Karyopharm Therapeutics (KPTI) 10-Q 5 Nov 24 2024 Q3 Quarterly report Financial data

Cover Page

Cover Page - shares	9 Months Ended
	Sep. 30, 2024	Oct. 31, 2024
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2024
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q3
Current Fiscal Year End Date	--12-31
Entity Registrant Name	Karyopharm Therapeutics Inc.
Trading Symbol	KPTI
Entity Central Index Key	0001503802
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		125,314,506
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity File Number	001-36167
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	26-3931704
Entity Address, Address Line One	85 Wells Avenue, 2nd Floor
Entity Address, City or Town	Newton
Entity Address, Postal Zip Code	02459
City Area Code	617
Local Phone Number	658-0600
Document Quarterly Report	true
Document Transition Report	false
Entity Shell Company	false
Entity Address, State or Province	MA
Title of 12(b) Security	Common Stock
Security Exchange Name	NASDAQ

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (unaudited) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 72,828	$ 52,231
Investments	60,698	139,212
Accounts receivable, net	31,778	26,962
Inventory	4,672	3,043
Prepaid expenses and other current assets	14,746	11,813
Restricted cash	33	660
Total current assets	184,755	233,921
Property and equipment, net	495	606
Operating lease right-of-use assets	2,586	4,276
Restricted cash	306	301
Other assets	1,334	1,334
Total assets	189,476	240,438
Current liabilities:
Accounts payable	5,783	3,123
Accrued expenses	50,105	61,394
Operating lease liabilities	3,668	3,308
Other current liabilities	1,937	1,654
Total current liabilities	61,493	69,479
Convertible senior notes due 2025	24,392	170,919
Convertible senior notes due 2029	72,091	0
Senior secured term loan	94,109	0
Deferred royalty obligation	73,499	132,479
Common stock warrants	17,355	0
Operating lease liabilities, net of current portion	0	2,789
Other liabilities	6,184	978
Total liabilities	349,123	376,644
Stockholders' deficit
Preferred stock, $0.0001 par value; 5,000 shares authorized; none issued and outstanding	0	0
Common stock, $0.0001 par value; 400,000 shares authorized; 125,303 and 114,915 shares issued and outstanding as of September 30, 2024 and December 31, 2023, respectively	13	12
Additional paid-in capital	1,373,242	1,350,981
Accumulated other comprehensive loss	(222)	(161)
Accumulated deficit	(1,532,680)	(1,487,038)
Total stockholders' deficit	(159,647)	(136,206)
Total liabilities and stockholders' deficit	$ 189,476	$ 240,438

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (unaudited) (Parenthetical) - $ / shares	Sep. 30, 2024	Dec. 31, 2023
Statement of Financial Position [Abstract]
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	400,000,000	400,000,000
Common stock, shares issued	125,303,000	114,915,000
Common stock, shares outstanding	125,303,000	114,915,000

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Revenues:
Revenue from contract with customer, license and other revenue	$ 38,783	$ 36,009	$ 114,695	$ 112,286
Operating expenses:
Research and development	36,134	35,553	109,930	99,369
Selling, general and administrative	27,632	30,805	88,251	101,193
Total operating expenses	65,066	67,269	202,857	204,018
Loss from operations	(26,283)	(31,260)	(88,162)	(91,732)
Other income (expense):
Interest income	1,832	2,750	5,918	8,423
Interest expense	(11,385)	(6,073)	(26,218)	(17,615)
Gain on extinguishment of debt	0	0	44,702	0
Other income (expense), net	3,792	89	18,284	(145)
Total other income (expense), net	(5,761)	(3,234)	42,686	(9,337)
Loss before income taxes	(32,044)	(34,494)	(45,476)	(101,069)
Income tax provision	(28)	(12)	(166)	(193)
Net loss	$ (32,072)	$ (34,506)	$ (45,642)	$ (101,262)
Basic net loss per share (Note 7)	$ (0.26)	$ (0.3)	$ (0.38)	$ (0.89)
Diluted net loss per share (Note 7)	$ (0.26)	$ (0.3)	$ (0.69)	$ (0.89)
Weighted-average number of common shares outstanding used to compute basic net loss per share	125,010	114,401	120,513	114,033
Weighted-average number of common shares outstanding used to compute diluted net loss per share	125,010	114,401	126,606	114,033
Product [Member]
Revenues:
Revenue from contract with customer, license and other revenue	$ 29,516	$ 30,207	$ 83,554	$ 86,955
Operating expenses:
Cost of sales	1,300	911	4,676	3,456
License and Other [Member]
Revenues:
Revenue from contract with customer, license and other revenue	$ 9,267	$ 5,802	$ 31,141	$ 25,331

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Statement of Comprehensive Income [Abstract]
Net Income (Loss)	$ (32,072)	$ (34,506)	$ (45,642)	$ (101,262)
Other comprehensive income (loss)
Unrealized gain (loss) on investments	291	169	242	(95)
Foreign currency translation adjustment	92	(128)	(303)	(9)
Comprehensive loss	$ (31,689)	$ (34,465)	$ (45,703)	$ (101,366)

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows (unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Operating activities
Net loss	$ (45,642)	$ (101,262)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	14,562	16,527
Depreciation and amortization	259	453
Amortization of debt issuance costs and discounts	4,012	597
Net amortization of premiums and discounts on investments	(2,112)	(3,077)
Gain on extinguishment of debt	(44,702)	0
Change in fair value of embedded derivatives and common stock warrants	(18,343)	0
Changes in operating assets and liabilities:
Accounts receivable, net	(4,816)	9,163
Inventory	(1,629)	1,119
Prepaid expenses and other assets	(2,933)	5,612
Operating lease right-of-use assets	1,690	1,442
Accounts payable	2,660	(1,830)
Accrued expenses and other liabilities	(2,253)	(776)
Operating lease liabilities	(2,429)	(2,106)
Net cash used in operating activities	(101,676)	(74,138)
Investing activities
Proceeds from maturities of investments	138,187	123,688
Purchases of investments	(57,316)	(142,591)
Purchases of property and equipment	(195)	0
Net cash provided by (used in) investing activities	80,676	(18,903)
Financing activities
Proceeds from issuance of senior secured term loan	83,300	0
Proceeds from the exercise of stock options and shares issued under employee stock purchase plan	772	860
Payment of debt issuance costs	(2,588)	0
Payment of deferred royalty obligation	(40,518)	0
Net cash provided by financing activities	40,966	860
Effect of exchange rate on cash, cash equivalents and restricted cash	9	(123)
Net increase (decrease) in cash, cash equivalents and restricted cash	19,975	(92,304)
Cash, cash equivalents and restricted cash at beginning of period	53,192	136,885
Cash, cash equivalents and restricted cash at end of period	73,167	44,581
Reconciliation of cash, cash equivalents and restricted cash reported within the condensed consolidated balance sheets
Cash and cash equivalents	72,828	43,655
Short-term restricted cash	33	545
Long-term restricted cash	306	381
Total cash, cash equivalents and restricted cash	73,167	44,581
Supplemental disclosures:
Cash paid for interest on deferred royalty obligation	18,926	12,225
Cash paid for interest on convertible debt and term loan	11,472	2,588
Cash paid for amounts included in the measurement of operating lease liabilities	2,844	2,770
Convertible senior notes due 2029 issued with warrants to purchase 45,776,213 shares of common stock in exchange for a $148.0 million reduction of convertible senior notes due 2025	111,000	0
Senior secured term loan issued in exchange for a $14.7 million reduction of deferred royalty obligation	15,000	0
Issuance of common stock used to settle a financial advisory fee related to financing activities	7,697
Convertible senior notes due 2029 issued in exchange for a $5.0 million reduction of deferred royalty obligation	$ 5,000	$ 0

Condensed Consolidated Statem_4

Condensed Consolidated Statement of Cash Flows (unaudited) (Parenthetical)	9 Months Ended
	Sep. 30, 2024 shares
Statement of Cash Flows [Abstract]
Convertible senior notes issued to purchase common stock	45,776,213,000
Reduction of convertible senior notes	148,000,000
Senior secured term loan isuued	14,700,000
Convertible senior notes issued	5,000,000

Condensed Consolidated Statem_5

Condensed Consolidated Statements of Stockholders' Deficit (unaudited) - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Other Comprehensive (loss) Income [Member]	Accumulated Deficit [Member]
Beginning balance at Dec. 31, 2022	$ (16,656)	$ 12	$ 1,327,909	$ (638)	$ (1,343,939)
Beginning balance,Shares at Dec. 31, 2022		113,213,000
Vesting of restricted stock (in shares)		1,019,000
Exercise of stock options and shares issued under the employee stock purchase plan	860		860
Exercise of stock options and shares issued under the employee stock purchase plan, (shares)		291,000
Stock-based compensation	16,527		16,527
Issuance of common stock warrants	239		239
Unrealized gain (loss) on investments	(95)			(95)
Foreign currency cumulative translation adjustment	(9)			(9)
Net Income (Loss)	(101,262)				(101,262)
Ending balance at Sep. 30, 2023	(100,396)	$ 12	1,345,535	(742)	(1,445,201)
Ending balance,Shares at Sep. 30, 2023		114,523,000
Beginning balance at Jun. 30, 2023	(71,248)	$ 12	1,340,218	(783)	(1,410,695)
Beginning balance,Shares at Jun. 30, 2023		114,340,000
Vesting of restricted stock (in shares)		183,000
Stock-based compensation	5,078		5,078
Issuance of common stock warrants	239		239
Unrealized gain (loss) on investments	169			169
Foreign currency cumulative translation adjustment	(128)			(128)
Net Income (Loss)	(34,506)				(34,506)
Ending balance at Sep. 30, 2023	(100,396)	$ 12	1,345,535	(742)	(1,445,201)
Ending balance,Shares at Sep. 30, 2023		114,523,000
Beginning balance at Dec. 31, 2023	(136,206)	$ 12	1,350,981	(161)	(1,487,038)
Beginning balance,Shares at Dec. 31, 2023		114,915,000
Vesting of restricted stock (in shares)		2,361,000
Exercise of stock options and shares issued under the employee stock purchase plan	772		772
Exercise of stock options and shares issued under the employee stock purchase plan, (shares)		1,155,000
Issuance of common stock for financial advisory fee	6,928	$ 1	6,927
Issuance of common stock for financial advisory fee, (Shares)		6,872,000
Stock-based compensation	14,562		14,562
Unrealized gain (loss) on investments	242			242
Foreign currency cumulative translation adjustment	(303)			(303)
Net Income (Loss)	(45,642)				(45,642)
Ending balance at Sep. 30, 2024	(159,647)	$ 13	1,373,242	(222)	(1,532,680)
Ending balance,Shares at Sep. 30, 2024		125,303,000
Beginning balance at Jun. 30, 2024	(132,140)	$ 13	1,369,060	(605)	(1,500,608)
Beginning balance,Shares at Jun. 30, 2024		124,635,000
Vesting of restricted stock (in shares)		668,000
Stock-based compensation	4,182		4,182
Unrealized gain (loss) on investments	291			291
Foreign currency cumulative translation adjustment	92			92
Net Income (Loss)	(32,072)				(32,072)
Ending balance at Sep. 30, 2024	$ (159,647)	$ 13	$ 1,373,242	$ (222)	$ (1,532,680)
Ending balance,Shares at Sep. 30, 2024		125,303,000

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Pay vs Performance Disclosure
Net Income (Loss)	$ (32,072)	$ (34,506)	$ (45,642)	$ (101,262)

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Sep. 30, 2024
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Nature of Business and Basis of

