0001326732-24-000029 | 10-Q | XBRL Viewer

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Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2024	Dec. 31, 2023
Statement of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	200,000,000	200,000,000
Common stock, shares issued (in shares)	61,634,685	60,998,191
Common stock, shares outstanding (in shares)	61,634,685	60,998,191

Leases

3 Months Ended

Mar. 31, 2024

Leases [Abstract]

Leases

The Company leases office and laboratory space in Monrovia, California under a lease that expires in December 2025 with an option to renew for an additional five years at then market rates. The Company has assessed that it is unlikely to exercise the option to extend the lease term.

In June 2021, the Company entered into an Agreement of Lease (Lease Agreement) for laboratory and office space in Pasadena, California, which will expire in July 2035. The Lease Agreement provides for two separate phases of lease and occupancy. The first phase commenced on August 1, 2022 and provides the Company with an improvement allowance up to $17.0 million. The second phase of the lease agreement will commence no later than September 30, 2026 and includes an additional improvement allowance up to $3.3 million. In August 2022, the Company entered into an amendment, which the Company received an additional $5.0 million in tenant improvement allowance in exchange for an increase in the rental rate of the phase 1 space. The Company received delivery of the second phase premises on December 1, 2022. The Company placed the new facility into service in February 2023. In January 2024, the Company entered into an amendment, in which the Company will be paid for $0.7 million of tenant improvement allowance from the second phase for HVAC costs in the first phase.

In August 2023, the Company entered into a Sublease Agreement for office space in San Diego, California. The term of the Sublease Agreement begins in September 2023 and ends in December 2027. In connection with the Sublease Agreement, the Company provided a $0.4 million Letter of Credit to the landlord. The Letter of Credit will decline over the term of the lease. The Company also entered into a Cash Collateral Agreement for $0.4 million, which is classified as restricted cash in the Consolidated Balance Sheets.

The Company’s lease agreements do not contain any residual value guarantees or restrictive covenants.

The following table reconciles the undiscounted cash flows for the operating leases at March 31, 2024 to the operating lease liabilities recorded on the balance sheet (in thousands):


Years ending December 31,
For the remainder of 2024	$	4,460
2025	8,022
2026	9,238
2027	9,560
2028	9,076
2029	9,331
Thereafter	57,104
Total undiscounted lease payments	106,791
Less: Tenant allowance	(3,252)
Less: Imputed interest	(34,650)
Present value of lease payments	$	68,889

Lease liabilities - short-term	$	2,079
Lease liabilities - long-term	66,810
Total lease liabilities	$	68,889

The following table summarizes lease costs and cash payments for the three months ended March 31, 2024 and 2023 (in thousands):


	Three Months Ended March 31,
	2024		2023

Operating lease cost	$	1,881	$	2,181
Variable lease cost	830		234
Total lease costs	$	2,711	$	2,415

Cash paid for amounts included in the measurement of lease liabilities	$	1,070	$	724

As of March 31, 2024, the weighted-average remaining lease term for operating leases is 10.9 years, and the weighted-average discount rate for operating leases is 7.0%. As of March 31, 2023, the weighted-average remaining lease term for operating leases was 11.8 years, and the weighted-average discount rate for operating leases was 8.9%.

Subsequent Event	3 Months Ended
Subsequent Event	Mar. 31, 2024
Subsequent Events [Abstract]
Subsequent Event	Subsequent Event On May 3, 2024, Zenas closed on a Series C financing transaction. We expect the financing will result in an impairment in the fair value of our investment in Zenas of approximately $20.6 million, using the difference between the carrying value of our investment and the share price in the financing transaction. We have recorded the amount as an impairment charge on equity securities in our statement of loss. We are evaluating the magnitude of this impairment, including an assessment of the liquidation preferences of the various classes of Zenas securities, which will be reflected in our next Quarterly Report on Form 10-Q.

Summary of Significant Accounting Policies (Details) - USD ($)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Patents, licenses, and other intangible assets
Impairment of intangible assets	$ 0	$ 0
Abandonment of capitalized intangible assets	415,000	321,000
Impairment loss or recoveries	0	0
Net loss attributable to non-controlling interest	(1,400,000)	3,300,000
Impairment on equity securities	20,650,000	0
Zenas
Patents, licenses, and other intangible assets
Impairment on equity securities	20,600,000	0
Zenas \| Preferred Stock
Patents, licenses, and other intangible assets
Equity shares estimated fair value	43,560,000		$ 64,210,000
Zenas \| Milestone \| Preferred Stock \| License Agreement
Patents, licenses, and other intangible assets
Equity shares estimated fair value			$ 10,000,000
In-process intangible assets
Patents, licenses, and other intangible assets
Abandonment of capitalized intangible assets	$ 400,000	$ 300,000

Marketable Debt and Equity Securities - Equity Securities with Readily Determinable Fair Value (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Equity Securities
Net gains (losses) recognized on equity securities	$ 2,325	$ (2,898)
Equity securities with readily determinable fair value	44,535		$ 42,210
Common Stock
Equity Securities
Equity securities with readily determinable fair value	44,535		42,210
Astria/Catabasis \| Common Stock
Equity Securities
Equity securities with readily determinable fair value	9,823		5,360
INmune \| Common Stock
Equity Securities
Equity securities with readily determinable fair value	22,155		21,231
Viridian \| Common Stock
Equity Securities
Equity securities with readily determinable fair value	$ 12,557		$ 15,619

Marketable Debt and Equity Securities - Maturities (Details) $ in Thousands	Mar. 31, 2024 USD ($)
Amortized Cost
Mature in one year or less	$ 460,336
Mature within two years	155,134
Amortized Cost	615,470
Estimated Fair Value
Mature in one year or less	460,367
Mature within two years	154,960
Estimated Fair Value	$ 615,327

Stock-Based Compensation - Option Activity (Details) - Stock options - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Number of Shares Subject to Outstanding Options
Balance at the beginning of the period (in shares)	11,142,986
Options granted (in shares)	1,763,778	1,620,256
Options forfeited (in shares)	(206,485)
Options exercised (in shares)	(152,682)
Balance at the end of the period (in shares)	12,547,597		11,142,986
Exercisable options (in shares)	8,185,860
Weighted Average Exercise Price (Per Share)
Balance at the beginning of the period (in dollars per share)	$ 29.60
Options granted (in dollars per share)	22.81
Options forfeited (in dollars per share)	31.55
Options exercised (in dollars per share)	11.70
Balance at the end of the period (in dollars per share)	28.84		$ 29.60
Exercisable (in dollars per share)	$ 29.38
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Additional Disclosures [Abstract]
Weighted-average remaining contractual term, balance outstanding	6 years 2 months 19 days		6 years 10 days
Weighted-average remaining contractual term, exercisable	4 years 9 months 3 days
Aggregate intrinsic value, balance outstanding	$ 9,618		$ 9,977
Aggregate intrinsic value, exercisable	$ 9,465

Sales of Future Royalties

3 Months Ended

Mar. 31, 2024

Receivables [Abstract]

Sale of Future Royalties

Ultomiris Royalty Sale Agreement

The Company evaluated the arrangement and determined that the proceeds from the sale of future royalties should be recorded as deferred income on the balance sheets as none of the criteria for classification as debt were met in accordance with ASC 470 Debt. The Company records the non-cash royalty revenue under the “units-of-revenue” method in the consolidated statements of income (loss). For the three months ended March 31, 2024, the Company recognized $9.4 million of non-cash royalty revenue. There is $147.5 million in deferred income as of March 31, 2024.

Monjuvi Royalty Sale Agreement

The Company evaluated the arrangement and determined that the proceeds from the sale of future royalties should be classified as debt according to ASC 470 Debt. As of March 31, 2024, the estimated effective rate under the agreement remains to be 21.1%. The Company will continue to reassess the estimate of total future royalty payment and prospectively adjust the imputed interest rate and related amortization if the estimate is materially different. For the three months ended March 31, 2024, the Company recognized $2.9 million of non-cash royalty revenue and $1.1 million of non-cash interest expense.

The following table shows the activity within debt for the quarter ended March 31, 2024 (in thousands):


	March 31, 2024

Beginning balance of debt related to sale of future royalties	$	20,974
Royalties owed to OMERS	349
Royalties paid to OMERS	(1,950)
Non-cash interest expense recognized	1,067
Ending balance of debt related to sale of future royalties	$	20,440

Debt - short-term	7,951
Debt - long-term	12,489
Total debt	$	20,440

Consolidated Statements of Loss (unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Revenue
Collaborations, milestones, and royalties	$ 12,805	$ 18,962
Operating expenses
Research and development	56,873	65,552
General and administrative	13,787	14,154
Total operating expenses	70,660	79,706
Loss from operations	(57,855)	(60,744)
Other income (expenses)
Interest income, net	7,471	2,892
Other expense, net	0	(13)
Impairment on equity securities	(20,650)	0
Gain (loss) on equity securities, net	2,325	(2,898)
Total other expense, net	(10,854)	(19)
Net loss	(68,709)	(60,763)
Net loss attributable to non-controlling interest	(676)	0
Net loss attributable to Xencor, Inc.	$ (68,033)	$ (60,763)
Basic net loss per common share (in dollars per share)	$ (1.11)	$ (1.02)
Diluted net loss per common share (in dollars per share)	$ (1.11)	$ (1.02)
Weighted average shares used to compute net income (loss) per share attributable to common stockholders:
Basic weighted average common shares outstanding (in shares)	61,212,324	59,771,674
Diluted weighted average common shares outstanding (in shares)	61,212,324	59,771,674

Stock-Based Compensation - FV of Employee Stock Options (Details)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Stock options
Weighted average assumptions for estimated fair value of employee stock options
Expected term (years)	6 years 4 months 24 days	6 years
Expected volatility (as a percent)	50.00%	50.50%
Risk-free interest rate (as a percent)	4.12%	4.26%
Expected dividend yield	0.00%	0.00%
ESPP
Weighted average assumptions for estimated fair value of employee stock options
Expected volatility, low end of range (as a percent)	43.00%	43.20%
Expected volatility, high end of range (as a percent)		55.70%
Risk-free interest rate, low end of range (as a percent)	4.71%	0.13%
Risk-free interest rate, high end of range (as a percent)	5.39%	4.72%
Expected dividend yield	0.00%	0.00%
ESPP \| Minimum
Weighted average assumptions for estimated fair value of employee stock options
Expected term (years)	6 months	6 months
ESPP \| Maximum
Weighted average assumptions for estimated fair value of employee stock options
Expected term (years)	2 years	2 years

Commitments and Contingencies	3 Months Ended
Commitments and Contingencies	Mar. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies From time to time, the Company may be subject to various litigation and related matters arising in the ordinary course of business. The Company does not believe it is currently subject to any material matters where there is at least a reasonable possibility that a material loss may be incurred. The Company is obligated to make future payments to third parties pursuant to certain license agreements, including sublicense fees, royalties, and payments that become due and payable on the achievement of certain development and commercialization milestones. As the amount and timing of sublicense fees and the achievement and timing of these milestones are not probable and estimable, such commitments have not been included on the Company’s balance sheets for the periods ended March 31, 2024 and December 31, 2023. The Company has also entered into agreements with third-party vendors that will require us to make future payments upon the delivery of goods and services in future periods.

