0001326732-24-000006 | 10-K | XBRL Viewer

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Collaboration and Licensing Agreements - MorphoSys AG/Incyte Corporation (Details) - USD ($) $ in Thousands		12 Months Ended
	Nov. 03, 2023	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Sep. 30, 2023
Collaboration research and licensing agreements
Accounts receivable		$ 11,290	$ 28,997
MorphoSys \| Collaboration and License Agreement
Collaboration research and licensing agreements
Deferred revenue		0
MorphoSys \| Royalties \| Collaboration and License Agreement
Collaboration research and licensing agreements
Proceeds from upfront payment	$ 22,500
Accounts receivable					$ 2,200
Revenue recognized		8,700	$ 7,800	$ 5,900
Non-cash revenue recognized		2,100
Contract asset		$ 2,100
MorphoSys \| Milestone \| Collaboration and License Agreement
Collaboration research and licensing agreements
Revenue recognized				$ 12,500

Property and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Property and Equipment
Total gross carrying amount	$ 102,350	$ 87,472
Less accumulated depreciation and amortization	(36,226)	(28,289)
Total property and equipment, net	66,124	59,183
Depreciation expense	10,100	7,400	$ 6,300
Computers, software and equipment
Property and Equipment
Total gross carrying amount	49,782	45,159
Furniture and fixtures
Property and Equipment
Total gross carrying amount	158	539
Leasehold and tenant improvements
Property and Equipment
Total gross carrying amount	$ 52,410	$ 41,774

Marketable Debt and Equity Securities

12 Months Ended

Dec. 31, 2023

Marketable Securities [Abstract]

Marketable Debt and Equity Securities

The Company’s marketable debt securities held as of December 31, 2023 and 2022 are summarized below:


	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


	December 31, 2022
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
(in thousands)
Money Market Funds	$	40,967	$	—	$	—	$	40,967
Corporate Securities	201,752		—		(1,126)		200,626
Government Securities	335,705		3		(5,819)		329,889
	$	578,424	$	3	$	(6,945)	$	571,482

Reported as
Cash and cash equivalents							$	40,967
Marketable securities							530,515
Total investments							$	571,482

The maturities of the Company’s marketable debt securities as of December 31, 2023 are as follows:


	Amortized Cost		Estimated Fair Value
(in thousands)
Mature in one year or less	$	497,326	$	497,725
Mature within two years	144,609		145,511
	$	641,935	$	643,236

The unrealized losses on available-for-sale investments and their related fair values as of December 31, 2023 and 2022 are as follows:


	December 31, 2023
	Less than 12 months				12 months or greater
	Fair value		Unrealized losses		Fair value		Unrealized losses
(in thousands)
Corporate Securities	$	8,073	$	(1)	$	—	$	—
Government Securities	66,546		(77)		—		—
	$	74,619	$	(78)	$	—	$	—


	December 31, 2022
	Less than 12 months				12 months or greater
	Fair value		Unrealized losses		Fair value		Unrealized losses
(in thousands)
Corporate Securities	$	132,658	$	(1,121)	$	3,826	$	(5)
Government Securities	324,933		(5,819)		—		—
	$	457,591	$	(6,940)	$	3,826	$	(5)

The unrealized losses from the listed securities are due to a change in the interest rate environment and not a change in the credit quality of the securities.

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). Equity securities with a readily determinable fair value and their fair values (in thousands) as of December 31, 2023 and 2022 are as follows:


	Fair Value December 31, 2023		Fair Value December 31, 2022
Astria Common Stock	$	5,360	$	9,529
INmune Common Stock	21,231		11,954
Viridian Common Stock	15,619		20,948
	$	42,210	$	42,431

The Company also has an investment in an equity security 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. During the year ended December 31, 2022, the Company recorded an impairment

charge of $0.1 million related to the Astria preferred stock. Equity securities without a readily determinable fair value and their carrying values (in thousands) as of December 31, 2023 and 2022 are as follows:


	Carrying Value December 31, 2023		Carrying Value December 31, 2022
Astria Preferred Stock	$	—	$	174
Zenas Preferred Stock	64,210		54,209
	$	64,210	$	54,383

In 2018, the Company received common and preferred stock in Astria (formerly Quellis Biosciences, Inc.) in connection with a licensing transaction. In January 2023, the Company exchanged its preferred shares for additional shares of common stock in Astria. The common stock has a readily determinable fair value, and difference in the fair value of the common stock and the carrying value of the preferred stock has been recorded as a gain in equity securities for the year ended December 31, 2023. The Company accounts for the shares in Astria common stock at their fair value each reporting period and the adjustment in the fair value of the Astria common stock has been recorded in unrealized gain (loss) on equity securities for the year ended December 31, 2023.

