Seelos Therapeutics (SEELQ) 10-Q 14 Aug 20 2020 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - $ / shares	6 Months Ended
	Jun. 30, 2020	Aug. 06, 2020
Document And Entity Information [Abstract]
Entity Registrant Name	Seelos Therapeutics, Inc.
Trading Symbol	SEEL
Entity Listing, Security Trading Currency	USD
Entity Listing, Par Value Per Share	$ 0.001
Title of 12(b) Security	Common Stock
Security Exchange Name	NASDAQ
Entity File Number	000-22245
Entity Incorporation, State or Country Code	NV
Interactive Data Current	Yes
Entity Central Index Key	0001017491
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q2
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Shell Company	false
Entity Emerging Growth Company	false
Is Entity's Reporting Status Current?	Yes
Entity Common Stock, Shares Outstanding		44,405,044

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Current assets
Cash	$ 5,854	$ 10,261
Prepaid expenses and other current assets	1,906	835
Total current assets	7,760	11,096
Total assets	7,760	11,096
Current liabilities
Accounts payable	630	796
Accrued expenses	1,229	1,919
License payables	1,125	7,100
Warrant liabilities, at fair value	722	963
Total current liabilities	3,706	10,778
License payables - long-term	200	325
Note payable	147	0
Total liabilities	4,053	11,103
Stockholders' equity (deficit)
Preferred stock, $.001 par value, 10,000,000 shares authorized, no shares issued or outstanding as of June 30, 2020 and December 31, 2019	0	0
Common stock, $.001 par value, 120,000,000 shares authorized, 44,405,044 and 27,028,533 issued and outstanding as of June 30, 2020 and December 31, 2019, respectively	44	27
Additional paid-in-capital	68,285	56,027
Accumulated deficit	(64,622)	(56,061)
Total stockholders' equity (deficit)	3,707	(7)
Total liabilities and stockholders' equity (deficit)	$ 7,760	$ 11,096

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2020	Dec. 31, 2019
Stockholders' equity
Preferred stock, par value (in usd per share)	$ 0.001	$ 0.001
Preferred stock, authorized (in shares)	10,000,000	10,000,000
Preferred stock, issued (in shares)	0	0
Preferred stock, outstanding (in shares)	0	0
Common stock, par value (in usd per share)	$ 0.001	$ 0.001
Common stock, authorized (in shares)	120,000,000	120,000,000
Common stock, issued (in shares)	44,405,044	27,028,533
Common stock, outstanding (in shares)	44,405,044	27,028,533

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Operating expense
Research and development	$ 1,444	$ 1,704	$ 5,137	$ 10,724
General and administrative	1,876	1,690	3,692	5,012
Total operating expense	3,320	3,394	8,829	15,736
Loss from operations	(3,320)	(3,394)	(8,829)	(15,736)
Other income (expense)
Interest income	7	39	34	64
Interest expense	(3)	(11)	(7)	(27)
Loss on warrant issuance	0	0	0	(5,020)
Change in fair value of warrant liabilities	(413)	1,503	241	(16,547)
Change in fair value of convertible notes payable	0	0	0	(109)
Total other income (expense)	(409)	1,531	268	(21,639)
Net loss	$ (3,729)	$ (1,863)	$ (8,561)	$ (37,375)
Net loss per share basic and diluted	$ (0.08)	$ (0.09)	$ (0.22)	$ (2.50)
Weighted average common shares outstanding for basic and diluted loss	44,157,059	20,944,617	39,136,126	14,971,064

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Changes in Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Total
Beginning balance (in shares) at Dec. 31, 2018	3,081,546
Beginning balance at Dec. 31, 2018	$ 3	$ 97	$ (4,806)	$ (4,706)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	$ 0	182	0	182
Issuance of common stock and warrants in a private offering, net of $16.5 million warrant liability, shares	1,829,407
Issuance of common stock and warrants in a private offering, net of $16.5 million warrant liability	$ 2	0	0	2
Effect of reverse merger, shares	947,218
Effect of reverse merger	$ 1	(300)	0	(299)
Warrants exercised for cash, shares	14,253,992
Warrants exercised for cash	$ 14	4,429	0	4,443
Issuance of common stock for license acquired, shares	992,782
Issuance of common stock for license acquired	$ 1	2,999	0	3,000
Reclass of warrant liabilites related to Series A warrants exercised for cash, shares	0
Reclass of warrant liabilites related to Series A warrants exercised for cash	$ 0	5,504	0	5,504
Reclass of Series B warrants from warrant liability to stockholders' equity, shares	0
Reclass of Series B warrants from warrant liability to stockholders' equity	$ 0	31,473	0	31,473
Issuance of common stock for conversion of debt and accrued interest, shares	172,284
Issuance of common stock for conversion of debt and accrued interest	$ 0	2,715	0	2,551
Net loss	$ 0	0	(37,375)	(37,375)
Ending balance (in shares) at Jun. 30, 2019	21,277,229
Ending balance at Jun. 30, 2019	$ 21	47,099	(42,181)	4,939
Beginning balance (in shares) at Mar. 31, 2019	20,213,762
Beginning balance at Mar. 31, 2019	$ 20	43,335	(40,318)	3,037
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	$ 0	144	0	144
Warrants exercised for cash, shares	1,063,467
Warrants exercised for cash	$ 1	1,772	0	1,773
Reclass of warrant liabilites related to Series A warrants exercised for cash, shares	0
Reclass of warrant liabilites related to Series A warrants exercised for cash	$ 0	1,848	0	1,848
Net loss	$ 0	0	(1,863)	(1,863)
Ending balance (in shares) at Jun. 30, 2019	21,277,229
Ending balance at Jun. 30, 2019	$ 21	47,099	(42,181)	4,939
Beginning balance (in shares) at Dec. 31, 2019	27,028,533
Beginning balance at Dec. 31, 2019	$ 27	56,027	(56,061)	(7)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	$ 0	652	0	652
Issuance of common stock for prepaid services, shares	400,000
Issuance of common stock for prepaid services	$ 0	330	0	330
Issuance of common stock for license acquired, shares	1,809,845
Issuance of common stock for license acquired	$ 2	2,441	0	2,443
Issuance of common stock, net of issuance costs, shares	15,166,666
Issuance of common stock, net of issuance costs	$ 15	8,835	0	8,850
Reclass of Series B warrants from warrant liability to stockholders' equity				0
Issuance of common stock for conversion of debt and accrued interest				0
Net loss	$ 0	0	(8,561)	(8,561)
Ending balance (in shares) at Jun. 30, 2020	44,405,044
Ending balance at Jun. 30, 2020	$ 44	68,285	(64,622)	3,707
Beginning balance (in shares) at Mar. 31, 2020	44,005,044
Beginning balance at Mar. 31, 2020	$ 44	67,614	(60,893)	6,765
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	$ 0	341	0	341
Issuance of common stock for prepaid services, shares	400,000
Issuance of common stock for prepaid services	$ 0	330	0	330
Net loss	$ 0	0	(3,729)	(3,729)
Ending balance (in shares) at Jun. 30, 2020	44,405,044
Ending balance at Jun. 30, 2020	$ 44	$ 68,285	$ (64,622)	$ 3,707

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Cash flows from operating activities:
Net loss	$ (8,561)	$ (37,375)
Adjustments to reconcile net loss to net cash used in operating activities
Stock-based compensation expense	652	182
Shares issued for services	124	0
Research and development expensed - license acquired	192	3,000
Change in fair value of convertible notes payable	0	109
Change in fair value of warrant liability	(241)	16,547
Loss on warrant issuance	0	5,020
Changes in operating assets and liabilities from continuing operations:
Prepaid expenses and other current assets	(864)	(402)
Accounts payable	(166)	(1,195)
Accrued expenses	(690)	2,825
Accrued interest	0	12
Licenses payable	(3,850)	0
Net cash used in operating activities	(13,404)	(11,277)
Cash flows from financing activities:
Proceeds from issuance of common stock and warrants in a private offering	0	16,520
Proceeds from issuance of common stock, pursuant to Securities Purchase Agreement, net of issuance costs	8,850	0
Proceeds from note payable	147	0
Proceeds from exercise of warrants	0	4,443
Net cash provided by financing activities	8,997	20,963
Cash flows from discontinued operations:
Net increase (decrease) in cash	(4,407)	9,686
Cash, beginning of period	10,261	42
Cash, end of period	5,854	9,728
Supplemental disclosure of cash flow information:
Cash paid for interest	8	11
Cash paid for income taxes	0	0
Non-cash investing and financing activities:
Issuance of common stock for license payable	2,443	0
Issuance of common stock for conversion of debt	0	2,551
Issuance of common stock for conversion of accrued interest	0	164
Effect of reverse merger	0	299
Reclass of warrant liabilities related to Series A warrants exercised for cash	0	5,504
Reclass of Series B warrants from warrant liability to stockholders' equity	$ 0	$ 31,473

1. Organization and Description

1. Organization and Description of Business	6 Months Ended
	Jun. 30, 2020
Accounting Policies [Abstract]
Organization and Description of Business	1. Organization and Description of Business Seelos Therapeutics, Inc. and its subsidiaries (the "Company") plan on developing its clinical and regulatory strategy with its internal research and development team with a view toward prioritizing market introduction as quickly as possible. The Company's lead programs are SLS-002 for the potential treatment of acute suicidal ideation and behavior in patients with major depressive disorder ("ASIB in MDD") and in post-traumatic stress disorder ("PTSD"), SLS-005 for the potential treatment of Sanfilippo syndrome and SLS-006 for the potential treatment of Parkinson's Disease ("PD"). Additionally, the Company is developing several preclinical programs, most of which have well-defined mechanisms of action, including: SLS-004 and SLS-007 for the potential treatment of PD, SLS-008 targeted at chronic inflammation in asthma and orphan indications such as pediatric esophagitis, SLS-010, in narcolepsy and related disorders and SLS-012, an injectable therapy for post-operative pain management. Liquidity The Company had generated limited revenues, incurred operating losses since inception, and expects to continue to incur significant operating losses for the foreseeable future and may never become profitable. As of June 30, 2020, the Company had $5.9 million in cash and an accumulated deficit of $64.6 million. The Company has historically funded its operations through the issuance of convertible notes (the "Notes") (see Note 6), the sale of common stock (see Note 3) and the sale of warrants (see Note 7). On March 16, 2020, the Company completed an underwritten public offering pursuant to which it sold 7,500,000 shares of its common stock at a price to the public of $0.60 per share. The net proceeds to the Company from this offering were approximately $4.0 million, after deducting underwriting discounts and commissions and other offering expenses payable by the Company. On February 13, 2020, the Company completed an underwritten public offering, pursuant to which it sold 6,666,667 shares of its common stock at a price to the public of $0.75 per share. On February 19, 2020, the Company sold an additional 999,999 shares of its common stock at a price to the public of $0.75 per share pursuant to the full exercise of the underwriters' option to cover over-allotments. The net proceeds to the Company from this offering were approximately $4.8 million, after deducting underwriting discounts and commissions and other offering expenses payable by the Company. Pursuant to the asset purchase agreement with Phoenixus AG f/k/a Vyera Pharmaceuticals, AG and Turing Pharmaceuticals AG ("Vyera"), as amended by an amendment thereto entered into on May 18, 2018 and an amendment thereto entered into on December 31, 2018 and as amended by an amendment thereto entered into on October 15, 2019 (as amended, the "Vyera Agreement"), the Company is required to make a cash payment to Vyera in the amount of $1.0 million in July 2020. Pursuant to the amended and restated license agreement with Stuart Weg, M.D., the Company is required to make a cash payment to Dr. Weg in the amount of $0.125 million in January 2021 and, if certain conditions are not met, make an additional cash payment of $0.2 million in January 2022. The Company believes that in order for it to meet its obligations arising from normal business operations for the next twelve months, the Company requires additional capital in the form of equity, debt or both. Without additional capital, the Company's ability to continue to operate will be limited. These financial statements do not include any adjustments to the recoverability and classification of recorded assets amounts and classification of liabilities that might be necessary should the Company not be able to continue as a going concern. The Company currently has an effective shelf registration statement on Form S-3 filed with the Securities and Exchange Commission (the "SEC"). As of June 30, 2020, the Company had approximately $80.2 million available under its Form S-3 shelf registration statement. Under current SEC regulations, in the event the aggregate market value of the Company's common stock held by non-affiliates ("public float"), is less than $75.0 million, the amount it can raise through primary public offerings of securities, including sales under the Equity Distribution Agreement with Piper Jaffray & Co. (the "Equity Distribution Agreement"), in any twelve-month period using shelf registration statements is limited to an aggregate of one-third of the Company's public float. SEC regulations permit the Company to use the highest closing sales price of the Company's common stock (or the average of the last bid and last ask prices of the Company's common stock) on any day within 60 days of sales under the shelf registration statement. As of August 6, 2020, the Company's public float was approximately $62.2 million based on 44.4 million shares of the Company's common stock outstanding at a price of $1.51 per share, which was the closing sale price of the Company's common stock on June 22, 2020. As the Company's public float was less than $75.0 million as of August 6, 2020, and the Company has sold securities pursuant to its previously effective shelf registration statement in the last 12 months, the Company's usage of any S-3 shelf registration statement is currently limited. The Company still maintains the ability to raise funds through other means, such as through the filing of a registration statement on Form S-1 or in private placements. The rules and regulations of the SEC or any other regulatory agencies may restrict the Company's ability to conduct certain types of financing activities, or may affect the timing of and amounts it can raise by undertaking such activities. The Company evaluated whether there are any conditions and events, considered in the aggregate, that raise substantial doubt about its ability to continue as a going concern within one year beyond the filing of this Quarterly Report on Form 10-Q. Based on such evaluation and the Company's current plans, which are subject to change, management believes that the Company's existing cash and cash equivalents as of June 30, 2020 are not sufficient to satisfy its operating cash needs for the year after the filing of this Quarterly Report on Form 10-Q. The accompanying unaudited condensed consolidated financial statements have been prepared assuming the Company will continue to operate as a going concern, which contemplates the realization of assets and settlement of liabilities in the normal course of business, and do not include any adjustments to reflect the possible future effects on the recoverability and classification of assets or the amounts and classifications of liabilities that may result from uncertainty related to its ability to continue as a going concern. The Company's future liquidity and capital funding requirements will depend on numerous factors, including: its ability to raise additional funds to finance its operations; its ability to maintain compliance with the listing requirements of the Nasdaq Capital Market; the outcome, costs and timing of clinical trial results for the Company's current or future product candidates; the extent and amount of any indemnification claims, including any made by Ferring International Center S.A. ("Ferring") under the asset purchase agreement with Ferring, entered into on March 8, 2017, pursuant to which the Company sold to Ferring its ex-U.S. assets and rights related to products in development, intended for the topical treatment of erectile dysfunction, which are known as Vitaros in certain countries outside of the United States; potential litigation expenses; the emergence and effect of competing or complementary products or product candidates; its ability to maintain, expand and defend the scope of its intellectual property portfolio, including the amount and timing of any payments the Company may be required to make, or that it may receive, in connection with the licensing, filing, prosecution, defense and enforcement of any patents or other intellectual property rights; its ability to retain its current employees and the need and ability to hire additional management and scientific and medical personnel; the terms and timing of any collaborative, licensing or other arrangements that it has or may establish; the trading price of its common stock; its ability to secure a development partner for its product candidate in the United States for the treatment of erectile dysfunction (the "CVR Product Candidate") in order to overcome deficiencies raised in the 2018 complete response letter issued by the U.S. Food and Drug Administration (the "FDA") related to the CVR Product Candidate; and its ability to increase the number of authorized shares outstanding to facilitate future financing events. The Company will need to raise substantial additional funds through one or more of the following: issuance of additional debt or equity and/or the completion of a licensing or other commercial transaction for one or more of the Company's product candidates. If the Company is unable to maintain sufficient financial resources, its business, financial condition and results of operations will be materially and adversely affected. This could affect future development and business activities and potential future clinical studies and/or other future ventures. There can be no assurance that the Company will be able to obtain the needed financing on acceptable terms or at all. Additionally, equity or convertible debt financings will likely have a dilutive effect on the holdings of the Company's existing stockholders.