Marketable Debt and Equity Securities - Equity Securities without Readily Determinable Fair Value (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Equity securities without readily determinable fair value
Impairment on equity securities	$ (20,650)	$ 0
Zenas
Equity securities without readily determinable fair value
Impairment on equity securities	(20,600)
Zenas
Equity securities without readily determinable fair value
Impairment on equity securities	(20,600)	$ 0
Preferred Stock \| Zenas
Equity securities without readily determinable fair value
Equity shares estimated fair value	$ 43,560		$ 64,210

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Cash flows from operating activities
Net loss	$ (68,709)	$ (60,763)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	3,035	2,245
Accretion of discount on marketable debt securities	(5,601)	(1,661)
Stock-based compensation	11,421	12,599
Abandonment of capitalized intangible assets	415	321
Gain on sale of marketable debt securities	(3)	0
Change in fair value of equity securities	(2,325)	2,898
Impairment on equity securities	20,650	0
Non-cash interest expense	1,067	0
Loss on disposal of assets	6	1,379
Changes in operating assets and liabilities:
Accounts receivable and contract asset	1,710	9,135
Interest receivable from marketable debt securities	(1,310)	248
Prepaid expenses and other assets	1,559	1,204
Accounts payable	2,097	5,254
Accrued expenses	(10,073)	(3,588)
Lease liabilities and ROU assets	213	331
Deferred revenue	0	(216)
Deferred income	(9,410)	0
Net cash used in operating activities	(55,258)	(30,614)
Cash flows from investing activities
Purchase of marketable securities	(136,532)	(95,228)
Purchase of intangible assets	(929)	(407)
Purchase of property and equipment	(132)	(10,783)
Proceeds from maturities of marketable securities	159,942	154,562
Proceeds from sale of marketable securities	9,969	0
Net cash provided by investing activities	32,318	48,144
Cash flows from financing activities
Proceeds from issuance of common stock upon exercise of stock awards	1,787	922
Repayment of liability for sale of future royalties	(1,601)	0
Net cash provided by financing activities	186	922
Net (decrease) increase in cash, cash equivalents, and restricted cash	(22,754)	18,452
Cash, cash equivalents, and restricted cash, beginning of period	54,170	53,942
Cash, cash equivalents, and restricted cash, end of period	31,416	72,394
Cash paid during the period for:
Interest	11	7
Supplemental disclosures of non-cash activities
Unrealized (loss) gain on marketable securities	(1,445)	3,327
ROU assets obtained	7,166	0
Cash and cash equivalents	31,034	72,394
Restricted cash	$ 382	$ 0

Collaboration and Licensing Agreements - Revenue Recognition (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Collaboration research and licensing agreements
Revenue recorded	$ 12,805	$ 18,962
Research collaboration
Collaboration research and licensing agreements
Revenue recorded	0	200
Milestone
Collaboration research and licensing agreements
Revenue recorded	500	5,000
Royalties
Collaboration research and licensing agreements
Revenue recorded	0	13,800
Non-cash royalties
Collaboration research and licensing agreements
Revenue recorded	12,300	0
Alexion
Collaboration research and licensing agreements
Revenue recorded	9,400	10,500
Janssen
Collaboration research and licensing agreements
Revenue recorded	0	5,200
MorphoSys
Collaboration research and licensing agreements
Revenue recorded	2,900	1,800
Vir
Collaboration research and licensing agreements
Revenue recorded	$ 0	$ 1,500

Net Loss Per Common Share (Tables)

3 Months Ended

Mar. 31, 2024

Earnings Per Share [Abstract]

Schedule of Basic and Diluted Net Loss per Common Share

Basic and diluted net loss per common share is computed as follows:


	Three Months Ended March 31,
	2024		2023
	(in thousands, except share and per share data)
Numerator:
Net loss attributable to Xencor, Inc.	$	(68,033)	$	(60,763)
Denominator:


Weighted-average common shares outstanding used in computing basic and diluted net loss	61,212,324		59,771,674
Basic and diluted net loss per common share attributable to Xencor, Inc.	$	(1.11)	$	(1.02)

Net Loss Per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Numerator:
Net loss attributable to Xencor, Inc.	$ (68,033)	$ (60,763)
Denominator:
Weighted-average common shares outstanding used in computing basic net loss (in shares)	61,212,324	59,771,674
Weighted-average common shares outstanding used in computing diluted net loss (in shares)	61,212,324	59,771,674
Basic net loss per common share (in dollars per share)	$ (1.11)	$ (1.02)
Diluted net loss per common share (in dollars per share)	$ (1.11)	$ (1.02)

- Definition

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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- Definition

The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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+ Details

- Definition

Amount, after deduction of tax, noncontrolling interests, dividends on preferred stock and participating securities; of income (loss) available to common shareholders.

+ References

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+ Details

Summary of Significant Accounting Policies (Polices)	3 Months Ended
Summary of Significant Accounting Policies (Polices)	Mar. 31, 2024
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited consolidated interim financial statements for Xencor, Inc. (the Company, Xencor, we or us) have been prepared in accordance with U.S. generally accepted accounting principles (GAAP) for interim financial information. The consolidated financial statements include all adjustments (consisting only of normal recurring adjustments) that the management of the Company believes are necessary for a fair presentation of the periods presented. The preparation of consolidated interim financial statements requires the use of management’s estimates and assumptions that affect reported amounts of assets and liabilities at the date of the consolidated interim financial statements and the reported revenues and expenditures during the reported periods. These interim financial results are not necessarily indicative of the results expected for the full fiscal year or for any subsequent interim period. The accompanying unaudited consolidated interim financial statements and related notes should be read in conjunction with the audited consolidated financial statements and notes thereto included in the Company’s 2023 Annual Report on Form 10-K filed with the Securities and Exchange Commission (SEC) on February 29, 2024.
Principles of Consolidation	Principles of Consolidation The accompanying consolidated financial statements include the accounts of Xencor, Inc. and Gale Therapeutics Inc. (Gale), a variable interest entity (VIE) in which we are the primary beneficiary. Since we own less than 100% of Gale, the Company records net loss attributable to non-controlling interests in its consolidated statements of income (loss) equal to the percentage of the economic or ownership interests retained in Gale by the non-controlling party. In determining whether we are the primary beneficiary of a VIE, we apply a qualitative approach that determines whether we have (1) the power to direct the activities of the VIE that most significantly impact the entity's economic performance and (2) the obligation to absorb losses of, or the right to receive benefits from the VIE that could potentially be significant to the VIE. We continuously assess whether we are the primary beneficiary of Gale as changes to existing relationships or future transactions result in us consolidating or deconsolidating Gale.
Use of Estimates	Use of Estimates The preparation of consolidated interim financial statements in conformity with GAAP requires management to make certain estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses, other comprehensive gain (loss) and the related disclosures. On an ongoing basis, management evaluates its estimates, including estimates related to its accrued clinical trial and manufacturing development expenses, stock-based compensation expense, evaluation of intangible assets, investments, leases and other assets for evidence of impairment, fair value measurements, and contingencies. Significant estimates in these consolidated interim financial statements include estimates made for royalty revenue, accrued research and development expenses, stock-based compensation expenses, intangible assets, incremental borrowing rate for right-of-use asset and lease liability, estimated standalone selling price of performance obligations, estimated time for completing delivery of performance obligations under certain arrangements, the likelihood of recognizing variable consideration, the carrying value of equity instruments without a readily determinable fair value, and recoverability of deferred tax assets.
Reclassifications	Reclassifications Certain prior year amounts in the consolidated financial statements and the notes thereto have been reclassified to conform to the current period's presentation. These reclassifications did not affect the prior period's total assets, liabilities, stockholders' equity, net loss or cash flows. During the three months ended March 31, 2024, we adopted a change in presentation on our consolidated statements of loss to include loss from disposal of fixed assets in operating expenses. The prior period has been revised to reflect this change in the presentation.
Intangible Assets	Intangible Assets The Company maintains definite-lived intangible assets related to certain capitalized costs of acquired licenses and third-party costs incurred in establishing and maintaining its intellectual property rights to its platform technologies and development candidates. These assets are amortized over their useful lives, which are estimated to be the remaining patent life or the contractual term of the license. The straight-line method is used to record amortization expense. The Company assesses its intangible assets for impairment if indicators are present or changes in circumstances suggest that impairment may exist. There was no impairment charge recorded for the three months ended March 31, 2024 and 2023. The Company capitalizes certain in-process intangible assets that are then abandoned when they are no longer pursued or used in current research activities. We abandoned $0.4 million of in-process intangible assets for the three months ended March 31, 2024. We abandoned $0.3 million of in-process intangible assets during the three months ended March 31, 2023.
Marketable Debt and Equity Securities	Marketable Debt and Equity Securities The Company has an investment policy that includes guidelines on acceptable investment securities, minimum credit quality, maturity parameters, and concentration and diversification. The investment policy limits the maturity of any individual security to a maximum of 36 months. The average maturity of securities in the portfolio as of March 31, 2024 is less than 12 months. The Company invests its excess cash primarily in marketable debt securities issued by investment grade institutions. The Company considers its marketable debt securities to be available-for-sale because it is not more likely than not that the Company will be required to sell the securities before recovery of the amortized cost. These assets are carried at fair value and any impairment losses and recoveries related to the underlying issuer’s credit standing are recognized within other income (expense), while non-credit related impairment losses and recoveries are recognized within accumulated other comprehensive income (loss). There were no impairment losses or recoveries recorded for the three months ended March 31, 2024 and 2023. Accrued interest on marketable debt securities is included in the marketable securities’ carrying value. Each reporting period, the Company reviews its portfolio of marketable debt securities, using both quantitative and qualitative factors, to determine if each security’s fair value has declined below its amortized cost basis. During the three months ended March 31, 2024, the Company recorded an unrealized loss of $1.4 million in its portfolio of marketable debt securities. During the three months ended March 31, 2023, the Company recorded an unrealized gain of $3.3 million. The unrealized loss is due to the changing interest rate environment and is not due to changes in the credit quality of the underlying securities. The unrealized gain (loss) is recorded in other comprehensive income (loss) for the three months ended March 31, 2024 and 2023. The Company receives equity securities in connection with certain licensing transactions with its partners. These investments in equity securities are carried at fair value with changes in fair value recognized each period and reported within other income (expense). For equity securities with a readily determinable fair value, the Company remeasures these equity investments at each reporting period until such time that the investment is sold or disposed. If the Company sells an investment, any realized gain or loss on the sale of the securities will be recognized within other income (expense) in the consolidated statements of loss in the period of sale. The Company also has investments in equity securities without a readily determinable fair value, where the Company elects the measurement alternative to record the investment at its initial cost minus impairment, plus or minus changes resulting from observable price changes in orderly transactions for the identical or a similar investment of the same issuer. There was an impairment charge of $20.6 million recorded for the three months ended March 31, 2024 in connection with equity securities without a readily determinable fair value. There was no impairment charge recorded for the three months ended March 31, 2023.
Liability Related to the Sale of Future Royalties and Non-Cash Interest Expense on the Liability Related to the Sale of Future Royalties and Deferred Income Related to the Sale of Future Revenues	Liability Related to the Sale of Future Revenues We treat the sale of future Monjuvi royalties as debt, amortized under the effective interest rate method over the estimated life of the Monjuvi Royalty Sale Agreement. See Note 11. The amortization of the liability related to the sale of future Monjuvi royalties is based on our current estimate of future royalty payments. Royalty revenue will be recognized as earned and the payments made will be a reduction of the liability when paid. Non-cash Interest Expense on the Liability Related to the Sale of Future Royalties The total expected royalty payments less the net proceeds received are recorded as non-cash interest expense over the life of the liability. Interest is imputed on the unamortized portion using the effective interest method and is recorded based on the timing of the payments received over the term of the Monjuvi Royalty Sale Agreement. The actual interest rate will be affected by the timing of the royalty payments and changes in the forecasted revenue. Deferred Income Related to the Sale of Future Revenues We treat the sale of future Ultomiris royalties as deferred income, amortized under the units-of-revenue method by computing a ratio of the proceeds received to the total expected payments over the term of the Ultomiris Royalty Sale Agreement. See Note 11. The amortization of the liability related to the sale of future royalties is based on our current estimate of future royalty payments. Royalty revenue will be recognized as earned and the payments made will be a reduction of the liability when paid.
Recent Accounting Pronouncements	Recent Accounting Pronouncements There have been no material changes in recently issued or adopted accounting standards from those disclosed in the Company's 2023 Annual Report on Form 10-K. The Company has reviewed all recently issued accounting pronouncements and does not believe they will have a material impact on our results of operations, financial condition or cash flows. There have been no other material changes to the significant accounting policies previously disclosed in the Company’s 2023 Annual Report on Form 10-K.
Fair Value Measurement	Financial instruments included in the financial statements include cash and cash equivalents, marketable debt and equity securities, accounts receivable, accounts payable, and accrued expenses. Marketable debt securities, equity securities, and cash equivalents are carried at fair value. The fair value of the other financial instruments closely approximates their fair value due to their short-term maturities. The Company accounts for recurring and non-recurring fair value measurements in accordance with FASB Accounting Standards Codification 820, Fair Value Measurements and Disclosures (ASC 820). ASC 820 defines fair value, establishes a fair value hierarchy for assets and liabilities measured at fair value, and requires expanded disclosure about fair value measurements. The ASC 820 hierarchy ranks the quality of reliable inputs, or assumptions, used in the determination of fair value and requires assets and liabilities carried at fair value to be classified and disclosed in one of the following three categories: Level 1—Fair value is determined by using unadjusted quoted prices that are available in active markets for identical assets or liabilities. Level 2—Fair value is determined by using inputs other than Level 1 quoted prices that are directly or indirectly observable. Inputs can include quoted prices for similar assets or liabilities in active markets or quoted prices for identical assets or liabilities in markets that are not active. Related inputs can also include those used in valuation or other pricing models, such as interest rates and yield curves that can be corroborated by observable market data. Level 3—Fair value is determined by inputs that are unobservable and not corroborated by market data. Use of these inputs involves significant and subjective judgments to be made by the reporting entity – e.g., determining an appropriate discount factor for illiquidity associated with a given security. The Company measures the fair value of financial assets using the highest level of inputs that are reasonably available as of the measurement date.Our policy is to record transfers of assets between Level 1 and Level 2 at their fair values as of the end of each reporting period, consistent with the date of the determination of fair value. During the three months ended March 31, 2024 and 2023, there were no transfers between Level 1 and Level 2.