Nature of Business and Basis of Presentation	9 Months Ended
	Sep. 30, 2024
Accounting Policies [Abstract]
Nature of Business and Basis of Presentation	1. Nature of Business and Basis of Presentation Nature of Business Karyopharm Therapeutics Inc., a Delaware corporation (collectively with its subsidiaries, the “Company,” “we,” “us,” or “our”), is 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. We were incorporated in Delaware on December 22, 2008 and have a principal place of business in Newton, Massachusetts. 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 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. 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 45 countries outside the U.S. and is commercially available in a growing number of countries as our partners continue to secure reimbursement approvals. Liquidity, Capital Resources and Going Concern As of September 30, 2024, we had $ 133.5 million of cash, cash equivalents and investments and an accumulated deficit of $ 1.5 billion. We have incurred significant operating losses since our inception and we anticipate that we will continue to incur significant operating losses to maintain our research and development programs, including as we continue to develop and seek regulatory approval of selinexor for multiple cancer indications, and to support our continued operations. As a result, our continued operations are dependent on our ability to raise additional funding and marketing XPOVIO in its currently approved indications. Based on our current business plan and current capital resources, combined with the uncertainty regarding the availability of additional funding, we have concluded that there is substantial doubt regarding our ability to continue as a going concern within one year after the date these condensed consolidated financial statements are issued. We plan to address the conditions that raise substantial doubt regarding our ability to continue as a going concern by, among other things, obtaining additional funding through equity offerings, debt financings and refinancings, collaborations, strategic alliances and/or licensing arrangements. However, there is no assurance that such additional funding will be available on terms acceptable to us, or at all. We may also be required to reduce our current spending requirements where possible. If we utilize our capital resources more quickly than anticipated or are unable to obtain additional funding, we may have to significantly curtail, delay, reduce or eliminate one or more of our research and development programs or any current or future commercialization efforts for one or more of our products or product candidates, which could materially adversely affect our business, financial condition, and results of operations. If we are unable to continue as a going concern, we may have to liquidate our assets and may receive less than the value at which those assets are carried on our financial statements, and it is likely that investors will lose all or part of their investment. If we seek additional financing to fund our business activities in the future and there remains substantial doubt about our ability to continue as a going concern, investors or other financing sources may be unwilling to provide funding to us on commercially reasonable terms, if at all. The accompanying condensed consolidated financial statements do not include any adjustments to the carrying amounts and classification of assets and liabilities that may be necessary if we were unable to continue as a going concern. Basis of Presentation The accompanying unaudited condensed consolidated financial statements of the Company have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) for interim financial reporting and as required by Regulation S-X, Rule 10-01. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. In our opinion, all adjustments (including those which are normal and recurring) considered necessary for a fair presentation of the interim financial information have been included. When preparing financial statements in conformity with GAAP, we must make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues, expenses and related disclosures at the date of the financial statements. Actual results could differ from those estimates. Additionally, operating results for the three and nine months ended September 30, 2024 are not necessarily indicative of the results that may be expected for any other interim period or for the fiscal year ending December 31, 2024. For further information, refer to the financial statements and footnotes included in our Annual Report on Form 10-K for the year ended December 31, 2023 as filed with the Securities and Exchange Commission on February 29, 2024 (“Annual Report”). Basis of Consolidation The condensed consolidated financial statements as of September 30, 2024 include the accounts of Karyopharm Therapeutics Inc. and its wholly-owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. The significant accounting policies used in preparation of these condensed consolidated financial statements in this Form 10-Q are consistent with those discussed in Note 2, “ Summary of Significant Accounting Policies ,” in our Annual Report.

Product Revenue

Product Revenue	9 Months Ended
	Sep. 30, 2024
Product Revenue [Member]
Product Revenue	2. Product Revenue To date, our only source of product revenue has been from the U.S. sales of XPOVIO. Net product revenue, including provisions primarily consisting of distribution fees and cash discounts, as well as reserves for chargebacks, rebates and returns, were as follows (in thousands): For the Three Months For the Nine Months 2024 2023 2024 2023 Gross product revenue $ 43,031 $ 37,981 $ 119,457 $ 111,387 Provisions for product revenue ( 13,515 ) ( 7,774 ) ( 35,903 ) ( 24,432 ) Total product revenue, net $ 29,516 $ 30,207 $ 83,554 $ 86,955 As of September 30, 2024 and December 31, 2023, net product revenue of $ 24.5 million and $ 17.8 million, respectively, were included in accounts receivable. To date, we have had no bad debt write-offs and we do not currently have credit issues with any customers. There were no credit losses associated with accounts receivable as of September 30, 2024 and December 31, 2023.

Inventory

Inventory	9 Months Ended
	Sep. 30, 2024
Inventory Disclosure [Abstract]
Inventory	3. Inventory The following table presents our inventory (in thousands), all of which was related to XPOVIO: As of September 30, 2024 As of December 31, 2023 Raw materials $ 720 $ 553 Work in process 3,410 1,732 Finished goods 542 758 Total inventory $ 4,672 $ 3,043

License Agreements

License Agreements	9 Months Ended
	Sep. 30, 2024
License Agreements
License Agreements	4. License Agreements In prior periods, we entered into license agreements with Berlin-Chemie AG, an affiliate of the Menarini Group (“Menarini”), and Antengene Therapeutics Limited (“Antengene”), both of which are accounted for within the scope of Accounting Standards Codification 606, Revenue from Contracts with Customers . For further details on the terms and accounting treatment considerations for these contracts, please refer to Note 5, “ License and Asset Purchase Agreements ,” to our consolidated financial statements contained in Item 8 of our Annual Report. The following table presents information about our license and other revenue (in thousands): For the Three Months For the Nine Months 2024 2023 2024 2023 Menarini $ 8,753 $ 5,564 $ 27,232 $ 19,912 Antengene 273 80 1,272 1,952 Other 241 158 2,637 3,467 Total license and other revenue $ 9,267 $ 5,802 $ 31,141 $ 25,331 During the three months ended September 30, 2024 , we recognized $ 6.0 million of milestone revenue, $ 2.0 million of revenue for the reimbursement of development-related expenses, and $ 0.5 million of royalty revenue from Menarini. We also recognized $ 0.3 million of royalty revenue from Antengene. During the three months ended September 30, 2023, we recognized $ 5.4 million of revenue for the reimbursement of development-related expenses from Menarini. During the nine months ended September 30, 2024 , we recognized $ 15.0 million of revenue for the reimbursement of development-related expenses, $ 10.0 million of milestone revenue, $ 1.6 million of royalty revenue, and $ 0.6 million of other revenue from Menarini. We also recognized $ 1.2 million of royalty revenue from Antengene and $ 2.0 million of other milestone-related revenue. During the nine months ended September 30, 2023, we recognized $ 15.0 million of revenue for the reimbursement of development-related expenses, $ 3.5 million of license-related revenue, $ 0.7 million of royalty revenue, and $ 0.7 million of other revenue from Menarini. We also recognized $ 1.5 million of royalty revenue and $ 0.5 million of other revenue from Antengene. In addition, we recognized $ 2.5 million of other milestone-related revenue and $ 0.5 million of other royalty revenue. As of September 30, 2024, license and other revenue of $ 7.2 million was included in accounts receivable. At December 31, 2023, license and other revenue of $ 9.1 million and $ 1.0 million were included in accounts receivable and other current assets, respectively.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2024
Fair Value Disclosures [Abstract]
Fair Value Measurements	5. Fair Value Measurements Financial instruments, including cash, cash equivalents, accounts receivable, net, other current assets, other assets, restricted cash, accounts payable, and accrued expenses, are presented at amounts that approximate fair value as of September 30, 2024 and December 31, 2023. Fair value is the price 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. We disclose information on all assets and liabilities reported at fair value that enables an assessment of the inputs used in determining the reported fair values. The fair value hierarchy prioritizes valuation inputs based on the observable nature of those inputs. The fair value hierarchy applies only to the valuation inputs used in determining the reported fair value and is not a measure of credit quality. The hierarchy defines three levels of valuation inputs: Level 1 - Quoted prices in active markets for identical assets or liabilities Level 2 - Inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly Level 3 - Unobservable inputs that reflect the assumptions market participants would use in pricing the asset or liability Items classified as Level 2 consist of corporate debt securities, commercial paper and U.S. government and agency securities. We estimate the fair value of these marketable securities by taking into consideration valuations obtained from third-party pricing sources. These pricing sources utilize industry standard valuation models, including both income and market-based approaches, for which all significant inputs are observable, either directly or indirectly, to estimate fair value. These inputs include market pricing based on real-time trade data for the same or similar securities, issuer credit spreads, benchmark yields, and other observable inputs. We validate the prices provided by our third-party pricing sources by understanding the models used, obtaining market values from other pricing sources and analyzing pricing data in certain instances. The following tables present information about our financial assets that have been measured at fair value and indicate the fair value hierarchy of the valuation inputs utilized to determine such fair value (in thousands): As of September 30, 2024 Quoted Significant Significant Cash equivalents: Money market funds $ 58,412 $ 58,412 $ — $ — Commercial paper 1,988 — 1,988 — Investments: Corporate debt securities 44,192 — 44,192 — Commercial paper 7,601 — 7,601 — U.S. government and agency securities 8,905 — 8,905 — $ 121,098 $ 58,412 $ 62,686 $ — As of December 31, 2023 Quoted Significant Significant Cash equivalents: Money market funds $ 27,963 $ 27,963 $ — $ — U.S. government and agency securities 1,998 — 1,998 — Investments: Corporate debt securities 77,961 — 77,961 — Commercial paper 13,744 — 13,744 — U.S. government and agency securities 47,507 — 47,507 — $ 169,173 $ 27,963 $ 141,210 $ — In certain cases where there is limited activity or less transparency around inputs to valuation, the related assets or liabilities are classified as Level 3. The following liabilities are measured at fair value at the end of each reporting period, with changes in fair value recognized as a component of other income (expense), net on our condensed consolidated statements of operations. See Note 10, “ Long-Term Obligations ” to our condensed consolidated financial statements for further discussion of these liabilities: (1) The embedded derivative liability (the “HCRx Derivative”) associated with a Revenue Interest Financing Agreement (the “Revenue Interest Agreement”) we entered into with HealthCare Royalty Partners III, L.P. and HealthCare Royalty Partners IV, L.P. (“HCRx”) in September 2019 and as amended in June 2021, August 2023 and May 2024 (as amended, the “Amended Revenue Interest Agreement”) is included as a component of the deferred royalty obligation on our condensed consolidated balance sheets. The valuation method for the HCRx Derivative incorporates certain unobservable Level 3 key inputs including: (i) the probability-weighted net sales of XPOVIO and any of our other future products, including worldwide net product sales, upfront payments, milestones and royalties; (ii) our risk-adjusted discount rate; and (iii) the probability of a change in control occurring during the term of the instrument. The HCRx Derivative was deemed to have a de-minimus value as of September 30, 2024 primarily due to a $ 56.2 million decrease in the deferred royalty obligation during the nine months ended September 30, 2024. (2) The embedded derivative liabilities (the “2029 Notes Derivatives”) associated with our 6.00% convertible senior notes due 2029 (the “2029 Notes”) is included as a component of the 2029 Notes on our condensed consolidated balance sheet. The valuation method for the 2029 Notes Derivatives incorporates certain unobservable Level 3 key inputs including: (i) the volatility of our common stock price and (ii) our estimated credit spread. (3) The warrants to purchase up to 45.8 million shares of our common stock issued in May 2024 (the “May 2024 Warrants”) are classified as a long-term liability on our condensed consolidated balance sheets. The valuation method for the May 2024 Warrants incorporates certain unobservable Level 3 key inputs including: (i) the volatility of our common stock price and (ii) an estimate of when the May 2024 Warrants will be exercised based on an option pricing model. The following table sets forth a summary of the changes in the estimated fair value of these liabilities, which are all classified as Level 3 (in thousands): HCRx Derivative 2029 Notes Derivatives May 2024 Warrants Balance as of December 31, 2023 $ 2,800 $ — $ — Initial recognition — 28,877 23,284 Change in fair value ( 2,800 ) ( 9,614 ) ( 5,929 ) Balance as of September 30, 2024 $ — $ 19,263 $ 17,355