The Company records its investment in the shares of Astria preferred stock as an equity interest without a readily determinable fair value. The Company elected to record the original shares of preferred stock at their initial cost and to review the carrying value for impairment or other changes in carrying value at each reporting period. The Company subsequently recorded impairment charges of $0.1 million and $0.8 million related to its investment in Astria’s preferred stock in 2022 and 2021, respectively.

In 2017, the Company received shares of common stock of INmune Bio, Inc. (INmune) and an option to acquire additional shares of INmune’s common stock in connection with a licensing transaction. In June 2021, the Company entered into an Option Cancellation Agreement with INmune and received $15.0 million in proceeds and an additional shares of INmune common stock in exchange for the initial option. During 2021, the Company determined that it should no longer account for its investment in INmune under the equity method. In September 2021, the Company exercised its second option to purchase 108,000 shares of INmune common stock for $0.8 million and the Company recorded a gain of $0.9 million on the purchase. The Company's current share holdings, which consist of common stock of INmune, have a readily determinable fair value, and the adjustment in the fair value of the shares of INmune common stock was recorded in gain (loss) on equity securities for the year ended December 31, 2023.

In December 2021, the Company received shares of common stock of Viridian Therapeutics, Inc. (Viridian) in connection with the Viridian Agreement. In December 2022, the Company received additional shares of common stock of Viridian in connection with the Second Viridian Agreement (defined below). 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 in gain (loss) on equity securities for the year ended at December 31, 2023.

In 2020, the Company received an equity interest in Zenas BioPharma (Cayman) Limited (Zenas), in connection with the Zenas Agreement (defined below). 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 an identical or a similar investment of the same issuer. In 2021, the Company received a warrant to receive equity from Zenas in connection with the Second Zenas Agreement (defined below). In 2021, the Company purchased a convertible promissory note from Zenas. In 2022, the Zenas warrant was exchanged for additional equity in Zenas. In 2022, the convertible note and accrued interest through the conversion date were exchanged for equity shares in Zenas. During 2022, the Company recognized an unrealized gain of $21.9 million from the warrant exchange and the conversion of the promissory note. In 2023, Zenas initiated a Phase 3 trial and we received a milestone of additional equity in Zenas with a fair value of $10.0 million. The Company recorded the additional equity at its fair value. During the year ended December 31, 2023, there was no impairment related to this investment.

Unrealized gains and losses recognized on equity securities (in thousands) during the year ended December 31, 2023 and 2022 consist of the following:


	Year Ended December 31,
	2023		2022		2021

Net (losses) gains recognized on equity securities	$	(395)	$	23,434	$	39,289
Less: net gains recognized on equity securities redeemed	—		—		18,301
Unrealized (losses) gain recognized on equity securities	$	(395)	$	23,434	$	20,988

Marketable Debt and Equity Securities - Narrative (Details) - USD ($) $ in Thousands	1 Months Ended		12 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Nov. 30, 2022
Equity Securities
Equity securities impairment			$ 0	$ 100
Net gain (loss) recognized on equity securities			(395)	23,434	$ 39,289
Preferred Stock
Equity Securities
Equity shares estimated fair value			64,210	54,383
Astria Common Stock \| Preferred Stock
Equity Securities
Equity securities impairment				100	800
Equity shares estimated fair value			0	174
Zenas \| Warrant
Equity Securities
Equity shares estimated fair value						$ 34,500
Zenas \| Warrant \| Notes Receivable
Equity Securities
Unrealized gain on warrant exchange and conversion of promissory note				21,900
Zenas \| Preferred Stock
Equity Securities
Equity shares estimated fair value			64,210	$ 54,209
License Agreement \| INmune Common Stock
Equity Securities
Cash consideration on sale of option		$ 15,000
License Agreement \| INmune Common Stock \| Common Stock
Equity Securities
Cash consideration on sale of option		$ 15,000
Number of shares acquired (in shares)	108,000
Purchase amount of share options or equity in noncash transaction					$ 800
Net gain (loss) recognized on equity securities	$ 900
License Agreement \| Zenas \| Preferred Stock \| Milestone
Equity Securities
Equity shares estimated fair value			$ 10,000