Fair Value of Financial Instruments

3 Months Ended

Mar. 31, 2024

Fair Value Disclosures [Abstract]

Fair Value of Financial Instruments

Financial instruments included in the financial statements include cash and cash equivalents, marketable debt and equity securities, accounts receivable, accounts payable, and accrued expenses. Marketable debt securities, equity securities, and cash equivalents are carried at fair value. The fair value of the other financial instruments closely approximates their fair value due to their short-term maturities.

The Company accounts for recurring and non-recurring fair value measurements in accordance with FASB Accounting Standards Codification 820, Fair Value Measurements and Disclosures (ASC 820). ASC 820 defines fair value, establishes a fair value hierarchy for assets and liabilities measured at fair value, and requires expanded disclosure about fair value measurements. The ASC 820 hierarchy ranks the quality of reliable inputs, or assumptions, used in the determination of fair value and requires assets and liabilities carried at fair value to be classified and disclosed in one of the following three categories:

Level 1—Fair value is determined by using unadjusted quoted prices that are available in active markets for identical assets or liabilities.

Level 2—Fair value is determined by using inputs other than Level 1 quoted prices that are directly or indirectly observable. Inputs can include quoted prices for similar assets or liabilities in active markets or quoted prices for identical assets or liabilities in markets that are not active. Related inputs can also include those used in valuation or other pricing models, such as interest rates and yield curves that can be corroborated by observable market data.

Level 3—Fair value is determined by inputs that are unobservable and not corroborated by market data. Use of these inputs involves significant and subjective judgments to be made by the reporting entity – e.g., determining an appropriate discount factor for illiquidity associated with a given security.

The Company measures the fair value of financial assets using the highest level of inputs that are reasonably available as of the measurement date. The assets recorded at fair value are classified within the hierarchy as follows for the periods reported (in thousands):


	March 31, 2024 (unaudited)						December 31, 2023
	Total Fair Value		Level 1		Level 2		Total Fair Value		Level 1		Level 2
Money Market Funds	$	3,447	$	3,447	$	—	$	25,520	$	25,520	$	—
Corporate Securities	264,629		—		264,629		228,723		—		228,723
Government Securities	350,698		—		350,698		414,514		—		414,514
	$	618,774	$	3,447	$	615,327	$	668,757	$	25,520	$	643,237

Our policy is to record transfers of assets between Level 1 and Level 2 at their fair values as of the end of each reporting period, consistent with the date of the determination of fair value. During the three months ended March 31, 2024 and 2023, there were no transfers between Level 1 and Level 2.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Collaboration and Licensing Agreements

3 Months Ended

Mar. 31, 2024

Collaboration and Licensing Agreements

Collaboration and Licensing Agreements

The following is a summary description of the material collaboration arrangements in the three months ended March 31, 2024 and 2023.

Alexion Pharmaceuticals, Inc.

In January 2013, the Company entered into an Option and License Agreement (the Alexion Agreement) with Alexion Pharmaceuticals, Inc. (Alexion). Under the terms of the Alexion Agreement, the Company granted to Alexion an exclusive research license, with limited sublicensing rights, to make and use the Company’s Xtend technology to evaluate and advance compounds. Alexion exercised its rights to one target program, ALXN1210, which is now marketed as Ultomiris®.

The Company is entitled to receive royalties based on a percentage of net sales of Ultomiris sold by Alexion, its affiliates or its sublicensees, which percentage is in the low single digits. Alexion’s royalty obligations continue on a product-by-product and country-by-country basis until the expiration of the last-to-expire valid claim in a licensed patent covering the applicable product in such country.

On November 3, 2023, the Company entered into the Ultomiris Royalty Sale Agreement with OMERS, in which OMERS acquired the rights to certain royalties associated with the existing license relating to Ultomiris. For the three months ended March 31, 2024, Company earned and recognized $9.4 million in non-cash royalty revenue under the Ultomiris Royalty Sale Agreement.

The Company recognized $9.4 million of non-cash royalty revenue and $10.5 million of royalty revenue under this arrangement for the three months ended March 31, 2024 and 2023, respectively. As of March 31, 2024, there is no receivable and no deferred revenue related to this agreement.

Astria Therapeutics, Inc.

In connection with a licensing transaction, the Company received preferred and common stock in Astria. In January 2023, the Company exchanged its preferred stock for additional common stock in Astria.

The Company recognized an unrealized gain of $4.5 million related to its equity interest in Astria for the three months ended March 31, 2024. The Company recognized an unrealized loss of $0.4 million related to its equity interest in Astria for the three months ended March 31, 2023. There is no deferred revenue as of March 31, 2024 related to this agreement.

Genentech, Inc., and F. Hoffmann-La Roche Ltd

In February 2019, the Company entered into a collaboration and license agreement (the Genentech Agreement) with Genentech, Inc. and F. Hoffmann-La Roche Ltd (collectively, Genentech) for the development and commercialization of novel IL-15 collaboration products (Collaboration Products), including efbalropendekin alfa (also named XmAb306 and RG6323), the Company’s IL-15/IL15Rα-Fc candidate.

Under the terms of the Genentech Agreement, Genentech received an exclusive worldwide license to XmAb306 and we share in 45% of development and commercialization costs of Collaboration Products, and we are eligible to share in 45% of net profits and losses from the sale of approved products. However, in the fourth quarter of 2023, we agreed with Genentech to convert our current development cost and profit-sharing arrangement into a royalty and milestone payment-based arrangement. Pursuant to the terms of the amended agreement with Genentech, effective June 1, 2024, Genentech will assume sole responsibility over all clinical, regulatory and commercial activities. We are eligible to receive up to $600.0 million in milestones, including $115.0 million in development milestones, $185.0 million in regulatory milestones and $300.0 million in sales-based milestones and tiered royalties ranging from low double-digit to mid-teens percentages.

The Company did not recognize revenue related to the Genentech Agreement for the three months ended March 31, 2024 or 2023. As of March 31, 2024, there is a $3.1 million payable related to cost-sharing development activities during the first quarter of 2024 for development studies being conducted under the Genentech Agreement. There is no deferred revenue as of March 31, 2024, as obligations to perform research activities have expired.

INmune Bio, Inc.

In connection with a licensing transaction, the Company received common stock in INmune.

For the three months ended March 31, 2024 and 2023, the Company recorded unrealized gains of $0.9 million and $0.2 million, respectively, related to its investment in INmune.

Janssen Biotech, Inc., a Johnson & Johnson company

J&J Agreement

In November 2020, the Company entered into a Collaboration and License Agreement (the J&J Agreement) with Janssen Biotech, Inc., a Johnson & Johnson company, pursuant to which the Company and J&J conducted research and development activities to discover novel CD28 bispecific antibodies for the treatment of prostate cancer. Xencor together with J&J conducted joint research activities to discover XmAb bispecific antibodies against CD28 and against an undisclosed prostate tumor-target with J&J maintaining exclusive worldwide rights to develop and commercialize licensed products identified from the research activities.

Under the J&J Agreement, the Company conducted research activities and applied its bispecific Fc technology to antibodies targeting prostate cancer provided by J&J. Upon completion of the research activities J&J had a candidate selection option to advance an identified candidate for development and commercialization. In November 2021, the Company completed its performance obligations under the research activities and delivered CD28 bispecific antibodies to J&J. In December 2021, J&J selected a bispecific CD28 candidate for further development. J&J will assume full responsibility for development and commercialization of the CD28 bispecific antibody candidate.

The Company did not recognize revenue for the three months ended March 31, 2024 and 2023 under the J&J Agreement. As of March 31, 2024, there is no deferred revenue related to this Agreement.

Second J&J Agreement

On October 1, 2021, the Company entered into a second Collaboration and License Agreement (the Second J&J Agreement) with J&J pursuant to which the Company granted J&J an exclusive worldwide license to develop, manufacture, and commercialize plamotamab, the Company’s CD20 x CD3 development candidate, and pursuant to which Xencor and J&J conducted research and development activities to discover novel CD28 bispecific antibodies. The parties conducted joint research activities for a two-year period to discover XmAb bispecific antibodies against CD28 and undisclosed B cell tumor-targets with J&J receiving exclusive worldwide rights, subject to certain Xencor opt-in rights, to develop, manufacture and commercialize pharmaceutical products that contain one or more of such discovered antibodies (CD28 Licensed Antibodies). The Agreement became effective on November 5, 2021.

The Company will collaborate with J&J on further clinical development of plamotamab with J&J and share development costs with J&J paying 80% and the Company paying 20% of certain development costs.

The Company is generally responsible for conducting research activities under the Second J&J Agreement, and J&J is generally responsible for all development, manufacturing, and commercialization activities for CD28 Licensed Antibodies that are advanced. Revenue from the research activities was recognized over a period of time through the end of the research term that services were rendered as we determined that the input method was the appropriate approach to recognize income for such services.

There is a receivable of $1.9 million as of March 31, 2024, related to cost-sharing activities for development of plamotamab under the Second J&J Agreement. No revenue was recognized for the three months ended March 31, 2024, and the Company recognized $5.2 million of revenue for the three months ended March 31, 2023. There is no deferred revenue as of March 31, 2024 related to the Second J&J Agreement as obligations to perform research activities have expired.