Investments

Investments	9 Months Ended
	Sep. 30, 2024
Investments, Debt and Equity Securities [Abstract]
Investments	6. Investments The following tables summarize our investments, which are classified as available-for-sale and recorded at fair value (in thousands): As of September 30, 2024 Amortized Total Total Aggregate Fair Value Corporate debt securities $ 44,024 $ 171 $ ( 3 ) $ 44,192 Commercial paper 7,596 6 ( 1 ) 7,601 U.S. government and agency securities 8,904 2 ( 1 ) 8,905 Total $ 60,524 $ 179 $ ( 5 ) $ 60,698 As of December 31, 2023 Amortized Total Total Aggregate Fair Value Corporate debt securities $ 78,004 $ 79 $ ( 122 ) $ 77,961 Commercial paper 13,734 13 ( 3 ) 13,744 U.S. government and agency securities 47,543 4 ( 40 ) 47,507 Total $ 139,281 $ 96 $ ( 165 ) $ 139,212 We determine the appropriate classification of our investments at the time of purchase. All of our investments are reported as short-term as they are available for use during the normal cycle of business. We review any investment when its fair value is less than its amortized cost and when evidence indicates that the investment’s carrying amount is not recoverable within a reasonable period. We evaluate whether the decline in fair value has resulted from credit losses or other factors. In making this assessment, we consider the extent to which fair value is less than amortized cost, any changes to the rating of the security by a rating agency, and adverse conditions specifically related to the security, among other factors. If this assessment indicates that a credit loss exists, the present value of cash flows expected to be collected from the investment is compared to its amortized cost basis. If the present value of cash flows expected to be collected is less than the amortized cost basis, a credit loss exists and an allowance for credit losses is recorded on our condensed consolidated balance sheet, limited by the amount that the fair value is less than the amortized cost basis. Any impairment that is not related to a credit loss is recognized in other comprehensive income (loss). Changes in the allowance for credit losses are recorded as a provision for (or reversal of) credit loss expense. Losses are charged against the allowance when we believe the uncollectability of an investment is confirmed or when either of the criteria regarding intent or requirement to sell is met. We held 8 and 41 debt securities as of September 30, 2024 and December 31, 2023, respectively, that were in an unrealized loss position. The unrealized losses as of September 30, 2024 and December 31, 2023 were attributable to changes in interest rates, and we do no t believe any unrealized losses represented credit losses. We do not intend to sell the investments before recovery of their amortized cost bases, which may be at maturity. All of our investments mature within two years from September 30, 2024 . The following tables summarize our investments in an unrealized loss position for which an allowance for credit losses has not been recorded, aggregated by investment type and length of time in a continuous unrealized loss position (in thousands): As of September 30, 2024 Less than 12 Months 12 Months or Longer Total Aggregate Related Fair Value Unrealized Aggregate Related Fair Value Unrealized Aggregate Related Fair Value Unrealized Corporate debt securities $ 5,688 $ ( 3 ) $ — $ — $ 5,688 $ ( 3 ) Commercial paper 2,660 ( 1 ) — — 2,660 ( 1 ) U.S. government and agency securities 3,933 ( 1 ) — — 3,933 ( 1 ) Total $ 12,281 $ ( 5 ) $ — $ — $ 12,281 $ ( 5 ) As of December 31, 2023 Less than 12 Months 12 Months or Longer Total Aggregate Related Fair Value Unrealized Aggregate Related Fair Value Unrealized Aggregate Related Fair Value Unrealized Corporate debt securities $ 50,322 $ ( 112 ) $ 4,279 $ ( 10 ) $ 54,601 $ ( 122 ) Commercial paper 6,952 ( 3 ) — — 6,952 ( 3 ) U.S. government and agency securities 27,191 ( 37 ) 1,997 ( 3 ) 29,188 ( 40 ) Total $ 84,465 $ ( 152 ) $ 6,276 $ ( 13 ) $ 90,741 $ ( 165 )

Net Loss Per Share

Net Loss Per Share	9 Months Ended
	Sep. 30, 2024
Earnings Per Share [Abstract]
Net Loss Per Share	7. Net Loss Per Share Basic net loss per common share is calculated using the two-class method by dividing the net loss allocated to common shares by the weighted-average number of common shares outstanding for the period. Diluted net loss per common share is calculated by adjusting net loss to remove the effects from potential dilutive common shares and dividing this adjusted amount by the weighted average number of common shares and potential dilutive common shares outstanding for the period. Potential dilutive common shares are not included if their effect is anti-dilutive. As discussed further in Note 10, “ Long-Term Obligations ”, we have the option to settle the conversion obligation for our 3.00 % convertible senior notes due 2025 (the “2025 Notes”) in cash, shares or any combination of the two. There was no impact of the 2025 Notes on the calculation of dilutive loss per common share during the three months ended September 30, 2024 and the three and nine months ended September 30, 2023 because they were anti-dilutive in these periods. As discussed further in Note 10, “ Long-Term Obligations ”, we have the option to settle the conversion obligation for our 2029 Notes in cash, shares or any combination of the two. There was no impact of the 2029 Notes on the calculation of dilutive loss per common share during the three and nine months ended September 30, 2024 because they were anti-dilutive in these periods. As discussed further in Note 11, “ Common Share Warrants ”, warrants to purchase up to 55,563,775 shares of our common stock were outstanding as of September 30, 2024. These warrants are not included in the calculation of basic net loss per share because the warrant holders do not have an obligation to share in our losses. There was no impact of these warrants on the calculation of dilutive loss per common share during the three and nine months ended September 30, 2024 and 2023 because they were anti-dilutive in these periods. The following is a reconciliation of the numerator and denominator used to calculate diluted net loss per common share for the nine months ended September 30, 2024 (in thousands except per share amounts): For the Nine Months Ended September 30, 2024 Net loss $ ( 45,642 ) Add back interest expense on the 2025 Notes 2,518 Add back gain on extinguishment of debt ( 44,702 ) Numerator for diluted net loss per common share (A) $ ( 87,826 ) Weighted-average number of common shares outstanding 120,513 Dilutive effect of 2025 Notes calculated using the if-converted method 6,093 Denominator for diluted net loss per common share (B) 126,606 Diluted net loss per common share (= A / B) $ ( 0.69 ) The following potentially dilutive securities were excluded from the calculation of diluted net loss per common share due to their anti-dilutive effect under the treasury method (in thousands): As of September 30, 2024 2023 Outstanding common share warrants 55,563,775 9,787,563 Outstanding stock options 6,346 9,775 Unvested restricted stock units 12,914 7,818

Stock-based Compensation Expens

Stock-based Compensation Expense	9 Months Ended
	Sep. 30, 2024
Share-Based Payment Arrangement [Abstract]
Stock-based Compensation Expense	8. Stock-based Compensation Expense The following table summarizes stock-based compensation expense included in operating expenses (in thousands): For the Three Months Ended September 30, For the Nine Months Ended September 30, 2024 2023 2024 2023 Cost of sales $ 61 $ 96 $ 177 $ 281 Research and development 1,062 1,298 3,775 5,138 Selling, general and administrative 3,059 3,684 10,610 11,108 Total $ 4,182 $ 5,078 $ 14,562 $ 16,527 Our 2022 Equity Incentive Plan, as amended (the “2022 Plan”), provides for the grant of incentive stock options, non-statutory stock options, stock appreciation rights, restricted stock awards, restricted stock unit awards and other stock-based awards. On May 29, 2024, our stockholders approved an amendment to the 2022 Plan to increase the number of shares of our common stock available for issuance under the 2022 Plan by 6,000,000 shares. On May 29, 2024, our stockholders also approved an amendment to our Amended & Restated 2013 Employee Stock Purchase Plan (the “ESPP”) to increase the number of shares of our common stock available for issuance under the ESPP by 5,000,000 shares. We agreed with our financial advisor to settle our fee for services provided in connection with the May 2024 refinancing transactions described in Note 10, “ Long-Term Obligations ” through the private placement of 6,872,027 shares of our common stock, resulting in $ 6.9 million being capitalized to our condensed consolidated balance sheet as a debt issuance cost and $ 0.8 million being expensed to selling, general and administrative expense as stock-based compensation expense on our condensed consolidated statements of operations during the nine months ended September 30, 2024 .

Stockholders' Equity

Stockholders' Equity	9 Months Ended
	Sep. 30, 2024
Equity [Abstract]
Stockholders' Equity	9. Stockholders’ Equity On February 17, 2023, we entered into an Open Market Sale Agreement (the “2023 Open Market Sale Agreement”) with Jefferies LLC, as agent (“Jefferies”). Under the 2023 Open Market Sale Agreement, we may issue and sell shares of our common stock having an aggregate offering price of up to $ 100.0 million (the “Shares”) from time to time through Jefferies (the “2023 Open Market Offering”). Under the 2023 Open Market Sale Agreement, Jefferies may sell the Shares by methods deemed to be an “at the market offering” as defined in Rule 415(a)(4) promulgated under the Securities Act of 1933, as amended (the “Securities Act”). We may sell the Shares in amounts and at times to be determined by us from time to time subject to the terms and conditions of the 2023 Open Market Sale Agreement, but we have no obligation to sell any of the Shares in the 2023 Open Market Offering. We or Jefferies may suspend or terminate the offering of Shares upon notice to the other party and subject to other conditions. We have agreed to pay Jefferies commissions for its services in acting as agent in the sale of the Shares in the amount of up to 3.00 % of gross proceeds from the sale of the Shares pursuant to the 2023 Open Market Sale Agreement. We have also agreed to provide Jefferies with customary indemnification and contribution rights. We did no t sell any Shares under the 2023 Open Market Sale Agreement during the three and nine months ended September 30, 2024 and 2023. As of September 30, 2024, $ 100.0 million of Shares was available for issuance and sale under the 2023 Open Market Sale Agreement.

