Organization and Operations	12 Months Ended
Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Operations	1. Organization and Operations We are a commercial-stage pharmaceutical company pioneering novel cancer therapies and dedicated to the discovery, development and commercialization of first-in-class drugs directed against nuclear export for the treatment of cancer and other diseases. Our scientific expertise is based upon an understanding of the regulation of intracellular communication between the nucleus and the cytoplasm. We have discovered and are developing and commercializing novel, small molecule Selective Inhibitor of Nuclear Export compounds that inhibit the nuclear export protein exportin 1. Our primary focus is on marketing XPOVIO® (selinexor) in its currently approved indications, as well as developing and seeking the regulatory approval of selinexor as an oral agent targeting multiple high unmet cancer indications, including our core programs in endometrial cancer, multiple myeloma, and myelofibrosis. We were incorporated in Delaware on December 22, 2008 and have a principal place of business in Newton, Massachusetts. Our lead asset, XPOVIO, received its initial U.S. approval from the U.S. Food and Drug Administration (the “FDA”) in July 2019 and is currently approved and marketed for the following indications: (i) in combination with bortezomib and dexamethasone for the treatment of adult patients with multiple myeloma who have received at least one prior therapy; (ii) in combination with dexamethasone for the treatment of adult patients with relapsed or refractory multiple myeloma who have received at least four prior therapies and whose disease is refractory to at least two proteasome inhibitors, at least two immunomodulatory agents, and an anti-CD38 monoclonal antibody; and (iii) for the treatment of adult patients with relapsed or refractory diffuse large B-cell lymphoma (“DLBCL”), not otherwise specified, including DLBCL arising from follicular lymphoma, after at least two lines of systemic therapy. The commercialization of XPOVIO and NEXPOVIO (the brand name for selinexor in Europe and the United Kingdom) outside of the U.S. is managed by our partners in their respective territories. XPOVIO/NEXPOVIO has received regulatory approval in various indications in over 40 countries outside the U.S. and is commercially available in a growing number of countries as our partners continue to secure reimbursement approvals. To date, we have financed our operations primarily through a combination of product revenue sales, private placements of our common stock, proceeds from our initial public offering and follow-on offerings of our common stock, proceeds from the issuance of convertible debt, proceeds pursuant to a revenue interest financing agreement and subsequent amendment (deferred royalty obligation), proceeds from our “at the market offering” program and cash generated from our business development activities. As of December 31, 2023, we had an accumulated deficit of $1.5 billion. We expect that our cash, cash equivalents and investments at December 31, 2023 will be sufficient to fund our current operating plans and capital expenditure requirements for at least twelve months from the date of issuance of these financial statements.

Organization and Operations

12 Months Ended

Dec. 31, 2023

Organization, Consolidation and Presentation of Financial Statements [Abstract]

1. Organization and Operations

We are a commercial-stage pharmaceutical company pioneering novel cancer therapies and dedicated to the discovery, development and commercialization of first-in-class drugs directed against nuclear export for the treatment of cancer and other diseases. Our scientific expertise is based upon an understanding of the regulation of intracellular communication between the nucleus and the cytoplasm. We have discovered and are developing and commercializing novel, small molecule Selective Inhibitor of Nuclear Export compounds that inhibit the nuclear export protein exportin 1. Our primary focus is on marketing XPOVIO® (selinexor) in its currently approved indications, as well as developing and seeking the regulatory approval of selinexor as an oral agent targeting multiple high unmet cancer indications, including our core programs in endometrial cancer, multiple myeloma, and myelofibrosis. We were incorporated in Delaware on December 22, 2008 and have a principal place of business in Newton, Massachusetts.

Our lead asset, XPOVIO, received its initial U.S. approval from the U.S. Food and Drug Administration (the “FDA”) in July 2019 and is currently approved and marketed for the following indications: (i) in combination with bortezomib and dexamethasone for the treatment of adult patients with multiple myeloma who have received at least one prior therapy; (ii) in combination with dexamethasone for the treatment of adult patients with relapsed or refractory multiple myeloma who have received at least four prior therapies and whose disease is refractory to at least two proteasome inhibitors, at least two immunomodulatory agents, and an anti-CD38 monoclonal antibody; and (iii) for the treatment of adult patients with relapsed or refractory diffuse large B-cell lymphoma (“DLBCL”), not otherwise specified, including DLBCL arising from follicular lymphoma, after at least two lines of systemic therapy. The commercialization of XPOVIO and NEXPOVIO (the brand name for selinexor in Europe and the United Kingdom) outside of the U.S. is managed by our partners in their respective territories. XPOVIO/NEXPOVIO has received regulatory approval in various indications in over 40 countries outside the U.S. and is commercially available in a growing number of countries as our partners continue to secure reimbursement approvals.

To date, we have financed our operations primarily through a combination of product revenue sales, private placements of our common stock, proceeds from our initial public offering and follow-on offerings of our common stock, proceeds from the issuance of convertible debt, proceeds pursuant to a revenue interest financing agreement and subsequent amendment (deferred royalty obligation), proceeds from our “at the market offering” program and cash generated from our business development activities. As of December 31, 2023, we had an accumulated deficit of $1.5 billion. We expect that our cash, cash equivalents and investments at December 31, 2023 will be sufficient to fund our current operating plans and capital expenditure requirements for at least twelve months from the date of issuance of these financial statements.