MorphoSys AG/Incyte Corporation

In June 2010, the Company entered into a Collaboration and License Agreement with MorphoSys AG (MorphoSys), which was subsequently amended. Under the agreement, we granted MorphoSys an exclusive worldwide

license to the Company’s patents and know-how to research, develop and commercialize the XmAb5574 product candidate (subsequently renamed MOR208 and tafasitamab) with the right to sublicense under certain conditions. In February 2024, Incyte Corporation acquired exclusive global development and commercialization rights to tafasitamab. If certain developmental, regulatory and sales milestones are achieved, the Company is eligible to receive future milestone payments and royalties.

On November 3, 2023, the Company entered into the Monjuvi Royalty Sale Agreement with OMERS, pursuant to which OMERS acquired the rights to certain royalties earned after July 1, 2023 associated with the existing license relating to Monjuvi. For the three months ended March 31, 2024, the Company earned and recognized $2.9 million in royalty revenue, all of which was non-cash royalty revenue under the Monjuvi Royalty Sale Agreement.

The Company recognized $2.9 million of non-cash royalty revenue and $1.8 million of royalty revenue during the three months ended March 31, 2024 and 2023, respectively. As of March 31, 2024, there is a receivable of $3.4 million related to estimated royalties due under the arrangement. As of March 31, 2024, there is no deferred revenue related to this agreement.

Vega Therapeutics, Inc.

In October 2021, the Company entered into a Technology License Agreement (the Vega Agreement) with Vega Therapeutics, Inc. (Vega), in which the Company provided Vega a non-exclusive license to its Xtend Fc technology. In March 2024, Vega notified the Company that it initiated a Phase 1 study, and the Company recorded milestone revenue of $0.5 million.

The Company recognized $0.5 million of revenue for the three months ended March 31, 2024. No revenue was recognized for the three months ended March 31, 2023.

Vir Biotechnology, Inc.

In 2019, the Company entered into a Patent License Agreement (the Vir Agreement) with Vir Biotechnology, Inc. (Vir) pursuant to which the Company provided a non-exclusive license to its Xtend technology for up to two targets.

In March 2020, the Company entered into a second Patent License Agreement (the Second Vir Agreement) with Vir pursuant to which the Company provided a non-exclusive license to its Xtend technology to extend the half-life of novel antibodies Vir developed as potential treatments for patients with COVID-19, including sotrovimab. Under the terms of the Second Vir Agreement, Vir is responsible for all research, development, regulatory and commercial activities for the antibodies, and the Company is eligible to receive royalties on the net sales of approved products in the mid-single digit percentage range. Vir and its marketing partner, GSK, began recording sales for sotrovimab beginning in June 2021.

No revenue was recognized for the three months ended March 31, 2024, and the Company recognized $1.5 million of royalty revenue for the three months ended March 31, 2023. As of March 31, 2024, there is no receivable related to estimated royalty due under this agreement, and there is no deferred revenue related to this agreement.

Viridian Therapeutics, Inc.

In December 2020 and in December 2021, the Company entered two separate license agreements with Viridian and received shares of Viridian common stock for each license. During 2023, Viridian terminated the initial license agreement, and the research term under the second license expired.

The Company reported unrealized losses of $3.1 million and $2.7 million for the three months ended March 31, 2024 and 2023, respectively, related to the shares of Viridian common stock. The Company did not recognize revenue for the three months ended March 31, 2024 or 2023. There is no deferred revenue as of March 31, 2024 related to this agreement.

Zenas BioPharma, Inc.

In November 2020, the Company entered into a License Agreement (the Zenas Agreement) with Zenas, pursuant to which the Company received an equity interest in Zenas in exchange for the exclusive, worldwide rights to develop and commercialize drug candidates from the Company.

The equity in Zenas is recorded at the fair value as of the date of the Zenas Agreement and is reviewed each reporting period for impairment or other evidence of change in value.

In November 2021, the Company entered into a second License Agreement (Second Zenas Agreement) with Zenas, pursuant to which the Company received additional equity in Zenas in exchange for the exclusive worldwide rights to develop and commercialize the Company’s obexelimab (XmAb5871) drug candidate. Under the license, the Company is eligible to receive development, regulatory and sales milestones in connection with the development of obexelimab and royalties on net sales of approved products. The original equity received for the second license was a warrant to acquire additional shares of Zenas. The warrant was exchanged for additional preferred stock in Zenas in November 2022.

The warrant in Zenas was recorded at its fair value as of the date of the Second Zenas Agreement and was reviewed each reporting period for impairment or other evidence of change in value. The preferred shares received in exchange for the warrant were recorded at their fair value at the date of the exchange and is reviewed each reporting period for impairment or other evidence of change in value.

In 2023, Zenas initiated a Phase 3 clinical study with obexelimab and also dosed a second patient in the study. The Company received a development milestone in the form of additional preferred stock in Zenas with a fair value of $10.0 million.

The Company recognized an impairment charge of $20.6 million in the three months ended March 31, 2024 due to an impairment analysis of the Zenas' Series C financing transaction. The Company did not record an impairment charge or change in the value of the Zenas equity in the three months ended March 31, 2023. The Company did not recognize any revenue for the three months ended March 31, 2024 or 2023, and there is no deferred revenue related to this agreement.

Gale Therapeutics Inc.

In the fourth quarter of 2023, the Company formed a subsidiary, Gale Therapeutics Inc. (Gale), to develop novel drug candidates with its Fc technologies. In December 2023, the Company entered into a Technology License Agreement (Gale License Agreement) with Gale in which Gale received an exclusive worldwide, royalty-bearing, non-transferable license to preclinical assets in exchange for royalties on future sales and an option for future drug candidates that Gale will develop. Concurrently, the Company entered into a Service Agreement (Gale Services Agreement) to provide research and development services and administrative support for Gale. In exchange for $7.5 million of funding, the Company acquired a majority stake in Gale. Total charges of $2.7 million under the Services Agreement for the three months ended March 31, 2024 were eliminated in consolidation.

Revenues earned

The revenues recorded for the three months ended March 31, 2024 and 2023 were earned principally from the following licensees (in millions):


	Three Months Ended March 31,
	2024		2023

Alexion	$	9.4	$	10.5



Janssen	—		5.2
MorphoSys	2.9		1.8


Vega	0.5		—
Vir	—		1.5


Total	$	12.8	$	19.0

The table below summarizes the disaggregation of revenue recorded for the three months ended March 31, 2024 and 2023 (in millions):


	Three Months Ended March 31,
	2024		2023

Research collaboration	$	—	$	0.2
Milestone	0.5		5.0
Royalties	—		13.8
Non-cash royalties	12.3		—
Total	$	12.8	$	19.0

Remaining Performance Obligations and Deferred Revenue

The Company does not have any remaining performance obligation as of March 31, 2024. As of March 31, 2023, the Company had deferred revenue of $30.1 million for conducting research activities pursuant to the Second J&J Agreement. All deferred revenue as of March 31, 2023 was classified as current liabilities as the Company’s obligations to perform services are due on demand when requested by J&J under the Second J&J Agreement.

Marketable Debt and Equity Securities (Tables)

3 Months Ended

Mar. 31, 2024

Marketable Securities [Abstract]

Schedule of Marketable Securities

The Company’s marketable debt securities held as of March 31, 2024 and December 31, 2023 are summarized below:


March 31, 2024	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
(in thousands)
Money Market Funds	$	3,447	$	—	$	—	$	3,447
Corporate Securities	264,706		69		(146)		264,629
Government Securities	350,764		141		(207)		350,698
	$	618,917	$	210	$	(353)	$	618,774

Reported as
Cash and cash equivalents							$	3,447
Marketable securities							615,327
Total investments							$	618,774


December 31, 2023	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
(in thousands)
Money Market Funds	$	25,520	$	—	$	—	$	25,520
Corporate Securities	228,382		342		(1)		228,723
Government Securities	413,553		1,037		(76)		414,514
	$	667,455	$	1,379	$	(77)	$	668,757

Reported as
Cash and cash equivalents							$	25,520
Marketable securities							643,237
Total investments							$	668,757

Schedule of Maturities of Marketable Securities

The maturities of the Company’s marketable debt securities as of March 31, 2024 are as follows:


March 31, 2024	Amortized Cost		Estimated Fair Value
(in thousands)
Mature in one year or less	$	460,336	$	460,367
Mature within two years	155,134		154,960
	$	615,470	$	615,327

Schedule of Unrealized Losses on Available-for-Sale Investments

The unrealized losses on available-for-sale investments and their related fair values as of March 31, 2024 and December 31, 2023 are as follows:


	Less than 12 months				12 months or greater
March 31, 2024	Fair value		Unrealized losses		Fair value		Unrealized losses
(in thousands)
Corporate Securities	$	51,230	$	(42)	$	53,122	$	(104)
Government Securities	110,170		(35)		36,427		(172)
	$	161,400	$	(77)	$	89,549	$	(276)


	Less than 12 months				12 months or greater
December 31, 2023	Fair value		Unrealized losses		Fair value		Unrealized losses
(in thousands)
Corporate Securities	$	8,073	$	(1)	$	—	$	—
Government Securities	66,546		(76)		—		—
	$	74,619	$	(77)	$	—	$	—

Schedule of Equity Securities with Readily Determinable Fair Value

Equity securities with a readily determinable fair value, which are categorized as Level 1 in the fair value hierarchy under ASC 820, and their fair values (in thousands) as of March 31, 2024 and December 31, 2023 are as follows:


	Fair Value		Fair Value
	March 31, 2024		December 31, 2023
Astria Common Stock	$	9,823	$	5,360
INmune Common Stock	22,155		21,231
Viridian Common Stock	12,557		15,619
	$	44,535	$	42,210

Schedule of Net Gains and Losses

Unrealized gain (loss) recognized on equity securities during each of the three-month periods ended March 31, 2024 and 2023, consist of the following:


	Three Months Ended March 31,
	2024		2023


Net and unrealized gain (loss) recognized on equity securities	$	2,325	$	(2,898)

Schedule of Equity Securities Without Readily Determinable Fair Value

Equity securities without a readily determinable fair value and their carrying values (in thousands) as of March 31, 2024 and December 31, 2023 are as follows:


	Carrying Value		Carrying Value
	March 31, 2024		December 31, 2023

Zenas Preferred Stock	$	43,560	$	64,210

Marketable Debt and Equity Securities

3 Months Ended

Mar. 31, 2024

Marketable Securities [Abstract]

Marketable Debt and Equity Securities

The Company’s marketable debt securities held as of March 31, 2024 and December 31, 2023 are summarized below:


March 31, 2024	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
(in thousands)
Money Market Funds	$	3,447	$	—	$	—	$	3,447
Corporate Securities	264,706		69		(146)		264,629
Government Securities	350,764		141		(207)		350,698
	$	618,917	$	210	$	(353)	$	618,774

Reported as
Cash and cash equivalents							$	3,447
Marketable securities							615,327
Total investments							$	618,774


December 31, 2023	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
(in thousands)
Money Market Funds	$	25,520	$	—	$	—	$	25,520
Corporate Securities	228,382		342		(1)		228,723
Government Securities	413,553		1,037		(76)		414,514
	$	667,455	$	1,379	$	(77)	$	668,757

Reported as
Cash and cash equivalents							$	25,520
Marketable securities							643,237
Total investments							$	668,757

The maturities of the Company’s marketable debt securities as of March 31, 2024 are as follows:


March 31, 2024	Amortized Cost		Estimated Fair Value
(in thousands)
Mature in one year or less	$	460,336	$	460,367
Mature within two years	155,134		154,960
	$	615,470	$	615,327

The unrealized losses on available-for-sale investments and their related fair values as of March 31, 2024 and December 31, 2023 are as follows:


	Less than 12 months				12 months or greater
March 31, 2024	Fair value		Unrealized losses		Fair value		Unrealized losses
(in thousands)
Corporate Securities	$	51,230	$	(42)	$	53,122	$	(104)
Government Securities	110,170		(35)		36,427		(172)
	$	161,400	$	(77)	$	89,549	$	(276)


	Less than 12 months				12 months or greater
December 31, 2023	Fair value		Unrealized losses		Fair value		Unrealized losses
(in thousands)
Corporate Securities	$	8,073	$	(1)	$	—	$	—
Government Securities	66,546		(76)		—		—
	$	74,619	$	(77)	$	—	$	—

The unrealized losses from the available-for-sale securities are due to changes in the interest rate environment and not changes in the credit quality of the underlying securities in the portfolio.

