-funded, and the exercise price was $0.01 per share. The remaining warrants were exercisable at $10.00 per share. Each 2019 Warrant had an exercise price equal to $23.04 per share at December 31, 2019. The exercise price was subsequently adjusted to $10.00 per share upon the pricing of a $22,000 offering on May 5, 2020, as discussed below, which resulted in the recognition of a $54.5 deemed dividend.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2020
Fair Value Disclosures [Abstract]
Fair Value Measurements	(10) Fair Value Measurements As a result of the expiration of certain provisions in the 2019 Warrants, the 2019 Warrants were reclassified from liability to equity on February 19, 2020. The table below presents the activity within Level 3 of the fair value hierarchy for the nine months ended September 30, 2020: Fair Value Measurements Using Significant Unobservable Inputs (Level 3) (in thousands) Warrant Liability Balance at December 31, 2019 $ 3,368 Total change in the liability included in earnings 2,832 Fair value of warrants reclassified from liability to equity (6,200 ) Balance at September 30, 2020 $ — The fair value of the outstanding warrants at February 19, 2020, the date the 2019 Warrants were no longer classified as a liability, and December 31, 2019 was determined by using option pricing models with the following assumptions: February 19, December 31, 2020 2019 Expected life (in years) 4.3 4.6 Expected volatility 208.2% 207.5% Risk-free interest rates 1.4% 1.7% The table below presents the Company’s assets and liabilities measured at fair value on a recurring basis as of September 30, 2020, aggregated by the level in the fair value hierarchy within which those measurements fall in accordance with ASC 820. Assets and Liabilities Measured at Fair Value on a Recurring Basis (in thousands) Level 1 Level 2 Level 3 Total September 30, 2020 December 31, 2019 September 30, 2020 December 31, 2019 September 30, 2020 December 31, 2019 September 30, 2020 December 31, 2019 Liabilities Derivative instrument liabilities $ — $ — $ — $ — $ — $ 3,368 $ — $ 3,368

Net Loss per Common Share

Net Loss per Common Share	9 Months Ended
	Sep. 30, 2020
Earnings Per Share [Abstract]
Net Loss per Common Share	(11) Net Loss per Common Share Basic net loss per share is determined by dividing net loss by the weighted average shares of common stock outstanding during the period, without consideration of potentially dilutive securities, except for those shares that are issuable for little or no cash consideration. Diluted net loss per share is determined by dividing net loss by diluted weighted average shares outstanding. Diluted weighted average shares reflects the dilutive effect, if any, of potentially dilutive common shares, such as stock options and warrants calculated using the treasury stock method. In periods with reported net operating losses, all common stock options and warrants are generally deemed anti-dilutive such that basic net loss per share and diluted net loss per share are equal. The following potentially dilutive securities were excluded from the computation of earnings per share as of September 30, 2020 and 2019 because their effects would be anti-dilutive: September 30, 2020 2019 Stock options 499 1,643 Common stock warrants - equity 3,991,373 - Common stock warrants - liabilities — 1,001,962 Common stock reserved for conversion of preferred shares 2,147,394 1,001,962 Assumed conversion of convertible notes 146,288 31,746 Total 6,285,554 2,037,313 The following table reconciles net loss per share for the three and nine months ended September 30, 2020 and 2019: Three months ended September 30, Nine months ended September 30, (in thousands, except share data) 2020 2019 2020 2019 Net loss $ (4,991 ) $ (7,519 ) $ (17,127 ) $ (21,371 ) Deemed dividend for triggering of warrant down round feature — — (55 ) — Net loss attributable to common stockholders $ (4,991 ) $ (7,519 ) $ (17,182 ) $ (21,371 ) Weighted average shares outstanding - basic* 4,288,593 101,862 2,217,611 102,956 Weighted average shares outstanding - diluted* 4,288,593 101,862 2,217,611 102,956 Net loss per share - basic* $ (1.16 ) $ (73.82 ) $ (7.75 ) $ (207.58 ) Net loss per share - diluted* $ (1.16 ) $ (73.82 ) $ (7.75 ) $ (207.58 ) * reflects, one-for-seven hundred (1:700) reverse stock split effected on December 24, 2019. At September 30, 2020, the Company had 371,000 pre-funded warrants outstanding. The following table provides a reconciliation of the weighted average shares outstanding calculation for the three and nine months ended September 30, 2020 and 2019: Three months ended September 30, Nine months ended September 30, 2020 2019 2020 2019 Weighted average shares issued 3,917,593 25,587 2,015,863 26,681 Weighted average pre-funded warrants 371,000 76,275 201,748 76,275 Weighted average shares outstanding 4,288,593 101,862 2,217,611 102,956

