Delcath Systems (DCTH) 10-Q 13 Aug 20 2020 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2020	Aug. 13, 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		3,935,968
Document Fiscal Year Focus	2020
Trading Symbol	DCTH
Title of 12(b) Security	Common stock
Document Fiscal Period Focus	Q2
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2020
Security Exchange Name	NASDAQ

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Current assets
Cash and cash equivalents	$ 16,011	$ 10,002
Restricted cash	181	181
Accounts receivables, net	147	21
Inventories	723	654
Prepaid expenses and other current assets	1,992	1,759
Total current assets	19,054	12,617
Property, plant and equipment, net	864	735
Right-of-use assets	525	860
Total assets	20,443	14,212
Current liabilities
Accounts payable	2,174	4,533
Accrued expenses	5,429	6,947
Lease liabilities, current portion	508	664
Warrant liability		3,368
Total current liabilities	8,111	15,512
Deferred revenue	2,613	2,860
Lease liabilities, long-term portion	17	197
Convertible notes payable, long-term	2,000	2,000
Total liabilities	12,741	20,569
Commitments and contingencies (Note 13)
Stockholders' equity (deficit)
Preferred stock, $.01 par value; 10,000,000 shares authorized; 25,950 and 41,517 shares issued and outstanding at June 30, 2020 and December 31, 2019, respectively	0	0
Common stock, $.01 par value; 1,000,000,000 shares authorized; 3,521,641 and 67,091 shares issued and outstanding at June 30, 2020 and December 31, 2019, respectively*	35	1
Additional paid-in capital	390,882	364,785
Accumulated deficit	(383,307)	(371,171)
Accumulated other comprehensive income	92	28
Total stockholders' equity (deficit)	7,702	(6,357)
Total liabilities and stockholders' equity (deficit)	$ 20,443	$ 14,212

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - $ / shares	Jun. 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)	25,950	41,517
Preferred stock, shares outstanding (in shares)	25,950	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)	3,521,641	67,091
Common stock, shares outstanding (in shares)	3,521,641	67,091

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Cost of goods sold		$ (168)	$ (172)	$ (246)	$ (268)
Gross profit		211	240	426	414
Operating expenses:
Research and development expenses		2,223	1,714	5,197	5,011
Selling, general and administrative expenses		2,257	2,653	4,573	5,203
Total operating expenses		4,480	4,367	9,770	10,214
Operating loss		(4,269)	(4,127)	(9,344)	(9,800)
Change in fair value of the warrant liability, net			10	(2,832)	17
Loss on issuance of financial instrument			6		6
Interest expense		(52)	(1,837)	(109)	(4,064)
Other income		46	1	149
Net loss		(4,275)	(5,959)	(12,136)	(13,853)
Deemed dividend for triggering of warrant down round feature		(55)		(55)
Net loss attributable to common stockholders		(4,330)	(5,959)	(12,191)	(13,853)
Net loss		(4,275)	(5,959)	(12,136)	(13,853)
Other comprehensive (loss) income:
Foreign currency translation adjustments		(1)	(23)	65	(74)
Total other comprehensive loss		$ (4,276)	$ (5,982)	$ (12,071)	$ (13,927)
Common share data:
Basic loss per common share	[1],[2]	$ (1.90)	$ (58.50)	$ (10.40)	$ (134.55)
Diluted loss per common share	[1],[2]	$ (1.90)	$ (58.50)	$ (10.40)	$ (134.55)
Weighted average number of basic shares outstanding	[1],[2]	2,273,187	101,862	1,171,994	102,956
Weighted average number of diluted shares outstanding	[1],[2]	2,273,187	101,862	1,171,994	102,956
Product Revenue [Member]
Revenue		$ 262	$ 221	$ 437	$ 311
Other Revenue [Member]
Revenue		$ 117	$ 191	$ 235	$ 371
[1]	* reflects, one-for-seven hundred (1:700) reverse stock split effected on December 24, 2019.
[2]	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	(13,853)
Balance at Jun. 30, 2019	(29,729)			328,201	(357,907)	(23)
Balance (in shares) at Jun. 30, 2019		26,110
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
Exchange of warrants	13			13
Exchange of warrants (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
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)	1,549,609
Exercise of pre-funded warrants (in shares)	6,000
Net loss	$ (12,136)
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
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