Long-Term Obligations

Long-Term Obligations	9 Months Ended
	Sep. 30, 2024
Debt Disclosure [Abstract]
Long-Term Obligations	10. Long-Term Obligation s 2025 Notes In October 2018, we issued $ 172.5 million aggregate principal amount of the 2025 Notes in a private offering to qualified institutional buyers in reliance on Rule 144A under the Securities Act. In connection with the issuance of the 2025 Notes, we incurred $ 5.6 million of debt issuance costs, which was being amortized to interest expense using the effective interest method over seven years . In May 2024, we exchanged $ 148.0 million aggregate principal amount of our 2025 Notes for (i) $ 111.0 million aggregate principal amount of our 2029 Notes and (ii) the May 2024 Warrants to purchase up to 45.8 million shares of our common stock. The 2029 Notes and the May 2024 Warrants are described in more detail below. $ 24.5 million in aggregate principal amount of the 2025 Notes remained outstanding following completion of the May 2024 exchange transactions (the “Remaining 2025 Notes”). The Remaining 2025 Notes are senior unsecured obligations and bear interest at a rate of 3.00 % per year payable semiannually in arrears on April 15 and October 15 of each year. Upon conversion, the Remaining 2025 Notes will be converted into cash, shares of our common stock, or a combination of cash and shares of our common stock, at our election. The Remaining 2025 Notes are subject to redemption at our option, in whole or in part, if the conditions described below are satisfied. Holders may require us to repurchase their Remaining 2025 Notes following a fundamental change (as defined within the indenture governing the 2025 Notes) at a cash repurchase price generally equal to the principal amount of the Remaining 2025 Notes to be repurchased, plus accrued and unpaid interest. The Remaining 2025 Notes will mature on October 15, 2025 , unless earlier converted, redeemed or repurchased in accordance with their terms. Subject to satisfaction of certain conditions and during the periods described below, the Remaining 2025 Notes may be converted at an initial conversion rate of 63.0731 shares of common stock per $ 1,000 principal amount of the Remaining 2025 Notes (equivalent to an initial conversion price of approximately $ 15.85 per share of common stock). Holders of the Remaining 2025 Notes may convert all or any portion of their Remaining 2025 Notes, in multiples of $ 1,000 principal amount, at their option at any time prior to the close of business on the business day immediately preceding June 15, 2025 only under the following circumstances: (1) during any calendar quarter, if the last reported sale price of our common stock for at least 20 trading days (whether or not consecutive) during the period of 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter is greater than or equal to 130 % of the conversion price for the Remaining 2025 Notes on each applicable trading day; (2) during the five-business day period immediately after any five consecutive trading day period (the “Measurement Period”) in which the trading price p er $ 1,000 principal amount o f Remaining 2025 Notes for each trading day of the Measurement Period was less than 98 % of the product of the last reported sale price of our common stock and the conversion rate on each such trading day; (3) if we call the Remaining 2025 Notes for redemption, until the close of business on the business day immediately preceding the redemption date; or (4) upon the occurrence of specified corporate events as described within the indenture governing the 2025 Notes. As of September 30, 2024, none of the above circumstances had occurred and as such, the Remaining 2025 Notes could not have been converted. We may redeem for cash all or part of the Remaining 2025 Notes at our option if the last reported sale price of our common stock equals or exceeds 130 % of the conversion price then in effect for at least 20 trading days (whether or not consecutive) during any 30 consecutive trading day period ending within five trading days prior to the date on which we send any notice of redemption. The redemption price will be 100 % of the principal amount of the Remaining 2025 Notes to be redeemed, plus accrued and unpaid interest, if any. In addition, calling any convertible note for redemption will constitute a make-whole fundamental change with respect to that convertible note, in which case the conversion rate applicable to the conversion of that convertible note, if it is converted in connection with the redemption, will be increased in certain circumstances. We did not redeem any of the Remaining 2025 Notes as of September 30, 2024. The outstanding balances of the 2025 Notes consisted of the following (in thousands): As of September 30, 2024 As of December 31, 2023 Principal $ 24,500 $ 172,500 Less: unamortized debt issuance costs ( 108 ) ( 1,581 ) 2025 Notes $ 24,392 $ 170,919 We determined the expected life of the 2025 Notes was equal to its seven-year term and the effective interest rate was 3.53 % . As of September 30, 2024, the “if-converted value” did not exceed the remaining principal amount of the 2025 Notes. The fair value of the 2025 Notes is influenced by market interest rates, our stock price and stock price volatility, and has been classified as Level 2 within the fair value hierarchy as it uses quoted prices in active markets. The estimated fair value of the 2025 Notes as of September 30, 2024 and December 31, 2023 was approximately $ 19.2 million and $ 87.9 million, respectively. The following table sets forth total interest expense recognized related to the 2025 Notes (in thousands): For the Three Months For the Nine Months 2024 2023 2024 2023 Contractual interest expense $ 184 $ 1,293 $ 2,170 $ 3,881 Amortization of debt issuance costs 33 205 348 597 Total interest expense $ 217 $ 1,498 $ 2,518 $ 4,478 Future minimum payments on the 2025 Notes as of September 30, 2024 were as follows (in thousands): Years ended December 31, Future Minimum 2024 $ 368 2025 25,236 Total minimum payments 25,604 Less: interest expense and unamortized debt issuance costs ( 1,212 ) 2025 Notes $ 24,392 Senior Secured Term Loan On May 8, 2024, we entered into a credit and guaranty agreement (the “Credit Agreement”) with certain existing holders of the 2025 Notes and HCRx, which provides for a senior secured term loan facility of $ 100.0 million (the “Term Loan”). The Term Loan matures in May 2028 and bears interest at a variable rate equal to the applicable secured overnight financing rate plus 9.25 %, subject to a floor of 3.00 %. Principal payments under the Term Loan will begin in June 2026, and consist of quarterly cash payments in the amount of 6.25 % of the aggregate principal amount of the Term Loan, with the remaining principal due when the Term Loan matures in May 2028. We can prepay the Term Loan at any time. All repayments, including prepayments, are subject to a redemption fee of 3.00 % of the principal paid. Prepayments made before May 8, 2027 are subject to a prepayment premium ranging from 3.00 % to 5.00 % of the principal prepaid. The prepayment premium for prepayments made before May 8, 2025 also includes the unpaid interest that would have accrued on the amount being prepaid through May 8, 2025. In addition, we are required to repay the Term Loan with proceeds from certain asset sales and condemnation events, subject, in some cases, to reinvestment rights. All obligations under the Credit Agreement are secured on a first priority basis, subject to certain exceptions, by substantially all of our assets. The Credit Agreement contains customary covenants, including a requirement to maintain cash, cash equivalents and investments of at least $ 25.0 million at all times, and restrictions on indebtedness, liens, investments, fundamental changes, asset sales, licensing transactions, dividends, modifications to material agreements, payment of subordinated indebtedness, and other matters customarily restricted in such agreements. Specifically, we are prohibited from exclusively licensing, selling or otherwise disposing of U.S. rights to oncology indications of selinexor. As of September 30, 2024, we were in compliance with these covenants. If certain events of default occur, the Term Loan may be due and payable immediately. These events include the withdrawal of approval of certain indications of selinexor, payment defaults, covenant defaults, bankruptcy, cross-defaults to certain other agreements, change in control and lien priority. The outstanding balance of the Term Loan consisted of the following (in thousands): As of September 30, 2024 Principal $ 100,000 Less: unamortized debt issuance costs ( 5,891 ) Term Loan $ 94,109 We determined the expected life of the Term Loan was equal to its four-year term and the effective interest rate is 17.86 % . The carrying value of the Term Loan approximates its fair value due to the variable interest rate. In connection with the issuance of the Term Loan, we incurred $ 6.8 million of debt issuance costs, which are being amortized to interest expense using the effective interest method over four years . We recognized $ 4.3 million of interest expense related to the Term Loan during the three months ended September 30, 2024 , which consisted of $ 3.7 million of contractual interest expense and $ 0.6 million of debt issuance cost amortization. We recognized $ 6.7 million of interest expense related to the Term Loan during the nine months ended September 30, 2024 , which consisted of $ 5.8 million of contractual interest expense and $ 0.9 million of debt issuance cost amortization. Future minimum payments on the Term Loan as of September 30, 2024 were as follows (in thousands): Years ended December 31, Future Minimum 2024 $ 9,517 2025 14,582 2026 33,211 2027 36,230 2028 60,747 Total minimum payments 154,287 Less: interest expense and unamortized debt issuance costs ( 60,178 ) Term Loan $ 94,109 2029 Notes On May 13, 2024, pursuant to privately-negotiated agreements with certain holders of the 2025 Notes, we exchanged $ 148.0 million aggregate principal amount of 2025 Notes for (i) $ 111.0 million aggregate principal amount of the 2029 Notes and (ii) May 2024 Warrants to purchase up to 45.8 million shares of our common stock. This will create additional taxable income related to the cancellation of debt, however, we expect this taxable income will be fully offset by our net operating loss carryforwards. On May 13, 2024, we also issued $ 5.0 million aggregate principal amount of the 2029 Notes to HCRx in exchange for a $ 5.0 million reduction in our deferred royalty obligation. The 2029 Notes are second-lien secured obligations of the Company and bear interest at a rate of 6.00 % per year payable quarterly in arrears beginning on June 30, 2024. The 2029 Notes will mature on May 13, 2029, unless earlier converted, redeemed or repurchased in accordance with their terms. The 2029 Notes will be convertible into shares of our common stock at an initial conversion rate of 444.4444 shares per $ 1,000 principal amount (the “Conversion Option”), which is equivalent to a conversion price of $ 2.25 per share of common stock and subject to adjustment upon the occurrence of certain events and customary anti-dilution adjustments. Upon conversion of the 2029 Notes, we will deliver shares of our common stock plus cash in lieu of any fractional shares to the holders of the 2029 Notes. Holders of the 2029 Notes may convert their 2029 Notes at any time prior to the close of business on May 13, 2029. On or after May 13, 2026, we may redeem for cash all or a portion of the 2029 Notes if the last reported sale price of our common stock equals or exceeds 130 % of the conversion price then in effect for at least 20 trading days during any 30 consecutive trading day period (the “Redemption Option”). The redemption price will be equal to the principal amount of the 2029 Notes to be redeemed, plus any accrued and unpaid interest as of the redemption date. The redemption price will also include an amount equal to the aggregate value of all remaining interest payments on the 2029 Notes to be redeemed from the redemption date through maturity, which is payable in cash or, under certain circumstances and if we so elect, in shares of our common stock or a combination of cash and our common stock. Any sha res of our common stock used to pay this amount will be valued based on their market price at the time of the redemption. In some cases, we will be required to make an offer to repurchase the 2029 Notes at a 101 % premium with proceeds from certain asset sales, subject, in some cases, to reinvestment rights. If certain corporate events occur prior to the maturity date, a holder that elects to convert their 2029 Notes may be entitled to receive a payment from us, in cash or, under certain circumstances and if we so elect, in shares of our common stock, or a combination of cash and our common stock, based on an increase in the conversion rate in connection with such corporate event. In addition, if we undergo certain fundamental changes, holders may require us to repurchase for cash all or any portion of their 2029 Notes at a price equal to the principal amount of the 2029 Notes to be repurchased, plus any accrued and unpaid interest as of the repurchase date. No holder will be entitled to receive shares of our common stock in connection with the 2029 Notes if such receipt would cause the holder (together with its affiliates) to own more than 4.99 % (subject to increase or decrease at the election of the holder, but in no event to exceed 19.99 %) of the number of shares of the common stock outstanding immediately after giving effect to such event. In addition, a holder may elect to receive pre-funded warrants with respect to any shares of common stock that would otherwise be issuable in connection with the 2029 Notes but for the foregoing ownership limitations. These pre-funded warrants will have an exercise price of $ 0.0001 per share and will not expire. As of September 30, 2024, no pre-funded warrants have been issued. All obligations under the 2029 Notes are secured on a second priority basis by the same collateral that secures the obligations under the Term Loan. The 2029 Notes contain covenants and events of default that are generally consistent with the Term Loan. As of September 30, 2024, we were in compliance with these covenants. We accounted for the exchange of the 2025 Notes for the 2029 Notes and May 2024 Warrants as a debt extinguishment because the terms of the 2029 Notes are substantially different from the terms of the 2025 Notes. We recognized a $ 44.7 million gain on extinguishment of debt during the nine months ended September 30, 2024, the components of which are shown in the following table (in thousands): Condensed Consolidated Balance Sheet Line Transaction Amount Convertible senior notes due 2025 Extinguishment of 2025 Notes - principal $ 148,000 Convertible senior notes due 2025 Extinguishment of 2025 Notes - debt issuance costs ( 1,125 ) Convertible senior notes due 2029 Issuance of 2029 Notes recorded at fair value ( 78,889 ) Common stock warrants Issuance of May 2024 Warrants recorded at fair value ( 23,284 ) Gain on extinguishment of debt $ 44,702 As required by extinguishment accounting, the 2029 Notes received by the holders of the 2025 Notes were recorded at their initial fair value of $ 78.9 million as of May 8, 2024, which was estimated using a risk-neutral convertible bond model implemented using a binomial lattice which incorporates certain unobservable Level 3 key inputs including: (i) the volatility of our common stock price and (ii) our estimated credit spread. The $ 32.1 million difference between the initial fair value of $ 78.9 million and the principal amount of $ 111.0 million will be amortized to interest expense over the term of the 2029 Notes using the effective interest method over five years. In connection with the issuance of the 2029 Notes, we incurred $ 4.8 million of debt issuance costs, which are being amortized to interest expense using the effective interest method over five years . We have determined that the Conversion Option and Redemption Option are embedded derivatives that require bifurcation from the debt instrument and fair value recognition. These derivatives are referred to as the 2029 Notes Derivatives in Note 5, “ Fair Value Measurements” to our condensed consolidated financial statements. The 2029 Notes Derivatives were bifurcated at their initial fair value of $ 28.9 million. The following is a summary of the debt issuance costs and discounts being amortized to interest expense over the term of the 2029 Notes using the effective interest method, resulting in an effective interest rate of 26.94 % (in thousands): Amount Initial fair value adjustment $ 32,111 Debt issuance costs 4,758 Bifurcation of embedded derivatives 28,877 Debt issuance costs and discounts related to the 2029 Notes $ 65,746 The outstanding balance of the 2029 Notes consisted of the following (in thousands): As of September 30, 2024 Principal $ 116,000 Less: unamortized debt issuance costs and discounts ( 63,172 ) Plus: fair value of bifurcated derivative 19,263 2029 Notes $ 72,091 We determined the expected life of the 2029 Notes was equal to its five-year term. As of September 30, 2024, the “if-converted value” did not exceed the remaining principal amount of the 2029 Notes. The fair value of the 2029 Notes is influenced by market interest rates, our stock price and stock price volatility, and has been classified as Level 3 within the fair value hierarchy as it uses unobservable inputs. The estimated fair value of the 2029 Notes as of September 30, 2024 was approximately $ 87.2 million. We recognized $ 3.5 million of interest expense related to the 2029 Notes during the three months ended September 30, 2024 , which consisted of $ 1.8 million of amortization and $ 1.7 million of contractual interest expense. We recognized $ 5.5 million of interest expense related to the 2029 Notes during the nine months ended September 30, 2024 , which consisted of $ 2.8 million of amortization and $ 2.7 million of contractual interest expense. Future minimum payments on the 2029 Notes as of September 30, 2024 were as follows (in thousands): Years ended December 31, Future Minimum 2024 $ 1,740 2025 6,960 2026 6,960 2027 6,960 2028 6,960 2029 118,552 Total minimum payments 148,132 Less: interest expense and unamortized debt issuance costs and discounts ( 95,304 ) Plus: fair value of bifurcated derivative 19,263 2029 Notes $ 72,091 Deferred Royalty Obligation In September 2019, we entered into the Revenue Interest Agreement with HCRx, which was subsequently amended in June 2021, August 2023, and May 2024, under which we have received a total of $ 135.0 million, less certain transaction expenses. In exchange for this amount, HCRx receives payments from us at a percentage of net revenues of selinexor and any of our other future products, including worldwide net product sales and upfront payments, milestones, and royalties. Total payments to HCRx are capped at $ 263.3 million (the “Payment Cap”). In May 2024, we entered into an amendment (the “HCRx Amendment”) to the Amended Revenue Interest Agreement with HCRx, pursuant to which we: (1) made a cash payment to HCRx in the amount of $ 49.5 million; (2) delivered to HCRx a Term Loan note with a principal amount of $ 15.0 million; and (3) delivered to HCRx 2029 Notes with a principal amount of $ 5.0 million. As the repayment of the funded amount is contingent upon worldwide net product sales and upfront payments, milestones, and royalties, the repayment term may be shortened or extended depending on actual worldwide net product sales and upfront payments, milestones, and royalties. The repayment period expires on the earlier of (i) the date in which HCRx has received cash payments totaling $263.3 million or (ii) the legal maturity date of October 1, 2031. If HCRx has not received total payments equal to $263.3 million by September 2031, we will be required to pay an amount equal to $135.0 million plus a specific annual rate of return less payments previously paid to HCRx. In the event of a change of control, an event of default, including, among others, our failure to pay any amounts due to HCRx, insolvency, our failure to pay indebtedness when due, the revocation of regulatory approval of XPOVIO in the U.S. or our breach of any covenant contained in the Amended Revenue Interest Agreement and our failure to cure the breach within the prescribed time frame, we are obligated to pay HCRx an amount equal to $263.3 million less payments previously paid to HCRx. After giving effect to the above, as of May 2024, we had made aggregate payments under the Amended Revenue Interest Agreement totaling $ 135.0 million and the maximum remaining amount we owed to HCRx was $ 128.3 million. After May 2024, we are obligated to make quarterly payments in the amount of a fixed percentage of our net product revenues, upfront payments, milestones, and royalties earned in the applicable quarter, subject to the provisions in the Amended Revenue Interest Agreement described earlier in this footnote. The HCRx Amendment also subordinates the indebtedness and liens under the Amended Revenue Interest Agreement to the indebtedness and liens under the Term Loan, and, subject to certain exceptions, makes the indebtedness and liens under the Amended Revenue Interest Agreement pari passu with the indebtedness and liens under the 2029 Notes. In addition, the HCRx Amendment reduces the exercise price of 250,000 warrants to purchase shares of common stock issued to HCRx on August 1, 2023 from $ 2.25 per share to $ 1.10 per share. We have evaluated the terms of the Amended Revenue Interest Agreement and concluded that its features are similar to those of a debt instrument. Accordingly, we have accounted for the transaction as long-term debt and presented it as a deferred royalty obligation on our condensed consolidated balance sheets. We have also determined that the repayment of $ 263.3 million, less all payments made to date, upon a change of control is an embedded derivative that requires bifurcation from the debt instrument and fair value recognition as further described in Note 5, “ Fair Value Measurements” . As of September 30, 2024, we have made $ 140.9 million in payments to HCRx. The effective interest rate as of September 30, 2024 was approximately 16.08 % . We have incurred debt issuance costs totalin g $ 1.7 million which have been netted against the debt and are being amortized over the estimated term of the debt using the effective interest method, adjusted on a prospective basis for changes in the underlying assumptions and inputs. The carrying value of the deferred royalty obligation as of September 30, 2024 and December 31, 2023 was $ 73.5 million and $ 129.7 million, respectively, which included the carrying amount of the debt, the fair value of the bifurcated embedded derivative liability, and unamortized debt issuance costs. The carrying value of the deferred royalty obligation approximated fair value as of September 30, 2024 and December 31, 2023 and was based on our estimates of future payments to HCRx over the life of the arrangement, which are considered Level 3 inputs.