Taxes

Taxes	9 Months Ended
	Sep. 30, 2020
Income Tax Disclosure [Abstract]
Taxes	( 12) Taxes As discussed in Note 14 Income Taxes of the Company’s Annual Report, the Company has a valuation allowance against the full amount of its net deferred tax assets. The Company currently provides a valuation allowance against deferred tax assets when it is more likely than not that some portion or all of its deferred tax assets will not be realized. The Company has not recognized any unrecognized tax benefits in its balance sheets. The Company is subject to income tax in the U.S., as well as various state and international jurisdictions. The federal and state tax authorities can generally reduce a net operating loss (but not create taxable income) for a period outside the statute of limitations in order to determine the correct amount of net operating loss which may be allowed as a deduction against income for a period within the statute of limitations. Additional information regarding the statutes of limitations can be found in Note 14 Income Taxes of the Company’s Annual Report. On March 27, 2020, President Trump signed into law the $2 trillion bipartisan Coronavirus Aid, Relief, and Economic Security (CARES) Act (H.R. 748). The CARES Act includes a variety of economic and tax relief measures intended to stimulate the economy, including loans for small businesses, payroll tax credits/deferrals, and corporate income tax relief. Due to the Company’s history of tax loss carryforwards and full valuation allowance, the CARES Act did not have a significant effect to the income tax provision, as the corporate income tax relief was directed towards cash taxpayers. During the nine months ended September 30, 2020 the Company settled intercompany debt of its two Ireland subsidiaries, Delcath Systems Limited and Delcath Holdings Limited, as capital contributions. During the nine months ended September 30, 2020, Delcath Holdings Limited ceased operations with an intent to liquidate after the receipt of tax clearance. When Delcath Holdings Limited liquidates, the Company will generate a $20,000 U.S. deferred tax benefit from a loss on its investment, which may be subject to limitations under Internal Revenue Code Sections 382 and 383 and will be fully offset by a valuation allowance.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2020
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	(13) Commitments and Contingencies Litigation, Claims and Assessments Following the May 18, 2020 resignation (effective June 1, 2020) of Jennifer Simpson, the Company’s former President and Chief Executive Officer, and Barbra Keck, the Company’s former Chief Financial Officer (the “Claimants”), it became evident that there was a dispute regarding the Company’s compensation obligations to the Claimants. In a letter dated, June 29, 2020, an attorney representing the Claimants made certain claims and threatened litigation against the Company. On or about July 27, 2020, the Claimants filed a statement of claim with the American Arbitration Association against the Company. The Claimants seek payment of certain purported unpaid compensation amounts claimed to be due to them, in an approximate amount of $1,140 in the aggregate, as well as unspecified statutory damages under New York Labor Law, attorneys’ fees and costs, and statutory interest. The Company intends to defend the claims vigorously. The arbitrator has scheduled hearings to take place during the week of May 17, 2021. However, the Claimants and the Company have recently agreed to participate in non-binding mediation of their dispute before a neutral mediator, which will result in the arbitration proceedings being placed in abeyance pending the outcome of the mediation process. At this time, the Company is unable to predict the timing for the mediation process, nor whether mediation will result in an amicable resolution of its dispute with the Claimants. As of September 30, 2020, the Company has accrued for the full purported unpaid compensation amounts. Operating Leases Pursuant to a 2014 sublease agreement (the “2014 Sublease”) and a 2015 sublease agreement (the “2015 Sublease”) the Company subleased portions of its leased premises in Dublin, Ireland to a sublessee. On May 15, 2020, the Company and its sublessee entered into amendments to the 2014 Sublease and 2015 Sublease pursuant to which (i) the 2014 Sublease and 2015 Sublease were extended from May 31, 2020 to August 2, 2021, (ii) effective July 1, 2020, the leased premises under the 2015 Sublease would be expanded to include an additional 4,999 square feet of space, and (iii) effective July 1, 2020, the rent under the 2015 Sublease would increase from approximately $14.6 per month to $20.6 per month. The Company analyzed the terms of the amended 2014 Sublease and 2015 Sublease and determined that its ROU asset for the master operating lease was not impaired as a result of the amendments. On June 25, 2020, the Company entered into a sub-lease agreement (the “2021 Sub-Lease”) with its current sublessee under the 2014 Sublease and 2015 Sublease pursuant to which, effective August 2, 2021, the current sublessee would become the lessee and the Company would then sub-lease its portion of the premises from the current sublessee. The Company rent under the 2021 Sub-Lease will be approximately $3.7 per month for a term of five years. Aside from the 2021 Sub-Lease, the Company has no operating or financing leases that have not yet commenced. On September 22, 2020, the Company entered into an amendment (the “Second Amendment to Sublease”) to a sub-lease agreement executed in March 2016 for approximately 6,877 square feet of office space at 1633 Broadway, New York, NY. The term began in April 2016 and under the terms of the Second Amendment to Sublease is extended through February 2023 and provides for total annual base rent of $405.7.

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2020
Subsequent Events [Abstract]
Subsequent Events	(1 4 ) Subsequent Events Stock Warrant Exercises Subsequent to September 30, 2020, warrants to purchase 9,653 shares of the Company’s common stock with an exercise price of $10.00 per share were exercised for proceeds of $93.5. Common Stock Sold - ATM Offering Subsequent to September 30, 2020 71,544 shares of the Company’s common stock were sold in the ATM Offering at the prevailing market prices for proceeds of $814.7. Officer Appointment – Chief Executive Officer On October 1, 2020, Gerard Michel was appointed as the Company’s new Chief Executive Officer and a Class I Director. Pursuant to an employment agreement dated as of August 31, 2020 between the Company and Mr. Michel (the “Employment Agreement”), the term of Mr. Michel’s employment began on October 1, 2020. Under the Employment Agreement, Mr. Michel will receive an annual base salary of $450 subject to annual review by the Board’s Compensation and Stock Option Committee, and will be eligible to participate in the Company’s annual incentive plan with a target annual cash bonus equal to 50% of his then-current base salary. In addition, the Company will reimburse Mr. Michel up to $6.5 per month to cover his temporary expenses incurred in connection with traveling to and living in the New York City tristate area to work onsite at the Company’s principal corporate office for the initial eighteen (18) months of his employment. Pursuant to the Employment Agreement, on October 1, 2020, the Company granted to Mr. Michel a nonqualified and non-plan stock option to purchase 498,000 shares of the Company’s common stock. The option vests ratably over a 36-month period. The exercise price of the option is equal to (i) $11.67 per share , the closing trading price per share of the Company’s common stock on October 1, 2020 as to the first 396,000 option shares to vest, (ii) 1.5 times the closing trading price per share of the Company’s common stock on October 1, 2020 as to the next 51,000 option shares to vest and (iii) 2.0 times the closing trading price per share of the Company’s common stock on October 1, 2020 as to the remaining 51,000 option shares to vest. If Mr. Michel resigns his at-will employment for Good Reason, as defined, or the Company terminates Mr. Michel’s employment other than for Cause, as defined, then Mr. Michel shall be entitled to his accrued and unpaid compensation and, subject to him entering into and not revoking a general release of claims in favor of the Company and fully complying with the terms of an Employee Confidentiality, Invention Assignment and Restrictive Covenants Agreement (the “Restrictive Covenants Agreement”), Mr. Michel shall also be entitled to: (a) a severance payment equal in the aggregate to twelve (12) months of his annual base salary at the time of termination, payable in twelve (12) equal monthly installments; and (b) specified continuing health plan benefits until the earlier of (i) the twelve (12) month anniversary of his termination date; (ii) the last day he’s eligible for coverage pursuant to COBRA; or (iii) the date on which he becomes eligible for similar coverage from another employer. Officer Appointment – Chief Operating Officer On October 1, 2020, John Purpura was elevated to the position of Chief Operating Officer and he resigned from his position as the Company’s Interim Chief Executive Officer. In connection with his promotion, Mr. Purpura will be paid an annual base salary of $385 and will have an annual bonus opportunity of up to 45% of his annual base salary. Option Grants On October 1, 2020, the Company granted ten-year options to directors and employees to purchase an aggregate of 550,000 shares of common stock at an exercise price of $11.67 per share, subject to shareholder approval of the pending 2020 Plan. The options vest ratably on a monthly basis over 36 months.