Marketable Debt and Equity Securities - Net Gains and Losses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Marketable Securities [Abstract]
Net (losses) gains recognized on equity securities	$ (395)	$ 23,434	$ 39,289
Less: net gains recognized on equity securities redeemed	0	0	18,301
Unrealized (losses) gain recognized on equity securities	$ (395)	$ 23,434	$ 20,988

401(k) Plan (Details) - USD ($) $ in Millions		12 Months Ended
401(k) Plan (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan employer matching contribution percent	4.00%
Vesting period		3 years
Annual vesting percentage		33.00%
Employer contributions		$ 1.7	$ 1.4	$ 1.1
1% of participating employee contributions
Defined Benefit Plan Disclosure [Line Items]
Percentage of company matching to defined contribution plan	100.00%
Defined contribution plan employer matching contribution percent	1.00%
6% of participating employee contributions
Defined Benefit Plan Disclosure [Line Items]
Percentage of company matching to defined contribution plan	50.00%
Defined contribution plan employer matching contribution percent	6.00%

Collaboration and Licensing Agreements - Gilead Sciences, Inc. (Details) - Gilead - Technology License Agreement	1 Months Ended	12 Months Ended
	Jan. 31, 2020 compound	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Collaboration research and licensing agreements
Number of additional antibody compounds \| compound	3
Revenue recognized		$ 6,000,000	$ 0
Deferred revenue		$ 0

Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2023

Accounting Policies [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):


	December 31, 2023
	Total Fair Value		Level 1		Level 2

Money Market Funds in Cash and Cash Equivalents	$	25,520	$	25,520	$	—
Corporate Securities	228,723		—		228,723
Government Securities	414,514		—		414,514

	$	668,757	$	25,520	$	643,237


	December 31, 2022
	Total Fair Value		Level 1		Level 2

Money Market Funds in Cash and Cash Equivalents	$	40,967	$	40,967	$	—
Corporate Securities	200,626		—		200,626
Government Securities	329,889		—		329,889

	$	571,482	$	40,967	$	530,515

Schedule of useful lives by asset category

Useful lives by asset category are as follows:


Computers, software and equipment			3 - 5 years
Furniture and fixtures			5 - 7 years
Leasehold improvements			5 - 7 years or remaining
			lease term, whichever is less

Schedule of finite-lived intangible assets

The carrying amount and accumulated amortization of patents, licenses, and other intangibles is as follows (in thousands):


	December 31,
	2023		2022
Patents, definite life	$	15,340	$	14,535
Patents, pending issuance	9,723		9,328
Licenses and other amortizable intangible assets	4,007		3,908
Nonamortizable intangible assets (trademarks)	399		399
Total gross carrying amount	29,469		28,170
Accumulated amortization—patents	(8,663)		(7,781)
Accumulated amortization—licenses and other	(2,143)		(1,889)
Total intangible assets, net	$	18,663	$	18,500

Schedule of indefinite-lived intangible assets

The carrying amount and accumulated amortization of patents, licenses, and other intangibles is as follows (in thousands):


	December 31,
	2023		2022
Patents, definite life	$	15,340	$	14,535
Patents, pending issuance	9,723		9,328
Licenses and other amortizable intangible assets	4,007		3,908
Nonamortizable intangible assets (trademarks)	399		399
Total gross carrying amount	29,469		28,170
Accumulated amortization—patents	(8,663)		(7,781)
Accumulated amortization—licenses and other	(2,143)		(1,889)
Total intangible assets, net	$	18,663	$	18,500

Future amortization expense for patents, licenses, and other intangible assets

Future amortization expense for patents, licenses, and other intangible assets recorded as of December 31, 2023, and for which amortization has commenced, is as follows:


	Year ended December 31,
	(in thousands)
2024	$	1,076
2025	1,059
2026	961
2027	908
2028	776
Thereafter	3,760
Total	$	8,540

Schedule of basic and diluted net income (loss) per common share

Basic and diluted net income (loss) per common share attributable to Xencor is computed as follows:

Basic net income (loss) per common share is computed by dividing the net income or loss attributable to Xencor by the weighted-average number of common shares outstanding during the period.