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	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Cash flows from operating activities:
Net loss	$ (12,136)	$ (13,853)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock option compensation expense	25	129
Restricted stock compensation expense	635	4
Depreciation expense	92	122
Amortization of right of use assets	335	552
Warrant liability fair value adjustment	2,832	(17)
Loss on issuance of financial instruments	0	6
Interest expense accrued related to convertible notes	80	329
Debt discount amortization	0	3,444
Changes in assets and liabilities:
(Increase) decrease in prepaid expenses and other assets	(232)	232
(Increase) decrease in accounts receivable	(125)	404
(Increase) decrease in inventories	(70)	143
Increase (decrease) in accounts payable and accrued expenses	(3,957)	3,827
Decrease in deferred revenue	(248)	(240)
Decrease in operating lease liabilities	(313)	(540)
Decrease in other non-current liabilities	0	(504)
Net cash used in operating activities	(13,082)	(5,962)
Cash flows from investing activities:
Purchase of property, plant and equipment	(221)	(2)
Net cash used in investing activities	(221)	(2)
Cash flows from financing activities:
Principal payments on financing leases	(23)	0
Net proceeds from the issuance of debt	0	3,719
Net payments related to reserve stock split	(106)	0
Net proceeds from Public Offering	19,378	0
Net cash provided by financing activities	19,249	3,869
Foreign currency effects on cash	63	(69)
Net increase (decrease) in cash and cash equivalents	6,009	(2,162)
Cash and cash equivalents:
Beginning of period	10,183	3,578
End of period	16,192	1,416
Supplemental Disclosure of Cash Flow Information:
Interest expense	7	0
Supplemental Disclosure of Non-Cash Investing and Financing Activities:
Conversions of preferred stock into common stock	15	0
Reclassification of 2019 warrants from liability to equity	6,199	0
Exchange of 2019 warrants	0	13
Adoption of ASC 842 lease standard	0	1,652
Right of use assets obtained in exchange for lease obligations	0	874
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	6 Months Ended
	Jun. 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 six months ended June 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. Our investigational product—Melphalan Hydrochloride for Injection for use with the Delcath Hepatic Delivery System (“Melphalan/HDS”) —is designed to administer high-dose chemotherapy to the liver while controlling systemic exposure and associated side effects. In Europe, our system is commercially available under the trade name Delcath CHEMOSAT ® Our clinical development program (“CDP”) for Melphalan/HDS is comprised of The FOCUS Clinical Trial for Patients with Hepatic Dominant Ocular Melanoma (the “FOCUS Trial”), a global registration clinical trial that is investigating objective response rate in ocular melanoma liver metastases, or mOM, and the ALIGN Trial, a global Phase 3 clinical trial for intrahepatic cholangiocarcinoma, or ICC (the “ALIGN Trial”). 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 The recent outbreak of a novel strain of coronavirus (COVID-19) has had an impact on our ability to monitor data at our clinical trial sites and is likely to cause a decline in product revenue for the foreseeable future as many hospitals are prioritizing the treatment of patients diagnosed with COVID-19. We expected to announce top-line data from our FOCUS trial in mid-2020; however, COVID-19 has impacted our ability to enroll and treat patients in this trial and to monitor data at our clinical trial sites. As a result, we will not be able to release the top-line data from the FOCUS Trial within the timeframe we had anticipated. Once our clinical trial sites are able to return to normal operating procedures, we will assess the impact and update our expected timing accordingly. This situation is rapidly changing 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 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 June 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 A description of our significant accounting policies has been provided in Note 3 Summary of Significant Accounting Policies 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	6 Months Ended
	Jun. 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: June 30, December 31, (in thousands) 2020 2019 Cash and cash equivalents $ 16,011 $ 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 $ 16,192 $ 10,183

Inventories

Inventories	6 Months Ended
	Jun. 30, 2020
Inventory Disclosure [Abstract]
Inventories	(3) Inventories Inventories consist of the following: June 30, December 31, (in thousands) 2020 2019 Raw materials $ 389 $ 375 Work-in-process 334 279 Total inventories $ 723 $ 654

Prepaid Expenses and Other Curr

Prepaid Expenses and Other Current Assets	6 Months Ended
	Jun. 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: June 30, December 31, (in thousands) 2020 2019 Clinical trial expenses $ 1,497 $ 725 Insurance premiums 244 589 Other 1 251 445 Total prepaid expenses and other current assets $ 1,992 $ 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 June 30, 2020 and December 31, 2019.

Property, Plant, and Equipment

Property, Plant, and Equipment	6 Months Ended
	Jun. 30, 2020
Property Plant And Equipment [Abstract]
Property, Plant, and Equipment	(5) Property, Plant, and Equipment Property, plant, and equipment consist of the following: June 30, December 31, Estimated (in thousands) 2020 2019 Useful Life Buildings and land $ 634 $ 589 30 years - Buildings Enterprise hardware and software 1,802 1,739 3 years Leaseholds 1,797 1,695 Lesser of lease term or estimated useful life Equipment 1,032 1,025 7 years Furniture 202 198 5 years Property, plant and equipment, gross 5,467 5,246 Accumulated depreciation (4,603 ) (4,511 ) Property, plant and equipment, net $ 864 $ 735 Depreciation expense for the three and six months ended June 30, 2020 was approximately $44 thousand and $92 thousand as compared to approximately $57 thousand and $122 thousand for the same periods in 2019.