Common Share Warrants

Common Share Warrants	9 Months Ended
	Sep. 30, 2024
Warrants and Rights Note Disclosure [Abstract]
Common Share Warrants	11. Common Share Warrants Equity Classified Common Share Warrants On December 5, 2022, we issued to certain institutional investors, in a private placement offering of securities, warrants to purchase up to 9,537,563 shares of common stock at an exercise price of $ 6.36 per share. The warrants are exercisable through December 7, 2027. As of September 30, 2024, all of these warrants were outstanding. On August 1, 2023, in connection with the Second Amendment to the Revenue Interest Agreement dated as of August 1, 2023, we issued warrants to HCRx to purchase up to 250,000 shares of common stock at an exercise price of $ 2.25 per share. In May 2024, the exercise price was reduced to $ 1.10 per share in connection with the HCRx Amendment. The warrants are exercisable through August 1, 2030. As of September 30, 2024, all of these warrants were outstanding. Liability Classified Common Share Warrants In connection with the exchange of 2025 Notes for the 2029 Notes described in further detail in Note 10, “ Long-Term Obligations ”, we issued the May 2024 Warrants to purchase up to 45,776,213 shares of our common stock at an exercise price of $ 1.10 per share, subject to customary antidilution adjustments. The May 2024 Warrants are exercisable through May 13, 2029. If the closing price of our common stock exceeds two times the then current exercise price of the warrants, which is currently equal to $2.20, for 20 trading days during any 30 consecutive trading day period, we can require the holder to exercise the May 2024 Warrants. As of September 30, 2024, the May 2024 Warrants to purchase 45,776,212 shares of our common stock were outstanding. Under the terms of the May 2024 Warrants, a holder cannot receive shares of our common stock if such receipt would cause the holder (together with its affiliates) to own more than 4.99 % (subject to increase or decrease at the election of the holder, but in no event to exceed 19.99 %) of our common stock outstanding on the date of receipt. In addition, a holder may elect to receive pre-funded warrants with respect to any common stock that would otherwise be issuable but for the foregoing ownership limitations. These pre-funded warrants will have an exercise price of $ 0.0001 per share and will not expire. As of September 30, 2024 , no pre-funded warrants have been issued. The May 2024 Warrants were classified as a long-term liability in our condensed consolidated balance sheet because they did not meet the criteria for equity classification and are measured at fair value at the end of each reporting period as further described in Note 5, “ Fair Value Measurements.”

Nature of Business and Basis _2

Nature of Business and Basis of Presentation (Policies)	9 Months Ended
	Sep. 30, 2024
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements of the Company have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) for interim financial reporting and as required by Regulation S-X, Rule 10-01. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. In our opinion, all adjustments (including those which are normal and recurring) considered necessary for a fair presentation of the interim financial information have been included. When preparing financial statements in conformity with GAAP, we must make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues, expenses and related disclosures at the date of the financial statements. Actual results could differ from those estimates. Additionally, operating results for the three and nine months ended September 30, 2024 are not necessarily indicative of the results that may be expected for any other interim period or for the fiscal year ending December 31, 2024. For further information, refer to the financial statements and footnotes included in our Annual Report on Form 10-K for the year ended December 31, 2023 as filed with the Securities and Exchange Commission on February 29, 2024 (“Annual Report”).
Basis of Consolidation	Basis of Consolidation The condensed consolidated financial statements as of September 30, 2024 include the accounts of Karyopharm Therapeutics Inc. and its wholly-owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. The significant accounting policies used in preparation of these condensed consolidated financial statements in this Form 10-Q are consistent with those discussed in Note 2, “ Summary of Significant Accounting Policies ,” in our Annual Report.

Product Revenue (Tables)

Product Revenue (Tables)	9 Months Ended
	Sep. 30, 2024
XPOVIO [Member]
Summary of Product Revenue	To date, our only source of product revenue has been from the U.S. sales of XPOVIO. Net product revenue, including provisions primarily consisting of distribution fees and cash discounts, as well as reserves for chargebacks, rebates and returns, were as follows (in thousands): For the Three Months For the Nine Months 2024 2023 2024 2023 Gross product revenue $ 43,031 $ 37,981 $ 119,457 $ 111,387 Provisions for product revenue ( 13,515 ) ( 7,774 ) ( 35,903 ) ( 24,432 ) Total product revenue, net $ 29,516 $ 30,207 $ 83,554 $ 86,955

Inventory (Tables)

Inventory (Tables)	9 Months Ended
	Sep. 30, 2024
Inventory Disclosure [Abstract]
Schedule of Inventory, Current	The following table presents our inventory (in thousands), all of which was related to XPOVIO: As of September 30, 2024 As of December 31, 2023 Raw materials $ 720 $ 553 Work in process 3,410 1,732 Finished goods 542 758 Total inventory $ 4,672 $ 3,043

License Agreements (Tables)

License Agreements (Tables)	9 Months Ended
	Sep. 30, 2024
License and other revenue [Member]
Schedule of License and Other Revenue	The following table presents information about our license and other revenue (in thousands): For the Three Months For the Nine Months 2024 2023 2024 2023 Menarini $ 8,753 $ 5,564 $ 27,232 $ 19,912 Antengene 273 80 1,272 1,952 Other 241 158 2,637 3,467 Total license and other revenue $ 9,267 $ 5,802 $ 31,141 $ 25,331

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2024
Fair Value Disclosures [Abstract]
Schedule of Financial Assets That Have Been Measured at Fair Value	The following tables present information about our financial assets that have been measured at fair value and indicate the fair value hierarchy of the valuation inputs utilized to determine such fair value (in thousands): As of September 30, 2024 Quoted Significant Significant Cash equivalents: Money market funds $ 58,412 $ 58,412 $ — $ — Commercial paper 1,988 — 1,988 — Investments: Corporate debt securities 44,192 — 44,192 — Commercial paper 7,601 — 7,601 — U.S. government and agency securities 8,905 — 8,905 — $ 121,098 $ 58,412 $ 62,686 $ — As of December 31, 2023 Quoted Significant Significant Cash equivalents: Money market funds $ 27,963 $ 27,963 $ — $ — U.S. government and agency securities 1,998 — 1,998 — Investments: Corporate debt securities 77,961 — 77,961 — Commercial paper 13,744 — 13,744 — U.S. government and agency securities 47,507 — 47,507 — $ 169,173 $ 27,963 $ 141,210 $ —
Summary of the Changes in the Estimated Fair Value of Liabilities	The following table sets forth a summary of the changes in the estimated fair value of these liabilities, which are all classified as Level 3 (in thousands): HCRx Derivative 2029 Notes Derivatives May 2024 Warrants Balance as of December 31, 2023 $ 2,800 $ — $ — Initial recognition — 28,877 23,284 Change in fair value ( 2,800 ) ( 9,614 ) ( 5,929 ) Balance as of September 30, 2024 $ — $ 19,263 $ 17,355