The Company’s equity securities include securities with a readily determinable fair value. These investments are carried at fair value with changes in fair value recognized each period and reported within other income (expense), net. For the three months ended March 31, 2024, a gain of $2.3 million was recorded under other income (expense) related to these securities. For the three months ended March 31, 2023, a loss of $2.9 million was recorded under other income (expense). Equity securities with a readily determinable fair value, which are categorized as Level 1 in the fair value hierarchy under ASC 820, and their fair values (in thousands) as of March 31, 2024 and December 31, 2023 are as follows:


	Fair Value		Fair Value
	March 31, 2024		December 31, 2023
Astria Common Stock	$	9,823	$	5,360
INmune Common Stock	22,155		21,231
Viridian Common Stock	12,557		15,619
	$	44,535	$	42,210

The Company holds 697,867 shares of common stock of Astria as of March 31, 2024. The common stock has a readily determinable fair value, and the Company recorded a gain in equity securities related to the adjustment in the fair value of Astria common stock for the three months ended March 31, 2024.

The Company currently holds 1,885,533 shares of common stock of INmune Bio, Inc. (INmune). The 1,885,533 shares of INmune common stock are classified as equity securities with a readily determinable fair value, and the adjustment in the fair value of the shares of INmune common stock has been recorded as a gain in equity securities for the three months ended March 31, 2024.

The Company currently holds 717,144 shares of common stock of Viridian Therapeutics, Inc. (Viridian). The shares of Viridian common stock are classified as equity securities with a readily determinable fair value, and the adjustment in the fair value of the shares of Viridian common stock was recorded as a loss in equity securities for the three months ended March 31, 2024.

Unrealized gain (loss) recognized on equity securities during each of the three-month periods ended March 31, 2024 and 2023, consist of the following:


	Three Months Ended March 31,
	2024		2023


Net and unrealized gain (loss) recognized on equity securities	$	2,325	$	(2,898)

The Company also has investments in equity securities without a readily determinable fair value. The Company elects the measurement alternative to record these investments at their initial cost and evaluates such investments at each reporting period for evidence of impairment, or observable price changes in orderly transactions for the identical or a similar investment of the same issuer. Equity securities without a readily determinable fair value and their carrying values (in thousands) as of March 31, 2024 and December 31, 2023 are as follows:


	Carrying Value		Carrying Value
	March 31, 2024		December 31, 2023

Zenas Preferred Stock	$	43,560	$	64,210

The Company currently holds an equity interest in Zenas BioPharma, Inc. (Zenas), a private biotechnology company. The Company’s equity interests include preferred stock in Zenas which were received as upfront payments and a milestone payment for licensing certain clinical and preclinical assets from the Company. The Company elected the measurement alternative to carry the Zenas equity at cost minus impairment, plus or minus changes resulting from observable price changes in orderly transactions for the identical or a similar investment of the same issuer. During the three months ended March 31, 2024, we recorded a $20.6 million impairment charge as a result of Zenas closing a Series C financing transaction on May 3, 2024 as the transaction suggested an indicator of impairment that existed at March 31, 2024.

Leases - Undiscounted Cash Flows (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Leases [Abstract]
For the remainder of 2024	$ 4,460
2025	8,022
2026	9,238
2027	9,560
2028	9,076
2029	9,331
Thereafter	57,104
Total undiscounted lease payments	106,791
Less: Tenant allowance	(3,252)
Less: Imputed interest	(34,650)
Present value of lease payments	68,889
Lease liabilities - short-term	2,079	$ 3,435
Lease liabilities - long-term	$ 66,810	$ 59,025

Stock Based Compensation - Narrative (Details) $ / shares in Units, $ in Millions	3 Months Ended		123 Months Ended
	Mar. 31, 2024 USD ($) installment $ / shares shares	Mar. 31, 2023 $ / shares shares	Mar. 31, 2024 USD ($) $ / shares shares	Jun. 14, 2023 shares
ESPP
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Total number of shares of common stock available for issuance (in shares)	1,041,340		1,041,340
Awards issued under the plan (in shares)			733,478
Unamortized compensation expense \| $	$ 1.4		$ 1.4
Period to recognize unamortized compensation expense	1 year 8 months 12 days
ESPP \| Maximum
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Annual percentage increase in shares of common stock available for issuance	1.00%
Annual increase in shares of common stock available for issuance (in shares)	621,814
RSUs
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Granted (in shares)	796,660
Annual installment vesting periods \| installment	3
Period to recognize unamortized compensation expense	2 years 3 months 18 days
Unamortized compensation expense related to unvested restricted stock units \| $	$ 40.6		$ 40.6
Stock options
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Options granted (in shares)	1,763,778	1,620,256
Closing price of common stock (in dollars per share) \| $ / shares	$ 22.13		$ 22.13
Weighted average fair value of options granted (in dollars per share) \| $ / shares	$ 22.81	$ 31.40
Unamortized compensation expense \| $	$ 61.5		$ 61.5
Period to recognize unamortized compensation expense	2 years 9 months 18 days
The 2023 Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Total number of shares of common stock available for issuance (in shares)	18,798,477		18,798,477	3,000,000
The 2023 Plan \| RSUs
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Granted (in shares)	883,327
The 2013 and 2023 Plans
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Options granted (in shares)			1,977,176

Collaboration and Licensing Agreements - Narrative (Details) $ in Thousands		1 Months Ended			3 Months Ended			13 Months Ended
	Oct. 01, 2021	Oct. 31, 2021 USD ($)	Feb. 28, 2019 USD ($)	Jan. 31, 2013 program	Mar. 31, 2024 USD ($)	Mar. 31, 2023 USD ($)	Sep. 30, 2019 target	Dec. 31, 2021 agreement	Dec. 31, 2023 USD ($)
Collaboration research and licensing agreements
Receivable					$ 9,580				$ 11,290
Unrealized gain (loss) on equity securities					2,325	$ (2,898)
Number of technology license agreements \| agreement								2
Impairment on equity securities					(20,650)	0
Deferred revenue					0	30,100
Zenas
Collaboration research and licensing agreements
Impairment on equity securities					(20,600)	0
Zenas \| Preferred Stock
Collaboration research and licensing agreements
Equity shares estimated fair value					43,560				64,210
Option and License agreement \| Alexion
Collaboration research and licensing agreements
Number of different target programs \| program				1
Receivable					0
Deferred revenue					0
Option and License agreement \| Alexion \| Royalties
Collaboration research and licensing agreements
Revenue recognized					9,400	10,500
Technology License Agreement \| Astria/Catabasis
Collaboration research and licensing agreements
Deferred revenue					0
Unrealized gain (loss) on equity securities					4,500	(400)
Technology License Agreement \| Viridian
Collaboration research and licensing agreements
Revenue recognized					0	0
Deferred revenue					0
Unrealized gain (loss) on equity securities					(3,100)	(2,700)
Technology License Agreement \| Vega Therapeutics, Inc.
Collaboration research and licensing agreements
Revenue recognized		$ 500			500	0
Technology License Agreement \| Gale
Collaboration research and licensing agreements
Transaction price					7,500
Service agreement charges					2,700
Collaboration and License Agreement \| Genentech
Collaboration research and licensing agreements
Revenue recognized					0	0
Initial cost-sharing percentage			45.00%
Royalty milestones			$ 600,000
Collaboration and License Agreement \| Genentech \| Development-based
Collaboration research and licensing agreements
Royalty milestones			115,000
Collaboration and License Agreement \| Genentech \| Regulatory-based
Collaboration research and licensing agreements
Royalty milestones			185,000
Collaboration and License Agreement \| Genentech \| Sales-based
Collaboration research and licensing agreements
Royalty milestones			$ 300,000
Collaboration and License Agreement \| Genentech \| Research service
Collaboration research and licensing agreements
Deferred revenue					0
Collaboration and License Agreement \| Genentech \| XmAb24306
Collaboration research and licensing agreements
Payable related to cost-sharing development activities					3,100
Collaboration and License Agreement \| Janssen
Collaboration research and licensing agreements
Revenue recognized					0
Deferred revenue					0
Collaboration and License Agreement \| MorphoSys
Collaboration research and licensing agreements
Deferred revenue					0
Collaboration and License Agreement \| MorphoSys \| Royalties
Collaboration research and licensing agreements
Revenue recognized					2,900	1,800
Receivable					3,400
License Agreement \| INmune
Collaboration research and licensing agreements
Unrealized gain (loss) on equity securities					900	200
License Agreement \| Zenas
Collaboration research and licensing agreements
Revenue recognized					0
Deferred revenue					0
License Agreement \| Zenas \| Milestone \| Preferred Stock
Collaboration research and licensing agreements
Equity shares estimated fair value									$ 10,000
Second Collaboration And License Agreement \| Janssen
Collaboration research and licensing agreements
Revenue recognized					0	5,200
Receivable					1,900
Deferred revenue					0
Research license term	2 years
Second Collaboration And License Agreement \| Janssen \| Maximum
Collaboration research and licensing agreements
Percentage of responsibility for development costs	20.00%
Second Collaboration And License Agreement \| Janssen \| Minimum
Collaboration research and licensing agreements
Share development percentage	80.00%
Patent License Agreement \| Vir
Collaboration research and licensing agreements
Number of different target programs \| target							2
Receivable					0
Deferred revenue					0
Patent License Agreement \| Vir \| Royalties
Collaboration research and licensing agreements
Revenue recognized					$ 0	$ 1,500

Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023
Fair Value of Financial Instruments
Money Market Funds	$ 31,034	$ 53,790	$ 72,394
Marketable securities	615,327
Fair Value, Recurring
Fair Value of Financial Instruments
Total Fair Value	618,774	668,757
Money Market Funds
Fair Value of Financial Instruments
Money Market Funds	3,447	25,520
Money Market Funds \| Fair Value, Recurring
Fair Value of Financial Instruments
Money Market Funds	3,447	25,520
Corporate Securities
Fair Value of Financial Instruments
Marketable securities	264,629	228,723
Corporate Securities \| Fair Value, Recurring
Fair Value of Financial Instruments
Marketable securities	264,629	228,723
Government Securities
Fair Value of Financial Instruments
Marketable securities	350,698	414,514
Government Securities \| Fair Value, Recurring
Fair Value of Financial Instruments
Marketable securities	350,698	414,514
Level 1 \| Fair Value, Recurring
Fair Value of Financial Instruments
Total Fair Value	3,447	25,520
Level 1 \| Money Market Funds \| Fair Value, Recurring
Fair Value of Financial Instruments
Money Market Funds	3,447	25,520
Level 1 \| Corporate Securities \| Fair Value, Recurring
Fair Value of Financial Instruments
Marketable securities	0	0
Level 1 \| Government Securities \| Fair Value, Recurring
Fair Value of Financial Instruments
Marketable securities	0	0
Level 2 \| Fair Value, Recurring
Fair Value of Financial Instruments
Total Fair Value	615,327	643,237
Level 2 \| Money Market Funds \| Fair Value, Recurring
Fair Value of Financial Instruments
Money Market Funds	0	0
Level 2 \| Corporate Securities \| Fair Value, Recurring
Fair Value of Financial Instruments
Marketable securities	264,629	228,723
Level 2 \| Government Securities \| Fair Value, Recurring
Fair Value of Financial Instruments
Marketable securities	$ 350,698	$ 414,514