Accrued Expenses

Accrued Expenses	6 Months Ended
	Jun. 30, 2020
Payables And Accruals [Abstract]
Accrued Expenses	(6) Accrued Expenses Accrued expenses consist of the following: June 30, December 31, (in thousands) 2020 2019 Clinical expenses $ 2,565 $ 2,497 Compensation, excluding taxes 2,379 3,525 Other 1 485 925 Total accrued expenses $ 5,429 $ 6,947 1 Other consists of various accrued expenses, with no individual item accounting for more than 5% of current liabilities at June 30, 2020 and December 31, 2019.

Leases

Leases	6 Months Ended
	Jun. 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. Pursuant to a 2014 sublease agreement (the “2014 Sublease”) and a 2015 sublease agreement (the “2015 Sublease”) the Company subleases 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, and (ii) effective July 1, 2020, the leased premises under the 2015 Sublease would be expanded to include an additional 4,999 square ft of space, and (ii) effective July 1, 2020, the rent under the 2015 Sublease would increase from approximately $14,559 per month to $20,643 per month. The Company analyzed the terms of the amended 2014 Sublease and 2015 Sublease and determined that its ROU 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 such current sublessee. The Company Rent under the 2021 Sub-Lease will be approximately $3,721.50 per month. Aside from the 2021 Lease, the Company has no operating or financing leases that have not yet commenced. The following table summarizes the Company’s operating and financing leases as of and for the six months ended June 30, 2020: (in thousands) US Ireland Total Lease cost Operating lease cost $ 236 $ 103 $ 339 Financing lease cost 23 — 23 Sublease income — (98 ) (98 ) Total $ 259 $ 5 $ 264 Other information Operating cash flows out from operating leases (236 ) (103 ) (339 ) Operating cash flows in from operating leases - 98 98 Operating cash flows out from financing leases (22 ) — (22 ) Weighted average remaining lease term 0.7 1.1 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 $ 239 $ 105 $ 344 Year ended December 31, 2021 $ 78 122 200 Total $ 317 227 544 Less present value discount $ (9 ) (10 ) (19 ) Operating lease liabilities included in the condensed consolidated balance sheet at June 30, 2020 $ 308 $ 217 $ 525

Outstanding Debt

Outstanding Debt	6 Months Ended
	Jun. 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 $2.0 million 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 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, long-term on the Condensed Consolidated Balance Sheet. The following tables provide a summary of the notes outstanding at June 30, 2020: Conversion price Current interest rate Principal Long term convertible notes payable 8.0% July 2019 Notes $ 1,500 8 % $ 2,000,000

Stockholders' Equity

Stockholders' Equity	6 Months Ended
	Jun. 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 $11.8 million of debt, interest and Series D Warrants for 11,500 shares of Series E Preferred Stock and related 2019 E Warrants, $0.1 million 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 $22.0 million offering 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 $12.0 million. 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 at December 31, 2019. The exercise price was subsequently adjusted to $10.00 upon the pricing of a $22.0 million offering on May 5, 2020, as discussed further below, which resulted in the recognition of a $55 thousand deemed dividend. The 2019 Warrants are exercisable until 5:00 p.m. (NYC time) on December 24, 2024. As of June 30, 2020, there were 25,950 shares of Preferred Stock outstanding and 1.8 million 2019 Warrants outstanding. Public Offering and Nasdaq Uplisting 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. Delcath received gross proceeds of approximately $22.0 million from the offering, before deducting the underwriting discount and estimated offering expenses. The securities were offered pursuant to a registration statement on Form S-1 (File No. 333-235904) previously filed with the SEC and declared effective on April 30, 2020. In connection with this offering, the Company’s common stock was approved for listing and began trading on the Nasdaq Capital Market on May 1, 2020. As a result of this offering, the Preferred Stock conversion price was adjusted to $10.00 and the exercise price of the 2019 Warrants was adjusted to $10.00 and neither instrument is subject to further price resets. Other Common Stock Issuances During the six months ended June 30, 2020 the Company issued 1,549,609 shares of the Company’s common stock pursuant to conversions of Preferred Stock. During the six months ended June 30, 2020, the Company issued 6,000 shares of common stock associated with the exercise of pre-funded warrants. During the six months ended June 30, 2020, the Company issued 72,976 shares of common stock as compensation. 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 June 30, 2020, the Plan had approximately 502 shares available for grant. The following is a summary of stock option activity under the Plan for the six months ended June 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 — Outstanding at June 30, 2020 1,640 $ 196.70 8.6 $ — Exercisable at June 30, 2020 1,640 $ 196.70 8.6 $ — At June 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: Three months ended June 30, Six months ended June 30, (in thousands) 2020 2019 2020 2019 Selling, general and administrative $ 606 $ 58 $ 655 $ 106 Research and development — 17 5 27 Total $ 606 $ 75 $ 660 $ 133 Warrants The following is a summary of warrant activity for the six months ended June 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 (6,000 ) 0.01 Expired (9 ) 7.00 Outstanding at June 30, 2020 4,422,499 $0.01- $10.00 $ 9.16 4.7 As of June 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.