General (Policies)

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.

Cash, Cash Equivalents and Re_2

Cash, Cash Equivalents and Restricted Cash (Tables)	9 Months Ended
	Sep. 30, 2020
Cash And Cash Equivalents [Abstract]
Schedule of Cash, Cash Equivalents, and Restricted Cash	Cash, cash equivalents, and r estricted cash balances were as follows: September 30, December 31, (in thousands) 2020 2019 Cash and cash equivalents $ 10,899 $ 10,002 Letters of credit 131 131 Security for credit cards 50 50 Total cash, cash equivalents and restricted cash shown in the statements of cash flows $ 11,080 $ 10,183

Inventories (Tables)

Inventories (Tables)	9 Months Ended
	Sep. 30, 2020
Inventory Disclosure [Abstract]
Schedule of inventories	Inventories consist of the following: September 30, December 31, (in thousands) 2020 2019 Raw materials $ 376 $ 375 Work-in-process 463 279 Total inventories $ 839 $ 654

Prepaid Expenses and Other Cu_2

Prepaid Expenses and Other Current Assets (Tables)	9 Months Ended
	Sep. 30, 2020
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]
Prepaid Expenses and Other Current Assets	Prepaid expenses and other current assets consist of the following: September 30, December 31, (in thousands) 2020 2019 Clinical trial expenses $ 1,497 $ 725 Insurance premiums 63 589 Other 1 300 445 Total prepaid expenses and other current assets $ 1,860 $ 1,759 1 Other consists of various prepaid expenses and other current assets, with no individual item accounting for more than 5% of prepaid expenses and other current assets at September 30, 2020 and December 31, 2019.

Property, Plant, and Equipment

Property, Plant, and Equipment (Tables)	9 Months Ended
	Sep. 30, 2020
Property Plant And Equipment [Abstract]
Components of property, plant and equipment	Property, plant, and equipment consist of the following: September 30, December 31, Estimated (in thousands) 2020 2019 Useful Life Buildings and land $ 1,109 $ 589 30 years - Buildings Enterprise hardware and software 1,805 1,739 3 years Leaseholds 1,808 1,695 Lesser of lease term or estimated useful life Equipment 1,045 1,025 7 years Furniture 203 198 5 years Property, plant, and equipment, gross 5,970 5,246 Accumulated depreciation (4,652 ) (4,511 ) Property, plant and equipment, net $ 1,318 $ 735

Accrued Expenses (Tables)

Accrued Expenses (Tables)	9 Months Ended
	Sep. 30, 2020
Payables And Accruals [Abstract]
Schedule of accrued expenses	Accrued expenses consist of the following: September 30, December 31, (in thousands) 2020 2019 Clinical expenses $ 2,919 $ 2,497 Compensation, excluding taxes 2,499 3,525 Other 1 667 925 Total accrued expenses $ 6,085 $ 6,947 1 Other consists of various accrued expenses, with no individual item accounting for more than 5% of current liabilities at September 30, 2020 and December 31, 2019.

Leases (Tables)

Leases (Tables)	9 Months Ended
	Sep. 30, 2020
Leases [Abstract]
Summary of Operating and Financing Leases	The following table summarizes the Company’s operating and financing leases as of and for the nine months ended September 30, 2020: (in thousands) US Ireland Total Lease cost Operating lease cost $ 353 $ 156 $ 509 Financing lease cost 27 — 27 Sublease income — (162 ) (162 ) Total $ 380 $ (6 ) $ 374 Other information Operating cash flows out from operating leases (353 ) (156 ) (509 ) Operating cash flows in from operating leases - 162 162 Operating cash flows out from financing leases (26 ) — (26 ) Right-of-use assets exchanged for new operating lease liabilities 729 — 729 Weighted average remaining lease term 2.4 0.8 Weighted average discount rate - operating leases 8 % 8 %
Schedule of Remaining Maturity of Operating Leases Excluding Short-Term Leases	Remaining maturities of the Company’s operating leases, excluding short-term leases, are as follows: (in thousands) US Ireland Total Year ended December 31, 2020 $ 118 $ 55 $ 173 Year ended December 31, 2021 416 128 544 Year ended December 31, 2022 406 - 406 Year ended December 31, 2023 68 - 68 Total 1,008 183 1,191 Less present value discount (86 ) (7 ) (93 ) Operating lease liabilities included in the condensed consolidated balance sheets at September 30, 2020 $ 922 $ 176 $ 1,098