2. Significant Accounting Polic

2. Significant Accounting Policies	6 Months Ended
	Jun. 30, 2020
Accounting Policies [Abstract]
Significant Accounting Policies	2. Significant Accounting Policies Basis of presentation The accompanying unaudited interim condensed consolidated financial statements should be read in conjunction with the audited financial statements and notes thereto as of and for the year ended December 31, 2019 included in the Company's Annual Report on Form 10-K ("Annual Report") filed with the SEC on March 17, 2020. The accompanying financial statements have been prepared by the Company in accordance with United States generally accepted accounting principles ("U.S. GAAP") for interim financial information and in accordance with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, certain information and footnote disclosures normally included in financial statements prepared in accordance with U.S. GAAP have been condensed or omitted. In the opinion of management, the accompanying unaudited condensed consolidated financial statements for the periods presented reflect all adjustments, consisting of only normal, recurring adjustments, necessary to fairly state the Company's financial position, results of operations and cash flows. The December 31, 2019 condensed consolidated balance sheet was derived from audited financial statements, but does not include all U.S. GAAP disclosures. The unaudited condensed consolidated financial statements for the interim periods are not necessarily indicative of results for the full year. The preparation of these unaudited condensed consolidated financial statements requires the Company to make estimates and judgments that affect the amounts reported in the financial statements and the accompanying notes. The Company's actual results may differ from these estimates under different assumptions or conditions. Use of estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. The most significant estimates in the Company's financial statements relate to the valuation of warrants, valuation of common stock and the valuation of stock options. These estimates and assumptions are based on current facts, historical experience and various other factors believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities and the recording of expenses that are not readily apparent from other sources. Actual results may differ materially and adversely from these estimates. To the extent there are material differences between the estimates and actual results, the Company's future results of operations will be affected. Fair Value Measurements The Company follows the accounting guidance in the Financial Accounting Standards Board ("FASB") Accounting Standards Codification ("ASC") Topic 820, Fair Value Measurements and Disclosures ("ASC 820"), for its fair value measurements of financial assets and liabilities measured at fair value on a recurring basis. Under this accounting guidance, fair value is defined as an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or a liability. The accounting guidance requires fair value measurements be classified and disclosed in one of the following three categories: Level 1: Quoted prices in active markets for identical assets or liabilities. Level 2: Observable inputs other than Level 1 prices, for similar assets or liabilities that are directly or indirectly observable in the marketplace. Level 3: Unobservable inputs which are supported by little or no market activity and that are financial instruments whose values are determined using pricing models, discounted cash flow methodologies, or similar techniques, as well as instruments for which the determination of fair value requires significant judgment or estimation. The fair value hierarchy also requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. Assets and liabilities measured at fair value are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. The Company's warrant liabilities and convertible notes were classified within Level 3 of the fair value hierarchy because their fair values were estimated by utilizing valuation models and significant unobservable inputs. The warrants and convertible notes were valued using a scenario-based discounted cash flow analysis. Two primary scenarios were considered and probability weighted to arrive at the valuation conclusion for each convertible note. The first scenario considers the value impact of conversion at the stated discount to the issue price in a qualified financing event, while the second scenario assumes the convertible notes are held to maturity. The following tables present information about the Company's financial assets and liabilities measured at fair value on a recurring basis and indicate the level of the fair value hierarchy utilized to determine such fair values (in thousands): Fair Value Measurements as of June 30, 2020 (Level 1) (Level 2) (Level 3) Total Assets Cash $ 5,854 $ - $ - $ 5,854 Liabilities Warrant liabilities, at fair value $ - $ - $ 722 $ 722 Fair Value Measurements as of December 31, 2019 (Level 1) (Level 2) (Level 3) Total Assets Cash $ 10,261 $ - $ - $ 10,261 Liabilities Warrant liabilities, at fair value $ - $ - $ 963 $ 963 There were no transfers between fair value measurement levels during the six months ended June 30, 2020. The Company's warrant liabilities were classified within Level 3 of the fair value hierarchy because their fair values were estimated by utilizing valuation models and significant unobservable inputs. The common stock warrant liabilities were recorded at fair value using the Black-Scholes option pricing model. The following assumptions were used in determining the fair value of the warrant liabilities valued using the Black-Scholes option pricing model as of June 30, 2020: Six Months Ended June 30, 2020 Risk-free interest rate 0.21% Volatility 113.50% Dividend yield - % Expected term 3.57 Weighted-average fair value $ 0.79 The following table is a reconciliation for the common stock warrant liabilities measured at fair value using Level 3 unobservable inputs (in thousands): Warrant liabilities Balance as of December 31, 2019 $ 963 Change in fair value measurement of warrant liability (241) Balance as of June 30, 2020 $ 722 Stock-based compensation The Company expenses stock-based compensation to employees, non-employees and board members over the requisite service period based on the estimated grant-date fair value of the awards and forfeitures rates. The Company accounts for forfeitures as they occur. Stock-based awards with graded-vesting schedules are recognized on a straight-line basis over the requisite service period for each separately vesting portion of the award. The Company estimates the fair value of stock option grants using the Black-Scholes option pricing model, and the assumptions used in calculating the fair value of stock-based awards represent management's best estimates and involve inherent uncertainties and the application of management's judgment. All stock-based compensation costs are recorded in general and administrative or research and development costs in the statements of operations based upon the underlying individual's role at the Company. Net Loss Per Share Basic loss per share is computed by dividing net loss applicable to common stockholders by the weighted average number of shares of common stock outstanding during each period. Diluted loss per share includes the effect, if any, from the potential exercise or conversion of securities, such as convertible debt, warrants and stock options that would result in the issuance of incremental shares of common stock. In computing the basic and diluted net loss per share applicable to common stockholders, the weighted average number of shares remains the same for both calculations due to the fact that when a net loss exists, dilutive shares are not included in the calculation as the impact is anti-dilutive. The following potentially dilutive securities outstanding for the three and six months ended June 30, 2020 and 2019 have been excluded from the computation of diluted weighted average shares outstanding, as they would be anti-dilutive (in thousands): Three and Six Months Ended June 30, 2020 2019 Outstanding stock options 4,925 411 Unvested restricted stock 67 - Outstanding warrants 3,584 1,425 8,576 1,836 Amounts in the table reflect the common stock equivalents of the noted instruments. Recent Accounting Pronouncements In August 2018, the FASB issued Accounting Standards Update ("ASU") No. 2018-13, Fair Value Measurement ("Topic 820"), Disclosure Framework-Changes to the Disclosure Requirements for Fair Value Measurement ("ASU 2018-13"). The amendments in this ASU require certain existing disclosure requirements in Topic 820 to be modified or removed, and certain new disclosure requirements to be added to the Topic. In addition, this ASU allows entities to exercise more discretion when considering fair value measurement disclosures. The Company adopted ASU 2018-13 effective January 1, 2020. The adoption of ASU 2018-13 did not have a material effect on the Company's financial statements.

3. Common Stock Offerings

3. Common Stock Offerings	6 Months Ended
	Jun. 30, 2020
Business Combinations [Abstract]
Common Stock Offerings	3. Common Stock Offerings Consulting Agreement On May 11, 2020, the Company entered into a consulting agreement (the "Consulting Agreement") with an advisory firm, pursuant to which the advisory firm agreed to provide the Company with certain management consulting, business and advisory services. The Company agreed to issue the advisory firm 300,000 unregistered shares of the Company's common stock, which shares were issued on May 11, 2020, plus $80 thousand in cash. On June 9, 2020, the Company and the advisory firm entered into an amendment to the Consulting Agreement (the "Amendment"). Pursuant to the Amendment, the advisory firm agreed to provide the Company with additional services and, in consideration, the Company agreed to issue the advisory firm an additional 200,000 unregistered shares of the Company's common stock (the "Additional Shares"), plus $20 thousand in cash. The Additional Shares were issued to the advisory firm on June 9, 2020 and are subject to certain vesting restrictions. Through June 30, 2020, the Company has recognized approximately $148,000 of consulting expense under this Consulting Agreement. On July 9, 2020, the Company cancelled the Consulting Agreement with an effective date of August 9, 2020 and will record the remaining expense of $283,000 during the three months ended September 30, 2020. The Company also cancelled the 100,000 shares that will not vest due to the cancellation of the Consulting Agreement. Public Offerings On March 16, 2020, the Company completed an underwritten public offering pursuant to which it sold 7,500,000 shares of its common stock at a price to the public of $0.60 per share. The net proceeds to the Company from this offering were approximately $4.0 million, after deducting underwriting discounts and commissions and other offering expenses payable by the Company. The shares were offered by the Company pursuant to the Company's shelf registration statement on Form S-3 filed with the SEC on November 2, 2017, as amended. On February 13, 2020, the Company completed an underwritten public offering, pursuant to which it sold 6,666,667 shares of its common stock at a price to the public of $0.75 per share. On February 19, 2020, the Company sold an additional 999,999 shares of its common stock at a price to the public of $0.75 per share pursuant to the full exercise of the underwriters' option to cover over-allotments. The net proceeds to the Company from this offering were approximately $4.8 million, after deducting underwriting discounts and commissions and other offering expenses payable by the Company. The shares were offered by the Company pursuant to the Company's registration statement on Form S-1 filed with the SEC on January 22, 2020, as amended. Stock Purchase Agreement with Vyera On January 2, 2020, the Company entered into a stock purchase agreement (the "Stock Purchase Agreement") with Vyera, pursuant to which the Company issued to Vyera 1,809,845 registered shares of the Company's common stock (the "Shares"). The Company entered into the Stock Purchase Agreement in accordance with the Vyera Agreement, as amended by the amendment entered into on October 15, 2019 (see Note 4). As partial consideration for the assets of Vyera, the Company agreed to issue the Shares pursuant to the Stock Purchase Agreement. The Shares were issued on January 2, 2020, pursuant to the Company's registration statement on Form S-3 (File No. 333-221285), as amended, which was declared effective by the SEC on December 7, 2017, a base prospectus dated December 7, 2017 and a prospectus supplement dated January 2, 2020. Securities Purchase Agreement On August 23, 2019, the Company entered into a Securities Purchase Agreement with certain institutional investors (the "Securities Purchase Agreement"), pursuant to which the Company issued and sold an aggregate of 4,475,000 shares of common stock in a registered direct offering, resulting in total gross proceeds of approximately $6.7 million, before deducting the placement agents' fees and other offering expenses. The shares were offered by the Company pursuant to the Company's shelf registration statement on Form S-3 filed with the SEC on November 2, 2017, as amended. The Company issued to the investors unregistered warrants to purchase up to 2,237,500 shares of common stock in a concurrent private placement (the "August 2019 Warrants"). The August 2019 Warrants have an exercise price of $1.78 per share of common stock, will be exercisable six months from the date of issuance and will expire four years following the date of issuance. The combined purchase price for one share and one warrant to purchase half of a share of common stock in the offerings was $1.50. The closing of the offerings occurred on August 27, 2019. The Company filed a registration statement on Form S-1 on November 21, 2019 to provide for the resale of the shares of common stock issuable upon the exercise of the August 2019 Warrants (the "Warrant Shares"), and is obligated to use commercially reasonable efforts to keep such registration statement effective from the date the warrants initially become exercisable until the earlier of (i) the date on which the Warrant Shares may be sold without registration pursuant to Rule 144 under the Securities Act during any 90 day period, and (ii) the date on which no purchaser owns any warrants or Warrant Shares. On August 23, 2019, the Company also entered into a Placement Agency Agreement (the "Placement Agency Agreement") with Roth Capital Partners, LLC ("Roth"), pursuant to which Roth served as the placement agent for the issuance and sale of the shares and the warrants, and the Company paid Roth an aggregate fee equal to 7.0% of the gross proceeds received by the Company in the offerings. The Placement Agency Agreement includes indemnity and other customary provisions for transactions of this nature. Equity Distribution Agreement On June 17, 2019, the Company entered into the Equity Distribution Agreement with Piper Jaffray & Co., as sales agent ("Piper Jaffray"), pursuant to which the Company may offer and sell, from time to time, through Piper Jaffray (the "Offering") up to $50,000,000 in shares. Any shares offered and sold in the offering will be issued pursuant to the Company's shelf registration statement on Form S-3 filed with the SEC on November 2, 2017, as amended on December 1, 2017 and declared effective on December 7, 2017, the prospectus supplement relating to the offering filed with the SEC on June 17, 2019 and any applicable additional prospectus supplements related to the offering that form a part of the registration statement. The number of shares eligible for sale under the Equity Distribution Agreement will be subject to the limitations of General Instruction I.B.6 of Form S-3. Subject to the terms and conditions of the Equity Distribution Agreement, Piper Jaffray will use its commercially reasonable efforts to sell the shares from time to time, based upon the Company's instructions. Under the Equity Distribution Agreement, Piper Jaffray may sell the shares by any method permitted by law deemed to be an "at the market offering" as defined in Rule 415 promulgated under the Securities Act of 1933, as amended (the "Securities Act"), including sales made directly on the Nasdaq Capital Market or on any other existing trading market for the shares. Subject to the Company's prior written consent, Piper Jaffray may also sell shares by any other method permitted by law including, but not limited to, privately negotiated transactions. The Company has no obligation to sell any of the shares, and may at any time suspend offers under the Equity Distribution Agreement. The Offering will terminate upon the earlier of (i) the sale of all of the shares, or (ii) the termination of the Equity Distribution Agreement according to its terms by either the Company or Piper Jaffray. The Company and Piper Jaffray may each terminate the Equity Distribution Agreement at any time by giving advance written notice to the other party as required by the Equity Distribution Agreement. Under the terms of the Equity Distribution Agreement, Piper Jaffray will be entitled to a commission at a fixed rate of 3.0% of the gross proceeds from each sale of shares under the Equity Distribution Agreement. The Company will also reimburse Piper Jaffray for certain expenses incurred in connection with the Equity Distribution Agreement, and agreed to provide indemnification and contribution to Piper Jaffray with respect to certain liabilities, including liabilities under the Securities Act and the Securities Exchange Act of 1934, as amended (the "Exchange Act"). During the year ended December 31, 2019, the Company sold 1,197,676 shares for net proceeds of approximately $2.6 million pursuant to the Equity Distribution Agreement. On August 23, 2019, the Company suspended its continuous offering under the Equity Distribution Agreement. Pre-Merger Financing On January 24, 2019, Apricus Biosciences, Inc., a Nevada corporation ("Apricus"), completed a business combination with Seelos Therapeutics, Inc., a Delaware corporation ("STI"), in accordance with the terms of the Agreement and Plan of Merger and Reorganization (the "Merger Agreement") entered into on July 30, 2018. Pursuant to the Merger Agreement, (i) a subsidiary of Apricus merged with and into STI, with STI (renamed as "Seelos Corporation") continuing as a wholly owned subsidiary of Apricus and the surviving corporation of the merger and (ii) Apricus was renamed as "Seelos Therapeutics, Inc." (the "Merger"). On January 24, 2019, STI and Apricus closed a private placement transaction with certain accredited investors (the "Investors"), whereby, among other things, STI issued to investors shares of STI's common stock immediately prior to the Merger in a private placement transaction (the "Financing"), pursuant to the Securities Purchase Agreement, made and entered into as of October 16, 2018, by and among STI, Apricus and the investors, as amended (the "Purchase Agreement"). Pursuant to the Purchase Agreement, STI (i) issued and sold to the Investors an aggregate of 2,374,672 shares of STIs common stock which converted pursuant to the exchange ratio in the Merger into the right to receive 1,829,407 shares of the Company's common stock and (ii) issued warrants representing the right to acquire 1,463,519 shares of common stock at a price per share of $4.15, subject to adjustment as provided therein (the "Series A Warrants"), currently adjusted to a price per share of $0.60 per share, and additional warrants initially representing the right to acquire no shares of common stock at a price per share of $0.001, subject to adjustment as provided therein (the "Series B Warrants" together with the Series A Warrants, the "Investor Warrants"), for aggregate gross proceeds of $18.0 million, or $16.5 million net of financing fees. The terms of the Investor Warrants included certain provisions that could result in adjustments to both the number of warrants issued and the exercise price of each warrant, which resulted in the warrants being classified as a liability upon issuance (see Note 7). The Investor Warrants were recorded at fair value of $21.5 million upon issuance and given the liability exceed the proceeds received, a loss of $5.0 million was recognized. On March 7, 2019, the Company entered into Amendment Agreements (collectively, the "Amendment Agreements") with each Investor amending: (i) the Purchase Agreement, (ii) the Series A Warrants, and (iii) the Series B Warrants. The Amendment Agreements, among other things, fixed the aggregate number of shares of common stock issued and issuable pursuant to the Series A Warrants at 3,629,023 (none of which were exercised as of March 7, 2019). The terms of the Investor Warrants continue to include certain provisions that could result in a future adjustment to the exercise price of the Investor Warrants and accordingly, they continue to be classified as a liability after the Amendment Agreements. At June 30, 2020, 0.9 million Series A Warrants remain unexercised. All Series B Warrants were exercised during the year ended December 31, 2019.