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 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 six months ended June 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 June 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 June 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 June 30, 2020 December 31, 2019 June 30, 2020 December 31, 2019 June 30, 2020 December 31, 2019 June 30, 2020 December 31, 2019 Liabilities Derivative instrument liabilities $ — $ — $ — $ — $ — $ 3,368 $ — $ 3,368

Net Loss per Common Share

Net Loss per Common Share	6 Months Ended
	Jun. 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 June 30, 2020 and 2019 because their effects would be anti-dilutive: June 30, (in thousands, except share data) 2020 2019 Stock options 1,640 1,667 Common stock warrants - equity 4,051,499 6,004 Common stock warrants - liabilities — 179 Common stock reserved for conversion of preferred shares 2,595,087 — Assumed conversion of convertible notes 146,288 480 Total 6,794,514 8,329 However, in certain periods in which the exercise price of the warrants was less than the last reported sales price of Delcath’s common stock on the final trading day of the period and there is a gain recorded pursuant to the change in fair value of the warrant derivative liability, the impact of gains related to the mark-to-market adjustment of the warrants outstanding at the end of the period is reversed and the treasury stock method is used to determine diluted earnings per share. The following table reconciles net loss per share for the three and six months ended June 30, 2020 and 2019: Three months ended June 30, Six months ended June 30, (in thousands, except share data) 2020 2019 2020 2019 Net loss $ (4,275 ) $ (5,959 ) $ (12,136 ) $ (13,853 ) Deemed dividend for triggering of warrant down round feature (55 ) — (55 ) — Net loss attributable to common stockholders $ (4,330 ) $ (5,959 ) $ (12,191 ) $ (13,853 ) Weighted average shares outstanding - basic* 2,273,187 101,862 1,171,994 102,956 Weighted average shares outstanding - diluted* 2,273,187 101,862 1,171,994 102,956 Net loss per share - basic* $ (1.90 ) $ (58.50 ) $ (10.40 ) $ (134.55 ) Net loss per share - diluted* $ (1.90 ) $ (58.50 ) $ (10.40 ) $ (134.55 ) * reflects, one-for-seven hundred (1:700) reverse stock split effected on December 24, 2019. At June 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 six months ended June 30, 2020 and 2019: Three months ended June 30, Six months ended June 30, 2020 2019 2020 2019 Weighted average shares issued 2,038,297 25,587 1,054,549 26,681 Weighted average pre-funded warrants 234,890 76,275 117,445 76,275 Weighted average shares outstanding 2,273,187 101,862 1,171,994 102,956

Taxes

Taxes	6 Months Ended
	Jun. 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 sheet. 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 six months ending June 30, 2020, the Company settled intercompany debt of its two Ireland subsidiaries, Delcath Systems Limited and Delcath Holdings Limited, as capital contributions. During the six months ending June 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 $19.9 million 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	6 Months Ended
	Jun. 30, 2020
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	(13) Commitments and Contingencies Following the May 18, 2020 resignation 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 $1.14 million 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. As of June 30, 2020, the Company has accrued for the full purported unpaid compensation amounts.

Subsequent Events

Subsequent Events	6 Months Ended
	Jun. 30, 2020
Subsequent Events [Abstract]
Subsequent Events	(1 4 ) Subsequent Events Preferred Stock Conversions Subsequent to June 30, 2020, the Company issued 372,500 shares of the Company’s common stock upon the conversion of Preferred Stock. Property Purchase On July 31, 2020, the Company exercised its option to purchase its 95-97 Park Road office location in Queensbury, NY for $460,263, 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. Stock Warrant Exercises Subsequent to June 30, 2020, warrants to purchase 41,827 shares of the Company’s common stock with an exercise price of $10.00 per share were exercised for proceeds of $418,270.

