Description of Business, Basis of Presentation, and Operating Segment	3 Months Ended
	Mar. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business, Basis of Presentation, and Operating Segment	Description of Business, Basis of Presentation, And Operating Segment (a) Description of Business Spectrum Pharmaceuticals, Inc. (“Spectrum”, the “Company”, “we”, “our”, or “us”) is a biopharmaceutical company, with a strategy of acquiring, developing, and commercializing novel and targeted oncology therapies. Our in-house development organization includes clinical development, regulatory, quality and data management. We have two drugs in late-stage development: •Eflapegrastim, a novel long-acting granulocyte colony-stimulating factor (“G-CSF”) for the treatment of chemotherapy-induced neutropenia. On August 6, 2021, the Company announced the receipt of a complete response letter (“CRL”), that cited manufacturing deficiencies related both to the drug substance and drug product manufacturers. The Company believes it has completed the remediation of these deficiencies and resubmitted the Biologics License Application (“BLA”) on March 11, 2022. On April 11, 2022, the Company announced that it had received notice that the BLA had been accepted and received a PDUFA date of September 9, 2022; and •Poziotinib, a novel irreversible tyrosine kinase inhibitor under investigation for non-small cell lung cancer (“NSCLC”) tumors with various mutations. On December 6, 2021, the Company announced it submitted its New Drug Application (“NDA”) for poziotinib to the FDA for use in patients with previously treated locally advanced or metastatic NSCLC with HER2 exon 20 insertion mutations. The NDA submission is based on the positive results of Cohort 2 from the ZENITH20 clinical trial, which assessed the safety and efficacy of poziotinib. The product has received Fast Track designation and there is currently no treatment specifically approved by the FDA for this indication. On February 11, 2022, the Company announced that it had received notice that the NDA had been accepted and received a PDUFA action date of November 24, 2022. Our business strategy is the development of late-stage assets through commercialization and the sourcing of additional assets that are synergistic with our existing portfolio (through purchase acquisitions, in-licensing transactions, or co-development and marketing arrangements). (b) Basis of Presentation Interim Financial Statements The interim financial data for the three months ended March 31, 2022 and 2021 is unaudited and is not necessarily indicative of our operating results for a full year. In the opinion of our management, the interim data includes normal and recurring adjustments necessary for a fair presentation of our financial results for the three months ended March 31, 2022 and 2021. Certain information and footnote disclosures normally included in annual financial statements prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) have been condensed or omitted pursuant to the Securities and Exchange Commission (“SEC”) rules and regulations relating to interim financial statements. Certain prior period amounts have been reclassified for consistency with the current year presentation. The accompanying Condensed Consolidated Financial Statements should be read in conjunction with our audited Consolidated Financial Statements and Notes thereto included within our Annual Report on Form 10-K for the fiscal year ended December 31, 2021 (filed with the SEC on March 17, 2022). Discontinued Operations - Sale of our Commercial Product Portfolio In March 2019, we completed the Commercial Product Portfolio Transaction (see Note 7) to Acrotech Biopharma LLC (“Acrotech”) (the “Commercial Product Portfolio Transaction”). In accordance with applicable GAAP (ASC 205-20, Presentation of Financial Statements), the revenue-deriving activities and allocable expenses of our sold commercial operation, connected to the Commercial Product Portfolio, are separately classified as “discontinued” for all periods presented within the accompanying Consolidated Statements of Operations. Principles of Consolidation The accompanying Condensed Consolidated Financial Statements have been prepared in accordance with GAAP and with the rules and regulations of the SEC. These financial statements include the financial position, results of operations, and cash flows of Spectrum and its subsidiaries, all of which are wholly-owned. All inter-company accounts and transactions among these legal entities have been eliminated in consolidation. Substantially all of the accumulated other comprehensive loss is comprised of foreign currency translation adjustments at March 31, 2022. Liquidity and Capital Resources The Company expects to incur future net losses as it continues to fund the advancement and commercialization of its product candidates. Based upon our current projections, including our intention to continue to place a disciplined focus on streamlining our business operations, we believe that our $89.2 million in aggregate cash, cash equivalents and marketable securities as of March 31, 2022, will be sufficient to fund our current and planned operations for at least the next twelve months. However, should our costs and expenses prove to be greater than we currently anticipate, or should we change our current business plan in a manner that increases or accelerates our anticipated costs and expenses, we may require additional liquidity earlier than expected. To the extent it becomes necessary to raise additional cash in the future, we will seek to raise it through the public or private sale of debt or equity securities, out-licensing arrangements, funding from joint-venture or strategic partners, debt financing or short-term loans, or a combination of the foregoing. However, we do not currently have any binding commitments for additional financing. Accordingly, we cannot provide any assurance that we will be able to obtain this additional liquidity on terms favorable to us or our current stockholders, or at all. Our liquidity and our ability to fund our capital requirements going forward are dependent, in part, on market and economic factors that are beyond our control. The Company may never achieve profitability or generate positive cash flows, and unless and until it does, the Company will continue to need to raise additional capital. (c) Operating Segment We operate one reportable operating segment that is focused exclusively on developing (and eventually marketing) oncology and hematology drug products. For the three months ended March 31, 2022 and 2021, all of our operating costs and expenses were solely attributable to these activities (and as applicable, classified as “discontinued” within the accompanying Condensed Consolidated Statements of Operations).