4. License Agreements

4. License Agreements	6 Months Ended
	Jun. 30, 2020
In-Licensing Agreement [Abstract]
License Agreements	4. License Agreements Acquisition of License from Ligand Pharmaceuticals Incorporated On September 21, 2016, the Company entered into a License Agreement (the "License Agreement") with Ligand Pharmaceuticals Incorporated ("Ligand"), Neurogen Corporation and CyDex Pharmaceuticals, Inc. (collectively, the "Licensors"), pursuant to which, among other things, the Licensors granted to the Company an exclusive, perpetual, irrevocable, worldwide, royalty-bearing, nontransferable right and license under (i) patents related to a product known as Aplindore, which is now known as SLS-006, acetaminophen (as it may have been or may be modified for use in a product to be administered by any method in any form including, without limitation injection and intravenously, the sole active pharmaceutical ingredient of which is acetaminophen), which is now known as SLS-012, an H3 receptor antagonist, which is now known as SLS-010, and either or both of the Licensors' two proprietary CRTh2 antagonists, which are now known collectively as SLS-008 (collectively, the "Licensed Products"), and (ii) copyrights, trade secrets, moral rights and all other intellectual and proprietary rights related thereto. The Company is obligated to use commercially reasonable efforts to (a) develop the Licensed Products, (b) obtain regulatory approval for the Licensed Products in the European Union (either in its entirety or including at least one of France, Germany or, if at the time the United Kingdom is a member of the European Union, the United Kingdom), the United Kingdom, if at the time the United Kingdom is not a member of the European Union, Japan or the People's Republic of China (each, a "Major Market") or the United States, and (c) commercialize the Licensed Products in each country where regulatory approval is obtained. The Company has the exclusive right and sole responsibility and decision-making authority to research and develop any Licensed Products and to conduct all clinical trials and non-clinical studies the Company believes appropriate to obtain regulatory approvals for commercialization of the Licensed Products. The Company also has the exclusive right and sole responsibility and decision-making authority to commercialize any of the Licensed Products. In connection with the closing of the Merger, the Company issued 801,253 shares of common stock to Ligand and recognized research and development expense totaling approximately $2.2 million during the three months ended March 31, 2019 for this License Agreement. The Company also agreed to pay to Ligand certain one-time, non-refundable regulatory milestone payments in connection with the Licensed Products, other than in connection with Aplindore for the indication of PD or Restless Leg Syndrome, consisting of (i) $750,000 upon submission of an application with the FDA or equivalent foreign body for a particular Licensed Product, (ii) $3.0 million upon FDA approval of an application for a particular Licensed Product, (iii) $1.125 million upon regulatory approval in a Major Market for a particular Licensed Product, and (iv) $1.125 million upon regulatory approval in a second Major Market for a particular Licensed Product. The Company also agreed to pay to Ligand certain one-time, non-refundable regulatory milestone payments in connection with the Licensed Products in connection with Aplindore for the indication of PD or Restless Leg Syndrome, consisting of (i) $100,000 upon submission of an application with the FDA or equivalent foreign body for such a particular Licensed Product, (ii) $350,000 upon FDA approval of an application for such a particular Licensed Product, (iii) $125,000 upon regulatory approval in a Major Market for such a particular Licensed Product, and (iv) $125,000 upon regulatory approval in a second Major Market for such a particular Licensed Product. The Company agreed to pay to Ligand certain one-time, non-refundable commercial milestone payments in connection with the Licensed Products, consisting of (i) $10.0 million upon the achievement of $1.0 billion of cumulative worldwide net sales of Licensed Products based upon Aplindore, (ii) $10.0 million upon the achievement of $1.0 billion of cumulative worldwide net sales of Licensed Products based upon an H3 receptor antagonist, (iii) $10.0 million upon the achievement of $1.0 billion of cumulative worldwide net sales of Licensed Products based upon acetaminophen (as it may have been or may be modified for use in a product to be administered by any method in any form including, without limitation injection and intravenously, the sole active pharmaceutical ingredient of which is acetaminophen), (iv) $10.0 million upon the achievement of $1.0 billion of cumulative worldwide net sales of Licensed Products based upon CRTh2 antagonists, (v) $20.0 million upon the achievement of $2.0 billion of cumulative worldwide net sales of Licensed Products based upon Aplindore, (vi) $20.0 million upon the achievement of $2.0 billion of cumulative worldwide net sales of Licensed Products based upon an H3 receptor antagonist, (vii) $20.0 million upon the achievement of $2.0 billion of cumulative worldwide net sales of Licensed Products based upon acetaminophen (as it may have been or may be modified for use in a product to be administered by any method in any form including, without limitation injection and intravenously, the sole active pharmaceutical ingredient of which is acetaminophen), and (viii) $20.0 million upon the achievement of $2.0 billion of cumulative worldwide net sales of Licensed Products based upon CRTh2 antagonists. The Company will also pay to Ligand middle single-digit royalties on aggregate annual net sales of Licensed Products other than in connection with Aplindore for the indication of PD or Restless Leg Syndrome in a country where such Licensed Products are covered under a licensed patent and a tiered incremental royalty in the upper single digit to lower double digit range on aggregate annual net sales of Licensed Products in connection with Aplindore for the indication of PD or Restless Leg Syndrome in a country where such Licensed Products are covered under a licensed patent. Additionally, the Company will pay to Ligand low single digit royalties on aggregate annual net sales of Licensed Products other than in connection with Aplindore for the indication of PD or Restless Leg Syndrome in a country where such Licensed Products are not covered under a licensed patent and a tiered incremental royalty in the lower single digit to middle single digit range on aggregate annual net sales of Licensed Products in connection with Aplindore for the indication of PD or Restless Leg Syndrome in a country where such Licensed Products are not covered under a licensed patent. The potential regulatory and commercial milestones are not yet considered probable, and no milestone payments have been accrued at June 30, 2020. Acquisition of Assets from Vyera On March 6, 2018, the Company entered into the Vyera Agreement with Vyera, pursuant to which the Company acquired the assets (the "Vyera Assets") and liabilities (the "Vyera Assumed Liabilities"), of Vyera related to TUR-002 (intranasal ketamine), which is now known as SLS-002. The Company is obligated to use commercially reasonable efforts to seek regulatory approval in the United States for and commercialize SLS-002. As consideration for the Vyera Assets, the Company paid to Vyera a non-refundable cash payment of $150,000 on May 21, 2018. As further consideration for the Vyera Assets, upon public announcement of the entry by Apricus and STI into the Merger Agreement, the Company paid to Vyera a non-refundable cash payment of $150,000. As further consideration for the Vyera Assets, the Company issued to Vyera 191,529 shares of common stock and paid Vyera a non-refundable cash payment of $1,000,000 on January 29, 2019. Pursuant to the amendment to the Asset Purchase Agreement entered into by the Company and Vyera on October 15, 2019, the Company issued Vyera 1,809,845 registered shares of the Company's common stock on January 2, 2020 and made cash payments to Vyera in the amounts of $750,000, $750,000and $1.0 million in October 2019, January 2020 and April 2020, respectively, and is obligated to pay $1.0 million in July 2020 (each, a "Payment Obligation"). In event the Company fails to timely meet a Payment Obligation (subject to a cure period), Vyera has the right to require that all of the Vyera Assets and the Vyera Assumed Liabilities be returned to Vyera. In the event that the Company sells, directly or indirectly, all or substantially all of the Vyera Assets to a third party, then the Company must pay Vyera an amount equal to 4% of the net proceeds actually received by the Company as an upfront payment in such sale. The Company agreed to pay to Vyera certain one-time, non-refundable milestone payments consisting of (i) $3.5 million upon dosing of the first patient in a Phase III clinical trial for SLS-002, (ii) $10.0 million upon approval by the FDA of a new drug application (an "NDA"), with respect to SLS-002, (iii) $5.0 million upon approval by the European Medicines Agency (the "EMA") of the foreign equivalent to an NDA with respect to SLS-002 in a Major Market, (iv) $2.5 million upon approval by the EMA of the foreign equivalent to an NDA with respect to SLS-002 in a second Major Market, (v) $5.0 million upon the achievement of $250.0 million in net sales of SLS-002, (vi) $10.0 million upon the achievement of $500.0 million in net sales of SLS-002, (vii) $15.0 million upon the achievement of $1.0 billion in net sales of SLS-002, (viii) $20.0 million upon the achievement of $1.5 billion in net sales of SLS-002, and (ix) $25.0 million upon the achievement of $2.0 billion in net sales of SLS-002. The Company will also pay to Vyera a royalty percentage in the mid-teens on aggregate annual net sales of SLS-002. The potential regulatory and commercial milestones are not yet considered probable, and no milestone payments have been accrued at June 30, 2020. Acquisition of License from Stuart Weg, MD On August 29, 2019, the Company entered into an amended and restated exclusive license agreement with Stuart Weg, M.D. (the "Weg License Agreement"), pursuant to which the Company was granted an exclusive worldwide license to certain intellectual property and regulatory materials related to SLS-002. Under the terms of the Weg License Agreement, the Company paid an upfront license fee of $75,000 upon execution of the agreement. The Company agreed to pay additional consideration to Dr. Weg as follows: (i) $0.1 million on January 2, 2020, (ii) $0.125 million on January 2, 2021, and (iii) in the event the FDA has not approved an NDA for a product containing ketamine in any dosage on or before December 31, 2021, $0.2 million on January 2, 2022. The Company paid the required $0.1 million on January 2, 2020. As further consideration, the Company agreed to pay Dr. Weg certain milestone payments consisting of (i) $0.1 million and shares of common stock equal to $0.15 million divided by the closing sales price of the Company's common stock upon the issuance of the first patent directed to an anxiety indication, (ii) $0.5 million after the locking of the database and unblinding the data for the statistically significant readout of a Phase III trial of an intranasal racemic ketamine product that has been conducted for the submission under an NDA or equivalent seeking regulatory approval in the United States, the United Kingdom, France, Germany, Italy, Spain, China or Japan, or seeking regulatory approval from the EMA in the EU, for such product (the "Milestone Product"), (iii) $3.0 million upon FDA approval of an NDA for the Milestone Product, (iv) $2.0 million upon regulatory approval by the EMA for the Milestone Product, (v) $1.5 million upon regulatory approval in Japan for the Milestone Product; provided, however, that the maximum amount to be paid by the Company under milestones (i)-(v) will be $6.6 million. The Company will also pay to Dr. Weg a royalty percentage equal to 2.25% on the sale of each product containing ketamine in any dosage. The potential regulatory and commercial milestones are not yet considered probable, and no milestone payments have been accrued at June 30, 2020. Acquisition of Assets from Bioblast Pharma Ltd. ("Bioblast") On February 15, 2019, the Company entered into an Asset Purchase Agreement (the "Bioblast Asset Purchase Agreement") with Bioblast. Pursuant to the Bioblast Asset Purchase Agreement, the Company acquired all of the assets of Bioblast relating to a therapeutic platform known as Trehalose (the "Bioblast Asset Purchase"). The Company paid to Bioblast $1.5 million in February 2019 and an additional $2.0 million in February 2020. Accordingly, the Company recognized a $3.5 million charge to research and development expense during the three months ended March 31, 2019. Under the terms of the Bioblast Asset Purchase Agreement, the Company agreed to pay additional consideration to Bioblast upon the achievement of certain milestones in the future, as follows: (i) within 15 days following the completion of the Company's first Phase II(b) clinical trial of Trehalose satisfying certain criteria, the Company will pay to Bioblast $8.5 million; and (ii) within 15 days following the approval for commercialization by the FDA or the Health Products and Food Branch of Health Canada of the first NDA or New Drug Submission, respectively, of Trehalose filed by the Company or its affiliates, the Company will pay to Bioblast $8.5 million. In addition, the Company agreed to pay Bioblast a cash royalty equal to 1% of the net sales of Trehalose. Under the terms of the Bioblast Asset Purchase, the Company assumed a collaborative agreement with TSF, a nonprofit medical research foundation founded by parents of children with Sanfilippo syndrome. TSF, upon approval by the FDA, planned to begin an open label, Phase II(b) clinical trial in up to 20 patients with Sanfilippo syndrome, which is now known under the study name SLS-005. The Company will provide the clinical supply of Trehalose. The terms of the Bioblast Asset Purchase Agreement entitle the Company access to all clinical data from this trial. On July 15, 2019, TSF and the Company amended the agreement whereby the Company agreed to assume responsibility for the Phase II(b)/III clinical trial and TSF agreed to provide a grant of up to $1.5 million towards the funding of the trial. The potential regulatory and commercial milestones are not yet considered probable, and no milestone payments have been accrued at June 30, 2020. Acquisition of License from The Regents of the University of California On March 7, 2019, the Company entered into an exclusive license agreement (the "UC Regents License Agreement") with The Regents of the University of California ("The UC Regents") pursuant to which the Company was granted an exclusive license to intellectual property owned by The UC Regents pertaining to a technology that was created by researchers at the University of California, Los Angeles (UCLA). Such technology relates to a family of rationally-designed peptide inhibitors that target the aggregation of alpha-synuclein (α-synuclein). The Company plans to study this initial approach in PD and will further evaluate the potential clinical approach in other disorders affecting the central nervous system ("CNS"). This program is now known as SLS-007. Upon entry into the UC Regents License Agreement, the Company paid to The UC Regents $0.1 million and recognized a $0.1 million charge to research and development expense during the three months ended March 31, 2019. Under the terms of the UC Regents License Agreement, the Company agreed to pay additional consideration upon the achievement of certain milestones in the future, as follows: (i) within 90 days following the completion of dosing of the first patient in a Phase I clinical trial, the Company will pay $50,000; (ii) within 90 days following dosing of the first patient in a Phase II clinical trial, the Company will pay $0.1 million; (iii) within 90 days following dosing of the first patient in a Phase III clinical trial, the Company will pay $0.3 million; (iv) within 90 days following the first commercial sales in the U.S., the Company will pay $1.0 million; (v) within 90 days following the first commercial sales in any European market, the Company will pay $1.0 million; and (vi) within 90 days following $250 million in cumulative worldwide net sales of a licensed product, the Company will pay $2.5 million. The Company is also obligated to pay a single digit royalty on sales of the product, if any. In addition, if the Company fails to achieve certain milestones within a specified timeframe, The UC Regents may terminate the agreement or reduce the Company's license to a nonexclusive license. The potential regulatory and commercial milestones are not yet considered probable, and no milestone payments have been accrued at June 30, 2020. Acquisition of License from Duke University On June 27, 2019, the Company entered into an exclusive license agreement (the "Duke License Agreement") with Duke University pursuant to which the Company was granted an exclusive license to a gene therapy program targeting the regulation of the SNCA gene, which encodes alpha-synuclein expression. The Company plans to study this initial approach in PD and will further evaluate the potential clinical approach in other disorders affecting the CNS. This program is now known as SLS-004. Upon entry into the Duke License Agreement, the Company paid to Duke University $0.1 million and recognized $0.1 million charge to research and development expense during the three months ended June 30, 2019. The Company agreed to pay additional consideration to Duke University upon the achievement of certain milestones in the future, as follows: (i) within 30 days following filing of an IND following the completion of preclinical studies including comprehensive validation of the platform, the Company will pay $0.1 million; (ii) within 30 days following dosing of the first patient in a Phase I clinical trial, the Company will pay $0.2 million; (iii) within 30 days following dosing of the first patient in a Phase II clinical trial, the Company will pay $0.5 million; (iv) within 30 days following dosing of the first patient in a Phase III clinical trial, the Company will pay $1.0 million; and (v) within 30 days following an NDA approval, the Company will pay $2.0 million. The Company is also obligated to pay a single digit royalty on sales of the product, if any. In addition, if the Company fails to achieve certain milestones within a specified timeframe, Duke University may terminate the agreement. The potential regulatory and commercial milestones are not yet considered probable, and no milestone payments have been accrued at June 30, 2020.