General (Policies)

General (Policies)	6 Months Ended
	Jun. 30, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Risk And Uncertainties	Risks and Uncertainties The recent outbreak of a novel strain of coronavirus (COVID-19) has had an impact on our ability to monitor data at our clinical trial sites and is likely to cause a decline in product revenue for the foreseeable future as many hospitals are prioritizing the treatment of patients diagnosed with COVID-19. We expected to announce top-line data from our FOCUS trial in mid-2020; however, COVID-19 has impacted our ability to enroll and treat patients in this trial and to monitor data at our clinical trial sites. As a result, we will not be able to release the top-line data from the FOCUS Trial within the timeframe we had anticipated. Once our clinical trial sites are able to return to normal operating procedures, we will assess the impact and update our expected timing accordingly. This situation is rapidly changing 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 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 June 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.
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)	6 Months Ended
	Jun. 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: June 30, December 31, (in thousands) 2020 2019 Cash and cash equivalents $ 16,011 $ 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 $ 16,192 $ 10,183

Inventories (Tables)

Inventories (Tables)	6 Months Ended
	Jun. 30, 2020
Inventory Disclosure [Abstract]
Schedule of inventories	Inventories consist of the following: June 30, December 31, (in thousands) 2020 2019 Raw materials $ 389 $ 375 Work-in-process 334 279 Total inventories $ 723 $ 654

Prepaid Expenses and Other Cu_2

Prepaid Expenses and Other Current Assets (Tables)	6 Months Ended
	Jun. 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: June 30, December 31, (in thousands) 2020 2019 Clinical trial expenses $ 1,497 $ 725 Insurance premiums 244 589 Other 1 251 445 Total prepaid expenses and other current assets $ 1,992 $ 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 June 30, 2020 and December 31, 2019.

Property, Plant, and Equipment

Property, Plant, and Equipment (Tables)	6 Months Ended
	Jun. 30, 2020
Property Plant And Equipment [Abstract]
Components of property, plant and equipment	Property, plant, and equipment consist of the following: June 30, December 31, Estimated (in thousands) 2020 2019 Useful Life Buildings and land $ 634 $ 589 30 years - Buildings Enterprise hardware and software 1,802 1,739 3 years Leaseholds 1,797 1,695 Lesser of lease term or estimated useful life Equipment 1,032 1,025 7 years Furniture 202 198 5 years Property, plant and equipment, gross 5,467 5,246 Accumulated depreciation (4,603 ) (4,511 ) Property, plant and equipment, net $ 864 $ 735

Accrued Expenses (Tables)

Accrued Expenses (Tables)	6 Months Ended
	Jun. 30, 2020
Payables And Accruals [Abstract]
Schedule of accrued expenses	Accrued expenses consist of the following: June 30, December 31, (in thousands) 2020 2019 Clinical expenses $ 2,565 $ 2,497 Compensation, excluding taxes 2,379 3,525 Other 1 485 925 Total accrued expenses $ 5,429 $ 6,947 1 Other consists of various accrued expenses, with no individual item accounting for more than 5% of current liabilities at June 30, 2020 and December 31, 2019.

Leases (Tables)

Leases (Tables)	6 Months Ended
	Jun. 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 six months ended June 30, 2020: (in thousands) US Ireland Total Lease cost Operating lease cost $ 236 $ 103 $ 339 Financing lease cost 23 — 23 Sublease income — (98 ) (98 ) Total $ 259 $ 5 $ 264 Other information Operating cash flows out from operating leases (236 ) (103 ) (339 ) Operating cash flows in from operating leases - 98 98 Operating cash flows out from financing leases (22 ) — (22 ) Weighted average remaining lease term 0.7 1.1 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 $ 239 $ 105 $ 344 Year ended December 31, 2021 $ 78 122 200 Total $ 317 227 544 Less present value discount $ (9 ) (10 ) (19 ) Operating lease liabilities included in the condensed consolidated balance sheet at June 30, 2020 $ 308 $ 217 $ 525

Outstanding Debt (Tables)

Outstanding Debt (Tables)	6 Months Ended
	Jun. 30, 2020
Debt Disclosure [Abstract]
Summary of Various Notes Issued	The following tables provide a summary of the notes outstanding at June 30, 2020: Conversion price Current interest rate Principal Long term convertible notes payable 8.0% July 2019 Notes $ 1,500 8 % $ 2,000,000

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	6 Months Ended
	Jun. 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 six months ended June 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 — Outstanding at June 30, 2020 1,640 $ 196.70 8.6 $ — Exercisable at June 30, 2020 1,640 $ 196.70 8.6 $ —
Summary of Recognized Share-based Compensation Cost	The following is a summary of share-based compensation expense in the statement of operations: Three months ended June 30, Six months ended June 30, (in thousands) 2020 2019 2020 2019 Selling, general and administrative $ 606 $ 58 $ 655 $ 106 Research and development — 17 5 27 Total $ 606 $ 75 $ 660 $ 133
Summary of Warrant Activity	The following is a summary of warrant activity for the six months ended June 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 (6,000 ) 0.01 Expired (9 ) 7.00 Outstanding at June 30, 2020 4,422,499 $0.01- $10.00 $ 9.16 4.7