Stock-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2024

Share-Based Payment Arrangement [Abstract]

Schedule of Total Employee, Director and Non-Employee Stock-Based Compensation Expense Recognized

Total employee, director and non-employee stock-based compensation expense recognized for the three months ended March 31, 2024 and 2023 are as follows (in thousands):


	Three Months Ended March 31,
	2024		2023
General and administrative	$	4,699	$	4,276
Research and development	6,722		8,323
	$	11,421	$	12,599


	Three Months Ended March 31,
	2024		2023
Stock options	$	6,873	$	6,983
ESPP	206		322
RSUs	4,342		5,294
	$	11,421	$	12,599

Summary of Stock Option Activity

The following table summarizes option activity under our stock plans and related information:


	Number of Shares Subject to Outstanding Options	Weighted Average Exercise Price (Per Share)		Weighted Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value (in thousands)
Balance at December 31, 2023	11,142,986	$	29.60	6.03	$	9,977
Options granted	1,763,778	$	22.81
Options forfeited	(206,485)	$	31.55
Options exercised	(152,682)	$	11.70
Balance at March 31, 2024	12,547,597	$	28.84	6.22	$	9,618
Exercisable	8,185,860	$	29.38	4.76	$	9,465

Schedule of Weighted Average Assumptions Used for Estimation of Fair Value of Stock Options

We estimated the fair value of each equity award, including stock options and shares issued under our ESPP, using the Black-Scholes option-pricing model based on the date of grant of such stock option or ESPP share issuance date, with the following weighted average assumptions for the three months ended March 31, 2024 and 2023:


	Options
	Three Months Ended March 31,
	2024		2023
Expected term (years)	6.4		6.0
Expected volatility	50.0	%	50.5	%
Risk-free interest rate	4.12	%	4.26	%
Expected dividend yield	—	%	—	%

Schedule of Weighted Average Assumptions Used for Estimation of Fair Value of ESPP


	ESPP
	Three Months Ended March 31,
	2024		2023
Expected term (years)	0.5 - 2.0		0.5 - 2.0
Expected volatility	43.0%		43.2% - 55.7%
Risk-free interest rate	4.71% - 5.39%		0.13% - 4.72%
Expected dividend yield	—	%	—	%

Summary of Restricted Stock Unit Activity

The following table summarizes the RSU activity for the three-month period ended March 31, 2024:


	Restricted Stock Units	Weighted Average Grant Date Fair Value (Per unit)

Unvested RSUs at December 31, 2023	1,490,040	$	30.66
Granted	796,660	22.83
Vested	(483,812)	32.34
Forfeited	(91,443)	30.76
Unvested RSUs at March 31, 2024	1,711,445	$	26.52

Fair Value of Financial Instruments (Tables)

3 Months Ended

Mar. 31, 2024

Fair Value Disclosures [Abstract]

Schedule of Assets Recorded at Fair Value

The assets recorded at fair value are classified within the hierarchy as follows for the periods reported (in thousands):


	March 31, 2024 (unaudited)						December 31, 2023
	Total Fair Value		Level 1		Level 2		Total Fair Value		Level 1		Level 2
Money Market Funds	$	3,447	$	3,447	$	—	$	25,520	$	25,520	$	—
Corporate Securities	264,629		—		264,629		228,723		—		228,723
Government Securities	350,698		—		350,698		414,514		—		414,514
	$	618,774	$	3,447	$	615,327	$	668,757	$	25,520	$	643,237

Stock-Based Compensation

3 Months Ended

Mar. 31, 2024

Share-Based Payment Arrangement [Abstract]

Stock-Based Compensation

Stock Based Compensation

In June 2023, our Board of Directors (the Board) and stockholders approved the 2023 Equity Incentive Plan (the 2023 Plan), which became effective as of June 14, 2023. The Board and the requisite stockholders previously approved the 2013 Equity Incentive Plan (the 2013 Plan). We suspended the 2013 Plan, and no additional award may be granted under the 2013 Plan. The 2023 Plan reserve consists of 3,000,000 shares and the remaining available shares from the 2013 Plan as of the effective date of the 2023 Plan. In addition, any shares of common stock covered by awards granted under the 2013 Plan that terminate on or after June 14, 2023 by expiration, forfeiture, cancellation, or other means without the issuance of such shares will be added to the 2023 Plan reserve. The 2023 Plan does not include a provision for an automatic increase in shares, also known as an evergreen provision.

As of March 31, 2024, the total number of shares of common stock available for issuance under the 2023 Plan is 18,798,477, which includes shares of common stock that were available for issuance under the prior Plans as of the effective date of the 2023 Plan. As of March 31, 2024, a total of 1,977,176 options have been granted under the 2023 Plan.

In November 2013, the Board and our stockholders approved the ESPP, which became effective as of December 5, 2013. As of March 31, 2024, the total number of shares of common stock available for issuance under the ESPP is 1,041,340. Unless otherwise determined by the Board, beginning on January 1, 2014, and continuing until January 1, 2023, the total number of shares of common stock available for issuance under the ESPP automatically increased annually on January 1 by the lesser of (i) 1% of the total number of issued and outstanding shares of common stock as of December 31 of the immediately preceding year, or (ii) 621,814 shares of common stock. The automatic increase has expired, and the number of shares of common stock available for issuance under the ESPP was not increased on January 1, 2024. As of March 31, 2024, we have issued a total of 733,478 shares of common stock under the ESPP.

During the three months ended March 31, 2024, the Company awarded 796,660 RSUs to certain employees. The standard vesting of these awards is generally in three equal annual installments and is contingent on an employee’s continued service to the Company. The fair value of these awards is determined based on the intrinsic value of the stock on

the date of grant and will be recognized as stock-based compensation expense over the requisite service period. As of March 31, 2024, a total of 883,327 RSUs have been granted under the 2023 Plan.

Total employee, director and non-employee stock-based compensation expense recognized for the three months ended March 31, 2024 and 2023 are as follows (in thousands):


	Three Months Ended March 31,
	2024		2023
General and administrative	$	4,699	$	4,276
Research and development	6,722		8,323
	$	11,421	$	12,599


	Three Months Ended March 31,
	2024		2023
Stock options	$	6,873	$	6,983
ESPP	206		322
RSUs	4,342		5,294
	$	11,421	$	12,599

The following table summarizes option activity under our stock plans and related information:


	Number of Shares Subject to Outstanding Options	Weighted Average Exercise Price (Per Share)		Weighted Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value (in thousands)
Balance at December 31, 2023	11,142,986	$	29.60	6.03	$	9,977
Options granted	1,763,778	$	22.81
Options forfeited	(206,485)	$	31.55
Options exercised	(152,682)	$	11.70
Balance at March 31, 2024	12,547,597	$	28.84	6.22	$	9,618
Exercisable	8,185,860	$	29.38	4.76	$	9,465

We calculate the intrinsic value as the difference between the exercise price of the options and the closing price of common stock of $22.13 per share as of March 31, 2024.

The weighted-average fair value of options granted during the three-month periods ended March 31, 2024 and 2023 were $22.81 and $31.40 per share, respectively. There were 1,620,256 options granted during the three-month period ended March 31, 2023. We estimated the fair value of each equity award, including stock options and shares issued under our ESPP, using the Black-Scholes option-pricing model based on the date of grant of such stock option or ESPP share issuance date, with the following weighted average assumptions for the three months ended March 31, 2024 and 2023:


	Options
	Three Months Ended March 31,
	2024		2023
Expected term (years)	6.4		6.0
Expected volatility	50.0	%	50.5	%
Risk-free interest rate	4.12	%	4.26	%
Expected dividend yield	—	%	—	%


	ESPP
	Three Months Ended March 31,
	2024		2023
Expected term (years)	0.5 - 2.0		0.5 - 2.0
Expected volatility	43.0%		43.2% - 55.7%
Risk-free interest rate	4.71% - 5.39%		0.13% - 4.72%
Expected dividend yield	—	%	—	%

As of March 31, 2024, the unamortized compensation expense related to unvested stock options was $61.5 million. The remaining unamortized compensation expense will be recognized over the next 2.8 years. As of March 31, 2024, the unamortized compensation expense under our ESPP was $1.4 million. The remaining unamortized expense will be recognized over the next 1.7 years.

The following table summarizes the RSU activity for the three-month period ended March 31, 2024:


	Restricted Stock Units	Weighted Average Grant Date Fair Value (Per unit)

Unvested RSUs at December 31, 2023	1,490,040	$	30.66
Granted	796,660	22.83
Vested	(483,812)	32.34
Forfeited	(91,443)	30.76
Unvested RSUs at March 31, 2024	1,711,445	$	26.52

As of March 31, 2024, the unamortized compensation expense related to unvested RSUs was $40.6 million. The remaining unamortized expense will be recognized over the next 2.3 years.

Stock Based Compensation - Restricted Stock Units (Details) - RSUs	3 Months Ended
	Mar. 31, 2024 $ / shares shares
Restricted Stock Units
Beginning balance (in shares) \| shares	1,490,040
Granted (in shares) \| shares	796,660
Vested (in shares) \| shares	(483,812)
Forfeited (in shares) \| shares	(91,443)
Ending balance (in shares) \| shares	1,711,445
Weighted Average Grant Date Fair Value (Per unit)
Weighted average grant date fair value, beginning balance (in dollars per share) \| $ / shares	$ 30.66
Weighted average grant date fair value, granted (in dollars per share) \| $ / shares	22.83
Weighted average grant date fair value, vested (in dollars per share) \| $ / shares	32.34
Weighted average grant date fair value, forfeited (in dollars per share) \| $ / shares	30.76
Weighted average grant date fair value, ending balance (in dollars per share) \| $ / shares	$ 26.52

Marketable Debt and Equity Securities - Unrealized Losses (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Schedule of Available-for-sale Securities
Fair value, less than 12 months	$ 161,400	$ 74,619
Unrealized losses, Less than 12 months	(77)	(77)
Fair value, 12 months or greater	89,549	0
Unrealized losses, 12 months or greater	(276)	0
Corporate Securities
Schedule of Available-for-sale Securities
Fair value, less than 12 months	51,230	8,073
Unrealized losses, Less than 12 months	(42)	(1)
Fair value, 12 months or greater	53,122	0
Unrealized losses, 12 months or greater	(104)	0
Government Securities
Schedule of Available-for-sale Securities
Fair value, less than 12 months	110,170	66,546
Unrealized losses, Less than 12 months	(35)	(76)
Fair value, 12 months or greater	36,427	0
Unrealized losses, 12 months or greater	$ (172)	$ 0

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
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-Paragraph 2
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
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-Section 50
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-URI https://asc.fasb.org//1943274/2147481800/320-10-50-2

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
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-Section 50
-Paragraph 2
-Subparagraph (aaa)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-2

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
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-Section 50
-Paragraph 2
-Subparagraph (b)
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-URI https://asc.fasb.org//1943274/2147481800/320-10-50-2

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
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-URI https://asc.fasb.org//1943274/2147481800/320-10-50-2

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
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Reference 8: http://www.xbrl.org/2003/role/disclosureRef
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Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
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Reference 10: http://www.xbrl.org/2003/role/disclosureRef
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Reference 11: http://www.xbrl.org/2003/role/disclosureRef
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Reference 12: http://www.xbrl.org/2003/role/disclosureRef
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-URI https://asc.fasb.org//1943274/2147481800/320-10-50-3