5. Business Combination

5. Business Combination	6 Months Ended
	Jun. 30, 2020
Business Combinations [Abstract]
Business Combination	5. Business Combination On January 24, 2019, Apricus completed the business combination with STI in accordance with the terms of the Merger Agreement. The Merger was accounted for as a reverse recapitalization under U.S. GAAP because the primary assets of Apricus were nominal at the close of the Merger. STI was determined to be the accounting acquirer based upon the terms of the Merger and other factors, including: (i) STI stockholders and other persons holding securities convertible, exercisable or exchangeable directly or indirectly for STI common stock owned the majority of the Company immediately following the effective time of the Merger, (ii) STI holds the majority (four of five) of board seats of the combined company, and (iii) STI's management holds all key positions in the management of the combined company. STI acquired no tangible assets and assumed no employees or operation from Apricus. Additionally, Apricus' intellectual property was considered to have no value. The remaining Apricus liabilities had a fair value of approximately $300 thousand. In connection with the Merger, STI entered into a Contingent Value Rights Agreement (the "CVR Agreement"). Pursuant to the CVR Agreement, Apricus stockholders received one contingent value right ("CVR") for each share of Apricus common stock held of record immediately prior to the closing of the Merger. Each CVR represents the right to receive payments based on Apricus' U.S. assets related to products in development, intended for the topical treatment of erectile dysfunction, which are known as Vitaros in certain countries outside of the United States (the "CVR Product Candidate"). In particular, CVR holders will be entitled to receive 90% of any cash payments (or the fair market value of any non-cash payments) exceeding $500,000 received, during a period of ten years from the closing of the Merger, based on the sale or out-licensing of Apricus' CVR Product Candidate intangible asset, including any milestone payments (the "Contingent Payments"), less reasonable transaction expenses. STI is entitled to retain the first $500,000 and 10% of any Contingent Payments. STI has agreed to pay up to $500,000 of such Contingent Payments that STI receives to a third party pursuant to a settlement agreement between STI and the third party. STI assigned no value to the CVR Product Candidate intangible asset as of June 30, 2020 or the CVR in the acquisition accounting.

6. Debt

6. Debt	6 Months Ended
	Jun. 30, 2020
Warrants Expiring March 2023, Tranche 2 [Member]
Debt	6. Debt Convertible Notes From May 2017 to October 2018, the Company entered into convertible note agreements with investors for the issuance of convertible notes (the "Notes"). The aggregate principal amount of the Notes was $2.3 million, and the Notes were due no later than April 30, 2019 with simple interest at the rate of 8% per annum. The Notes automatically converted, upon the issuance of preferred stock of the Company for capital-raising purposes occurring on or prior to the Notes' maturity date resulting in gross proceeds in excess of a specific amount, into shares of common stock of the Company by dividing the then-outstanding balance of each convertible note by 80% or 90%, depending on the terms for each note, of the lowest purchase price per share paid, or $9.70 to $10.91 per share, respectively, by another investor in the qualifying financing, which condition was satisfied by the Pre-Merger Financing. The Notes were carried at fair value. The Company did not recognize an adjustment relating to changes in the Notes fair value during the three months ended June 30, 2020 and 2019, respectively, and recognized an adjustment of $0 and $109 thousand during the six months ended June 30, 2020 and 2019, respectively. In connection with the closing of the Merger, the Notes plus unpaid interest were converted into 172,284 shares of common stock at a price of $9.70 or $10.91 per share. PPP Loan On May 4, 2020, the Company qualified for and received a loan pursuant to the Paycheck Protection Program, a program implemented by the U.S. Small Business Administration under the Coronavirus Aid, Relief, and Economic Security Act, from a qualified lender (the "PPP Lender"), for an aggregate principal amount of approximately $147,000 (the "PPP Loan"). The PPP Loan bears interest at a fixed rate of 1.0% per annum, with the first six months of interest deferred, has a term of two years, and is unsecured and guaranteed by the U.S. Small Business Administration. The principal amount of the PPP Loan is subject to forgiveness under the Paycheck Protection Program upon the Company's request to the extent that the PPP Loan proceeds are used to pay expenses permitted by the Paycheck Protection Program, including payroll costs, covered rent and mortgage obligations and covered utility payments incurred by the Company. The Company intends to apply for forgiveness of the PPP Loan with respect to these covered expenses. To the extent that all or part of the PPP Loan is not forgiven, the Company will be required to pay interest on the PPP Loan at a rate of 1.0% per annum, and commencing in October 2020, principal and interest payments will be required through the maturity date in May 2022. The terms of the PPP Loan provide for customary events of default including, among other things, payment defaults, breach of representations and warranties and insolvency events. The obligation to repay the PPP Loan may be accelerated upon the occurrence of an event of default.

7. Stockholders' Equity

7. Stockholders' Equity	6 Months Ended
	Jun. 30, 2020
Equity [Abstract]
Stockholders' Equity	7. Stockholders' Equity Preferred Stock The Company is authorized to issue 10.0 million shares of preferred stock, par value $0.001. No shares of preferred stock were outstanding as of June 30, 2020 or December 31, 2019. Common Stock The Company has authorized 120,000,000 shares of common stock as of June 30, 2020 and December 31, 2019. Each share of common stock is entitled to one voting right. Common stock owners are entitled to dividends when funds are legally available and declared by the Board of Directors. Warrants August 2019 Warrants The August 2019 Warrants are exercisable for 2,237,500 shares of common stock at an exercise price per share equal to $1.78. The August 2019 Warrants are exercisable beginning six months after the date of issuance and have a term of four years from the date of issuance. As of June 30, 2020, August 2019 Warrants exercisable for 2.2 million shares remain outstanding at an exercise price of $1.78 per share. Series A Warrants The Series A Warrants were initially exercisable for 1,463,519 shares of common stock at an exercise price per share equal to $4.15, which was adjusted several times pursuant to the terms thereof to 3,629,023 shares of common stock at an exercise price per share equal to $0.60 per share. The Series A Warrants were immediately exercisable upon issuance and have a term of five years from the date of issuance. During the three months ended June 30, 2020 and 2019, Series A Warrants for 0 and 1.1 million shares of common stock, respectively, were exercised for approximately $0 and $1.8 million, respectively. During the six months ended June 30, 2020 and 2019, Series A Warrants for 0 and 2.6 million shares of common stock, respectively, were exercised for approximately $0 and $4.4 million, respectively. As of June 30, 2020, Series A Warrants exercisable for 0.9 million shares of common stock remain outstanding at an exercise price of $0.60 per share. Series B Warrants The Series B Warrants were initially exercisable for no shares of common stock, which was adjusted to 7,951,090 shares of common stock on February 27, 2019 and which was further adjusted to 11,614,483 shares of common stock on March 7, 2019, in each case essentially due to trading at a lower price, pursuant to the terms thereof. The Series B Warrants had an exercise price of $0.001, were immediately exercisable upon issuance and provided for an expiration date of the day following the later to occur of (i) the Reservation Date (as defined therein), and (ii) the date on which the Series B Warrants have been exercised in full (without giving effect to any limitation on exercise contained therein) and no shares remain issuable thereunder. During the six months ended June 30, 2019, Series B Warrants for 11.6 million shares of common stock were exercised for approximately $11,614. As of December 31, 2019, no Series B Warrants remain outstanding and the Series B Warrants are therefore no longer subject to any further changes in warrants or exercise price. A summary of warrant activity during the six months ended June 30, 2020 is as follows (in thousands): Weighted- Weighted- Average Average Exercise Remaining Warrants Price Contractual Life Outstanding at December 31, 2019 3,584 $ 3.85 3.3 Issued - $ - - Exercised - $ - Cancelled - $ - Outstanding as of June 30, 2020 3,584 $ 3.77 3.3 Exercisable as of June 30, 2020 3,584 $ 3.77 3.3 The Series A Warrants and the Series B Warrants were each recognized as a liability at their fair value upon issuance. The warrant liability is remeasured to the then fair value prior to their exercise or at period end for warrants that are un-exercised and the gain or loss recognized in earnings during the period.

8. Stock-based Compensation

8. Stock-based Compensation	6 Months Ended
	Jun. 30, 2020
Warrants Expiring March 2023, Tranche 3 [Member]
Stock-based Compensation	8. Stock-based Compensation The Company has the Amended and Restated Apricus 2012 Stock Long Term Incentive Plan (the "2012 Plan"), which provides for the issuance of incentive and non-incentive stock options, restricted and unrestricted stock awards, stock unit awards and stock appreciation rights. Options and restricted stock units granted generally vest over a period of one to four years and have a maximum term of ten years from the date of grant. As of June 30, 2020, an aggregate of 8,038,582 shares of common stock were authorized under the Apricus 2012 Plan, of which 3.3 million shares of common stock were available for future grants. Upon completion of the Merger, the Company assumed the Seelos Therapeutics, Inc. 2016 Equity Incentive Plan (the "2016 Plan") and awards outstanding under the 2016 Plan became awards for common stock. Effective as of the Merger, no further awards may be issued under the 2016 Plan. On May 15, 2020, the Company's stockholders approved a 2020 Employee Stock Purchase Plan (the "ESPP"), whereby qualified employees are allowed to purchase limited amounts of the Company's common stock at the lesser of 85% of the market price at the beginning or end of the offering period. The stockholders have authorized an initial amount of 1.0 million shares for purchase by employees under the ESPP. The ESPP provides that an additional number of shares will automatically be added annually to the shares authorized for issuance under the ESPP on January 1st of each year commencing on January 1, 2021 and ending on (and including) January 1, 2030, which amount shall be equal to the lesser of (i) 1% of the number of shares of the Company's common stock issued and outstanding on the immediately preceding December 31, and (ii) a number of shares of Common Stock set by the Company's Board of Directors or the Compensation Committee of the Board of Directors (the "Compensation Committee") of the Company on or prior to each such January 1. On July 28, 2019, the Compensation Committee adopted the Seelos Therapeutics, Inc. 2019 Inducement Plan (the "2019 Inducement Plan"), which became effective on August 12, 2019. The 2019 Inducement Plan is substantially similar to the 2016 Plan. The 2019 Inducement Plan provides for the grant of equity-based awards in the form of stock options, stock appreciation rights, restricted stock, unrestricted stock, stock units, including restricted stock units, performance units and cash awards, solely to prospective employees of the Company or an affiliate of the Company provided that certain criteria are met. Awards under the 2019 Inducement Plan may only be granted to an individual, as a material inducement to such individual to enter into employment with the Company, who (i) has not previously been an employee or director of the Company or (ii) is rehired following a bona fide period of non-employment with the Company. The maximum number of shares available for grant under the 2019 Inducement Plan is 1,000,000 shares of the Company's common stock. The 2019 Inducement Plan is administered by the Compensation Committee and expires on August 12, 2029. Stock options During the six months ended June 30, 2020, the Company granted 1,134,339 incentive stock options and 3,190,556 non-qualified stock options to employees with a weighted average exercise price per share of $1.16 and a 10-year term, subject to the terms and conditions of the 2012 Plan above. The stock options are subject to time vesting requirements. The stock options granted to employees vest 25% on the first anniversary of the grant and monthly thereafter over the next three years. During the six months ended June 30, 2020, the Company also granted 104,000 non-qualified stock options to non-employee directors with a weighted average exercise price per share of $1.25 and a 10-year term, subject to the terms and conditions of the 2012 Plan above. These stock options granted to non-employee directors vest either monthly over the 12 months following the grant or over a three-year service period. The fair value of stock option grants are estimated on the date of grant using the Black-Scholes option-pricing model. The Company was historically a private company and lacked sufficient company-specific historical and implied volatility information. Therefore, it estimates its expected stock volatility based on the historical volatility of a publicly traded set of peer companies. Additionally, due to an insufficient history with respect to stock option activity and post-vesting cancellations, the expected term assumption for employee grants is based on a permitted simplified method, which is based on the vesting period and contractual term for each tranche of awards. The risk-free interest rate is determined by reference to the U.S. Treasury yield curve in effect for time periods approximately equal to the expected term of the award. Expected dividend yield is zero based on the fact that the Company has never paid cash dividends and does not expect to pay any cash dividends in the foreseeable future. During the six months ended June 30, 2020, no stock options were exercised or forfeited. The following assumptions were used in determining the fair value of the stock options granted during the six months ended June 30, 2020: Six Months Ended June 30, 2020 Risk-free interest rate 0.3%-1.7% Volatility 109%-117% Dividend yield - % Expected term 5-7 Weighted-average fair value $ 0.98 A summary of stock option activity during the six months ended June 30, 2020 is as follows (in thousands): Weighted- Weighted- Total Average Average Remaining Aggregate Stock Exercise Contractual Intrinsic Options Price Life (in years) Value Outstanding as of December 31, 2019 522 $ 9.18 9.0 $ 21 Granted 4,429 1.17 9.8 Exercised - - Cancelled (26) 1.96 - Outstanding as of June 30, 2020 4,925 $ 2.02 9.7 $ - Vested and expected to vest as of June 30, 2020 271 $ 15.70 7.5 $ - Exercisable as of June 30, 2020 271 $ 15.70 7.5 $ - The following table summarizes the total stock-based compensation expense resulting from share-based awards recorded in the Company's condensed consolidated statements of operations (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2020 2019 2020 2019 Research and development $ 62 $ 25 $ 130 $ 34 General and administrative 279 119 522 148 $ 341 $ 144 $ 652 $ 182

9. Related Party Transactions

9. Related Party Transactions	6 Months Ended
	Jun. 30, 2020
Related Party Transactions [Abstract]
Related Party Transactions	9. Related Party Transactions IRRAS AB ("IRRAS") is a commercial stage medical technology company of which a former director of the Company is also the President, Chief Executive Officer and director. In January 2018, the Company and IRRAS entered into a Sublease, pursuant to which the Company subleased to IRRAS excess capacity in its corporate headquarters. The sublease had a term of two years. On October 30, 2018, the Company and IRRAS entered into an amended and restated sublease, commencing January 1, 2019, pursuant to which the Company agreed to sublease to IRRAS the remainder of its San Diego, California location (the "IRRAS Restated Sublease"), which satisfied a closing condition related to the Merger. The IRRAS Restated Sublease had a term of one year and provides for aggregate payments due to the Company of approximately $0.4 million, which approximates fair value. This sublease expired in January 2020 and has not been renewed.