Investments (Tables)

Investments (Tables)	9 Months Ended
	Sep. 30, 2024
Investments, Debt and Equity Securities [Abstract]
Summary of Investments, Classified as Available-for-Sale	The following tables summarize our investments, which are classified as available-for-sale and recorded at fair value (in thousands): As of September 30, 2024 Amortized Total Total Aggregate Fair Value Corporate debt securities $ 44,024 $ 171 $ ( 3 ) $ 44,192 Commercial paper 7,596 6 ( 1 ) 7,601 U.S. government and agency securities 8,904 2 ( 1 ) 8,905 Total $ 60,524 $ 179 $ ( 5 ) $ 60,698 As of December 31, 2023 Amortized Total Total Aggregate Fair Value Corporate debt securities $ 78,004 $ 79 $ ( 122 ) $ 77,961 Commercial paper 13,734 13 ( 3 ) 13,744 U.S. government and agency securities 47,543 4 ( 40 ) 47,507 Total $ 139,281 $ 96 $ ( 165 ) $ 139,212
Debt Securities Available-For-Sale	The following tables summarize our investments in an unrealized loss position for which an allowance for credit losses has not been recorded, aggregated by investment type and length of time in a continuous unrealized loss position (in thousands): As of September 30, 2024 Less than 12 Months 12 Months or Longer Total Aggregate Related Fair Value Unrealized Aggregate Related Fair Value Unrealized Aggregate Related Fair Value Unrealized Corporate debt securities $ 5,688 $ ( 3 ) $ — $ — $ 5,688 $ ( 3 ) Commercial paper 2,660 ( 1 ) — — 2,660 ( 1 ) U.S. government and agency securities 3,933 ( 1 ) — — 3,933 ( 1 ) Total $ 12,281 $ ( 5 ) $ — $ — $ 12,281 $ ( 5 ) As of December 31, 2023 Less than 12 Months 12 Months or Longer Total Aggregate Related Fair Value Unrealized Aggregate Related Fair Value Unrealized Aggregate Related Fair Value Unrealized Corporate debt securities $ 50,322 $ ( 112 ) $ 4,279 $ ( 10 ) $ 54,601 $ ( 122 ) Commercial paper 6,952 ( 3 ) — — 6,952 ( 3 ) U.S. government and agency securities 27,191 ( 37 ) 1,997 ( 3 ) 29,188 ( 40 ) Total $ 84,465 $ ( 152 ) $ 6,276 $ ( 13 ) $ 90,741 $ ( 165 )

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	9 Months Ended
	Sep. 30, 2024
Earnings Per Share [Abstract]
Schedule of Reconciliation of the Numerator and Denominator Used to Calculate Diluted Net Loss per Common Share	The following is a reconciliation of the numerator and denominator used to calculate diluted net loss per common share for the nine months ended September 30, 2024 (in thousands except per share amounts): For the Nine Months Ended September 30, 2024 Net loss $ ( 45,642 ) Add back interest expense on the 2025 Notes 2,518 Add back gain on extinguishment of debt ( 44,702 ) Numerator for diluted net loss per common share (A) $ ( 87,826 ) Weighted-average number of common shares outstanding 120,513 Dilutive effect of 2025 Notes calculated using the if-converted method 6,093 Denominator for diluted net loss per common share (B) 126,606 Diluted net loss per common share (= A / B) $ ( 0.69 )
Schedule of Potentially Dilutive Securities were Excluded from the Calculation of Diluted Net Loss Per Share Due to Their Anti-Dilutive Effect	The following potentially dilutive securities were excluded from the calculation of diluted net loss per common share due to their anti-dilutive effect under the treasury method (in thousands): As of September 30, 2024 2023 Outstanding common share warrants 55,563,775 9,787,563 Outstanding stock options 6,346 9,775 Unvested restricted stock units 12,914 7,818

Stock-based Compensation Expe_2

Stock-based Compensation Expense (Tables)	9 Months Ended
	Sep. 30, 2024
Share-Based Payment Arrangement [Abstract]
Schedule of Total Stock-based Compensation Expense Recognized in Connection with All Share-based Payment Awards	The following table summarizes stock-based compensation expense included in operating expenses (in thousands): For the Three Months Ended September 30, For the Nine Months Ended September 30, 2024 2023 2024 2023 Cost of sales $ 61 $ 96 $ 177 $ 281 Research and development 1,062 1,298 3,775 5,138 Selling, general and administrative 3,059 3,684 10,610 11,108 Total $ 4,182 $ 5,078 $ 14,562 $ 16,527

Long-Term Obligations (Tables)

Long-Term Obligations (Tables)	9 Months Ended
	Sep. 30, 2024
Summary of Gain on Extinguishment of Debt	We recognized a $ 44.7 million gain on extinguishment of debt during the nine months ended September 30, 2024, the components of which are shown in the following table (in thousands): Condensed Consolidated Balance Sheet Line Transaction Amount Convertible senior notes due 2025 Extinguishment of 2025 Notes - principal $ 148,000 Convertible senior notes due 2025 Extinguishment of 2025 Notes - debt issuance costs ( 1,125 ) Convertible senior notes due 2029 Issuance of 2029 Notes recorded at fair value ( 78,889 ) Common stock warrants Issuance of May 2024 Warrants recorded at fair value ( 23,284 ) Gain on extinguishment of debt $ 44,702
Summary of the Debt Issuance Cost and Discounts	The following is a summary of the debt issuance costs and discounts being amortized to interest expense over the term of the 2029 Notes using the effective interest method, resulting in an effective interest rate of 26.94 % (in thousands): Amount Initial fair value adjustment $ 32,111 Debt issuance costs 4,758 Bifurcation of embedded derivatives 28,877 Debt issuance costs and discounts related to the 2029 Notes $ 65,746
Term Loan [Member]
Summary of Outstanding Balances of Convertible Notes	The outstanding balance of the Term Loan consisted of the following (in thousands): As of September 30, 2024 Principal $ 100,000 Less: unamortized debt issuance costs ( 5,891 ) Term Loan $ 94,109
Summary of Future Minimum Payments on Convertible Notes	Future minimum payments on the Term Loan as of September 30, 2024 were as follows (in thousands): Years ended December 31, Future Minimum 2024 $ 9,517 2025 14,582 2026 33,211 2027 36,230 2028 60,747 Total minimum payments 154,287 Less: interest expense and unamortized debt issuance costs ( 60,178 ) Term Loan $ 94,109
2029 Notes [Member]
Summary of Outstanding Balances of Convertible Notes	The outstanding balance of the 2029 Notes consisted of the following (in thousands): As of September 30, 2024 Principal $ 116,000 Less: unamortized debt issuance costs and discounts ( 63,172 ) Plus: fair value of bifurcated derivative 19,263 2029 Notes $ 72,091
Summary of Future Minimum Payments on Convertible Notes	Future minimum payments on the 2029 Notes as of September 30, 2024 were as follows (in thousands): Years ended December 31, Future Minimum 2024 $ 1,740 2025 6,960 2026 6,960 2027 6,960 2028 6,960 2029 118,552 Total minimum payments 148,132 Less: interest expense and unamortized debt issuance costs and discounts ( 95,304 ) Plus: fair value of bifurcated derivative 19,263 2029 Notes $ 72,091
2025 Notes [Member]
Summary of Outstanding Balances of Convertible Notes	The outstanding balances of the 2025 Notes consisted of the following (in thousands): As of September 30, 2024 As of December 31, 2023 Principal $ 24,500 $ 172,500 Less: unamortized debt issuance costs ( 108 ) ( 1,581 ) 2025 Notes $ 24,392 $ 170,919
Schedule of Interest Expense Recognized Related to 2025 Notes	The following table sets forth total interest expense recognized related to the 2025 Notes (in thousands): For the Three Months For the Nine Months 2024 2023 2024 2023 Contractual interest expense $ 184 $ 1,293 $ 2,170 $ 3,881 Amortization of debt issuance costs 33 205 348 597 Total interest expense $ 217 $ 1,498 $ 2,518 $ 4,478
Summary of Future Minimum Payments on Convertible Notes	Future minimum payments on the 2025 Notes as of September 30, 2024 were as follows (in thousands): Years ended December 31, Future Minimum 2024 $ 368 2025 25,236 Total minimum payments 25,604 Less: interest expense and unamortized debt issuance costs ( 1,212 ) 2025 Notes $ 24,392

Nature of Business and Basis _3

Nature of Business and Basis of Presentation (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Accounting Policies [Abstract]
Cash, cash equivalents and investments	$ 133,500
Accumulated deficit	$ 1,532,680	$ 1,487,038

Product Revenue - Summary of Pr

Product Revenue - Summary of Product Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Total product revenue, net	$ 38,783	$ 36,009	$ 114,695	$ 112,286
Product [Member]
Gross product revenue	43,031	37,981	119,457	111,387
Provisions for product revenue	(13,515)	(7,774)	(35,903)	(24,432)
Total product revenue, net	$ 29,516	$ 30,207	$ 83,554	$ 86,955

Product Revenue - Additional In

Product Revenue - Additional Information (Detail) - USD ($)	9 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Disaggregation of Revenue [Line Items]
Accounts receivable	$ 31,778,000	$ 26,962,000
Bad debt write-offs	0
Credit losses	0	0
Product Revenue [Member]
Disaggregation of Revenue [Line Items]
Accounts receivable	$ 24,500,000	$ 17,800,000

Inventory - Schedule of Invento

Inventory - Schedule of Inventory Current (Detail) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Inventory Disclosure [Abstract]
Raw materials	$ 720	$ 553
Work in process	3,410	1,732
Finished goods	542	758
Total inventory	$ 4,672	$ 3,043

License Agreements - Schedule o

License Agreements - Schedule of License and Other Revenue (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Total license and other revenue	$ 9,267	$ 5,802	$ 31,141	$ 25,331
License and other revenue [Member] | Menarini [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Total license and other revenue	8,753	5,564	27,232	19,912
License and other revenue [Member] | Antengene [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Total license and other revenue	273	80	1,272	1,952
Other [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Total license and other revenue	$ 241	$ 158	$ 2,637	$ 3,467

License Agreements - Additional

License Agreements - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Royalty revenue recognized	$ 38,783	$ 36,009	$ 114,695	$ 112,286
Revenue from contract with customer, license and other revenue	38,783	36,009	114,695	112,286
Antengene [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Royalty revenue recognized			1,200
Other milestone method revenue recognized			2,000	2,500
Other revenue				500
Revenue from contract with customer, license and other revenue			1,200
Menarini [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Reimbursement of development related expenses	2,000	$ 5,400	15,000	15,000
License-related revenue	6,000		10,000
Other revenue			600	700
License and other revenue [Member] | Other Current Assets [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Royalty revenue recognized					$ 1,000
Revenue from contract with customer, license and other revenue					1,000
License and other revenue [Member] | Accounts Receivable 1 [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Royalty revenue recognized			7,200		9,100
Revenue from contract with customer, license and other revenue			7,200		$ 9,100
License [Member] | Menarini [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Royalty revenue recognized				3,500
Revenue from contract with customer, license and other revenue				3,500
Royalty [Member] | Antengene [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Royalty revenue recognized	300			1,500
Revenue from contract with customer, license and other revenue	300			1,500
Royalty [Member] | Menarini [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Royalty revenue recognized	500		1,600	700
Revenue from contract with customer, license and other revenue	$ 500		$ 1,600	700
Other Royalty [Member] | Antengene [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Royalty revenue recognized				500
Revenue from contract with customer, license and other revenue				$ 500