Potentially dilutive securities were included in the calculation of diluted net income per common share attributable to Xencor for 2021. In 2023 and 2022, we excluded all options and awards from the calculations because we reported net losses in the period, and the inclusion of such shares would have had an antidilutive effect.


	Year Ended December 31,
	2023		2022		2021
	(in thousands, except share and per share data)
Basic
Numerator:
Net income (loss) attributable to Xencor, Inc.	$	(126,087)	$	(55,181)	$	82,631
Denominator:
Weighted-average common shares outstanding	60,503,283		59,652,461		58,379,641
Basic net income (loss) per common share attributable to Xencor, Inc.	$	(2.08)	$	(0.93)	$	1.42

Diluted
Numerator:
Net income (loss) attributable to Xencor, Inc.	$	(126,087)	$	(55,181)	$	82,631
Denominator:
Weighted average number of common shares outstanding used in computing basic net income (loss) per common share	60,503,283		59,652,461		58,379,641
Dilutive effect of employee stock options, RSUs, and ESPP	—		—		2,115,814
Weighted-average number of common shares outstanding used in computing diluted net income (loss) per common share	60,503,283		59,652,461		60,495,455
Diluted net income (loss) per common share attributable to Xencor, Inc.	$	(2.08)	$	(0.93)	$	1.37

Stock-Based Compensation - FV of Employee Stock Options (Details) - $ / shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Weighted average assumptions for estimated fair value of employee stock options
Expected dividend yield	0.00%	0.00%	0.00%
Stock options
Weighted average assumptions for estimated fair value of employee stock options
Common stock fair value per share minimum (in dollars per share)	$ 20.14	$ 19.74	$ 30.65
Common stock fair value per share maximum (in dollars per share)	$ 36.02	$ 38.08	$ 49.47
Expected volatility, low end of range (as a percent)	49.75%	51.51%	53.91%
Expected volatility, high end of range (as a percent)	52.48%	54.36%	56.82%
Risk-free interest rate, low end of range (as a percent)	3.50%	1.57%	0.47%
Risk-free interest rate, high end of range (as a percent)	4.55%	4.34%	1.33%
Stock options \| Minimum
Weighted average assumptions for estimated fair value of employee stock options
Expected term (in years)	6 years	6 years	6 years
Stock options \| Maximum
Weighted average assumptions for estimated fair value of employee stock options
Expected term (in years)	6 years 7 months 2 days	7 years 7 months 24 days	7 years 7 months 24 days
ESPP
Weighted average assumptions for estimated fair value of employee stock options
Expected volatility, low end of range (as a percent)	38.24%	43.19%	46.08%
Expected volatility, high end of range (as a percent)	55.72%	55.72%	66.37%
Risk-free interest rate, low end of range (as a percent)	0.13%	0.13%	0.04%
Risk-free interest rate, high end of range (as a percent)	5.39%	4.72%	1.65%
ESPP \| Minimum
Weighted average assumptions for estimated fair value of employee stock options
Expected term (in years)	6 months	6 months	6 months
ESPP \| Maximum
Weighted average assumptions for estimated fair value of employee stock options
Expected term (in years)	2 years	2 years	2 years

Collaboration and Licensing Agreements - Genentech, Inc., and F. Hoffmann-La Roche Ltd. (Details) - Genentech - Collaboration and License Agreement - USD ($)	1 Months Ended	12 Months Ended
	Feb. 28, 2019	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Mar. 31, 2021
Collaboration research and licensing agreements
Initial cost-sharing percentage	45.00%
Potential milestone payment	$ 600,000,000
Transaction price	120,000,000
Revenue recognized		$ 0	$ 0	$ 2,500,000
Cost sharing receivable (payable)		(3,300,000)
XmAb306
Collaboration research and licensing agreements
Standalone selling price	111,700,000
XmAb435
Collaboration research and licensing agreements
Standalone selling price					$ 4,100,000
Research service
Collaboration research and licensing agreements
Transaction price		8,300,000
Standalone selling price	4,200,000
Deferred revenue		$ 0
Development-based
Collaboration research and licensing agreements
Potential milestone payment	115,000,000
Regulatory-based
Collaboration research and licensing agreements
Potential milestone payment	185,000,000
Sales-based
Collaboration research and licensing agreements
Potential milestone payment	$ 300,000,000