10. Commitments and Contingenci

10. Commitments and Contingencies	6 Months Ended
	Jun. 30, 2020
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	10. Commitments and Contingencies Leases In March 2019, the Company entered into a nine-month office space rental agreement for its headquarters in New York, New York expiring November 2019. In November 2019, the Company renewed this rental agreement for an additional twelve months. The rental agreement contains a base rent of approximately $9,000 per month. In December 2011, Apricus entered into a five-year lease agreement for its original headquarters in San Diego, California expiring December 31, 2016. In December 2015, Apricus amended the lease agreement to extend the term through January 31, 2020. The Company had an option to extend the lease an additional three years. The original lease term contained a base rent of approximately $24,000 per month with 3% annual escalations, plus a supplemental real estate tax and operating expense charge to be determined annually. The Company elected to not renew this lease in January 2020. For the three months ended June 30, 2020 and 2019, rent expense totaled approximately $30,000 and $10,000, respectively. For the six months ended June 30, 2020 and 2019, rent expense totaled approximately $74,000 and $28,000, respectively. Future minimum rental payments under operating leases as of June 30, 2020 are approximately $43,000 for 2020. Contractual Commitments The Company has entered into long-term agreements with certain manufacturers and suppliers that require it to make contractual payment to these organizations. The Company expects to enter into additional collaborative research, contract research, manufacturing, and supplier agreements in the future, which may require up-front payments and long-term commitments of cash. Litigation As of June 30, 2020, there was no material litigation against the Company.

Organization and Summary of Sig

Organization and Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2020
Accounting Policies [Abstract]
Basis of Presentation and Principles of Consolidation	Liquidity The Company had generated limited revenues, incurred operating losses since inception, and expects to continue to incur significant operating losses for the foreseeable future and may never become profitable. As of June 30, 2020, the Company had $5.9 million in cash and an accumulated deficit of $64.6 million. The Company has historically funded its operations through the issuance of convertible notes (the "Notes") (see Note 6), the sale of common stock (see Note 3) and the sale of warrants (see Note 7). On March 16, 2020, the Company completed an underwritten public offering pursuant to which it sold 7,500,000 shares of its common stock at a price to the public of $0.60 per share. The net proceeds to the Company from this offering were approximately $4.0 million, after deducting underwriting discounts and commissions and other offering expenses payable by the Company. On February 13, 2020, the Company completed an underwritten public offering, pursuant to which it sold 6,666,667 shares of its common stock at a price to the public of $0.75 per share. On February 19, 2020, the Company sold an additional 999,999 shares of its common stock at a price to the public of $0.75 per share pursuant to the full exercise of the underwriters' option to cover over-allotments. The net proceeds to the Company from this offering were approximately $4.8 million, after deducting underwriting discounts and commissions and other offering expenses payable by the Company. Pursuant to the asset purchase agreement with Phoenixus AG f/k/a Vyera Pharmaceuticals, AG and Turing Pharmaceuticals AG ("Vyera"), as amended by an amendment thereto entered into on May 18, 2018 and an amendment thereto entered into on December 31, 2018 and as amended by an amendment thereto entered into on October 15, 2019 (as amended, the "Vyera Agreement"), the Company is required to make a cash payment to Vyera in the amount of $1.0 million in July 2020. Pursuant to the amended and restated license agreement with Stuart Weg, M.D., the Company is required to make a cash payment to Dr. Weg in the amount of $0.125 million in January 2021 and, if certain conditions are not met, make an additional cash payment of $0.2 million in January 2022. The Company believes that in order for it to meet its obligations arising from normal business operations for the next twelve months, the Company requires additional capital in the form of equity, debt or both. Without additional capital, the Company's ability to continue to operate will be limited. These financial statements do not include any adjustments to the recoverability and classification of recorded assets amounts and classification of liabilities that might be necessary should the Company not be able to continue as a going concern. The Company currently has an effective shelf registration statement on Form S-3 filed with the Securities and Exchange Commission (the "SEC"). As of June 30, 2020, the Company had approximately $80.2 million available under its Form S-3 shelf registration statement. Under current SEC regulations, in the event the aggregate market value of the Company's common stock held by non-affiliates ("public float"), is less than $75.0 million, the amount it can raise through primary public offerings of securities, including sales under the Equity Distribution Agreement with Piper Jaffray & Co. (the "Equity Distribution Agreement"), in any twelve-month period using shelf registration statements is limited to an aggregate of one-third of the Company's public float. SEC regulations permit the Company to use the highest closing sales price of the Company's common stock (or the average of the last bid and last ask prices of the Company's common stock) on any day within 60 days of sales under the shelf registration statement. As of August 6, 2020, the Company's public float was approximately $62.2 million based on 44.4 million shares of the Company's common stock outstanding at a price of $1.51 per share, which was the closing sale price of the Company's common stock on June 22, 2020. As the Company's public float was less than $75.0 million as of August 6, 2020, and the Company has sold securities pursuant to its previously effective shelf registration statement in the last 12 months, the Company's usage of any S-3 shelf registration statement is currently limited. The Company still maintains the ability to raise funds through other means, such as through the filing of a registration statement on Form S-1 or in private placements. The rules and regulations of the SEC or any other regulatory agencies may restrict the Company's ability to conduct certain types of financing activities, or may affect the timing of and amounts it can raise by undertaking such activities. The Company evaluated whether there are any conditions and events, considered in the aggregate, that raise substantial doubt about its ability to continue as a going concern within one year beyond the filing of this Quarterly Report on Form 10-Q. Based on such evaluation and the Company's current plans, which are subject to change, management believes that the Company's existing cash and cash equivalents as of June 30, 2020 are not sufficient to satisfy its operating cash needs for the year after the filing of this Quarterly Report on Form 10-Q. The accompanying unaudited condensed consolidated financial statements have been prepared assuming the Company will continue to operate as a going concern, which contemplates the realization of assets and settlement of liabilities in the normal course of business, and do not include any adjustments to reflect the possible future effects on the recoverability and classification of assets or the amounts and classifications of liabilities that may result from uncertainty related to its ability to continue as a going concern. The Company's future liquidity and capital funding requirements will depend on numerous factors, including: its ability to raise additional funds to finance its operations; its ability to maintain compliance with the listing requirements of the Nasdaq Capital Market; the outcome, costs and timing of clinical trial results for the Company's current or future product candidates; the extent and amount of any indemnification claims, including any made by Ferring International Center S.A. ("Ferring") under the asset purchase agreement with Ferring, entered into on March 8, 2017, pursuant to which the Company sold to Ferring its ex-U.S. assets and rights related to products in development, intended for the topical treatment of erectile dysfunction, which are known as Vitaros in certain countries outside of the United States; potential litigation expenses; the emergence and effect of competing or complementary products or product candidates; its ability to maintain, expand and defend the scope of its intellectual property portfolio, including the amount and timing of any payments the Company may be required to make, or that it may receive, in connection with the licensing, filing, prosecution, defense and enforcement of any patents or other intellectual property rights; its ability to retain its current employees and the need and ability to hire additional management and scientific and medical personnel; the terms and timing of any collaborative, licensing or other arrangements that it has or may establish; the trading price of its common stock; its ability to secure a development partner for its product candidate in the United States for the treatment of erectile dysfunction (the "CVR Product Candidate") in order to overcome deficiencies raised in the 2018 complete response letter issued by the U.S. Food and Drug Administration (the "FDA") related to the CVR Product Candidate; and its ability to increase the number of authorized shares outstanding to facilitate future financing events. The Company will need to raise substantial additional funds through one or more of the following: issuance of additional debt or equity and/or the completion of a licensing or other commercial transaction for one or more of the Company's product candidates. If the Company is unable to maintain sufficient financial resources, its business, financial condition and results of operations will be materially and adversely affected. This could affect future development and business activities and potential future clinical studies and/or other future ventures. There can be no assurance that the Company will be able to obtain the needed financing on acceptable terms or at all. Additionally, equity or convertible debt financings will likely have a dilutive effect on the holdings of the Company's existing stockholders. The accompanying unaudited interim condensed consolidated financial statements should be read in conjunction with the audited financial statements and notes thereto as of and for the year ended December 31, 2019 included in the Company's Annual Report on Form 10-K ("Annual Report") filed with the SEC on March 17, 2020. The accompanying financial statements have been prepared by the Company in accordance with United States generally accepted accounting principles ("U.S. GAAP") for interim financial information and in accordance with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, certain information and footnote disclosures normally included in financial statements prepared in accordance with U.S. GAAP have been condensed or omitted. In the opinion of management, the accompanying unaudited condensed consolidated financial statements for the periods presented reflect all adjustments, consisting of only normal, recurring adjustments, necessary to fairly state the Company's financial position, results of operations and cash flows. The December 31, 2019 condensed consolidated balance sheet was derived from audited financial statements, but does not include all U.S. GAAP disclosures. The unaudited condensed consolidated financial statements for the interim periods are not necessarily indicative of results for the full year. The preparation of these unaudited condensed consolidated financial statements requires the Company to make estimates and judgments that affect the amounts reported in the financial statements and the accompanying notes. The Company's actual results may differ from these estimates under different assumptions or conditions.
Merger	The Merger was accounted for as a reverse recapitalization under U.S. GAAP because the primary assets of Apricus were nominal at the close of the Merger. STI was determined to be the accounting acquirer based upon the terms of the Merger and other factors, including: (i) STI stockholders and other persons holding securities convertible, exercisable or exchangeable directly or indirectly for STI common stock owned the majority of the Company immediately following the effective time of the Merger, (ii) STI holds the majority (four of five) of board seats of the combined company, and (iii) STI's management holds all key positions in the management of the combined company.
Use of Estimates	Use of estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. The most significant estimates in the Company's financial statements relate to the valuation of warrants, valuation of common stock and the valuation of stock options. These estimates and assumptions are based on current facts, historical experience and various other factors believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities and the recording of expenses that are not readily apparent from other sources. Actual results may differ materially and adversely from these estimates. To the extent there are material differences between the estimates and actual results, the Company's future results of operations will be affected.
Fair Value of Financial Instruments	Fair Value Measurements The Company follows the accounting guidance in the Financial Accounting Standards Board ("FASB") Accounting Standards Codification ("ASC") Topic 820, Fair Value Measurements and Disclosures ("ASC 820"), for its fair value measurements of financial assets and liabilities measured at fair value on a recurring basis. Under this accounting guidance, fair value is defined as an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or a liability. The accounting guidance requires fair value measurements be classified and disclosed in one of the following three categories: Level 1: Quoted prices in active markets for identical assets or liabilities. Level 2: Observable inputs other than Level 1 prices, for similar assets or liabilities that are directly or indirectly observable in the marketplace. Level 3: Unobservable inputs which are supported by little or no market activity and that are financial instruments whose values are determined using pricing models, discounted cash flow methodologies, or similar techniques, as well as instruments for which the determination of fair value requires significant judgment or estimation. The fair value hierarchy also requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. Assets and liabilities measured at fair value are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. The Company's warrant liabilities and convertible notes were classified within Level 3 of the fair value hierarchy because their fair values were estimated by utilizing valuation models and significant unobservable inputs. The warrants and convertible notes were valued using a scenario-based discounted cash flow analysis. Two primary scenarios were considered and probability weighted to arrive at the valuation conclusion for each convertible note. The first scenario considers the value impact of conversion at the stated discount to the issue price in a qualified financing event, while the second scenario assumes the convertible notes are held to maturity. The following tables present information about the Company's financial assets and liabilities measured at fair value on a recurring basis and indicate the level of the fair value hierarchy utilized to determine such fair values (in thousands): Fair Value Measurements as of June 30, 2020 (Level 1) (Level 2) (Level 3) Total Assets Cash $ 5,854 $ - $ - $ 5,854 Liabilities Warrant liabilities, at fair value $ - $ - $ 722 $ 722 Fair Value Measurements as of December 31, 2019 (Level 1) (Level 2) (Level 3) Total Assets Cash $ 10,261 $ - $ - $ 10,261 Liabilities Warrant liabilities, at fair value $ - $ - $ 963 $ 963 There were no transfers between fair value measurement levels during the six months ended June 30, 2020.
Warrant Liabilities	The Company's warrant liabilities were classified within Level 3 of the fair value hierarchy because their fair values were estimated by utilizing valuation models and significant unobservable inputs. The common stock warrant liabilities were recorded at fair value using the Black-Scholes option pricing model. The following assumptions were used in determining the fair value of the warrant liabilities valued using the Black-Scholes option pricing model as of June 30, 2020: Six Months Ended June 30, 2020 Risk-free interest rate 0.21% Volatility 113.50% Dividend yield - % Expected term 3.57 Weighted-average fair value $ 0.79 The following table is a reconciliation for the common stock warrant liabilities measured at fair value using Level 3 unobservable inputs (in thousands): Warrant liabilities Balance as of December 31, 2019 $ 963 Change in fair value measurement of warrant liability (241) Balance as of June 30, 2020 $ 722
Stock-Based Compensation	Stock-based compensation The Company expenses stock-based compensation to employees, non-employees and board members over the requisite service period based on the estimated grant-date fair value of the awards and forfeitures rates. The Company accounts for forfeitures as they occur. Stock-based awards with graded-vesting schedules are recognized on a straight-line basis over the requisite service period for each separately vesting portion of the award. The Company estimates the fair value of stock option grants using the Black-Scholes option pricing model, and the assumptions used in calculating the fair value of stock-based awards represent management's best estimates and involve inherent uncertainties and the application of management's judgment. All stock-based compensation costs are recorded in general and administrative or research and development costs in the statements of operations based upon the underlying individual's role at the Company.
Net Loss Per Share	Net Loss Per Share Basic loss per share is computed by dividing net loss applicable to common stockholders by the weighted average number of shares of common stock outstanding during each period. Diluted loss per share includes the effect, if any, from the potential exercise or conversion of securities, such as convertible debt, warrants and stock options that would result in the issuance of incremental shares of common stock. In computing the basic and diluted net loss per share applicable to common stockholders, the weighted average number of shares remains the same for both calculations due to the fact that when a net loss exists, dilutive shares are not included in the calculation as the impact is anti-dilutive. The following potentially dilutive securities outstanding for the three and six months ended June 30, 2020 and 2019 have been excluded from the computation of diluted weighted average shares outstanding, as they would be anti-dilutive (in thousands): Three and Six Months Ended June 30, 2020 2019 Outstanding stock options 4,925 411 Unvested restricted stock 167 - Outstanding warrants 3,584 1,425 8,676 1,836 Amounts in the table reflect the common stock equivalents of the noted instruments.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In August 2018, the FASB issued Accounting Standards Update ("ASU") No. 2018-13, Fair Value Measurement ("Topic 820"), Disclosure Framework-Changes to the Disclosure Requirements for Fair Value Measurement ("ASU 2018-13"). The amendments in this ASU require certain existing disclosure requirements in Topic 820 to be modified or removed, and certain new disclosure requirements to be added to the Topic. In addition, this ASU allows entities to exercise more discretion when considering fair value measurement disclosures. The Company adopted ASU 2018-13 effective January 1, 2020. The adoption of ASU 2018-13 did not have a material effect on the Company's financial statements.

Summary of Significant Accounti

Summary of Significant Accounting Policies (Tables)	6 Months Ended
	Jun. 30, 2020
Accounting Policies [Abstract]
Schedule of Fair Value Hierarchy Assets and Liabilities	The following tables present information about the Company's financial assets and liabilities measured at fair value on a recurring basis and indicate the level of the fair value hierarchy utilized to determine such fair values (in thousands): Fair Value Measurements as of June 30, 2020 (Level 1) (Level 2) (Level 3) Total Assets Cash $ 5,854 $ - $ - $ 5,854 Liabilities Warrant liabilities, at fair value $ - $ - $ 722 $ 722 Fair Value Measurements as of December 31, 2019 (Level 1) (Level 2) (Level 3) Total Assets Cash $ 10,261 $ - $ - $ 10,261 Liabilities Warrant liabilities, at fair value $ - $ - $ 963 $ 963 There were no transfers between fair value measurement levels during the six months ended June 30, 2020.
Summary of Fair Value Measurements Valuation Assumptions	The following assumptions were used in determining the fair value of the warrant liabilities valued using the Black-Scholes option pricing model as of June 30, 2020: Six Months Ended June 30, 2020 Risk-free interest rate 0.21% Volatility 113.50% Dividend yield - % Expected term 3.57 Weighted-average fair value $ 0.79
Schedule of Fair Value Level 3 Reconciliation	The following table is a reconciliation for the common stock warrant liabilities measured at fair value using Level 3 unobservable inputs (in thousands): Warrant liabilities Balance as of December 31, 2019 $ 963 Change in fair value measurement of warrant liability (241) Balance as of June 30, 2020 $ 722
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share	The following potentially dilutive securities outstanding for the three and six months ended June 30, 2020 and 2019 have been excluded from the computation of diluted weighted average shares outstanding, as they would be anti-dilutive (in thousands): Three and Six Months Ended June 30, 2020 2019 Outstanding stock options 4,925 411 Unvested restricted stock 67 - Outstanding warrants 3,584 1,425 8,576 1,836 Amounts in the table reflect the common stock equivalents of the noted instruments.