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	9 Months Ended
	Sep. 30, 2020
Stockholders Equity Note [Abstract]
Summary of Stock Option Activity	The following is a summary of stock option activity under the Plan for the nine months ended September 30, 2020: Number of Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term (Years) Aggregate Intrinsic Value Outstanding at December 31, 2019 1,640 $ 196.70 9.1 $ — Granted — Exercised — Cancelled/Forfeited (1,141 ) Outstanding at September 30, 2020 499 $ 196.70 8.4 $ — Exercisable at September 30, 2020 499 $ 196.70 8.4 $ —
Summary of Recognized Share-based Compensation Cost	The following is a summary of share-based compensation expense in the statement of operations for the Three months ended September 30, Nine months ended September 30, (in thousands) 2020 2019 2020 2019 Selling, general and administrative $ — $ 54 $ 655 $ 160 Research and development — 16 5 43 Total $ — $ 70 $ 660 $ 203
Summary of Warrant Activity	The following is a summary of warrant activity for the nine months ended September 30, 2020: Warrants Exercise Share Weighted Average Exercise Price Weighted Average Remaining (Years) Outstanding at December 31, 2019 1,826,608 $7.00 - $23.04 $ 23.04 5.0 Issued 2,601,900 10.00 Exercised (66,117 ) 9.09 Expired (18 ) 7.00 Outstanding at September 30, 2020 4,362,373 $0.01- $10.00 $ 9.15 4.5

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2020
Fair Value Disclosures [Abstract]
Fair value measurements using significant unobservable inputs	The table below presents the activity within Level 3 of the fair value hierarchy for the nine months ended September 30, 2020 Fair Value Measurements Using Significant Unobservable Inputs (Level 3) (in thousands) Warrant Liability Balance at December 31, 2019 $ 3,368 Total change in the liability included in earnings 2,832 Fair value of warrants reclassified from liability to equity (6,200 ) Balance at September 30, 2020 $ —
Schedule of fair value of the outstanding warrants	The fair value of the outstanding warrants at February 19, 2020, the date the 2019 Warrants were no longer classified as a liability, and December 31, 2019 was determined by using option pricing models with the following assumptions: February 19, December 31, 2020 2019 Expected life (in years) 4.3 4.6 Expected volatility 208.2% 207.5% Risk-free interest rates 1.4% 1.7%
Assets and liabilities measured at fair value on a recurring basis	The table below presents the Company’s assets and liabilities measured at fair value on a recurring basis as of September 30, 2020, aggregated by the level in the fair value hierarchy within which those measurements fall in accordance with ASC 820. Assets and Liabilities Measured at Fair Value on a Recurring Basis (in thousands) Level 1 Level 2 Level 3 Total September 30, 2020 December 31, 2019 September 30, 2020 December 31, 2019 September 30, 2020 December 31, 2019 September 30, 2020 December 31, 2019 Liabilities Derivative instrument liabilities $ — $ — $ — $ — $ — $ 3,368 $ — $ 3,368

Net Loss per Common Share (Tabl

Net Loss per Common Share (Tables)	9 Months Ended
	Sep. 30, 2020
Earnings Per Share [Abstract]
Anti-dilutive securities excluded from the computation of earnings per share	The following potentially dilutive securities were excluded from the computation of earnings per share as of September 30, 2020 and 2019 because their effects would be anti-dilutive: September 30, 2020 2019 Stock options 499 1,643 Common stock warrants - equity 3,991,373 - Common stock warrants - liabilities — 1,001,962 Common stock reserved for conversion of preferred shares 2,147,394 1,001,962 Assumed conversion of convertible notes 146,288 31,746 Total 6,285,554 2,037,313
Calculation of net loss and number of shares used to compute basic and diluted earnings per share	The following table reconciles net loss per share for the three and nine months ended September 30, 2020 and 2019: Three months ended September 30, Nine months ended September 30, (in thousands, except share data) 2020 2019 2020 2019 Net loss $ (4,991 ) $ (7,519 ) $ (17,127 ) $ (21,371 ) Deemed dividend for triggering of warrant down round feature — — (55 ) — Net loss attributable to common stockholders $ (4,991 ) $ (7,519 ) $ (17,182 ) $ (21,371 ) Weighted average shares outstanding - basic* 4,288,593 101,862 2,217,611 102,956 Weighted average shares outstanding - diluted* 4,288,593 101,862 2,217,611 102,956 Net loss per share - basic* $ (1.16 ) $ (73.82 ) $ (7.75 ) $ (207.58 ) Net loss per share - diluted* $ (1.16 ) $ (73.82 ) $ (7.75 ) $ (207.58 ) * reflects, one-for-seven hundred (1:700) reverse stock split effected on December 24, 2019.
Summary of reconciliation of weighted average shares outstanding calculation	The following table provides a reconciliation of the weighted average shares outstanding calculation for the three and nine months ended September 30, 2020 and 2019: Three months ended September 30, Nine months ended September 30, 2020 2019 2020 2019 Weighted average shares issued 3,917,593 25,587 2,015,863 26,681 Weighted average pre-funded warrants 371,000 76,275 201,748 76,275 Weighted average shares outstanding 4,288,593 101,862 2,217,611 102,956

General - Additional Informatio

General - Additional Information (Details)	Sep. 30, 2020USD ($)
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Deferred offering costs	$ 268,000

Cash, Cash Equivalents and Re_3

Cash, Cash Equivalents and Restricted Cash - Schedule of Cash, Cash Equivalents, and Restricted Cash (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019	Sep. 30, 2019	Dec. 31, 2018
Cash And Cash Equivalents [Abstract]
Cash and cash equivalents	$ 10,899	$ 10,002
Letters of credit	131	131
Security for credit cards	50	50
Total cash, cash equivalents and restricted cash shown in the statements of cash flows	$ 11,080	$ 10,183	$ 15,515	$ 3,578

Inventories - Schedule of Inven

Inventories - Schedule of Inventories (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Inventory Disclosure [Abstract]
Raw materials	$ 376	$ 375
Work-in-process	463	279
Total inventories	$ 839	$ 654

Prepaid Expenses and Other Cu_3

Prepaid Expenses and Other Current Assets - Schedule of Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands		Sep. 30, 2020	Dec. 31, 2019
Prepaid Expense And Other Assets Current [Abstract]
Clinical trial expenses		$ 1,497	$ 725
Insurance premiums		63	589
Other	[1]	300	445
Total prepaid expenses and other current assets		$ 1,860	$ 1,759
[1]	1 Other consists of various prepaid expenses and other current assets, with no individual item accounting for more than 5% of prepaid expenses and other current assets at September 30, 2020 and December 31, 2019.