+ Details

Summary of Significant Accounting Policies	3 Months Ended
Summary of Significant Accounting Policies	Mar. 31, 2024
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Basis of Presentation The accompanying unaudited consolidated interim financial statements for Xencor, Inc. (the Company, Xencor, we or us) have been prepared in accordance with U.S. generally accepted accounting principles (GAAP) for interim financial information. The consolidated financial statements include all adjustments (consisting only of normal recurring adjustments) that the management of the Company believes are necessary for a fair presentation of the periods presented. The preparation of consolidated interim financial statements requires the use of management’s estimates and assumptions that affect reported amounts of assets and liabilities at the date of the consolidated interim financial statements and the reported revenues and expenditures during the reported periods. These interim financial results are not necessarily indicative of the results expected for the full fiscal year or for any subsequent interim period. The accompanying unaudited consolidated interim financial statements and related notes should be read in conjunction with the audited consolidated financial statements and notes thereto included in the Company’s 2023 Annual Report on Form 10-K filed with the Securities and Exchange Commission (SEC) on February 29, 2024. Principles of Consolidation The accompanying consolidated financial statements include the accounts of Xencor, Inc. and Gale Therapeutics Inc. (Gale), a variable interest entity (VIE) in which we are the primary beneficiary. Since we own less than 100% of Gale, the Company records net loss attributable to non-controlling interests in its consolidated statements of income (loss) equal to the percentage of the economic or ownership interests retained in Gale by the non-controlling party. In determining whether we are the primary beneficiary of a VIE, we apply a qualitative approach that determines whether we have (1) the power to direct the activities of the VIE that most significantly impact the entity's economic performance and (2) the obligation to absorb losses of, or the right to receive benefits from the VIE that could potentially be significant to the VIE. We continuously assess whether we are the primary beneficiary of Gale as changes to existing relationships or future transactions result in us consolidating or deconsolidating Gale. Use of Estimates The preparation of consolidated interim financial statements in conformity with GAAP requires management to make certain estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses, other comprehensive gain (loss) and the related disclosures. On an ongoing basis, management evaluates its estimates, including estimates related to its accrued clinical trial and manufacturing development expenses, stock-based compensation expense, evaluation of intangible assets, investments, leases and other assets for evidence of impairment, fair value measurements, and contingencies. Significant estimates in these consolidated interim financial statements include estimates made for royalty revenue, accrued research and development expenses, stock-based compensation expenses, intangible assets, incremental borrowing rate for right-of-use asset and lease liability, estimated standalone selling price of performance obligations, estimated time for completing delivery of performance obligations under certain arrangements, the likelihood of recognizing variable consideration, the carrying value of equity instruments without a readily determinable fair value, and recoverability of deferred tax assets. Reclassifications Certain prior year amounts in the consolidated financial statements and the notes thereto have been reclassified to conform to the current period's presentation. These reclassifications did not affect the prior period's total assets, liabilities, stockholders' equity, net loss or cash flows. During the three months ended March 31, 2024, we adopted a change in presentation on our consolidated statements of loss to include loss from disposal of fixed assets in operating expenses. The prior period has been revised to reflect this change in the presentation. Intangible Assets The Company maintains definite-lived intangible assets related to certain capitalized costs of acquired licenses and third-party costs incurred in establishing and maintaining its intellectual property rights to its platform technologies and development candidates. These assets are amortized over their useful lives, which are estimated to be the remaining patent life or the contractual term of the license. The straight-line method is used to record amortization expense. The Company assesses its intangible assets for impairment if indicators are present or changes in circumstances suggest that impairment may exist. There was no impairment charge recorded for the three months ended March 31, 2024 and 2023. The Company capitalizes certain in-process intangible assets that are then abandoned when they are no longer pursued or used in current research activities. We abandoned $0.4 million of in-process intangible assets for the three months ended March 31, 2024. We abandoned $0.3 million of in-process intangible assets during the three months ended March 31, 2023. Marketable Debt and Equity Securities The Company has an investment policy that includes guidelines on acceptable investment securities, minimum credit quality, maturity parameters, and concentration and diversification. The investment policy limits the maturity of any individual security to a maximum of 36 months. The average maturity of securities in the portfolio as of March 31, 2024 is less than 12 months. The Company invests its excess cash primarily in marketable debt securities issued by investment grade institutions. The Company considers its marketable debt securities to be available-for-sale because it is not more likely than not that the Company will be required to sell the securities before recovery of the amortized cost. These assets are carried at fair value and any impairment losses and recoveries related to the underlying issuer’s credit standing are recognized within other income (expense), while non-credit related impairment losses and recoveries are recognized within accumulated other comprehensive income (loss). There were no impairment losses or recoveries recorded for the three months ended March 31, 2024 and 2023. Accrued interest on marketable debt securities is included in the marketable securities’ carrying value. Each reporting period, the Company reviews its portfolio of marketable debt securities, using both quantitative and qualitative factors, to determine if each security’s fair value has declined below its amortized cost basis. During the three months ended March 31, 2024, the Company recorded an unrealized loss of $1.4 million in its portfolio of marketable debt securities. During the three months ended March 31, 2023, the Company recorded an unrealized gain of $3.3 million. The unrealized loss is due to the changing interest rate environment and is not due to changes in the credit quality of the underlying securities. The unrealized gain (loss) is recorded in other comprehensive income (loss) for the three months ended March 31, 2024 and 2023. The Company receives equity securities in connection with certain licensing transactions with its partners. These investments in equity securities are carried at fair value with changes in fair value recognized each period and reported within other income (expense). For equity securities with a readily determinable fair value, the Company remeasures these equity investments at each reporting period until such time that the investment is sold or disposed. If the Company sells an investment, any realized gain or loss on the sale of the securities will be recognized within other income (expense) in the consolidated statements of loss in the period of sale. The Company also has investments in equity securities without a readily determinable fair value, where the Company elects the measurement alternative to record the investment at its initial cost minus impairment, plus or minus changes resulting from observable price changes in orderly transactions for the identical or a similar investment of the same issuer. There was an impairment charge of $20.6 million recorded for the three months ended March 31, 2024 in connection with equity securities without a readily determinable fair value. There was no impairment charge recorded for the three months ended March 31, 2023. Liability Related to the Sale of Future Revenues We treat the sale of future Monjuvi royalties as debt, amortized under the effective interest rate method over the estimated life of the Monjuvi Royalty Sale Agreement. See Note 11. The amortization of the liability related to the sale of future Monjuvi royalties is based on our current estimate of future royalty payments. Royalty revenue will be recognized as earned and the payments made will be a reduction of the liability when paid. Non-cash Interest Expense on the Liability Related to the Sale of Future Royalties The total expected royalty payments less the net proceeds received are recorded as non-cash interest expense over the life of the liability. Interest is imputed on the unamortized portion using the effective interest method and is recorded based on the timing of the payments received over the term of the Monjuvi Royalty Sale Agreement. The actual interest rate will be affected by the timing of the royalty payments and changes in the forecasted revenue. Deferred Income Related to the Sale of Future Revenues We treat the sale of future Ultomiris royalties as deferred income, amortized under the units-of-revenue method by computing a ratio of the proceeds received to the total expected payments over the term of the Ultomiris Royalty Sale Agreement. See Note 11. The amortization of the liability related to the sale of future royalties is based on our current estimate of future royalty payments. Royalty revenue will be recognized as earned and the payments made will be a reduction of the liability when paid. Recent Accounting Pronouncements There have been no material changes in recently issued or adopted accounting standards from those disclosed in the Company's 2023 Annual Report on Form 10-K. The Company has reviewed all recently issued accounting pronouncements and does not believe they will have a material impact on our results of operations, financial condition or cash flows. There have been no other material changes to the significant accounting policies previously disclosed in the Company’s 2023 Annual Report on Form 10-K.

Comprehensive Income (Loss)	3 Months Ended
Comprehensive Income (Loss)	Mar. 31, 2024
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Comprehensive Income (Loss)	Comprehensive Income (Loss) Comprehensive income (loss) is comprised of net income (loss) and other comprehensive income (loss). For each of the three-month periods ended March 31, 2024 and 2023, the only component of other comprehensive income (loss) is net unrealized gain (loss) on marketable debt securities. There were no material reclassifications out of accumulated other comprehensive income (loss) during each of the three-month periods ended March 31, 2024 and 2023.

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit	Non-Controlling Interest
Beginning balance (in shares) at Dec. 31, 2022		59,997,713
Beginning balance at Dec. 31, 2022	$ 727,496	$ 601	$ 1,072,132	$ (6,952)	$ (338,285)	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock awards (in shares)		34,388
Issuance of common stock upon exercise of stock awards	924		924
Issuance of restricted stock units (in shares)		349,499
Issuance of restricted stock units	0	$ 4	(4)
Comprehensive income (loss)	(57,436)			3,327	(60,763)
Stock-based compensation	12,599		12,599
Ending balance (in shares) at Mar. 31, 2023		60,381,600
Ending balance at Mar. 31, 2023	683,583	$ 605	1,085,651	(3,625)	(399,048)	0
Beginning balance (in shares) at Dec. 31, 2023		60,998,191
Beginning balance at Dec. 31, 2023	669,133	$ 611	1,131,266	1,291	(464,372)	337
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock awards (in shares)		152,682
Issuance of common stock upon exercise of stock awards	1,787	$ 1	1,786
Issuance of restricted stock units (in shares)		483,812
Issuance of restricted stock units	0	$ 5	(5)
Comprehensive income (loss)	(70,154)			(1,445)	(68,033)	(676)
Stock-based compensation	11,421		11,421
Ending balance (in shares) at Mar. 31, 2024		61,634,685
Ending balance at Mar. 31, 2024	$ 612,187	$ 617	$ 1,144,468	$ (154)	$ (532,405)	$ (339)

- Definition

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income. Excludes changes in equity resulting from investments by owners and distributions to owners.

+ References + Details

- Definition

Amount of equity (deficit) attributable to parent and noncontrolling interest. Excludes temporary equity.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

Collaboration and Licensing Agreements (Tables)

3 Months Ended

Mar. 31, 2024

Collaboration and Licensing Agreements

Schedule of Revenue by Licensees

The revenues recorded for the three months ended March 31, 2024 and 2023 were earned principally from the following licensees (in millions):


	Three Months Ended March 31,
	2024		2023

Alexion	$	9.4	$	10.5



Janssen	—		5.2
MorphoSys	2.9		1.8


Vega	0.5		—
Vir	—		1.5


Total	$	12.8	$	19.0

Schedule of Disaggregation of Revenue

The table below summarizes the disaggregation of revenue recorded for the three months ended March 31, 2024 and 2023 (in millions):


	Three Months Ended March 31,
	2024		2023

Research collaboration	$	—	$	0.2
Milestone	0.5		5.0
Royalties	—		13.8
Non-cash royalties	12.3		—
Total	$	12.8	$	19.0

Sales of Future Royalties (Tables)

3 Months Ended

Mar. 31, 2024

Receivables [Abstract]

Debt of Future Royalties

The following table shows the activity within debt for the quarter ended March 31, 2024 (in thousands):


	March 31, 2024

Beginning balance of debt related to sale of future royalties	$	20,974
Royalties owed to OMERS	349
Royalties paid to OMERS	(1,950)
Non-cash interest expense recognized	1,067
Ending balance of debt related to sale of future royalties	$	20,440

Debt - short-term	7,951
Debt - long-term	12,489
Total debt	$	20,440

Marketable Debt and Equity Securities - Net Gains and Losses (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Marketable Securities [Abstract]
Net and unrealized gain (loss) recognized on equity securities	$ 2,325	$ (2,898)

Stock-Based Compensation - Employee Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Total employee, director and non-employee stock-based compensation expense	$ 11,421	$ 12,599
Stock options
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Total employee, director and non-employee stock-based compensation expense	6,873	6,983
ESPP
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Total employee, director and non-employee stock-based compensation expense	206	322
RSUs
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Total employee, director and non-employee stock-based compensation expense	4,342	5,294
General and administrative
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Total employee, director and non-employee stock-based compensation expense	4,699	4,276
Research and development
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Total employee, director and non-employee stock-based compensation expense	$ 6,722	$ 8,323

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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+ Details

Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Statement of Comprehensive Income [Abstract]
Net loss	$ (68,709)	$ (60,763)
Net unrealized gain (loss) on marketable debt securities	(1,445)	3,327
Comprehensive loss	(70,154)	(57,436)
Comprehensive loss attributable to non-controlling interest	(676)	0
Net loss attributable to Xencor, Inc.	$ (69,478)	$ (57,436)

- Definition

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income (loss) and other comprehensive income (loss), attributable to noncontrolling interests. Excludes changes in equity resulting from investments by owners and distributions to owners.