Income Taxes - Deferred tax assets and liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Deferred income tax assets
Net operating loss carryforwards	$ 22,466	$ 32,898
Research credits	53,198	54,825
Unrealized (gain) loss on securities	(278)	1,573
Capitalized lease assets	6,161	5,564
Accrued compensation	18,172	14,484
Deferred revenue	34,405	3,225
Capitalized research and development costs	45,783	21,338
Gross deferred income tax assets	179,907	133,907
Valuation allowance	(158,099)	(115,010)
Net deferred income tax assets	21,808	18,897
Deferred income tax liabilities
Patent costs	(2,218)	(2,885)
Licensing costs	(136)	(124)
Capitalized legal costs	(6)	(9)
Depreciation	(10,664)	(6,532)
Unrealized gain on securities	(8,784)	(9,347)
Gross deferred income tax liabilities	(21,808)	(18,897)
Net deferred income tax asset	$ 0	$ 0

Audit Information	12 Months Ended
Audit Information	Dec. 31, 2023
Audit Information [Abstract]
Auditor Firm ID	49
Auditor Name	RSM US LLP
Auditor Location	Los Angeles, California

Leases - Narrative (Details)		1 Months Ended			12 Months Ended
Leases - Narrative (Details)	Jul. 14, 2021 USD ($) ft² uSDollarPerSquareFoot	Jan. 31, 2023 lease	Aug. 31, 2022 USD ($) uSDollarPerSquareFoot	Jun. 30, 2021 ft² phase	Dec. 31, 2023 USD ($) lease	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Jul. 01, 2025 USD ($) ft²
Lessee, Lease, Description [Line Items]
Addition of right-of-use asset					$ 2,462,000	$ 6,155,000	$ 24,047,000
Restricted cash					380,000	$ 0
Letter of Credit
Lessee, Lease, Description [Line Items]
Letter of credit amount					$ 400,000
Monrovia, CA - office and laboratory space
Lessee, Lease, Description [Line Items]
Number of leases \| lease					2
Number of expired leases \| lease		1
Option to extend					true
Renewal term					5 years
Addition of right-of-use asset					$ 0
Monrovia, CA - office and laboratory space with additional space
Lessee, Lease, Description [Line Items]
Addition of right-of-use asset					0
Lease term				18 months
Pasadena, CA - office and laboratory space
Lessee, Lease, Description [Line Items]
Addition of right-of-use asset					0
Lease term	13 years
Area of property \| ft²	83,083			129,543
Phases of lease term \| phase				2
Improvement allowance	$ 17,000,000		$ 22,000,000
Initial base monthly rent	$ 386,336		$ 416,246
Rent expense per square foot \| uSDollarPerSquareFoot	4.65		5.01
Rent increase (as a percentage)	3.00%
Increase to tenant allowance			$ 5,000,000
San Diego, CA - office space
Lessee, Lease, Description [Line Items]
Addition of right-of-use asset					$ 2,500,000
Forecast \| Pasadena, CA - office and laboratory space
Lessee, Lease, Description [Line Items]
Area of property \| ft²								46,460
Improvement allowance								$ 3,300,000