Prepaid Expenses and Other Cu_4

Prepaid Expenses and Other Current Assets - Schedule of Prepaid Expenses and Other Current Assets (Details) (Parenthetical)	Sep. 30, 2020	Dec. 31, 2019
Prepaid Expense And Other Assets Current [Abstract]
Maximum percentage of prepaid expenses and other current assets (in hundredths)	5.00%	5.00%

Property, Plant, and Equipmen_2

Property, Plant, and Equipment - Components of Property, Plant, and Equipment (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 5,970	$ 5,246
Accumulated depreciation	(4,652)	(4,511)
Property, plant and equipment, net	1,318	735
Buildings and Land [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	1,109	589
Enterprise Hardware and Software [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 1,805	1,739
Property, plant and equipment, estimated useful life	3 years
Leaseholds [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 1,808	1,695
Property, plant and equipment, estimated useful life	Lesser of lease term or estimated useful life
Equipment [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 1,045	1,025
Property, plant and equipment, estimated useful life	7 years
Furniture [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 203	$ 198
Property, plant and equipment, estimated useful life	5 years
Buildings [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment, estimated useful life	30 years

Property, Plant, and Equipmen_3

Property, Plant, and Equipment - Additional Information (Details) - USD ($)	Jul. 31, 2020	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Property Plant And Equipment [Abstract]
Exercised option to purchase	$ 460,300
Depreciation expense		$ 32,700	$ 45,800	$ 124,700	$ 168,000

Accrued Expenses - Schedule of

Accrued Expenses - Schedule of Accrued Expenses (Details) - USD ($) $ in Thousands		Sep. 30, 2020	Dec. 31, 2019
Payables And Accruals [Abstract]
Clinical expenses		$ 2,919	$ 2,497
Compensation, excluding taxes		2,499	3,525
Other	[1]	667	925
Total accrued expenses		$ 6,085	$ 6,947
[1]	1 Other consists of various accrued expenses, with no individual item accounting for more than 5% of current liabilities at September 30, 2020 and December 31, 2019.

Accrued Expenses - Schedule o_2

Accrued Expenses - Schedule of Accrued Expenses (Parenthetical) (Details)	Sep. 30, 2020	Dec. 31, 2019
Payables And Accruals [Abstract]
Maximum percentage of current liabilities accrued (in hundredths)	5.00%	5.00%

Leases - Additional Information

Leases - Additional Information (Details)	Sep. 30, 2020
Leases [Abstract]
Lease term	12 months

Leases - Summary of Operating a

Leases - Summary of Operating and Financing Leases (Details) - USD ($)	Jun. 25, 2020	Sep. 30, 2020	Sep. 30, 2019
Lease cost
Operating lease cost		$ 509,000
Financing lease cost		27,000
Sublease income		(162,000)
Total	$ 0	374,000
Other information
Operating cash flows out from operating leases		(509,000)
Operating cash flows in from operating leases		162,000
Operating cash flows out from financing leases		(26,000)
Right of use assets obtained in exchange for lease obligations		729,000	$ 874,000
U.S. [Member]
Lease cost
Operating lease cost		353,000
Financing lease cost		27,000
Total		380,000
Other information
Operating cash flows out from operating leases		(353,000)
Operating cash flows out from financing leases		$ (26,000)
Weighted average remaining lease term		2 years 4 months 24 days
Weighted average discount rate - operating leases		8.00%
Right of use assets obtained in exchange for lease obligations		$ 729,000
Ireland [Member]
Lease cost
Operating lease cost		156,000
Sublease income		(162,000)
Total		(6,000)
Other information
Operating cash flows out from operating leases		(156,000)
Operating cash flows in from operating leases		$ 162,000
Weighted average remaining lease term		9 months 18 days
Weighted average discount rate - operating leases		8.00%

Leases - Schedule of Remaining

Leases - Schedule of Remaining Maturity of Operating Leases Excluding Short-Term Leases (Details) $ in Thousands	Sep. 30, 2020USD ($)
Lessee Lease Description [Line Items]
Year ended December 31, 2020	$ 173
Year ended December 31, 2021	544
Year ended December 31, 2022	406
Year ended December 31, 2023	68
Total	1,191
Less present value discount	(93)
Operating lease liabilities included in the condensed consolidated balance sheets at September 30, 2020	1,098
U.S. [Member]
Lessee Lease Description [Line Items]
Year ended December 31, 2020	118
Year ended December 31, 2021	416
Year ended December 31, 2022	406
Year ended December 31, 2023	68
Total	1,008
Less present value discount	(86)
Operating lease liabilities included in the condensed consolidated balance sheets at September 30, 2020	922
Ireland [Member]
Lessee Lease Description [Line Items]
Year ended December 31, 2020	55
Year ended December 31, 2021	128
Total	183
Less present value discount	(7)
Operating lease liabilities included in the condensed consolidated balance sheets at September 30, 2020	$ 176