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Financial Assets That Have Been Measured at Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	$ 60,698	$ 139,212
Total	121,098	169,173
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	58,412	27,963
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	62,686	141,210
Short-Term Investments, Corporate debt securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	44,192	77,961
Short-Term Investments, Corporate debt securities [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	44,192	77,961
Short-Term Investments, Commercial Paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	7,601	13,744
Short-Term Investments, Commercial Paper [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	7,601	13,744
Short-Term Investments, US Government Agencies Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	8,905	47,507
Short-Term Investments, US Government Agencies Debt Securities [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	8,905	47,507
Commercial Paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	1,988
Commercial Paper [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	1,988
U.S. government and agency securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents		1,998
Investments	8,905	47,507
U.S. government and agency securities [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents		1,998
Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	58,412	27,963
Money Market Funds [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	$ 58,412	$ 27,963

Fair Value Measurements - Summa

Fair Value Measurements - Summary of the Changes in the Estimated Fair Value of These Liabilities (Details) - Level 3 [Member] $ in Thousands	9 Months Ended
	Sep. 30, 2024 USD ($)
HCRx Derivative [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	$ 2,800
Change in fair value	(2,800)
2029 Notes Derivatives [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Initial recognition	28,877
Change in fair value	(9,614)
Ending Balance	19,263
May 2024 Warrants [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Initial recognition	23,284
Change in fair value	(5,929)
Ending Balance	$ 17,355

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details) shares in Millions, $ in Millions	Sep. 30, 2024 USD ($) shares
HCRx Derivative [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Deffered Royalty Obligation | $	$ 56.2
MayTwo Thousand Twenty four Warrants [Member] | Maximum [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Warrants purchased | shares	45.8

Investments - Summary of Invest

Investments - Summary of Investments, Classified as Available-for-Sale (Detail) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 60,524	$ 139,281
Gross Unrealized Gains	179	96
Total Unrealized Loss	(5)	(165)
Aggregate Fair Value	60,698	139,212
Corporate Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	44,024	78,004
Gross Unrealized Gains	171	79
Total Unrealized Loss	(3)	(122)
Aggregate Fair Value	44,192	77,961
Commercial Paper [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	7,596	13,734
Gross Unrealized Gains	6	13
Total Unrealized Loss	(1)	(3)
Aggregate Fair Value	7,601	13,744
U.S. government and agency securities [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	8,904	47,543
Gross Unrealized Gains	2	4
Total Unrealized Loss	(1)	(40)
Aggregate Fair Value	$ 8,905	$ 47,507

Investments - Additional Inform

Investments - Additional Information (Detail) $ in Thousands	Sep. 30, 2024 USD ($) Security	Dec. 31, 2023 USD ($) Security
Debt Securities, Available-for-sale [Line Items]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Less than One Year | Security	8	41
Unrealized losses, other-than-temporary impairments | $	$ 0	$ 0

Investments - Debt Securities A

Investments - Debt Securities Available-For-Sale (Detail) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Fair Value, Less than 12 Months	$ 12,281	$ 84,465
Unrealized Losses, Less than 12 Months	(5)	(152)
Fair Value, 12 Months or Longer	0	6,276
Unrealized Losses,12 Months or Longer	0	(13)
Fair Value	12,281	90,741
Unrealized Losses	(5)	(165)
Corporate Debt Securities [Member]
Fair Value, Less than 12 Months	5,688	50,322
Unrealized Losses, Less than 12 Months	(3)	(112)
Fair Value, 12 Months or Longer	0	4,279
Unrealized Losses,12 Months or Longer	0	(10)
Fair Value	5,688	54,601
Unrealized Losses	(3)	(122)
Commercial Paper [Member]
Fair Value, Less than 12 Months	2,660	6,952
Unrealized Losses, Less than 12 Months	(1)	(3)
Fair Value	2,660	6,952
Unrealized Losses	(1)	(3)
U.S. government and agency securities [Member]
Fair Value, Less than 12 Months	3,933	27,191
Unrealized Losses, Less than 12 Months	(1)	(37)
Fair Value, 12 Months or Longer	0	1,997
Unrealized Losses,12 Months or Longer	0	(3)
Fair Value	3,933	29,188
Unrealized Losses	$ (1)	$ (40)

Net Loss Per Share - Additional

Net Loss Per Share - Additional Information (Details) - shares		9 Months Ended
	Dec. 05, 2022	Sep. 30, 2024
Warrant [Member] | Private Placement [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Number of shares of common stock issued	9,537,563
Warrant [Member] | Maximum [Member] | Private Placement [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Number of shares of common stock issued		55,563,775
3% Convertible Senior Notes Due 2025 [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Notes, interest rate		3%

Net Loss Per Share - Schedule o

Net Loss Per Share - Schedule of Reconciliation of the Numerator and Denominator Used to Calculate Diluted Net Loss per Common Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Numerator
Net Income (Loss)	$ (32,072)	$ (34,506)	$ (45,642)	$ (101,262)
Add back gain on extinguishment of debt	$ 0	$ 0	(44,702)	$ 0
Numerator for diluted net loss per common share (A)			$ (87,826)
Denominator
Weighted-average number of common shares outstanding	125,010	114,401	120,513	114,033
Denominator for diluted net loss per common share (B)	125,010	114,401	126,606	114,033
Net Income per Common Share
Diluted net loss per common share (= A / B)	$ (0.26)	$ (0.3)	$ (0.69)	$ (0.89)
2025 Notes [Member]
Numerator
Add back interest expense			$ 2,518
Denominator
Dilutive effect of Notes calculated using the if-converted method			6,093
2029 Notes [Member]
Numerator
Add back gain on extinguishment of debt			$ (44,700)

Net Loss Per Share - Schedule_2

Net Loss Per Share - Schedule of Potentially Dilutive Securities were Excluded from the Calculation of Diluted Net Loss Per Share Due to Their Anti-Dilutive Effect (Detail) - shares shares in Thousands	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Outstanding Common Share Warrants [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Dilutive securities excluded from the calculation of diluted net loss per share due to anti-dilutive effect (in shares)	55,563,775	9,787,563
Outstanding Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Dilutive securities excluded from the calculation of diluted net loss per share due to anti-dilutive effect (in shares)	6,346	9,775
Unvested Restricted Stock Units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Dilutive securities excluded from the calculation of diluted net loss per share due to anti-dilutive effect (in shares)	12,914	7,818

Stock-based Compensation Expe_3

Stock-based Compensation Expense - Schedule of Total Stock-based Compensation Expense Recognized in Connection with All Share-based Payment Awards (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 4,182	$ 5,078	$ 14,562	$ 16,527
Cost of Sales [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	61	96	177	281
Research and Development [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	1,062	1,298	3,775	5,138
Selling,General and Administrative Expenses [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 3,059	$ 3,684	$ 10,610	$ 11,108

Stock-based Compensation Expe_4

Stock-based Compensation Expense - Additional Information (Detail) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
	May 29, 2024	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense		$ 4,182	$ 5,078	$ 14,562	$ 16,527
Selling,General and Administrative Expenses [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense		3,059	$ 3,684	10,610	$ 11,108
Private Placement [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Debt issuance costs		$ 6,900		6,900
Private Placement [Member] | Selling,General and Administrative Expenses [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense				$ 800
Private Placement [Member] | Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares of common stock issued	6,872,027
2022 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of additional shares available under the 2022 plan	6,000,000
Amended & Restated 2013 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of additional shares available under the 2022 plan	5,000,000

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - Open Market Sale Agreement [Member] - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Feb. 17, 2023
Common Stock [Member]
Equity Offering [Line Items]
Net proceeds from sale of common stock			$ 100
Jefferies LLC [Member] | Common Stock [Member]
Equity Offering [Line Items]
Number of shares of common stock issued	0	0	0	0
Maximum [Member] | Jefferies LLC [Member]
Equity Offering [Line Items]
Aggregate offering price					$ 100
Percentage of commission of gross proceeds from the sale of Shares			3%