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	6 Months Ended
	Jun. 30, 2020
Equity [Abstract]
Summary of Warrant Activity	A summary of warrant activity during the six months ended June 30, 2020 is as follows (in thousands): Weighted- Weighted- Average Average Exercise Remaining Warrants Price Contractual Life Outstanding at December 31, 2019 3,584 $ 3.85 3.3 Issued - $ - - Exercised - $ - Cancelled - $ - Outstanding as of June 30, 2020 3,584 $ 3.77 3.3 Exercisable as of June 30, 2020 3,584 $ 3.77 3.3

Equity Compensation Plans (Tabl

Equity Compensation Plans (Tables)	6 Months Ended
	Jun. 30, 2020
Share-based Payment Arrangement [Abstract]
Schedule of Valuation Assumptions for Stock Options	The following assumptions were used in determining the fair value of the stock options granted during the six months ended June 30, 2020: Six Months Ended June 30, 2020 Risk-free interest rate 0.3%-1.7% Volatility 109%-117% Dividend yield - % Expected term 5-7 Weighted-average fair value $ 0.98
Summary of Stock Option Activity	A summary of stock option activity during the six months ended June 30, 2020 is as follows (in thousands): Weighted- Weighted- Total Average Average Remaining Aggregate Stock Exercise Contractual Intrinsic Options Price Life (in years) Value Outstanding as of December 31, 2019 522 $ 9.18 9.0 $ 21 Granted 4,429 1.17 9.8 Exercised - - Cancelled (26) 1.96 - Outstanding as of June 30, 2020 4,925 $ 2.02 9.7 $ - Vested and expected to vest as of June 30, 2020 271 $ 15.70 7.5 $ - Exercisable as of June 30, 2020 271 $ 15.70 7.5 $ -
Schedule of Stock-Based Compensation Expense	The following table summarizes the total stock-based compensation expense resulting from share-based awards recorded in the Company's condensed consolidated statements of operations (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2020 2019 2020 2019 Research and development $ 62 $ 25 $ 130 $ 34 General and administrative 279 119 522 148 $ 341 $ 144 $ 652 $ 182

Summary of Significant Accoun_2

Summary of Significant Accounting Policies - Fair Value Assets and Liabilities Recurring Basis (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash, at fair value	$ 5,854	$ 10,261	$ 9,728	$ 11,292	$ 42
Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash, at fair value	5,854	10,261
Level 1 | Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash, at fair value	5,854	10,261
Level 2 | Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash, at fair value	0	0
Level 3 | Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash, at fair value	0	0
Warrant | Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities, at fair value	722	963
Warrant | Level 1 | Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities, at fair value	0	0
Warrant | Level 2 | Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities, at fair value	0	0
Warrant | Level 3 | Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities, at fair value	$ 722	$ 963

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Fair Value Valuation Warrant Assumptions (Details)	6 Months Ended
	Jun. 30, 2020$ / shares
Risk-free interest rate, minimum	0.30%
Risk-free interest rate, maximum	1.70%
Dividend yield	0.00%
Expected term (in years)	5 years
Weighted average fair value (USD per share)	$ 0.98
Level 3 | Warrant
Risk Free Interest Rate	0.21%
Volatility	113.50%
Dividend yield	0.00%
Expected term (in years)	3 years 205 days
Weighted average fair value (USD per share)	$ 0.79

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Change in Level 3 Fair Value (Details) - Warrant - Level 3 $ in Thousands	6 Months Ended
	Jun. 30, 2020USD ($)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 963
Change in fair value measurement of warrant liability	(241)
Ending balance	$ 722

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Net Loss Per Share - Antidilutive (Details) - shares	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Anti-dilutive shares	8,576,000	1,836,000
Stock options
Anti-dilutive shares	4,925,000	411,000
Unvested Restricted Stock
Anti-dilutive shares	67,000	0
Warrant
Anti-dilutive shares	3,584,000	1,425,000

Common Stock Offerings (Narrati

Common Stock Offerings (Narrative) (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2020USD ($)
Cash received from stock sale	$ 8,850
Warrants outstanding	$ 900,000,000
Consulting 2020
Terms and provisions	On May 11, 2020, the Company entered into a consulting agreement (the "Consulting Agreement") with an advisory firm, pursuant to which the advisory firm agreed to provide the Company with certain management consulting, business and advisory services. The Company agreed to issue the advisory firm 300,000 unregistered shares of the Company's common stock, which shares were issued on May 11, 2020, plus $80 thousand in cash. On June 9, 2020, the Company and the advisory firm entered into an amendment to the Consulting Agreement (the "Amendment"). Pursuant to the Amendment, the advisory firm agreed to provide the Company with additional services and, in consideration, the Company agreed to issue the advisory firm an additional 200,000 unregistered shares of the Company's common stock (the "Additional Shares"), plus $20 thousand in cash. The Additional Shares were issued to the advisory firm on June 9, 2020 and are subject to certain vesting restrictions. Through June 30, 2020, the Company has recognized approximately $148,000 of consulting expense under this Consulting Agreement. On July 9, 2020, the Company cancelled the Consulting Agreement with an effective date of August 9, 2020 and will record the remaining expense of $283,000 during the three months ended September 30, 2020. The Company also cancelled the 100,000 shares that will not vest due to the cancellation of the Consulting Agreement.
Consulting expense	$ 148,000
March 16 2020
Terms and provisions	On March 16, 2020, the Company completed an underwritten public offering pursuant to which it sold 7,500,000 shares of its common stock at a price to the public of $0.60 per share. The net proceeds to the Company from this offering were approximately $4.0 million, after deducting underwriting discounts and commissions and other offering expenses payable by the Company. The shares were offered by the Company pursuant to the Company's shelf registration statement on Form S-3 filed with the SEC on November 2, 2017, as amended.
February 13 2020
Terms and provisions	On February 13, 2020, the Company completed an underwritten public offering, pursuant to which it sold 6,666,667 shares of its common stock at a price to the public of $0.75 per share. On February 19, 2020, the Company sold an additional 999,999 shares of its common stock at a price to the public of $0.75 per share pursuant to the full exercise of the underwriters' option to cover over-allotments. The net proceeds to the Company from this offering were approximately $4.8 million, after deducting underwriting discounts and commissions and other offering expenses payable by the Company. The shares were offered by the Company pursuant to the Company's registration statement on Form S-1 filed with the SEC on January 22, 2020, as amended.
January 2 2020
Terms and provisions	On January 2, 2020, the Company entered into a stock purchase agreement (the "Stock Purchase Agreement") with Vyera, pursuant to which the Company issued to Vyera 1,809,845 registered shares of the Company's common stock (the "Shares"). The Company entered into the Stock Purchase Agreement in accordance with the Vyera Agreement, as amended by the amendment entered into on October 15, 2019 (see Note 4). As partial consideration for the assets of Vyera, the Company agreed to issue the Shares pursuant to the Stock Purchase Agreement. The Shares were issued on January 2, 2020, pursuant to the Company's registration statement on Form S-3 (File No. 333-221285), as amended, which was declared effective by the SEC on December 7, 2017, a base prospectus dated December 7, 2017 and a prospectus supplement dated January 2, 2020.
August 23 2019
Terms and provisions	On August 23, 2019, the Company entered into a Securities Purchase Agreement with certain institutional investors (the "Securities Purchase Agreement"), pursuant to which the Company issued and sold an aggregate of 4,475,000 shares of common stock in a registered direct offering, resulting in total gross proceeds of approximately $6.7 million, before deducting the placement agents' fees and other offering expenses. The shares were offered by the Company pursuant to the Company's shelf registration statement on Form S-3 filed with the SEC on November 2, 2017, as amended. The Company issued to the investors unregistered warrants to purchase up to 2,237,500 shares of common stock in a concurrent private placement (the "August 2019 Warrants"). The August 2019 Warrants have an exercise price of $1.78 per share of common stock, will be exercisable six months from the date of issuance and will expire four years following the date of issuance. The combined purchase price for one share and one warrant to purchase half of a share of common stock in the offerings was $1.50. The closing of the offerings occurred on August 27, 2019. The Company filed a registration statement on Form S-1 on November 21, 2019 to provide for the resale of the shares of common stock issuable upon the exercise of the August 2019 Warrants (the "Warrant Shares"), and is obligated to use commercially reasonable efforts to keep such registration statement effective from the date the warrants initially become exercisable until the earlier of (i) the date on which the Warrant Shares may be sold without registration pursuant to Rule 144 under the Securities Act during any 90 day period, and (ii) the date on which no purchaser owns any warrants or Warrant Shares. On August 23, 2019, the Company also entered into a Placement Agency Agreement (the "Placement Agency Agreement") with Roth Capital Partners, LLC ("Roth"), pursuant to which Roth served as the placement agent for the issuance and sale of the shares and the warrants, and the Company paid Roth an aggregate fee equal to 7.0% of the gross proceeds received by the Company in the offerings. The Placement Agency Agreement includes indemnity and other customary provisions for transactions of this nature.
June 17 2019
Terms and provisions	On June 17, 2019, the Company entered into the Equity Distribution Agreement with Piper Jaffray & Co., as sales agent ("Piper Jaffray"), pursuant to which the Company may offer and sell, from time to time, through Piper Jaffray (the "Offering") up to $50,000,000 in shares. Any shares offered and sold in the offering will be issued pursuant to the Company's shelf registration statement on Form S-3 filed with the SEC on November 2, 2017, as amended on December 1, 2017 and declared effective on December 7, 2017, the prospectus supplement relating to the offering filed with the SEC on June 17, 2019 and any applicable additional prospectus supplements related to the offering that form a part of the registration statement. The number of shares eligible for sale under the Equity Distribution Agreement will be subject to the limitations of General Instruction I.B.6 of Form S-3. Subject to the terms and conditions of the Equity Distribution Agreement, Piper Jaffray will use its commercially reasonable efforts to sell the shares from time to time, based upon the Company's instructions. Under the Equity Distribution Agreement, Piper Jaffray may sell the shares by any method permitted by law deemed to be an "at the market offering" as defined in Rule 415 promulgated under the Securities Act of 1933, as amended (the "Securities Act"), including sales made directly on the Nasdaq Capital Market or on any other existing trading market for the shares. Subject to the Company's prior written consent, Piper Jaffray may also sell shares by any other method permitted by law including, but not limited to, privately negotiated transactions. The Company has no obligation to sell any of the shares, and may at any time suspend offers under the Equity Distribution Agreement. The Offering will terminate upon the earlier of (i) the sale of all of the shares, or (ii) the termination of the Equity Distribution Agreement according to its terms by either the Company or Piper Jaffray. The Company and Piper Jaffray may each terminate the Equity Distribution Agreement at any time by giving advance written notice to the other party as required by the Equity Distribution Agreement. Under the terms of the Equity Distribution Agreement, Piper Jaffray will be entitled to a commission at a fixed rate of 3.0% of the gross proceeds from each sale of shares under the Equity Distribution Agreement. The Company will also reimburse Piper Jaffray for certain expenses incurred in connection with the Equity Distribution Agreement, and agreed to provide indemnification and contribution to Piper Jaffray with respect to certain liabilities, including liabilities under the Securities Act and the Securities Exchange Act of 1934, as amended (the "Exchange Act"). During the year ended December 31, 2019, the Company sold 1,197,676 shares for net proceeds of approximately $2.6 million pursuant to the Equity Distribution Agreement. On August 23, 2019, the Company suspended its continuous offering under the Equity Distribution Agreement.
January 24 2019
Terms and provisions	On January 24, 2019, Apricus Biosciences, Inc., a Nevada corporation ("Apricus"), completed a business combination with Seelos Therapeutics, Inc., a Delaware corporation ("STI"), in accordance with the terms of the Agreement and Plan of Merger and Reorganization (the "Merger Agreement") entered into on July 30, 2018. Pursuant to the Merger Agreement, (i) a subsidiary of Apricus merged with and into STI, with STI (renamed as "Seelos Corporation") continuing as a wholly owned subsidiary of Apricus and the surviving corporation of the merger and (ii) Apricus was renamed as "Seelos Therapeutics, Inc." (the "Merger"). On January 24, 2019, STI and Apricus closed a private placement transaction with certain accredited investors (the "Investors"), whereby, among other things, STI issued to investors shares of STI's common stock immediately prior to the Merger in a private placement transaction (the "Financing"), pursuant to the Securities Purchase Agreement, made and entered into as of October 16, 2018, by and among STI, Apricus and the investors, as amended (the "Purchase Agreement"). Pursuant to the Purchase Agreement, STI (i) issued and sold to the Investors an aggregate of 2,374,672 shares of STIs common stock which converted pursuant to the exchange ratio in the Merger into the right to receive 1,829,407 shares of the Company's common stock and (ii) issued warrants representing the right to acquire 1,463,519 shares of common stock at a price per share of $4.15, subject to adjustment as provided therein (the "Series A Warrants"), currently adjusted to a price per share of $0.60 per share, and additional warrants initially representing the right to acquire no shares of common stock at a price per share of $0.001, subject to adjustment as provided therein (the "Series B Warrants" together with the Series A Warrants, the "Investor Warrants"), for aggregate gross proceeds of $18.0 million, or $16.5 million net of financing fees. The terms of the Investor Warrants included certain provisions that could result in adjustments to both the number of warrants issued and the exercise price of each warrant, which resulted in the warrants being classified as a liability upon issuance (see Note 7). The Investor Warrants were recorded at fair value of $21.5 million upon issuance and given the liability exceed the proceeds received, a loss of $5.0 million was recognized.
March 7 2019
Terms and provisions	On March 7, 2019, the Company entered into Amendment Agreements (collectively, the "Amendment Agreements") with each Investor amending: (i) the Purchase Agreement, (ii) the Series A Warrants, and (iii) the Series B Warrants. The Amendment Agreements, among other things, fixed the aggregate number of shares of common stock issued and issuable pursuant to the Series A Warrants at 3,629,023 (none of which were exercised as of March 7, 2019). The terms of the Investor Warrants continue to include certain provisions that could result in a future adjustment to the exercise price of the Investor Warrants and accordingly, they continue to be classified as a liability after the Amendment Agreements.