Summary of Significant Accounting Policies - Patents, Licenses, and Other Intangible Assets (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($) criteria	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Patents, licenses, and other intangible assets
Number of primary criteria to determine capitalization of patent \| criteria	3
Abandonment of capitalized intangible assets	$ 1,267	$ 1,510	$ 934
Total gross carrying amount	29,469	28,170
Total intangible assets, net	18,663	18,500
Amortization expense for patents, licenses, and other intangible assets	1,300	1,400	$ 1,200
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
2024	1,076
2025	1,059
2026	961
2027	908
2028	776
Thereafter	3,760
Total	8,540
Nonamortizable intangible assets (trademarks)
Patents, licenses, and other intangible assets
Nonamortizable intangible assets (trademarks)	$ 399	399
Licensing Agreements \| Minimum
Patents, licenses, and other intangible assets
Estimated economic life	1 year
Licensing Agreements \| Maximum
Patents, licenses, and other intangible assets
Estimated economic life	20 years
Patents
Patents, licenses, and other intangible assets
Accumulated amortization	$ (8,663)	(7,781)
Patents \| Minimum
Patents, licenses, and other intangible assets
Estimated economic life	2 years
Patents \| Maximum
Patents, licenses, and other intangible assets
Estimated economic life	27 years
Patents, definite life
Patents, licenses, and other intangible assets
Amortizable intangible assets	$ 15,340	14,535
Patents, pending issuance
Patents, licenses, and other intangible assets
Amortizable intangible assets	9,723	9,328
Licenses and other amortizable intangible assets
Patents, licenses, and other intangible assets
Amortizable intangible assets	4,007	3,908
Accumulated amortization	$ (2,143)	$ (1,889)

Sales of Future Royalties - Narrative (Details) - USD ($) $ in Thousands				3 Months Ended	12 Months Ended		30 Months Ended	36 Months Ended
	Jan. 01, 2029	Nov. 03, 2023	Jul. 01, 2023	Sep. 30, 2023	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2025	Dec. 31, 2028	Dec. 31, 2022
Sales of Future Royalties [Line Items]
Accounts receivable						$ 11,290			$ 28,997
Alexion \| Option and license agreement
Sales of Future Royalties [Line Items]
Accounts receivable						0
Alexion \| Royalties \| Option and license agreement
Sales of Future Royalties [Line Items]
Proceeds from upfront payment		$ 192,500
Maximum annual receivable for specific sales		18,000
Accounts receivable		29,500
Revenue recognized of future sales		163,000
Non-cash revenue recognized						6,200
Alexion \| Royalties \| Option and license agreement \| Forecast
Sales of Future Royalties [Line Items]
Percent of receivable rights							100.00%
Maximum annual receivables	$ 12,000							$ 35,000
Maximum annual receivable for specific sales					$ 12,000
MorphoSys \| Royalties \| Collaboration and License Agreement
Sales of Future Royalties [Line Items]
Proceeds from upfront payment		$ 22,500
Maximum annual receivables			$ 29,300
Revenue recognized of future sales				$ 20,300
Non-cash revenue recognized						$ 2,100
Accounts receivable				$ 2,200
Interest rate						21.10%
Non-cash interest expense recognized						$ 700

Stock-Based Compensation - Narrative (Details) $ in Millions		11 Months Ended	12 Months Ended			120 Months Ended
	Jan. 01, 2023 shares	Dec. 03, 2023	Dec. 31, 2023 USD ($) period shares	Dec. 31, 2022 USD ($) shares	Dec. 31, 2021 shares	Dec. 31, 2023 USD ($) period shares	Jun. 14, 2023 shares
RSUs
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Restricted stock granted (in shares)			994,351	875,330	670,700
Cost not yet recognized, period of recognition			1 year 10 months 24 days
Cost not yet recognized amount \| $			$ 29.6	$ 28.3		$ 29.6
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
Increase in shares of common stock available for issuance (in shares)	599,977
Awards issued under the plan (in shares)						733,478
Initial term of plan			2 years
Number of six month purchase periods \| period			4			4
Purchase period			6 months
Second term of plan			2 years
Unamortized compensation expense related to unvested stock options and ESPP \| $			$ 1.8	1.2		$ 1.8
Cost not yet recognized, period of recognition			1 year 11 months 8 days
ESPP \| Minimum
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Percentage of compensation that employees may withhold to purchase stock at a discount			1.00%			1.00%
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%
Percentage of compensation that employees may withhold to purchase stock at a discount			15.00%			15.00%
Purchase price as percentage of stock price at the initial offering date			85.00%
Purchase price as percentage of stock price at the purchase date			85.00%
Annual increase in shares of common stock available for issuance (in shares)			621,814
Stock options
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Unamortized compensation expense related to unvested stock options and ESPP \| $			$ 49.2	$ 52.6		$ 49.2
Cost not yet recognized, period of recognition			2 years 4 months 20 days
The 2013 Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Expiration period		10 years
Total number of shares of common stock available for issuance (in shares)			19,434,971			19,434,971
Annual percentage increase in shares of common stock available for issuance			4.00%
Increase in shares of common stock available for issuance (in shares)	2,399,908
Awards issued under the plan (in shares)						16,616,038
The 2013 Plan \| RSUs
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Restricted stock granted (in shares)						2,994,168
The 2013 Plan \| RSUs \| Minimum
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting period			2 years
The 2013 Plan \| RSUs \| Maximum
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting period			3 years
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)							3,000,000
Prior Plans
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Total number of shares of common stock available for issuance (in shares)			16,932,548			16,932,548