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 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 six months ended June 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 June 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 June 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 June 30, 2020 December 31, 2019 June 30, 2020 December 31, 2019 June 30, 2020 December 31, 2019 June 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)	6 Months Ended
	Jun. 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 June 30, 2020 and 2019 because their effects would be anti-dilutive: June 30, (in thousands, except share data) 2020 2019 Stock options 1,640 1,667 Common stock warrants - equity 4,051,499 6,004 Common stock warrants - liabilities — 179 Common stock reserved for conversion of preferred shares 2,595,087 — Assumed conversion of convertible notes 146,288 480 Total 6,794,514 8,329
Calculation of net loss and number of shares used to compute basic and diluted earnings per share	However, in certain periods in which the exercise price of the warrants was less than the last reported sales price of Delcath’s common stock on the final trading day of the period and there is a gain recorded pursuant to the change in fair value of the warrant derivative liability, the impact of gains related to the mark-to-market adjustment of the warrants outstanding at the end of the period is reversed and the treasury stock method is used to determine diluted earnings per share. The following table reconciles net loss per share for the three and six months ended June 30, 2020 and 2019: Three months ended June 30, Six months ended June 30, (in thousands, except share data) 2020 2019 2020 2019 Net loss $ (4,275 ) $ (5,959 ) $ (12,136 ) $ (13,853 ) Deemed dividend for triggering of warrant down round feature (55 ) — (55 ) — Net loss attributable to common stockholders $ (4,330 ) $ (5,959 ) $ (12,191 ) $ (13,853 ) Weighted average shares outstanding - basic* 2,273,187 101,862 1,171,994 102,956 Weighted average shares outstanding - diluted* 2,273,187 101,862 1,171,994 102,956 Net loss per share - basic* $ (1.90 ) $ (58.50 ) $ (10.40 ) $ (134.55 ) Net loss per share - diluted* $ (1.90 ) $ (58.50 ) $ (10.40 ) $ (134.55 ) * 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 six months ended June 30, 2020 and 2019: Three months ended June 30, Six months ended June 30, 2020 2019 2020 2019 Weighted average shares issued 2,038,297 25,587 1,054,549 26,681 Weighted average pre-funded warrants 234,890 76,275 117,445 76,275 Weighted average shares outstanding 2,273,187 101,862 1,171,994 102,956

Cash, Cash Equivalents and Re_3

Cash, Cash Equivalents and Restricted Cash - Schedule of Cash, Cash Equivalents, and Restricted Cash (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019	Jun. 30, 2019	Dec. 31, 2018
Cash And Cash Equivalents [Abstract]
Cash and cash equivalents	$ 16,011	$ 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	$ 16,192	$ 10,183	$ 1,416	$ 3,578

Inventories - Schedule of Inven

Inventories - Schedule of Inventories (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Inventory Disclosure [Abstract]
Raw materials	$ 389	$ 375
Work-in-process	334	279
Total inventories	$ 723	$ 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		Jun. 30, 2020	Dec. 31, 2019
Prepaid Expense And Other Assets Current [Abstract]
Clinical trial expenses		$ 1,497	$ 725
Insurance premiums		244	589
Other	[1]	251	445
Total prepaid expenses and other current assets		$ 1,992	$ 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 June 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)	Jun. 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	6 Months Ended
	Jun. 30, 2020	Dec. 31, 2019
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 5,467	$ 5,246
Accumulated depreciation	(4,603)	(4,511)
Property, plant and equipment, net	864	735
Buildings and Land [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	634	589
Enterprise Hardware and Software [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 1,802	1,739
Property, plant and equipment, estimated useful life	3 years
Leaseholds [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 1,797	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	$ 1,032	1,025
Property, plant and equipment, estimated useful life	7 years
Furniture [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 202	$ 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 ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Property Plant And Equipment [Abstract]
Depreciation expense	$ 44	$ 57	$ 92	$ 122

Accrued Expenses - Schedule of

Accrued Expenses - Schedule of Accrued Expenses (Details) - USD ($) $ in Thousands		Jun. 30, 2020	Dec. 31, 2019
Payables And Accruals [Abstract]
Clinical expenses		$ 2,565	$ 2,497
Compensation, excluding taxes		2,379	3,525
Other	[1]	485	925
Total accrued expenses		$ 5,429	$ 6,947
[1]	1 Other consists of various accrued expenses, with no individual item accounting for more than 5% of current liabilities at June 30, 2020 and December 31, 2019.