License Agreements (Narrative)

License Agreements (Narrative) (Details)	1 Months Ended
	Aug. 31, 2019	Jun. 30, 2019	Mar. 31, 2019	Feb. 28, 2019	Jan. 31, 2019	Mar. 31, 2018	Sep. 30, 2016
Ligand License
License Agreement, Separately Recognized Transactions, Description							On September 21, 2016, the Company entered into a License Agreement (the "License Agreement") with Ligand Pharmaceuticals Incorporated ("Ligand"), Neurogen Corporation and CyDex Pharmaceuticals, Inc. (collectively, the "Licensors"), pursuant to which, among other things, the Licensors granted to the Company an exclusive, perpetual, irrevocable, worldwide, royalty-bearing, nontransferable right and license under (i) patents related to a product known as Aplindore, which is now known as SLS-006, acetaminophen (as it may have been or may be modified for use in a product to be administered by any method in any form including, without limitation injection and intravenously, the sole active pharmaceutical ingredient of which is acetaminophen), which is now known as SLS-012, an H3 receptor antagonist, which is now known as SLS-010, and either or both of the Licensors' two proprietary CRTh2 antagonists, which are now known collectively as SLS-008 (collectively, the "Licensed Products"), and (ii) copyrights, trade secrets, moral rights and all other intellectual and proprietary rights related thereto. The Company is obligated to use commercially reasonable efforts to (a) develop the Licensed Products, (b) obtain regulatory approval for the Licensed Products in the European Union (either in its entirety or including at least one of France, Germany or, if at the time the United Kingdom is a member of the European Union, the United Kingdom), the United Kingdom, if at the time the United Kingdom is not a member of the European Union, Japan or the People's Republic of China (each, a "Major Market") or the United States, and (c) commercialize the Licensed Products in each country where regulatory approval is obtained. The Company has the exclusive right and sole responsibility and decision-making authority to research and develop any Licensed Products and to conduct all clinical trials and non-clinical studies the Company believes appropriate to obtain regulatory approvals for commercialization of the Licensed Products. The Company also has the exclusive right and sole responsibility and decision-making authority to commercialize any of the Licensed Products. In connection with the closing of the Merger, the Company issued 801,253 shares of common stock to Ligand and recognized research and development expense totaling approximately $2.2 million during the three months ended March 31, 2019 for this License Agreement. The Company also agreed to pay to Ligand certain one-time, non-refundable regulatory milestone payments in connection with the Licensed Products, other than in connection with Aplindore for the indication of PD or Restless Leg Syndrome, consisting of (i) $750,000 upon submission of an application with the FDA or equivalent foreign body for a particular Licensed Product, (ii) $3.0 million upon FDA approval of an application for a particular Licensed Product, (iii) $1.125 million upon regulatory approval in a Major Market for a particular Licensed Product, and (iv) $1.125 million upon regulatory approval in a second Major Market for a particular Licensed Product. The Company also agreed to pay to Ligand certain one-time, non-refundable regulatory milestone payments in connection with the Licensed Products in connection with Aplindore for the indication of PD or Restless Leg Syndrome, consisting of (i) $100,000 upon submission of an application with the FDA or equivalent foreign body for such a particular Licensed Product, (ii) $350,000 upon FDA approval of an application for such a particular Licensed Product, (iii) $125,000 upon regulatory approval in a Major Market for such a particular Licensed Product, and (iv) $125,000 upon regulatory approval in a second Major Market for such a particular Licensed Product. The Company agreed to pay to Ligand certain one-time, non-refundable commercial milestone payments in connection with the Licensed Products, consisting of (i) $10.0 million upon the achievement of $1.0 billion of cumulative worldwide net sales of Licensed Products based upon Aplindore, (ii) $10.0 million upon the achievement of $1.0 billion of cumulative worldwide net sales of Licensed Products based upon an H3 receptor antagonist, (iii) $10.0 million upon the achievement of $1.0 billion of cumulative worldwide net sales of Licensed Products based upon acetaminophen (as it may have been or may be modified for use in a product to be administered by any method in any form including, without limitation injection and intravenously, the sole active pharmaceutical ingredient of which is acetaminophen), (iv) $10.0 million upon the achievement of $1.0 billion of cumulative worldwide net sales of Licensed Products based upon CRTh2 antagonists, (v) $20.0 million upon the achievement of $2.0 billion of cumulative worldwide net sales of Licensed Products based upon Aplindore, (vi) $20.0 million upon the achievement of $2.0 billion of cumulative worldwide net sales of Licensed Products based upon an H3 receptor antagonist, (vii) $20.0 million upon the achievement of $2.0 billion of cumulative worldwide net sales of Licensed Products based upon acetaminophen (as it may have been or may be modified for use in a product to be administered by any method in any form including, without limitation injection and intravenously, the sole active pharmaceutical ingredient of which is acetaminophen), and (viii) $20.0 million upon the achievement of $2.0 billion of cumulative worldwide net sales of Licensed Products based upon CRTh2 antagonists. The Company will also pay to Ligand middle single-digit royalties on aggregate annual net sales of Licensed Products other than in connection with Aplindore for the indication of PD or Restless Leg Syndrome in a country where such Licensed Products are covered under a licensed patent and a tiered incremental royalty in the upper single digit to lower double digit range on aggregate annual net sales of Licensed Products in connection with Aplindore for the indication of PD or Restless Leg Syndrome in a country where such Licensed Products are covered under a licensed patent. Additionally, the Company will pay to Ligand low single digit royalties on aggregate annual net sales of Licensed Products other than in connection with Aplindore for the indication of PD or Restless Leg Syndrome in a country where such Licensed Products are not covered under a licensed patent and a tiered incremental royalty in the lower single digit to middle single digit range on aggregate annual net sales of Licensed Products in connection with Aplindore for the indication of PD or Restless Leg Syndrome in a country where such Licensed Products are not covered under a licensed patent. The potential regulatory and commercial milestones are not yet considered probable, and no milestone payments have been accrued at June 30, 2020.
Vyera Assets
License Agreement, Separately Recognized Transactions, Description						On March 6, 2018, the Company entered into the Vyera Agreement with Vyera, pursuant to which the Company acquired the assets (the "Vyera Assets") and liabilities (the "Vyera Assumed Liabilities"), of Vyera related to TUR-002 (intranasal ketamine), which is now known as SLS-002. The Company is obligated to use commercially reasonable efforts to seek regulatory approval in the United States for and commercialize SLS-002. As consideration for the Vyera Assets, the Company paid to Vyera a non-refundable cash payment of $150,000 on May 21, 2018. As further consideration for the Vyera Assets, upon public announcement of the entry by Apricus and STI into the Merger Agreement, the Company paid to Vyera a non-refundable cash payment of $150,000. As further consideration for the Vyera Assets, the Company issued to Vyera 191,529 shares of common stock and paid Vyera a non-refundable cash payment of $1,000,000 on January 29, 2019. Pursuant to the amendment to the Asset Purchase Agreement entered into by the Company and Vyera on October 15, 2019, the Company issued Vyera 1,809,845 registered shares of the Company's common stock on January 2, 2020 and made cash payments to Vyera in the amounts of $750,000, $750,000and $1.0 million in October 2019, January 2020 and April 2020, respectively, and is obligated to pay $1.0 million in July 2020 (each, a "Payment Obligation"). In event the Company fails to timely meet a Payment Obligation (subject to a cure period), Vyera has the right to require that all of the Vyera Assets and the Vyera Assumed Liabilities be returned to Vyera. In the event that the Company sells, directly or indirectly, all or substantially all of the Vyera Assets to a third party, then the Company must pay Vyera an amount equal to 4% of the net proceeds actually received by the Company as an upfront payment in such sale. The Company agreed to pay to Vyera certain one-time, non-refundable milestone payments consisting of (i) $3.5 million upon dosing of the first patient in a Phase III clinical trial for SLS-002, (ii) $10.0 million upon approval by the FDA of a new drug application (an "NDA"), with respect to SLS-002, (iii) $5.0 million upon approval by the European Medicines Agency (the "EMA") of the foreign equivalent to an NDA with respect to SLS-002 in a Major Market, (iv) $2.5 million upon approval by the EMA of the foreign equivalent to an NDA with respect to SLS-002 in a second Major Market, (v) $5.0 million upon the achievement of $250.0 million in net sales of SLS-002, (vi) $10.0 million upon the achievement of $500.0 million in net sales of SLS-002, (vii) $15.0 million upon the achievement of $1.0 billion in net sales of SLS-002, (viii) $20.0 million upon the achievement of $1.5 billion in net sales of SLS-002, and (ix) $25.0 million upon the achievement of $2.0 billion in net sales of SLS-002. The Company will also pay to Vyera a royalty percentage in the mid-teens on aggregate annual net sales of SLS-002. The potential regulatory and commercial milestones are not yet considered probable, and no milestone payments have been accrued at June 30, 2020.
Weg License Agreement
License Agreement, Separately Recognized Transactions, Description	On August 29, 2019, the Company entered into an amended and restated exclusive license agreement with Stuart Weg, M.D. (the "Weg License Agreement"), pursuant to which the Company was granted an exclusive worldwide license to certain intellectual property and regulatory materials related to SLS-002. Under the terms of the Weg License Agreement, the Company paid an upfront license fee of $75,000 upon execution of the agreement. The Company agreed to pay additional consideration to Dr. Weg as follows: (i) $0.1 million on January 2, 2020, (ii) $0.125 million on January 2, 2021, and (iii) in the event the FDA has not approved an NDA for a product containing ketamine in any dosage on or before December 31, 2021, $0.2 million on January 2, 2022. The Company paid the required $0.1 million on January 2, 2020. As further consideration, the Company agreed to pay Dr. Weg certain milestone payments consisting of (i) $0.1 million and shares of common stock equal to $0.15 million divided by the closing sales price of the Company's common stock upon the issuance of the first patent directed to an anxiety indication, (ii) $0.5 million after the locking of the database and unblinding the data for the statistically significant readout of a Phase III trial of an intranasal racemic ketamine product that has been conducted for the submission under an NDA or equivalent seeking regulatory approval in the United States, the United Kingdom, France, Germany, Italy, Spain, China or Japan, or seeking regulatory approval from the EMA in the EU, for such product (the "Milestone Product"), (iii) $3.0 million upon FDA approval of an NDA for the Milestone Product, (iv) $2.0 million upon regulatory approval by the EMA for the Milestone Product, (v) $1.5 million upon regulatory approval in Japan for the Milestone Product; provided, however, that the maximum amount to be paid by the Company under milestones (i)-(v) will be $6.6 million. The Company will also pay to Dr. Weg a royalty percentage equal to 2.25% on the sale of each product containing ketamine in any dosage. The potential regulatory and commercial milestones are not yet considered probable, and no milestone payments have been accrued at June 30, 2020.
Bioblast Assets
License Agreement, Separately Recognized Transactions, Description				On February 15, 2019, the Company entered into an Asset Purchase Agreement (the "Bioblast Asset Purchase Agreement") with Bioblast. Pursuant to the Bioblast Asset Purchase Agreement, the Company acquired all of the assets of Bioblast relating to a therapeutic platform known as Trehalose (the "Bioblast Asset Purchase"). The Company paid to Bioblast $1.5 million in February 2019 and an additional $2.0 million in February 2020. Accordingly, the Company recognized a $3.5 million charge to research and development expense during the three months ended March 31, 2019. Under the terms of the Bioblast Asset Purchase Agreement, the Company agreed to pay additional consideration to Bioblast upon the achievement of certain milestones in the future, as follows: (i) within 15 days following the completion of the Company's first Phase II(b) clinical trial of Trehalose satisfying certain criteria, the Company will pay to Bioblast $8.5 million; and (ii) within 15 days following the approval for commercialization by the FDA or the Health Products and Food Branch of Health Canada of the first NDA or New Drug Submission, respectively, of Trehalose filed by the Company or its affiliates, the Company will pay to Bioblast $8.5 million. In addition, the Company agreed to pay Bioblast a cash royalty equal to 1% of the net sales of Trehalose. Under the terms of the Bioblast Asset Purchase, the Company assumed a collaborative agreement with TSF, a nonprofit medical research foundation founded by parents of children with Sanfilippo syndrome. TSF, upon approval by the FDA, planned to begin an open label, Phase II(b) clinical trial in up to 20 patients with Sanfilippo syndrome, which is now known under the study name SLS-005. The Company will provide the clinical supply of Trehalose. The terms of the Bioblast Asset Purchase Agreement entitle the Company access to all clinical data from this trial. On July 15, 2019, TSF and the Company amended the agreement whereby the Company agreed to assume responsibility for the Phase II(b)/III clinical trial and TSF agreed to provide a grant of up to $1.5 million towards the funding of the trial. The potential regulatory and commercial milestones are not yet considered probable, and no milestone payments have been accrued at June 30, 2020.
UC Regents License Agreement
License Agreement, Separately Recognized Transactions, Description			On March 7, 2019, the Company entered into an exclusive license agreement (the "UC Regents License Agreement") with The Regents of the University of California ("The UC Regents") pursuant to which the Company was granted an exclusive license to intellectual property owned by The UC Regents pertaining to a technology that was created by researchers at the University of California, Los Angeles (UCLA). Such technology relates to a family of rationally-designed peptide inhibitors that target the aggregation of alpha-synuclein (α-synuclein). The Company plans to study this initial approach in PD and will further evaluate the potential clinical approach in other disorders affecting the central nervous system ("CNS"). This program is now known as SLS-007. Upon entry into the UC Regents License Agreement, the Company paid to The UC Regents $0.1 million and recognized a $0.1 million charge to research and development expense during the three months ended March 31, 2019. Under the terms of the UC Regents License Agreement, the Company agreed to pay additional consideration upon the achievement of certain milestones in the future, as follows: (i) within 90 days following the completion of dosing of the first patient in a Phase I clinical trial, the Company will pay $50,000; (ii) within 90 days following dosing of the first patient in a Phase II clinical trial, the Company will pay $0.1 million; (iii) within 90 days following dosing of the first patient in a Phase III clinical trial, the Company will pay $0.3 million; (iv) within 90 days following the first commercial sales in the U.S., the Company will pay $1.0 million; (v) within 90 days following the first commercial sales in any European market, the Company will pay $1.0 million; and (vi) within 90 days following $250 million in cumulative worldwide net sales of a licensed product, the Company will pay $2.5 million. The Company is also obligated to pay a single digit royalty on sales of the product, if any. In addition, if the Company fails to achieve certain milestones within a specified timeframe, The UC Regents may terminate the agreement or reduce the Company's license to a nonexclusive license. The potential regulatory and commercial milestones are not yet considered probable, and no milestone payments have been accrued at June 30, 2020.
Duke License Agreement
License Agreement, Separately Recognized Transactions, Description		On June 27, 2019, the Company entered into an exclusive license agreement (the "Duke License Agreement") with Duke University pursuant to which the Company was granted an exclusive license to a gene therapy program targeting the regulation of the SNCA gene, which encodes alpha-synuclein expression. The Company plans to study this initial approach in PD and will further evaluate the potential clinical approach in other disorders affecting the CNS. This program is now known as SLS-004. Upon entry into the Duke License Agreement, the Company paid to Duke University $0.1 million and recognized $0.1 million charge to research and development expense during the three months ended June 30, 2019. The Company agreed to pay additional consideration to Duke University upon the achievement of certain milestones in the future, as follows: (i) within 30 days following filing of an IND following the completion of preclinical studies including comprehensive validation of the platform, the Company will pay $0.1 million; (ii) within 30 days following dosing of the first patient in a Phase I clinical trial, the Company will pay $0.2 million; (iii) within 30 days following dosing of the first patient in a Phase II clinical trial, the Company will pay $0.5 million; (iv) within 30 days following dosing of the first patient in a Phase III clinical trial, the Company will pay $1.0 million; and (v) within 30 days following an NDA approval, the Company will pay $2.0 million. The Company is also obligated to pay a single digit royalty on sales of the product, if any. In addition, if the Company fails to achieve certain milestones within a specified timeframe, Duke University may terminate the agreement. The potential regulatory and commercial milestones are not yet considered probable, and no milestone payments have been accrued at June 30, 2020.
Apricus Assets
License Agreement, Separately Recognized Transactions, Description					On January 24, 2019, Apricus completed the business combination with STI in accordance with the terms of the Merger Agreement. The Merger was accounted for as a reverse recapitalization under U.S. GAAP because the primary assets of Apricus were nominal at the close of the Merger. STI was determined to be the accounting acquirer based upon the terms of the Merger and other factors, including: (i) STI stockholders and other persons holding securities convertible, exercisable or exchangeable directly or indirectly for STI common stock owned the majority of the Company immediately following the effective time of the Merger, (ii) STI holds the majority (four of five) of board seats of the combined company, and (iii) STI's management holds all key positions in the management of the combined company. STI acquired no tangible assets and assumed no employees or operation from Apricus. Additionally, Apricus' intellectual property was considered to have no value. The remaining Apricus liabilities had a fair value of approximately $300 thousand. In connection with the Merger, STI entered into a Contingent Value Rights Agreement (the "CVR Agreement"). Pursuant to the CVR Agreement, Apricus stockholders received one contingent value right ("CVR") for each share of Apricus common stock held of record immediately prior to the closing of the Merger. Each CVR represents the right to receive payments based on Apricus' U.S. assets related to products in development, intended for the topical treatment of erectile dysfunction, which are known as Vitaros in certain countries outside of the United States (the "CVR Product Candidate"). In particular, CVR holders will be entitled to receive 90% of any cash payments (or the fair market value of any non-cash payments) exceeding $500,000 received, during a period of ten years from the closing of the Merger, based on the sale or out-licensing of Apricus' CVR Product Candidate intangible asset, including any milestone payments (the "Contingent Payments"), less reasonable transaction expenses. STI is entitled to retain the first $500,000 and 10% of any Contingent Payments. STI has agreed to pay up to $500,000 of such Contingent Payments that STI receives to a third party pursuant to a settlement agreement between STI and the third party. STI assigned no value to the CVR Product Candidate intangible asset as of June 30, 2020 or the CVR in the acquisition accounting.