Summary of Significant Accounting Policies - Marketable Debt and Equity Securities (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Accounting Policies [Abstract]
Impairment loss or recoveries	$ 0	$ 0
Accrued interest	2,300,000	1,300,000
Unrealized gain (loss) on marketable debt securities	8,200,000	(5,400,000)
Equity securities impairment	0	100,000
Net gain (loss) recognized on equity securities	$ (395,000)	$ 23,434,000	$ 39,289,000

Marketable Debt and Equity Securities - Equity Securities without Readily Determinable Fair Value (Details) - Preferred Stock - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Equity securities without readily determinable fair value
Equity securities without readily determinable fair value	$ 64,210	$ 54,383
Astria Common Stock
Equity securities without readily determinable fair value
Equity securities without readily determinable fair value	0	174
Zenas
Equity securities without readily determinable fair value
Equity securities without readily determinable fair value	$ 64,210	$ 54,209

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, 2020		57,873,444
Beginning balance at Dec. 31, 2020	$ 572,444	$ 580	$ 937,525	$ 74	$ (365,735)	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Sale of common stock (in shares)		748,062
Sale of common stock	28,920	$ 7	28,913
Issuance of common stock upon exercise of stock awards (in shares)		520,240
Issuance of common stock upon exercise of stock awards	12,281	$ 5	12,276
Issuance of common stock under the Employee Stock Purchase Plan (in shares)		62,257
Issuance of common stock under the Employee Stock Purchase Plan	1,837	$ 1	1,836
Issuance of restricted stock units (in shares)		151,555
Issuance of restricted stock units	0	$ 2	(2)
Comprehensive income (loss) attributable to Xencor, Inc.	81,047
Comprehensive income (loss)	81,047			(1,584)	82,631
Stock-based compensation	36,975		36,975
Ending balance (in shares) at Dec. 31, 2021		59,355,558
Ending balance at Dec. 31, 2021	733,504	$ 595	1,017,523	(1,510)	(283,104)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock awards (in shares)		195,485
Issuance of common stock upon exercise of stock awards	3,610	$ 2	3,608
Issuance of common stock under the Employee Stock Purchase Plan (in shares)		105,597
Issuance of common stock under the Employee Stock Purchase Plan	2,092	$ 1	2,091
Issuance of restricted stock units (in shares)		341,073
Issuance of restricted stock units	0	$ 3	(3)
Comprehensive income (loss) attributable to Xencor, Inc.	(60,623)
Comprehensive income (loss)	(60,623)			(5,442)	(55,181)
Stock-based compensation	48,913		48,913
Ending balance (in shares) at Dec. 31, 2022		59,997,713
Ending 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)		344,383
Issuance of common stock upon exercise of stock awards	3,412	$ 3	3,409
Issuance of common stock under the Employee Stock Purchase Plan (in shares)		98,029
Issuance of common stock under the Employee Stock Purchase Plan	1,977	$ 1	1,976
Issuance of restricted stock units (in shares)		558,066
Issuance of restricted stock units	0	$ 6	(6)
Contribution from non-controlling interest owners	500					500
Comprehensive income (loss) attributable to Xencor, Inc.	(118,007)			8,243	(126,087)	(163)
Comprehensive income (loss)	(117,844)
Stock-based compensation	53,755		53,755
Ending balance (in shares) at Dec. 31, 2023		60,998,191
Ending balance at Dec. 31, 2023	$ 669,133	$ 611	$ 1,131,266	$ 1,291	$ (464,372)	$ 337