Accrued Expenses - Schedule o_2

Accrued Expenses - Schedule of Accrued Expenses (Parenthetical) (Details)	Jun. 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)	Jul. 02, 2020USD ($)	Jul. 01, 2020USD ($)	Jun. 25, 2020USD ($)	Jun. 30, 2020USD ($)ft²
Lessor Lease Description [Line Items]
Lease term				12 months
Lease, description				(i) the 2014 Sublease and 2015 Sublease were extended from May 31, 2020 to August 2, 2021, and (ii) effective July 1, 2020, the leased premises under the 2015 Sublease would be expanded to include an additional 4,999 square ft of space, and (ii) effective July 1, 2020, the rent under the 2015 Sublease would increase from approximately $14,559 per month to $20,643 per month
Extension of sublease				May 31, 2020 to August 2, 2021
Sub lease expiration date				Aug. 2, 2021
Operating or finance lease			$ 0	$ 264,000
2015 Sub-Lease Agreement [Member]
Lessor Lease Description [Line Items]
Additional area of space | ft²				4,999
Increase in sublease rent	$ 20,643	$ 14,559
2021 Sub-Lease Agreement [Member]
Lessor Lease Description [Line Items]
Sublease rent			$ 3,721.50

Leases - Summary of Operating a

Leases - Summary of Operating and Financing Leases (Details) - USD ($) $ in Thousands	Jun. 25, 2020	Jun. 30, 2020
Lease cost
Operating lease cost		$ 339
Financing lease cost		23
Sublease income		(98)
Total	$ 0	264
Other information
Operating cash flows out from operating leases		(339)
Operating cash flows in from operating leases		98
Operating cash flows out from financing leases		(22)
U.S. [Member]
Lease cost
Operating lease cost		236
Financing lease cost		23
Total		259
Other information
Operating cash flows out from operating leases		(236)
Operating cash flows out from financing leases		$ (22)
Weighted average remaining lease term		8 months 12 days
Weighted average discount rate - operating leases		8.00%
Ireland [Member]
Lease cost
Operating lease cost		$ 103
Sublease income		(98)
Total		5
Other information
Operating cash flows out from operating leases		(103)
Operating cash flows in from operating leases		$ 98
Weighted average remaining lease term		1 year 1 month 6 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	Jun. 30, 2020USD ($)
Lessee Lease Description [Line Items]
Year ended December 31, 2020	$ 344
Year ended December 31, 2021	200
Total	544
Less present value discount	(19)
Operating lease liabilities included in the condensed consolidated balance sheet at June 30, 2020	525
U.S. [Member]
Lessee Lease Description [Line Items]
Year ended December 31, 2020	239
Year ended December 31, 2021	78
Total	317
Less present value discount	(9)
Operating lease liabilities included in the condensed consolidated balance sheet at June 30, 2020	308
Ireland [Member]
Lessee Lease Description [Line Items]
Year ended December 31, 2020	105
Year ended December 31, 2021	122
Total	227
Less present value discount	(10)
Operating lease liabilities included in the condensed consolidated balance sheet at June 30, 2020	$ 217

Outstanding Debt - Additional I

Outstanding Debt - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	Jun. 06, 2019	May 05, 2020
Debt Instrument [Line Items]
Debt instrument, warrants price per unit		$ 10
Series E Preferred Stock and Related Warrants [Member]
Debt Instrument [Line Items]
Debt instrument, warrants price per unit	$ 1,500
Senior Secured Promissory Notes [Member]
Debt Instrument [Line Items]
Debt instrument, principal face amount	$ 2
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

Outstanding Debt - Summary of V

Outstanding Debt - Summary of Various Notes Issued (Details) - USD ($)	Jun. 30, 2020	May 05, 2020
Debt Instrument [Line Items]
Conversion price		$ 10
Long Term Convertible Notes Payable [Member] | 8.0% July 2019 Notes [Member]
Debt Instrument [Line Items]
Interest rate	8.00%
Conversion price	$ 1,500
Principal	$ 2,000,000

Stockholders' Equity - Preferre

Stockholders' Equity - Preferred Stock Issuances - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	May 05, 2020	Jul. 11, 2019	Jun. 30, 2020	Jun. 30, 2020	Jun. 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		$ 0.01
Shares issued, par value per share			0.01	$ 0.01		$ 0.01
Conversion price	$ 10
Offering price				$ 19,378	$ 0
Warrant exercise price			$ 10	$ 10
Deemed dividend for triggering of warrant down round feature			$ (55)	$ (55)
Preferred stock, shares outstanding (in shares)			25,950	25,950		41,517
Number of warrants outstanding (in shares)			4,422,499	4,422,499		1,826,608
2019 Warrants [Member]
Stockholders Equity Note [Line Items]
Offering price	$ 22,000
Warrant exercise price	$ 10					$ 23.04
Deemed dividend for triggering of warrant down round feature	$ 55
Number of warrants outstanding (in shares)			1,800,000	1,800,000
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
Number of preferred stock and warrants issued upon conversion		11,500
Value of accounts payable exchanged		$ 100
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	$ 22,000
Excess of the fair value of the common stock	$ 12,000

Stockholders' Equity - Common S

Stockholders' Equity - Common Stock Issuances - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	May 05, 2020	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Stockholders Equity Note [Line Items]
Warrant exercise price		$ 10				$ 10
Net proceeds from Public Offering						$ 19,378	$ 0
Conversion price	$ 10
Conversion of Preferred stock into common stock						1,549,609
Exercise of pre-funded Series D Warrants (in shares)						6,000
Common stock shares issued						72,976
Remaining Warrants exercise price		10				$ 10
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	$ 22,000
Conversion of Preferred stock into common stock		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	$ 22,000
Remaining Warrants exercise price	$ 10							$ 23.04