Outstanding Debt - Additional I

Outstanding Debt - Additional Information (Details) $ / shares in Units, $ in Thousands	Jun. 06, 2019USD ($)$ / sharesshares
Series E Preferred Stock and Related Warrants [Member]
Debt Instrument [Line Items]
Debt instrument, warrants price per unit | $ / shares	$ 1,500
Senior Secured Promissory Notes [Member]
Debt Instrument [Line Items]
Debt instrument, principal face amount | $	$ 2,000
Debt instrument maturity date	Jul. 16, 2021
Interest rate	8.00%
Series D Warrants [Member]
Debt Instrument [Line Items]
Number of common shares issuable on cancellation of warrants	5,605
Pre-Funded Series D Warrants [Member]
Debt Instrument [Line Items]
Number of common shares issuable on cancellation of warrants	100,000

Stockholders' Equity - Preferre

Stockholders' Equity - Preferred Stock Issuances - Additional Information (Details) - USD ($)	May 05, 2020	Jul. 11, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Aug. 19, 2019	Jun. 06, 2019
Stockholders Equity Note [Line Items]
Preferred stock, par value (in dollars per share)			$ 0.01		$ 0.01
Shares issued, par value per share			$ 0.01		$ 0.01
Offering price	$ 22,000,000		$ 19,377,000	$ 0
Warrant exercise price			$ 10
Deemed dividend for triggering of warrant down round feature			$ (55,000)
Preferred stock, shares outstanding (in shares)			21,473		41,517
Number of warrants outstanding (in shares)			4,362,373		1,826,608
2019 Warrants [Member]
Stockholders Equity Note [Line Items]
Offering price	$ 21,996,000
Warrant exercise price	$ 10				$ 23.04
Deemed dividend for triggering of warrant down round feature	$ 54,500
Number of warrants outstanding (in shares)			1,826,579
Series E Convertible Preferred Stock [Member] | July 2019 Private Placement [Member] | Securities Purchase Agreement [Member]
Stockholders Equity Note [Line Items]
Number of shares issued		20,000
Preferred stock, par value (in dollars per share)		$ 0.01
Shares issued, price per share		1,000
Shares issued, par value per share		$ 0.01
Series E Preferred Stock and Related Warrants [Member]
Stockholders Equity Note [Line Items]
Conversion price							$ 1,500
Series E Preferred Stock and Related Warrants [Member] | July 2019 Private Placement [Member]
Stockholders Equity Note [Line Items]
Debt and warrants exchanged for preferred stock		$ 11,800,000
Number of preferred stock and warrants issued upon conversion		11,500
Value of accounts payable exchanged		$ 100,000
Number of shares issued upon exchange of accounts payable		149
Number of shares issued upon exchange of investor waiver rights		923
Series E-1 Convertible Preferred Stock [Member] | August 2019 Private Placement [Member] | Securities Purchase Agreement [Member]
Stockholders Equity Note [Line Items]
Number of shares issued						9,510
Preferred stock, par value (in dollars per share)						$ 0.01
Shares issued, price per share						1,000
Shares issued, par value per share						$ 0.01
Preferred Stock [Member]
Stockholders Equity Note [Line Items]
Conversion price	$ 10				$ 23.04
Offering price	$ 21,996,000
Excess of the fair value of the common stock	$ 12,000,000

Stockholders' Equity - Common S

Stockholders' Equity - Common Stock Issuances - Additional Information (Details) - USD ($)	May 05, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Stockholders Equity Note [Line Items]
Warrant exercise price		$ 10					$ 10
Net proceeds from Public Offering	$ 22,000,000						$ 19,377,000	$ 0
Conversion of Preferred stock into common stock							2,000,224
Exercise of pre-funded Series D Warrants (in shares)							6,000
Stock Issued During Period Shares associated other warrants							60,117
Common stock shares issued							72,976
Remaining Warrants exercise price		10					$ 10
Deemed dividend for triggering of warrant down round feature							$ (55,000)
Series F warrants [Member]
Stockholders Equity Note [Line Items]
Warrants issued to purchase of common stock	2,224,900
Warrant exercise price	$ 10
Warrants issued to purchase of common stock	2,224,900
Remaining Warrants exercise price	$ 10
Pre-Funded Warrants [Member]
Stockholders Equity Note [Line Items]
Warrants issued to purchase of common stock	377,000
Warrants issued to purchase of common stock	377,000
Common Stock [Member]
Stockholders Equity Note [Line Items]
Warrants issued to purchase of common stock							371,000
Warrant exercise price		$ 0.01					$ 0.01
Warrants issued to purchase of common stock							371,000
Net proceeds from Public Offering	$ 21,996,000
Conversion of Preferred stock into common stock		447,700	1,549,609	2,915
Exercise of pre-funded Series D Warrants (in shares)			6,000		5,399	5,885
Remaining Warrants exercise price		$ 0.01					$ 0.01
Common Stock [Member] | IPO [Member]
Stockholders Equity Note [Line Items]
Shares issued in public offering	1,823,000
2019 Warrants [Member]
Stockholders Equity Note [Line Items]
Warrant exercise price	$ 10								$ 23.04
Net proceeds from Public Offering	$ 21,996,000
Remaining Warrants exercise price	$ 10								$ 23.04
Deemed dividend for triggering of warrant down round feature	$ 54,500