Long-Term Obligations - Additio

Long-Term Obligations - Additional Information (Detail)		1 Months Ended		3 Months Ended		9 Months Ended
	May 13, 2024 USD ($) shares	May 31, 2024 USD ($) shares	Sep. 30, 2019 USD ($)	Sep. 30, 2024 USD ($) $ / shares shares	Sep. 30, 2023 USD ($)	Sep. 30, 2024 USD ($) Days $ / shares shares	Sep. 30, 2023 USD ($)	May 08, 2024 USD ($) shares	Dec. 31, 2023 USD ($)	Aug. 01, 2023 $ / shares shares	Oct. 31, 2018 USD ($)
Subsequent Event [Line Items]
Cash, cash equivalents and investments				$ 133,500,000		$ 133,500,000
Debt instrument convertible threshold consecutive trading days | Days						5
Description of debt instrument convertible period						during the five-business day period immediately after any five consecutive trading day period
Principal amount of notes used in conversion rate						$ 1,000
Debt instrument convertible threshold maximum percentage of product of last reported sale price of common stock						98%
Percentage of redemption fee						3%
Debt instrument exchange amount		$ 148,000,000
Exercise price | $ / shares				$ 0.0001		$ 0.0001
Gain on extinguishment of debt				$ 0	$ 0	$ 44,702,000	$ 0
Line of Credit [Member]
Subsequent Event [Line Items]
Quarterly cash payments						6.25%
Secured Overnight Financing Rate [Member] | Line of Credit [Member]
Subsequent Event [Line Items]
Rate margin						9.25%
Base Rate [Member] | Line of Credit [Member]
Subsequent Event [Line Items]
Rate margin						3%
Maximum [Member]
Subsequent Event [Line Items]
Prepayment premium						5%
Exercise price | $ / shares										$ 2.25
Minimum [Member]
Subsequent Event [Line Items]
Prepayment premium						3%
Exercise price | $ / shares										$ 1.1
May 2024 Warrants [Member]
Subsequent Event [Line Items]
Warrants purchased | shares				45,776,212		45,776,212		45,776,213
Exercise price | $ / shares				$ 1.1		$ 1.1
Conversion price description						The May 2024 Warrants are exercisable through May 13, 2029. If the closing price of our common stock exceeds two times the then current exercise price of the warrants, which is currently equal to $2.20, for 20 trading days during any 30 consecutive trading day period, we can require the holder to exercise the May 2024 Warrants.
May 2024 Warrants [Member] | Maximum [Member]
Subsequent Event [Line Items]
Warrants purchased | shares	45,800,000	45,800,000
Percentage common stock outstanding				19.99%		19.99%
May 2024 Warrants [Member] | Minimum [Member]
Subsequent Event [Line Items]
Percentage common stock outstanding				4.99%		4.99%
Pre Funded Warrants [Member]
Subsequent Event [Line Items]
Exercise price | $ / shares				$ 0.0001		$ 0.0001
Number of warrants unissued | shares				0		0
Deferred Royalty Obligation [Member] | Level 3 [Member]
Subsequent Event [Line Items]
Deferred royalty obligation at fair value				$ 73,500,000		$ 73,500,000			$ 129,700,000
HealthCare Royalty Partners IV LP [Member]
Subsequent Event [Line Items]
Maximum remaining amount		$ 128,300,000
HealthCare Royalty Partners IV LP [Member] | Warrant [Member]
Subsequent Event [Line Items]
Warrants purchased | shares										250,000,000
Revenue Interest Financing Agreement [Member]
Subsequent Event [Line Items]
Debt issuance costs				1,700,000		1,700,000
First investment amount			$ 135,000,000
Bifurcation of embedded derivatives				$ 263,300,000		$ 263,300,000
Aggregate Royalties			$ 263,300,000
Revenue Interest Financing Agreement [Member] | HealthCare Royalty Partners IV LP [Member]
Subsequent Event [Line Items]
Repayment terms						term may be shortened or extended depending on actual worldwide net product sales and upfront payments, milestones, and royalties. The repayment period expires on the earlier of (i) the date in which HCRx has received cash payments totaling $263.3 million or (ii) the legal maturity date of October 1, 2031. If HCRx has not received total payments equal to $263.3 million by September 2031, we will be required to pay an amount equal to $135.0 million plus a specific annual rate of return less payments previously paid to HCRx. In the event of a change of control, an event of default, including, among others, our failure to pay any amounts due to HCRx, insolvency, our failure to pay indebtedness when due, the revocation of regulatory approval of XPOVIO in the U.S. or our breach of any covenant contained in the Amended Revenue Interest Agreement and our failure to cure the breach within the prescribed time frame, we are obligated to pay HCRx an amount equal to $263.3 million less payments previously paid to HCRx.
Amended Revenue Interest Agreement [Member]
Subsequent Event [Line Items]
Aggregate principal amount		135,000,000
Revenue Interest Agreement and Amended Revenue Interest Agreement [Member]
Subsequent Event [Line Items]
Debt instrument interest rate				16.08%		16.08%
Revenue Interest Agreement and Amended Revenue Interest Agreement [Member] | HealthCare Royalty Partners IV LP [Member]
Subsequent Event [Line Items]
Cumulative payments		49,500,000		$ 140,900,000		$ 140,900,000
Convertible Note Offering [Member]
Subsequent Event [Line Items]
Notes converted in to common stock, amount | shares						63.0731
Notes converted in to common stock, shares						$ 1,000
Notes, conversion price per share | $ / shares				$ 15.85		$ 15.85
Term Loan [Member]
Subsequent Event [Line Items]
Aggregate principal amount		15,000,000
Debt issuance costs				$ 6,800,000		$ 6,800,000
Contractual interest expense				$ 3,700,000		$ 5,800,000
Debt discount and issuance costs amortized to interest expense, amortization period						4 years
Expected life						4 years
Debt instrument interest rate				17.86%		17.86%
Interest expense on debt				$ 4,300,000		$ 6,700,000
Amortization of debt issuance cost				600,000		900,000
6% Convertible Senior Notes Due 2029 [Member]
Subsequent Event [Line Items]
Aggregate principal amount		111,000,000
6% Convertible Senior Notes Due 2029 [Member] | HealthCare Royalty Partners IV LP [Member]
Subsequent Event [Line Items]
Aggregate principal amount		5,000,000
Credit Agreement and Term Loan [Member] | Line of Credit [Member]
Subsequent Event [Line Items]
Cash, cash equivalents and investments				25,000,000		25,000,000
Line of credit facility								$ 100,000,000
2029 Notes [Member]
Subsequent Event [Line Items]
Aggregate principal amount	$ 5,000,000			116,000,000		116,000,000
Debt issuance costs				4,758,000		4,758,000
Contractual interest expense				1,700,000		$ 2,700,000
Debt discount and issuance costs amortized to interest expense, amortization period						5 years
Notes, interest rate						6%
Proceeds from convertible debt						$ 111,000,000
Notes conversion price, percentage						130%
Notes instrument, trading days | Days						20
Debt instrument convertible threshold consecutive trading days | Days						30
Percentage of redeem notes at premium with proceeds						101%
Estimated fair value of convertible notes				$ 87,200,000		$ 87,200,000
Debt instrument interest rate				26.94%		26.94%
Long-term debt gross				$ 148,132,000		$ 148,132,000
Gain on extinguishment of debt						44,700,000
Initial fair value				78,900,000		78,900,000		$ 78,900,000
Initial fair value adjustment						32,100,000
Bifurcation of embedded derivatives				28,900,000		28,900,000
Interest expense on debt				3,500,000		5,500,000
Amortization of debt issuance cost				$ 1,800,000		$ 2,800,000
2029 Notes [Member] | Maximum [Member]
Subsequent Event [Line Items]
Percentage common stock outstanding				19.99%		19.99%
2029 Notes [Member] | Minimum [Member]
Subsequent Event [Line Items]
Percentage common stock outstanding				4.99%		4.99%
2029 Notes [Member] | HealthCare Royalty Partners IV LP [Member]
Subsequent Event [Line Items]
Aggregate principal amount	5,000,000
2029 Notes [Member] | Convertible Note Offering [Member]
Subsequent Event [Line Items]
Notes converted in to common stock, amount | shares						444.4444
Notes converted in to common stock, shares						$ 1,000
Proceeds from convertible debt						$ 111,000,000
Notes, conversion price per share | $ / shares				$ 2.25		$ 2.25
2025 Notes [Member]
Subsequent Event [Line Items]
Aggregate principal amount		$ 24,500,000		$ 24,500,000		$ 24,500,000			172,500,000		$ 172,500,000
Debt issuance costs				5,600,000		5,600,000
Contractual interest expense				184,000	1,293,000	$ 2,170,000	3,881,000
Debt discount and issuance costs amortized to interest expense, amortization period						7 years
Notes, interest rate						3%
Notes, maturity date						Oct. 15, 2025
Principal amount of notes used in conversion rate				1,000		$ 1,000
Debt instrument, convertible latest date						Jun. 15, 2025
Notes conversion price, percentage						130%
Notes instrument, trading days | Days						20
Debt instrument convertible threshold consecutive trading days | Days						30
Notes, repurchase price						100%
Estimated fair value of convertible notes				$ 19,200,000		$ 19,200,000			$ 87,900,000
Expected life						7 years
Debt instrument interest rate				3.53%		3.53%
Long-term debt gross				$ 25,604,000		$ 25,604,000
Interest expense on debt				217,000	1,498,000	2,518,000	4,478,000
Amortization of debt issuance cost				$ 33,000	$ 205,000	$ 348,000	$ 597,000
2025 Notes [Member] | Convertible Note Offering [Member]
Subsequent Event [Line Items]
Notes converted in to common stock, shares	$ 148,000,000

Long-Term Obligations - Summary

Long-Term Obligations - Summary of Outstanding Balances of 2025 Notes (Detail) - 2025 Notes [Member] - USD ($) $ in Thousands	Sep. 30, 2024	May 31, 2024	Dec. 31, 2023	Oct. 31, 2018
Liability component:
Principal	$ 24,500	$ 24,500	$ 172,500	$ 172,500
Less: unamortized debt issuance costs	(108)		(1,581)
2025 Notes	$ 24,392		$ 170,919

Long-Term Obligations - Schedul

Long-Term Obligations - Schedule of Interest Expense Recognized Related to 2025 Notes (Detail) - 2025 Notes [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Debt Instrument [Line Items]
Contractual interest expense	$ 184	$ 1,293	$ 2,170	$ 3,881
Amortization of debt issuance cost	33	205	348	597
Total interest expense	$ 217	$ 1,498	$ 2,518	$ 4,478

Long-Term Obligations - Summa_2

Long-Term Obligations - Summary of Future Minimum Payments on 2025 Notes (Detail) - 2025 Notes [Member] $ in Thousands	Sep. 30, 2024 USD ($)
Debt Instrument [Line Items]
2024	$ 368
2025	25,236
Total minimum payments	25,604
Less: interest expense and unamortized debt issuance costs	(1,212)
Term Loan	$ 24,392

Long-Term Obligations - Summa_3

Long-Term Obligations - Summary of Outstanding Balances of Term Loan (Detail) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Liability component:
Term Loan	$ 94,109	$ 0
Term Loan [Member]
Liability component:
Principal	100,000
Less: unamortized debt issuance costs	(5,891)
Term Loan	$ 94,109

Long-Term Obligations - Summa_4

Long-Term Obligations - Summary of Future Minimum Payments on Term Loan (Detail) - Term Loan [Member] $ in Thousands	Sep. 30, 2024 USD ($)
Debt Instrument [Line Items]
2024	$ 9,517
2025	14,582
2026	33,211
2027	36,230
2028	60,747
Total minimum payments	154,287
Less: interest expense and unamortized debt issuance costs	(60,178)
Term Loan	$ 94,109

Long-Term Obligations - Summa_5

Long-Term Obligations - Summary of Gain on Extinguishment of Debt (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Debt Instrument [Line Items]
Gain on extinguishment of debt	$ 0	$ 0	$ 44,702	$ 0
Common stock warrants [Member] | Issuance of May 2024 Warrants recorded at fair value [Member]
Debt Instrument [Line Items]
Gain on extinguishment of debt			(23,284)
Convertible senior notes due 2025 [Member] | Extinguishment of 2025 Notes - Principal [Member]
Debt Instrument [Line Items]
Gain on extinguishment of debt			148,000
Convertible senior notes due 2025 [Member] | Extinguishment of 2025 Notes - Debt issuance costs [Member]
Debt Instrument [Line Items]
Gain on extinguishment of debt			(1,125)
Convertible senior notes due 2029 [Member] | Issuance of 2029 Notes recorded at fair value [Member]
Debt Instrument [Line Items]
Gain on extinguishment of debt			$ (78,889)

Long-Term Obligations - Summa_6

Long-Term Obligations - Summary of The Debt Issuance Cost And Discounts (Detail) - 2029 Notes [Member] $ in Thousands	Sep. 30, 2024 USD ($)
Debt Instrument [Line Items]
Initial fair value adjustment	$ 32,111
Debt issuance costs	4,758
Bifurcation of embedded derivatives	28,877
Debt issuance costs and discounts related to the 2029 Notes	$ 65,746

Long-Term Obligations - Summa_7

Long-Term Obligations - Summary of Outstanding Balances of 2029 Notes (Detail) - 2029 Notes [Member] - USD ($) $ in Thousands	Sep. 30, 2024	May 13, 2024
Debt Instrument [Line Items]
Principal	$ 116,000	$ 5,000
Less: unamortized debt issuance costs	(63,172)
Plus: fair value of bifurcated derivative	19,263
Term Loan	$ 72,091

Long-Term Obligations - Summa_8

Long-Term Obligations - Summary of Future Minimum Payments on 2029 Notes (Detail) - Two Thousand Twenty Nine Notes [Member] $ in Thousands	Sep. 30, 2024 USD ($)
Debt Instrument [Line Items]
2024	$ 1,740
2025	6,960
2026	6,960
2027	6,960
2028	6,960
2029	118,552
Total minimum payments	148,132
Less: interest expense and unamortized debt issuance costs	(95,304)
Plus: fair value of bifurcated derivative	19,263
Term Loan	$ 72,091

Common Share Warrants - Additio

Common Share Warrants - Additional Information (Detail) - $ / shares			9 Months Ended
	Aug. 01, 2023	Dec. 05, 2022	Sep. 30, 2024	May 31, 2024	May 13, 2024	May 08, 2024
Class of Warrant or Right [Line Items]
Exercise price			$ 0.0001
HealthCare Royalty Partners IV LP [Member]
Class of Warrant or Right [Line Items]
Warrant, Exercise Price, Decrease	$ 1.1
Warrant [Member] | Private Placement [Member]
Class of Warrant or Right [Line Items]
Number of shares of common stock issued		9,537,563
Sale of stock price per share		$ 6.36
Warrant [Member] | HealthCare Royalty Partners IV LP [Member]
Class of Warrant or Right [Line Items]
Number of shares of common stock issued	250,000
Sale of stock price per share	$ 2.25
Warrants purchased	250,000,000
May 2024 Warrants [Member]
Class of Warrant or Right [Line Items]
Warrants purchased			45,776,212			45,776,213
Exercise price			$ 1.1
Conversion price description			The May 2024 Warrants are exercisable through May 13, 2029. If the closing price of our common stock exceeds two times the then current exercise price of the warrants, which is currently equal to $2.20, for 20 trading days during any 30 consecutive trading day period, we can require the holder to exercise the May 2024 Warrants.
Pre Funded Warrants [Member]
Class of Warrant or Right [Line Items]
Exercise price			$ 0.0001
Number of warrants unissued			0
Maximum [Member]
Class of Warrant or Right [Line Items]
Exercise price	$ 2.25
Maximum [Member] | Warrant [Member] | Private Placement [Member]
Class of Warrant or Right [Line Items]
Number of shares of common stock issued			55,563,775
Maximum [Member] | May 2024 Warrants [Member]
Class of Warrant or Right [Line Items]
Warrants purchased				45,800,000	45,800,000
Percentage common stock outstanding			19.99%
Minimum [Member]
Class of Warrant or Right [Line Items]
Exercise price	$ 1.1
Minimum [Member] | May 2024 Warrants [Member]
Class of Warrant or Right [Line Items]
Percentage common stock outstanding			4.99%