+ References + Details

- Definition

+ References + Details

- Definition

The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest.

+ References

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+ Details

Marketable Debt and Equity Securities - Summary (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023
Schedule of Available-for-sale Securities
Money Market Funds	$ 31,034	$ 53,790	$ 72,394
Amortized Cost	615,470
Amortized Cost	618,917	667,455
Gross Unrealized Gains	210	1,379
Gross Unrealized Losses	(353)	(77)
Marketable securities	615,327
Total investments	618,774	668,757
Money Market Funds
Schedule of Available-for-sale Securities
Money Market Funds	3,447	25,520
Corporate Securities
Schedule of Available-for-sale Securities
Amortized Cost	264,706	228,382
Gross Unrealized Gains	69	342
Gross Unrealized Losses	(146)	(1)
Marketable securities	264,629	228,723
Government Securities
Schedule of Available-for-sale Securities
Amortized Cost	350,764	413,553
Gross Unrealized Gains	141	1,037
Gross Unrealized Losses	(207)	(76)
Marketable securities	350,698	414,514
Cash and cash equivalents
Schedule of Available-for-sale Securities
Money Market Funds	3,447	25,520
Marketable securities
Schedule of Available-for-sale Securities
Marketable securities	$ 615,327	$ 643,237

Income Taxes	3 Months Ended
Income Taxes	Mar. 31, 2024
Income Tax Disclosure [Abstract]
Income Taxes	Income taxes There is no provision for income tax for the three months ended March 31, 2024 or 2023. As of March 31, 2024, the Company’s deferred income tax assets, consisting primarily of net operating loss and tax credit carryforwards, have been fully offset by a valuation allowance.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480990/946-20-50-13

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
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-Name Accounting Standards Codification
-Section S99
-Paragraph 1
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-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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-URI https://asc.fasb.org//740/tableOfContent

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
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Reference 9: http://www.xbrl.org/2003/role/disclosureRef
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Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
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-Section 50
-Paragraph 2
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-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482603/740-30-50-2

+ Details

Leases - Agreements (Details) $ in Thousands	1 Months Ended	123 Months Ended
Leases - Agreements (Details) $ in Thousands	Jun. 30, 2021 phase	Mar. 31, 2024 USD ($)	Sep. 30, 2026 USD ($)	Dec. 31, 2023 USD ($)	Aug. 31, 2022 USD ($)	Aug. 01, 2022 USD ($)
Lessee, Lease, Description [Line Items]
Payments for (proceeds from) tenant allowance		$ 700
Cash collateral for Letters of Credit		382		$ 380
Letter of Credit
Lessee, Lease, Description [Line Items]
Letter of Credit amount		$ 400
Monrovia, CA - office and laboratory space
Lessee, Lease, Description [Line Items]
Renewal term		5 years
Pasadena, CA - office and laboratory space
Lessee, Lease, Description [Line Items]
Phases of lease term \| phase	2
Improvement allowance					$ 5,000	$ 17,000
Forecast \| Pasadena, CA - office and laboratory space
Lessee, Lease, Description [Line Items]
Improvement allowance			$ 3,300

Net Loss Per Common Share

3 Months Ended

Mar. 31, 2024

Earnings Per Share [Abstract]

Net Loss Per Common Share

Basic net income (loss) per common share is computed by dividing the net income (loss) attributable to Xencor by the weighted-average number of common shares outstanding during the period without consideration of common stock equivalents. Diluted net income (loss) per common share is computed by dividing the net income (loss) attributable to Xencor by the weighted-average number of common stock equivalents outstanding for the period. Potentially dilutive securities consisting of stock issuable pursuant to outstanding options and restricted stock units (RSUs), and stock issuable pursuant to the 2013 Employee Stock Purchase Plan (ESPP) are not included in the per common share calculation in periods when the inclusion of such shares would have an anti-dilutive effect.

Basic and diluted net loss per common share is computed as follows:


	Three Months Ended March 31,
	2024		2023
	(in thousands, except share and per share data)
Numerator:
Net loss attributable to Xencor, Inc.	$	(68,033)	$	(60,763)
Denominator:


Weighted-average common shares outstanding used in computing basic and diluted net loss	61,212,324		59,771,674
Basic and diluted net loss per common share attributable to Xencor, Inc.	$	(1.11)	$	(1.02)

For the three months ended March 31, 2024 and 2023, all outstanding potentially dilutive securities have been excluded from the calculation of diluted net loss per common share as the effect of including such securities would have been anti-dilutive.

Leases (Tables)

3 Months Ended

Mar. 31, 2024

Leases [Abstract]

Schedule of Operating Lease Liabilities Maturities

The following table reconciles the undiscounted cash flows for the operating leases at March 31, 2024 to the operating lease liabilities recorded on the balance sheet (in thousands):


Years ending December 31,
For the remainder of 2024	$	4,460
2025	8,022
2026	9,238
2027	9,560
2028	9,076
2029	9,331
Thereafter	57,104
Total undiscounted lease payments	106,791
Less: Tenant allowance	(3,252)
Less: Imputed interest	(34,650)
Present value of lease payments	$	68,889

Lease liabilities - short-term	$	2,079
Lease liabilities - long-term	66,810
Total lease liabilities	$	68,889

Summary of Lease Costs and Cash Disclosures

The following table summarizes lease costs and cash payments for the three months ended March 31, 2024 and 2023 (in thousands):


	Three Months Ended March 31,
	2024		2023

Operating lease cost	$	1,881	$	2,181
Variable lease cost	830		234
Total lease costs	$	2,711	$	2,415

Cash paid for amounts included in the measurement of lease liabilities	$	1,070	$	724

Cover - shares	3 Months Ended
Cover - shares	Mar. 31, 2024	May 02, 2024
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2024
Document Transition Report	false
Entity File Number	001-36182
Entity Registrant Name	Xencor, Inc
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	20-1622502
Entity Address, Address Line One	465 North Halstead Street
Entity Address, Address Line Two	Suite 200
Entity Address, City or Town	Pasadena
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	91107
City Area Code	626
Local Phone Number	305-5900
Title of 12(b) Security	Common Stock, par value $0.01 per share
Trading Symbol	XNCR
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		61,662,550
Entity Central Index Key	0001326732
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q1
Amendment Flag	false

Sales of Future Royalties - Narrative (Details) - Royalties $ in Millions	3 Months Ended
	Mar. 31, 2024 USD ($)
Alexion \| Option and License agreement
Sales of Future Royalties [Line Items]
Non-cash revenue recognized	$ 9.4
Deferred revenue	147.5
MorphoSys \| Collaboration and License Agreement
Sales of Future Royalties [Line Items]
Non-cash revenue recognized	$ 2.9
Interest rate	21.10%
Non-cash interest expense recognized	$ 1.1

Sales of Future Royalties - Debt of Future Royalties (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2024 USD ($)
Sale of Future Royalty [Roll Forward]
Beginning balance of debt related to sale of future royalties	$ 20,974
Royalties owed to OMERS	349
Royalties paid to OMERS	(1,950)
Non-cash interest expense recognized	1,067
Ending balance of debt related to sale of future royalties	20,440
Debt - short-term	7,951
Debt - long-term	12,489
Total debt	$ 20,440

Income Taxes (Details) - USD ($)	3 Months Ended
Income Taxes (Details) - USD ($)	Mar. 31, 2024	Mar. 31, 2023
Income Tax Disclosure [Abstract]
Income tax expense	$ 0	$ 0

- Definition

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References + Details

Leases - Lease Costs (Details) - USD ($) $ in Thousands	3 Months Ended
Leases - Lease Costs (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Mar. 31, 2023
Leases [Abstract]
Operating lease cost	$ 1,881	$ 2,181
Variable lease cost	830	234
Total lease costs	2,711	2,415
Cash paid for amounts included in the measurement of lease liabilities	$ 1,070	$ 724
Remaining lease term	10 years 10 months 24 days	11 years 9 months 18 days
Discount rate	7.00%	8.90%

Marketable Debt and Equity Securities - Equity Securities Transactions (Details) - Common Stock	Mar. 31, 2024 shares
License Agreement \| Astria
Equity Securities
Number of shares owned (in shares)	697,867
License Agreement \| INmune
Equity Securities
Number of shares owned (in shares)	1,885,533
Technology License Agreement \| Viridian
Equity Securities
Number of shares owned (in shares)	717,144

Subsequent Event (Details) - USD ($) $ in Thousands		3 Months Ended
Subsequent Event (Details) - USD ($) $ in Thousands	May 03, 2024	Mar. 31, 2024	Mar. 31, 2023
Subsequent Event [Line Items]
Impairment on equity securities		$ (20,650)	$ 0
Zenas
Subsequent Event [Line Items]
Impairment on equity securities		$ (20,600)
Subsequent Event \| Series C Preferred Stock \| Zenas
Subsequent Event [Line Items]
Impairment on equity securities	$ (20,600)

Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Current assets
Cash and cash equivalents	$ 31,034	$ 53,790
Marketable debt securities	460,367	497,725
Marketable equity securities	44,535	42,210
Accounts receivable	9,580	11,290
Prepaid expenses and other current assets	16,736	18,145
Total current assets	562,252	623,160
Property and equipment, net	63,540	66,124
Patents, licenses, and other intangible assets, net	18,852	18,663
Restricted cash	382	380
Marketable debt securities - long term	154,960	145,512
Marketable equity securities - long term	43,560	64,210
Right of use (ROU) asset	40,211	33,995
Other assets	498	648
Total assets	884,255	952,692
Current liabilities
Accounts payable	16,011	13,914
Accrued expenses	13,491	23,564
Income tax payable	5,782	5,782
Lease liabilities	2,079	3,435
Deferred income	34,088	31,682
Debt	7,951	6,332
Total current liabilities	79,402	84,709
Lease liabilities, net of current portion	66,810	59,025
Deferred income, net of current portion	113,367	125,183
Debt, net of current portion	12,489	14,642
Total liabilities	272,068	283,559
Commitments and contingencies
Stockholders’ equity
Preferred stock, $0.01 par value: 10,000,000 authorized shares; -0- issued and outstanding shares at March 31, 2024 and December 31, 2023	0	0
Common stock, $0.01 par value: 200,000,000 authorized shares at March 31, 2024 and December 31, 2023; 61,634,685 issued and outstanding at March 31, 2024 and 60,998,191 issued and outstanding at December 31, 2023	617	611
Additional paid-in capital	1,144,468	1,131,266
Accumulated other comprehensive (loss) income	(154)	1,291
Accumulated deficit	(532,405)	(464,372)
Total stockholders’ equity attributable to Xencor, Inc.	612,526	668,796
Non-controlling interest	(339)	337
Total stockholders’ equity	612,187	669,133
Total liabilities and stockholders’ equity	$ 884,255	$ 952,692