Stockholders' Equity - At-the-M

Stockholders' Equity - At-the-Market Offering - Additional Information (Details) - USD ($)	Aug. 18, 2020	May 01, 2020	Mar. 11, 2020	Jan. 13, 2020	Sep. 30, 2020
Stockholders Equity Note [Line Items]
Common Stock Offering Period following underwriting agreement			2 years
Cantor Fitzgerald & Co [Member]
Stockholders Equity Note [Line Items]
Percentage of commission on aggregate gross proceeds	3.00%
Cantor Fitzgerald & Co [Member] | At-the-Market Offering [Member]
Stockholders Equity Note [Line Items]
Shares issued in public offering					6,100
Proceeds from issuance of common stock					$ 70,500
Roth Capital Partners L L C
Stockholders Equity Note [Line Items]
Percentage Of Underwriting Fee To Be Received on company offerings				35.00%
Common Stock Offering Period following underwriting agreement		90 days
Maximum [Member] | Cantor Fitzgerald & Co [Member]
Stockholders Equity Note [Line Items]
At-the-market offering, aggregate offering price	$ 10,000,000
Legal fees and disbursements	$ 50,000
Minimum [Member] | Roth Capital Partners L L C
Stockholders Equity Note [Line Items]
Percentage of fee on gross sale price per share	1.05%

Stockholders' Equity - Equity I

Stockholders' Equity - Equity Incentive Plan - Additional Information (Details)	Sep. 30, 2020shares
Stockholders Equity Note [Abstract]
Common Stock Reserved under 2020 plan	675,000

Stockholders' Equity - Share-Ba

Stockholders' Equity - Share-Based Compensation - Additional Information (Details) $ in Millions	9 Months Ended
	Sep. 30, 2020USD ($)shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common Stock Reserved under 2020 plan	675,000
Unrecognized compensation expense related to non-vested share-based compensation awards | $	$ 0
2019 Equity Incentive Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares available for grant	1,643
2019 Equity Incentive Plan [Member] | Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common Stock Reserved under 2020 plan	2,142
2019 Equity Incentive Plan [Member] | Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options, exercise price of common stock granted as percentage of fair value on the date of grant	100.00%

Stockholders' Equity - Summary

Stockholders' Equity - Summary of Stock Option Activity (Details) - $ / shares	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Stockholders Equity Note [Abstract]
Number of Shares, Outstanding	1,640
Number of Shares, Cancelled/Forfeited	(1,141)
Number of Shares, Outstanding	499	1,640
Number of Shares, Exercisable	499
Weighted Average Exercise Price, Outstanding	$ 196.70
Weighted Average Exercise Price, Outstanding	196.70	$ 196.70
Weighted Average Exercise Price, Exercisable	$ 196.70
Weighted Average Remaining Contractual Term (Years), Outstanding	8 years 4 months 24 days	9 years 1 month 6 days
Weighted Average Remaining Contractual Term (Years), Exercisable	8 years 4 months 24 days

Stockholders' Equity - Summar_2

Stockholders' Equity - Summary of Recognized Share-based Compensation Cost (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation (Income) expense	$ 70	$ 660	$ 203
Selling, General and Administrative [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation (Income) expense	54	655	160
Research and Development [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation (Income) expense	$ 16	$ 5	$ 43

Stockholders' Equity - Summar_3

Stockholders' Equity - Summary of Warrant Activity (Details) - $ / shares	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Warrants outstanding [Roll Forward]
Outstanding, beginning of period (in shares)	1,826,608
Warrants issued (in shares)	2,601,900
Exercised (in shares)	(66,117)
Warrants expired (in shares)	(18)
Outstanding, end of period (in shares)	4,362,373	1,826,608
Warrants, Exercise Price per Share [Roll Forward]
Outstanding, (in dollars per share)	$ 10
Warrants, Weighted Average Exercise Price [Roll Forward]
Outstanding, beginning of period (in dollars per share)	23.04
Issued (in dollars per share)	10
Exercised (in dollars per share)	9.09
Warrants expired (in dollars per share)	7
Outstanding, end of period (in dollars per share)	$ 9.15	$ 23.04
Weighted average remaining life	4 years 6 months	5 years
Minimum [Member]
Warrants, Exercise Price per Share [Roll Forward]
Outstanding, (in dollars per share)	$ 0.01	$ 7
Maximum [Member]
Warrants, Exercise Price per Share [Roll Forward]
Outstanding, (in dollars per share)	$ 10	$ 23.04

Fair Value Measurements - Fair

Fair Value Measurements - Fair Value Measurements Using Significant Unobservable Inputs (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2020USD ($)
Fair Value Measurements Using Significant Unobservable Inputs (Level 3) [Roll Forward]
Beginning balance	$ 3,368
Total change in the liability included in earnings	2,832
Fair value of warrants reclassified from liability to equity	$ (6,200)

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Fair Value of Outstanding Warrants (Details)	Feb. 19, 2020	Dec. 31, 2019
Contractual Term [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Warrants expiration period	4 years 3 months 18 days	4 years 7 months 6 days
Expected Volatility [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Warrants measurement input	208.2	207.5
Risk-free Interest Rates [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Warrants measurement input	1.4	1.7

Fair Value Measurements - Asset

Fair Value Measurements - Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - Derivative Instruments Liabilities [Member] - Recurring [Member] $ in Thousands	Dec. 31, 2019USD ($)
Liabilities [Abstract]
Total Liabilities	$ 3,368
Level 3 [Member]
Liabilities [Abstract]
Total Liabilities	$ 3,368

Net Loss per Common Share - Ant

Net Loss per Common Share - Anti-Dilutive Securities Excluded from Computation of Earnings Per Share (Details) - shares	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	6,285,554	2,037,313
Stock Options [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	499	1,643
Common Stock Warrants - Equity [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	3,991,373
Common Stock Warrants - Liabilities [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)		1,001,962
Common Stock Reserved For Conversion of Preferred Shares [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	2,147,394	1,001,962
Assumed Conversion of Convertible Notes [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	146,288	31,746

Net Loss per Common Share - Cal

Net Loss per Common Share - Calculation of Net Loss and Number of Shares Used to Compute Basic and Diluted Earnings per Share (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended						9 Months Ended
		Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Earnings Per Share [Abstract]
Net loss		$ (4,991)	$ (4,275)	$ (7,861)	$ (7,519)	$ (5,959)	$ (7,894)	$ (17,127)	$ (21,371)
Deemed dividend for triggering of warrant down round feature								(55)
Net loss attributable to common stockholders		$ (4,991)			$ (7,519)			$ (17,182)	$ (21,371)
Weighted average shares outstanding - basic	[1]	4,288,593			101,862			2,217,611	102,956
Weighted average shares outstanding - diluted	[1]	4,288,593			101,862			2,217,611	102,956
Net loss per share - basic	[1]	$ (1.16)			$ (73.82)			$ (7.75)	$ (207.58)
Net loss per share - diluted	[1]	$ (1.16)			$ (73.82)			$ (7.75)	$ (207.58)
[1]	* reflects, one-for-seven hundred (1:700) reverse stock split effected on December 24, 2019.