Business Combinations (Purchase

Business Combinations (Purchase Price Allocation and Narrative) (Details)	1 Months Ended
	Jan. 31, 2019
Apricus Assets
Business Combination, Separately Recognized Transactions, Description	On January 24, 2019, Apricus completed the business combination with STI in accordance with the terms of the Merger Agreement. The Merger was accounted for as a reverse recapitalization under U.S. GAAP because the primary assets of Apricus were nominal at the close of the Merger. STI was determined to be the accounting acquirer based upon the terms of the Merger and other factors, including: (i) STI stockholders and other persons holding securities convertible, exercisable or exchangeable directly or indirectly for STI common stock owned the majority of the Company immediately following the effective time of the Merger, (ii) STI holds the majority (four of five) of board seats of the combined company, and (iii) STI's management holds all key positions in the management of the combined company. STI acquired no tangible assets and assumed no employees or operation from Apricus. Additionally, Apricus' intellectual property was considered to have no value. The remaining Apricus liabilities had a fair value of approximately $300 thousand. In connection with the Merger, STI entered into a Contingent Value Rights Agreement (the "CVR Agreement"). Pursuant to the CVR Agreement, Apricus stockholders received one contingent value right ("CVR") for each share of Apricus common stock held of record immediately prior to the closing of the Merger. Each CVR represents the right to receive payments based on Apricus' U.S. assets related to products in development, intended for the topical treatment of erectile dysfunction, which are known as Vitaros in certain countries outside of the United States (the "CVR Product Candidate"). In particular, CVR holders will be entitled to receive 90% of any cash payments (or the fair market value of any non-cash payments) exceeding $500,000 received, during a period of ten years from the closing of the Merger, based on the sale or out-licensing of Apricus' CVR Product Candidate intangible asset, including any milestone payments (the "Contingent Payments"), less reasonable transaction expenses. STI is entitled to retain the first $500,000 and 10% of any Contingent Payments. STI has agreed to pay up to $500,000 of such Contingent Payments that STI receives to a third party pursuant to a settlement agreement between STI and the third party. STI assigned no value to the CVR Product Candidate intangible asset as of June 30, 2020 or the CVR in the acquisition accounting.

Debt (Narrative) (Details)

Debt (Narrative) (Details)	6 Months Ended
	Jun. 30, 2020USD ($)
Convertible Notes
Debt, Description	From May 2017 to October 2018, the Company entered into convertible note agreements with investors for the issuance of convertible notes (the "Notes"). The aggregate principal amount of the Notes was $2.3 million, and the Notes were due no later than April 30, 2019 with simple interest at the rate of 8% per annum. The Notes automatically converted, upon the issuance of preferred stock of the Company for capital-raising purposes occurring on or prior to the Notes' maturity date resulting in gross proceeds in excess of a specific amount, into shares of common stock of the Company by dividing the then-outstanding balance of each convertible note by 80% or 90%, depending on the terms for each note, of the lowest purchase price per share paid, or $9.70 to $10.91 per share, respectively, by another investor in the qualifying financing, which condition was satisfied by the Pre-Merger Financing. The Notes were carried at fair value. The Company did not recognize an adjustment relating to changes in the Notes fair value during the three months ended June 30, 2020 and 2019, respectively, and recognized an adjustment of $0 and $109 thousand during the six months ended June 30, 2020 and 2019, respectively. In connection with the closing of the Merger, the Notes plus unpaid interest were converted into 172,284 shares of common stock at a price of $9.70 or $10.91 per share.
PPP Loan
Debt, Description	On May 4, 2020, the Company qualified for and received a loan pursuant to the Paycheck Protection Program, a program implemented by the U.S. Small Business Administration under the Coronavirus Aid, Relief, and Economic Security Act, from a qualified lender (the "PPP Lender"), for an aggregate principal amount of approximately $147,000 (the "PPP Loan"). The PPP Loan bears interest at a fixed rate of 1.0% per annum, with the first six months of interest deferred, has a term of two years, and is unsecured and guaranteed by the U.S. Small Business Administration.
Long-term Debt, Maturities, Repayment Terms	The principal amount of the PPP Loan is subject to forgiveness under the Paycheck Protection Program upon the Company's request to the extent that the PPP Loan proceeds are used to pay expenses permitted by the Paycheck Protection Program, including payroll costs, covered rent and mortgage obligations and covered utility payments incurred by the Company. The Company intends to apply for forgiveness of the PPP Loan with respect to these covered expenses. To the extent that all or part of the PPP Loan is not forgiven, the Company will be required to pay interest on the PPP Loan at a rate of 1.0% per annum, and commencing in October 2020, principal and interest payments will be required through the maturity date in May 2022. The terms of the PPP Loan provide for customary events of default including, among other things, payment defaults, breach of representations and warranties and insolvency events. The obligation to repay the PPP Loan may be accelerated upon the occurrence of an event of default.
Long-term Debt, Percentage Bearing Fixed Interest, Percentage Rate	1.00%
Debt Instrument, Face Amount	$ 147,000

Stockholders' Equity - Warrant

Stockholders' Equity - Warrant Narrative (Details)	6 Months Ended
	Jun. 30, 2020$ / sharesshares
August 2019
Warrant Description	The August 2019 Warrants are exercisable for 2,237,500 shares of common stock at an exercise price per share equal to $1.78. The August 2019 Warrants are exercisable beginning six months after the date of issuance and have a term of four years from the date of issuance.
Warrant Outstanding | shares	2,237,500
Exercise Price of Warrant | $ / shares	$ 1.78
Series A
Warrant Description	The Series A Warrants were initially exercisable for 1,463,519 shares of common stock at an exercise price per share equal to $4.15, which was adjusted several times pursuant to the terms thereof to 3,629,023 shares of common stock at an exercise price per share equal to $0.60 per share. The Series A Warrants were immediately exercisable upon issuance and have a term of five years from the date of issuance. During the three months ended June 30, 2020 and 2019, Series A Warrants for 0 and 1.1 million shares of common stock, respectively, were exercised for approximately $0 and $1.8 million, respectively. During the six months ended June 30, 2020 and 2019, Series A Warrants for 0 and 2.6 million shares of common stock, respectively, were exercised for approximately $0 and $4.4 million, respectively. As of June 30, 2020, Series A Warrants exercisable for 0.9 million shares of common stock remain outstanding at an exercise price of $0.60 per share.
Warrant Outstanding | shares	900,000
Exercise Price of Warrant | $ / shares	$ 0.60
Series B
Warrant Description	The Series B Warrants were initially exercisable for no shares of common stock, which was adjusted to 7,951,090 shares of common stock on February 27, 2019 and which was further adjusted to 11,614,483 shares of common stock on March 7, 2019, in each case essentially due to trading at a lower price, pursuant to the terms thereof. The Series B Warrants had an exercise price of $0.001, were immediately exercisable upon issuance and provided for an expiration date of the day following the later to occur of (i) the Reservation Date (as defined therein), and (ii) the date on which the Series B Warrants have been exercised in full (without giving effect to any limitation on exercise contained therein) and no shares remain issuable thereunder. During the six months ended June 30, 2019, Series B Warrants for 11.6 million shares of common stock were exercised for approximately $11,614. As of December 31, 2019, no Series B Warrants remain outstanding and the Series B Warrants are therefore no longer subject to any further changes in warrants or exercise price.

Stockholders' Equity - Summary

Stockholders' Equity - Summary of Warrant Activity (Details)	6 Months Ended
	Jun. 30, 2020$ / sharesshares
Common Shares Issuable upon Exercise
Outstanding, beginning balance (in shares) | shares	3,584,000
Issued (in shares) | shares	0
Exercised (in shares) | shares	0
Cancelled (in shares) | shares	0
Outstanding, ending balance (in shares) | shares	3,584,000
Exercisable at balance sheet date (in shares) | shares	3,584,000
Weighted Average Exercise Price
Outstanding, beginning balance (in usd per share) | $ / shares	$ 3.85
Issued (in usd per share) | $ / shares	0
Exercised (in usd per share) | $ / shares	0
Cancelled (in usd per share) | $ / shares	0
Outstanding, ending balance (in usd per share) | $ / shares	3.77
Exercisable at balance sheet date (in dollars per share) | $ / shares	$ 3.77
Warrant Average Remaing Contractual Life
Warrants, outstanding, beginning	3 years 108 days
Warrants, outstanding, ending	3 years 180 days
Warrants exercisable	3 years 180 days

Equity Compensation Plans - Nar

Equity Compensation Plans - Narrative (Details)	6 Months Ended
	Jun. 30, 2020$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Description	The Company has the Amended and Restated Apricus 2012 Stock Long Term Incentive Plan (the "2012 Plan"), which provides for the issuance of incentive and non-incentive stock options, restricted and unrestricted stock awards, stock unit awards and stock appreciation rights. Options and restricted stock units granted generally vest over a period of one to four years and have a maximum term of ten years from the date of grant. As of June 30, 2020, an aggregate of 8,038,582 shares of common stock were authorized under the Apricus 2012 Plan, of which 3.3 million shares of common stock were available for future grants. Upon completion of the Merger, the Company assumed the Seelos Therapeutics, Inc. 2016 Equity Incentive Plan (the "2016 Plan") and awards outstanding under the 2016 Plan became awards for common stock. Effective as of the Merger, no further awards may be issued under the 2016 Plan. On May 15, 2020, the Company's stockholders approved a 2020 Employee Stock Purchase Plan (the "ESPP"), whereby qualified employees are allowed to purchase limited amounts of the Company's common stock at the lesser of 85% of the market price at the beginning or end of the offering period. The stockholders have authorized an initial amount of 1.0 million shares for purchase by employees under the ESPP. The ESPP provides that an additional number of shares will automatically be added annually to the shares authorized for issuance under the ESPP on January 1st of each year commencing on January 1, 2021 and ending on (and including) January 1, 2030, which amount shall be equal to the lesser of (i) 1% of the number of shares of the Company's common stock issued and outstanding on the immediately preceding December 31, and (ii) a number of shares of Common Stock set by the Company's Board of Directors or the Compensation Committee of the Board of Directors (the "Compensation Committee") of the Company on or prior to each such January 1. On July 28, 2019, the Compensation Committee adopted the Seelos Therapeutics, Inc. 2019 Inducement Plan (the "2019 Inducement Plan"), which became effective on August 12, 2019. The 2019 Inducement Plan is substantially similar to the 2016 Plan. The 2019 Inducement Plan provides for the grant of equity-based awards in the form of stock options, stock appreciation rights, restricted stock, unrestricted stock, stock units, including restricted stock units, performance units and cash awards, solely to prospective employees of the Company or an affiliate of the Company provided that certain criteria are met. Awards under the 2019 Inducement Plan may only be granted to an individual, as a material inducement to such individual to enter into employment with the Company, who (i) has not previously been an employee or director of the Company or (ii) is rehired following a bona fide period of non-employment with the Company. The maximum number of shares available for grant under the 2019 Inducement Plan is 1,000,000 shares of the Company's common stock. The 2019 Inducement Plan is administered by the Compensation Committee and expires on August 12, 2029.
Stock options exercisable (shares)	271,000
Stock options exercised (shares)	0
Weighted average exercise price per share | $ / shares	$ 1.17

Equity Compensation Plans - Ass

Equity Compensation Plans - Assumptions Of Black-Scholes Option Grant - Narrative (Details)	6 Months Ended
	Jun. 30, 2020$ / shares
Share-based Payment Arrangement [Abstract]
Risk-free interest rate, minimum	0.30%
Risk-free interest rate, maximum	1.70%
Volatility, minimum	109.00%
Volatility, maximum	117.00%
Dividend yield	0.00%
Expected term (in years)	5 years
Weighted average fair value	$ 0.98

Equity Compensation Plans - Sum

Equity Compensation Plans - Summary of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 30, 2020	Dec. 31, 2019
Number of Shares
Outstanding, beginning of period (shares)	522,000
Granted in Period (shares)	4,429,000
Exercised in Period (shares)	0
Cancelled (shares)	(26,000)
Outstanding, end of period (shares)	4,925,000
Vested and expected to vest, end of period (shares)	271,000
Exercisable, end of period (shares)	271,000
Weighted Average Exercise Price
Outstanding, beginning of period (USD per share)	$ 9.18
Granted in Period (USD per share)	1.17
Exercised in Period (USD per share)	0
Cancelled (USD per share)	1.96
Outstanding, end of period (USD per share)	2.02
Vested and expected to vest stock, end of period (USD per share)	15.70
Exercisable, end of period (USD per share)	$ 15.70
Weighted Average Remaining Contractual Life (in years)
Outstanding (in years)	9 years 252 days
Weighted Average Remaining Contractual Life (in years) of vested and expected to vest stock options	7 years 180 days
Weighted Average Remaining Contractual Life (in years) of exercisable stock options	7 years 180 days
Total Aggregate Intrinsic Value
Total aggregate intrinsic value shares outstanding	$ 0	$ 21
Total aggregate intrinsic value of vested or expected to vest stock options	0
Total aggregate intrinsic value of exercisable stock options	$ 0

Equity Compensation Plans - Sto

Equity Compensation Plans - Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 341	$ 144	$ 652	$ 182
Research and Development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	62	25	130	34
General and Administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 279	$ 119	$ 522	$ 148

Related Party Transactions - Na

Related Party Transactions - Narrative (Details)	6 Months Ended
	Jun. 30, 2020
Related Party Transactions [Abstract]
Sublease, term of contract (years)	1 year
Related Party Transaction, Description of Transaction	IRRAS AB ("IRRAS") is a commercial stage medical technology company of which a former director of the Company is also the President, Chief Executive Officer and director. In January 2018, the Company and IRRAS entered into a Sublease, pursuant to which the Company subleased to IRRAS excess capacity in its corporate headquarters. The sublease had a term of two years. On October 30, 2018, the Company and IRRAS entered into an amended and restated sublease, commencing January 1, 2019, pursuant to which the Company agreed to sublease to IRRAS the remainder of its San Diego, California location (the "IRRAS Restated Sublease"), which satisfied a closing condition related to the Merger. The IRRAS Restated Sublease had a term of one year and provides for aggregate payments due to the Company of approximately $0.4 million, which approximates fair value. This sublease expired in January 2020 and has not been renewed.

Commitments and contingencies -

Commitments and contingencies - Leases - Narrative (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Gain (Losses) on Extinguishment of Debt, Non Cash, Operating
Operating Lease, Description			In March 2019, the Company entered into a nine-month office space rental agreement for its headquarters in New York, New York expiring November 2019. In November 2019, the Company renewed this rental agreement for an additional twelve months. The rental agreement contains a base rent of approximately $9,000 per month. In December 2011, Apricus entered into a five-year lease agreement for its original headquarters in San Diego, California expiring December 31, 2016. In December 2015, Apricus amended the lease agreement to extend the term through January 31, 2020. The Company had an option to extend the lease an additional three years. The original lease term contained a base rent of approximately $24,000 per month with 3% annual escalations, plus a supplemental real estate tax and operating expense charge to be determined annually. The Company elected to not renew this lease in January 2020.
Rent expense	$ 30,000	$ 10,000	$ 74,000	$ 28,000

Commitments and Contingencies_2

Commitments and Contingencies - Future Minimum Rental Payments Under Operating Leases (Details) $ in Thousands	Jun. 30, 2020USD ($)
Future Minimum Rental Payments
2020	$ 43