Stockholders' Equity - Share-Ba

Stockholders' Equity - Share-Based Compensation - Additional Information (Details) $ in Millions	6 Months Ended
	Jun. 30, 2020USD ($)shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
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	502
2019 Equity Incentive Plan [Member] | Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares reserved for issuance	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	6 Months Ended	12 Months Ended
	Jun. 30, 2020	Dec. 31, 2019
Stockholders Equity Note [Abstract]
Number of Shares, Outstanding	1,640
Number of Shares, Outstanding	1,640	1,640
Number of Shares, Exercisable	1,640
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 7 months 6 days	9 years 1 month 6 days
Weighted Average Remaining Contractual Term (Years), Exercisable	8 years 7 months 6 days

Stockholders' Equity - Summar_2

Stockholders' Equity - Summary of Recognized Share-based Compensation Cost (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation (Income) expense	$ 606	$ 75	$ 660	$ 133
Selling, General and Administrative [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation (Income) expense	$ 606	58	655	106
Research and Development [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation (Income) expense		$ 17	$ 5	$ 27

Stockholders' Equity - Summar_3

Stockholders' Equity - Summary of Warrant Activity (Details) - $ / shares	6 Months Ended	12 Months Ended
	Jun. 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)	(6,000)
Warrants expired (in shares)	(9)
Outstanding, end of period (in shares)	4,422,499	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)	0.01
Warrants expired (in dollars per share)	7
Outstanding, end of period (in dollars per share)	$ 9.16	$ 23.04
Weighted average remaining life	4 years 8 months 12 days	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	6 Months Ended
	Jun. 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	2.082	2.075
Risk-free Interest Rates [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Warrants measurement input	0.014	0.017

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	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	6,794,514	8,329
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)	1,640	1,667
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)	4,051,499	6,004
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)		179
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)	2,595,087
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	480

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				6 Months Ended
		Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019
Earnings Per Share [Abstract]
Net loss		$ (4,275)	$ (7,861)	$ (5,959)	$ (7,894)	$ (12,136)	$ (13,853)
Deemed dividend for triggering of warrant down round feature		(55)				(55)
Net loss attributable to common stockholders		$ (4,330)		$ (5,959)		$ (12,191)	$ (13,853)
Weighted average shares outstanding - basic	[1],[2]	2,273,187		101,862		1,171,994	102,956
Weighted average shares outstanding - diluted	[1],[2]	2,273,187		101,862		1,171,994	102,956
Net loss per share - basic	[1],[2]	$ (1.90)		$ (58.50)		$ (10.40)	$ (134.55)
Net loss per share - diluted	[1],[2]	$ (1.90)		$ (58.50)		$ (10.40)	$ (134.55)
[1]	* reflects, one-for-seven hundred (1:700) reverse stock split effected on December 24, 2019.
[2]	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)	6 Months Ended
	Jun. 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		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Earnings Per Share [Abstract]
Weighted average shares issued	2,038,297	25,587	1,054,549	26,681
Weighted average pre-funded warrants	234,890	76,275	117,445	76,275
Weighted average shares outstanding	2,273,187	101,862	1,171,994	102,956

Taxes - Additional Information

Taxes - Additional Information (Details) $ in Millions	6 Months Ended
	Jun. 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 | $	$ 19.9

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) - Pending Litigation [Member] - USD ($) $ in Thousands	Jul. 27, 2020	Jun. 30, 2020
Loss Contingencies [Line Items]
Accrued unpaid compensation amounts		$ 1,140
Subsequent Event [Member]
Loss Contingencies [Line Items]
Unpaid compensation amounts claimed	$ 1,140

Subsequent Events - Additional

Subsequent Events - Additional Information (Details) - USD ($)	Jul. 31, 2020	Jul. 01, 2020	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2020
Subsequent Event [Line Items]
Convertible preferred stock, shares issued upon conversion					1,549,609
Warrant exercise price			$ 10		$ 10
95-97 Park Road office Queensbury, NY [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Payments to acquire real estate	$ 460,263
Common Stock [Member]
Subsequent Event [Line Items]
Convertible preferred stock, shares issued upon conversion			1,549,609	2,915
Warrant exercise price			$ 0.01		$ 0.01
Warrants issued to purchase of common stock					371,000
Common Stock [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Convertible preferred stock, shares issued upon conversion		372,500
Stock Warrant Exercises [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Warrant exercise price		$ 10
Warrants issued to purchase of common stock		41,827
Proceeds from warrant exercises		$ 418,270