Net Loss per Common Share - C_2

Net Loss per Common Share - Calculation of Net Loss and Number of Shares Used to Compute Basic and Diluted Earnings per Share (Parenthetical) (Details)	Dec. 24, 2019
Earnings Per Share [Abstract]
Reverse stock split	1:700
Reverse stock split ratio	0.00142

Net Loss per Common Share - Add

Net Loss per Common Share - Additional Information (Details)	9 Months Ended
	Sep. 30, 2020shares
Earnings Per Share [Abstract]
Pre-funded penny warrants outstanding	371,000

Net Loss per Common Share - Sum

Net Loss per Common Share - Summary of Reconciliation of Weighted Average Shares Outstanding Calculation (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Earnings Per Share [Abstract]
Weighted average shares issued	3,917,593	25,587	2,015,863	26,681
Weighted average pre-funded warrants	371,000	76,275	201,748	76,275
Weighted average shares outstanding	4,288,593	101,862	2,217,611	102,956

Taxes - Additional Information

Taxes - Additional Information (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2020USD ($)subsidiary
Ireland [Member]
Operating Loss Carryforwards [Line Items]
Number of subsidiaries | subsidiary	2
Delcath Holdings Limited [Member]
Operating Loss Carryforwards [Line Items]
Deferred tax benefit | $	$ 20,000

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details)	Sep. 22, 2020ft²	Jul. 27, 2020USD ($)	Jul. 02, 2020USD ($)	Jul. 01, 2020USD ($)ft²	Jun. 25, 2020USD ($)	Sep. 30, 2020USD ($)	Sep. 30, 2020USD ($)
Loss Contingencies [Line Items]
Lease, description							(i) the 2014 Sublease and 2015 Sublease were extended from May 31, 2020 to August 2, 2021, (ii) effective July 1, 2020, the leased premises under the 2015 Sublease would be expanded to include an additional 4,999 square feet of space, and (iii) effective July 1, 2020, the rent under the 2015 Sublease would increase from approximately $14.6 per month to $20.6 per month.
Extension of sublease				May 31, 2020 to August 2, 2021
Lease term						12 months	12 months
Operating or finance lease					$ 0		$ 374,000
Sub lease expiration date	Feb. 28, 2023
Sublease 2015 [Member]
Loss Contingencies [Line Items]
Additional area of space | ft²				4,999
Increase in sublease rent			$ 20,600,000	$ 14,600,000
2021 Sub-Lease Agreement [Member]
Loss Contingencies [Line Items]
Additional area of space | ft²	6,877
Sublease rent					$ 3,700	$ 405,700
Lease term					5 years
Pending Litigation [Member]
Loss Contingencies [Line Items]
Unpaid compensation amounts claimed		$ 1,140,000
Accrued unpaid compensation amounts						$ 1,140,000	$ 1,140,000

Subsequent Events - Additional

Subsequent Events - Additional Information (Details) - USD ($)	Oct. 01, 2020	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Subsequent Event [Line Items]
Warrant exercise price		$ 10
Net proceeds from the exercise of warrants		$ 601,000	$ 0
Maximum [Member]
Subsequent Event [Line Items]
Warrant exercise price		$ 10		$ 23.04
Minimum [Member]
Subsequent Event [Line Items]
Warrant exercise price		0.01		$ 7
Subsequent Event | Chief Executive Officer [Member]
Subsequent Event [Line Items]
Salary and wage, Officer	$ 450,000
Annual target cash bonus	50.00%
Number of Shares, Granted	498,000
Stock options vesting period	36 months
Stock options outstanding to vest	51,000
Subsequent Event | Chief Executive Officer [Member] | 1.5 times closing trading price per share [Member]
Subsequent Event [Line Items]
Stock options vested	396,000
Subsequent Event | Chief Executive Officer [Member] | 2.0 times closing trading price per share [Member]
Subsequent Event [Line Items]
Stock options vested	51,000
Subsequent Event | Chief Executive Officer [Member] | Maximum [Member]
Subsequent Event [Line Items]
Reimbursement for travel and stay, per month	$ 6,500
Subsequent Event | Chief Operating Officer [Member]
Subsequent Event [Line Items]
Salary and wage, Officer	$ 385,000
Annual target cash bonus	45.00%
Stock Warrant Exercises [Member] | Subsequent Event
Subsequent Event [Line Items]
Warrant exercise price	$ 10
Warrants issued to purchase of common stock	9,653
Net proceeds from the exercise of warrants	$ 93,500
Common Stock [Member]
Subsequent Event [Line Items]
Warrant exercise price		$ 0.01
Warrants issued to purchase of common stock		371,000
Common Stock [Member] | Subsequent Event | At-the-Market Offering [Member]
Subsequent Event [Line Items]
Shares issued in public offering	71,544
Proceeds from issuance of common stock	$ 814,700
2020 Omnibus Equity Incentive Plan [Member] | Subsequent Event | Director and Employees [Member]
Subsequent Event [Line Items]
Number of Shares, Granted	550,000
Stock options vesting period	36 months
Stock options contractual term	10 years