Marketable Debt and Equity Securities - Unrealized Losses (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Schedule of Available-for-sale Securities
Fair value, less than 12 months	$ 74,619	$ 457,591
Unrealized losses, less than 12 months	(78)	(6,940)
Fair value, 12 months or greater	0	3,826
Unrealized losses, 12 months or greater	0	(5)
Corporate Securities
Schedule of Available-for-sale Securities
Fair value, less than 12 months	8,073	132,658
Unrealized losses, less than 12 months	(1)	(1,121)
Fair value, 12 months or greater	0	3,826
Unrealized losses, 12 months or greater	0	(5)
Government Securities
Schedule of Available-for-sale Securities
Fair value, less than 12 months	66,546	324,933
Unrealized losses, less than 12 months	(77)	(5,819)
Fair value, 12 months or greater	0	0
Unrealized losses, 12 months or greater	$ 0	$ 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
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-2

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (aa)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-2

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

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-2

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-2

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-3

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-3

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-3

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-3

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-3

+ Details

Property and Equipment (Tables)

12 Months Ended

Dec. 31, 2023

Property, Plant and Equipment [Abstract]

Schedule of property and equipment

Property and equipment consist of the following:


	December 31,
	2023		2022
	(in thousands)
Computers, software and equipment	$	49,782	$	45,159
Furniture and fixtures	158		539
Leasehold and tenant improvements	52,410		41,774
Total gross carrying amount	102,350		87,472
Less accumulated depreciation and amortization	(36,226)		(28,289)
Total property and equipment, net	$	66,124	$	59,183

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Cash flows from operating activities
Consolidated net income (loss)	$ (126,250)	$ (55,181)	$ 82,631
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation and amortization	11,498	8,799	7,491
Amortization of premium (accretion of discount) on marketable securities	(13,635)	127	3,160
Stock-based compensation	53,755	48,913	36,975
Abandonment of capitalized intangible assets	1,267	1,510	934
Loss on disposal of assets	1,379	145	462
Equity received in connection with license agreement	(10,000)	(5,397)	(22,379)
Equity received in connection with sale of financial assets	0	0	(3,300)
Change in fair value of equity securities	395	(23,434)	(20,988)
Equity securities impairment	0	138	762
Noncash interest expense	681	0	0
Changes in operating assets and liabilities:
Accounts receivable and contract assets	17,707	37,387	(42,441)
Interest receivable from marketable debt securities	(1,028)	(530)	655
Prepaid expenses and other assets	5,103	634	(13,592)
Income tax	5,782	0	0
Accounts payable	3,826	(3,913)	5,047
Accrued expenses	4,836	(715)	1,840
Lease liabilities and ROU assets	3,250	22,976	1,211
Deferred revenue	(30,320)	(6,974)	(55,321)
Deferred income	156,865	0	0
Net cash provided by (used in) operating activities	85,111	24,485	(16,853)
Cash flows from investing activities
Proceeds from sale and maturities of marketable debt securities available-for-sale	693,090	306,607	485,152
Proceeds from sale of property and equipment	1	0	19
Purchase of marketable securities	(782,905)	(387,928)	(509,597)
Purchase of intangible assets	(2,803)	(4,910)	(2,682)
Purchase of property and equipment	(18,448)	(38,494)	(13,299)
Conversion (purchase) of convertible note	0	5,000	(5,000)
Exercise of stock options	0	0	(842)
Net cash used in investing activities	(111,065)	(119,725)	(46,249)
Cash flows from financing activities
Proceeds from issuance of common stock upon exercise of stock awards	3,412	3,610	12,281
Proceeds from issuance of common stock from Employee Stock Purchase Plan	1,977	2,092	1,837
Proceeds from issuance of common stock	0	0	28,920
Proceeds from sale of future royalties	20,293	0	0
Proceeds from non-controlling interest	500	0	0
Net cash provided by financing activities	26,182	5,702	43,038
Net increase (decrease) in cash, cash equivalents, and restricted cash	228	(89,538)	(20,064)
Cash, cash equivalents, and restricted cash, beginning of year	53,942	143,480	163,544
Cash, cash equivalents, and restricted cash, end of year	54,170	53,942	143,480
Cash paid for:
Interest	22	13	14
Taxes	0	700	0
Supplemental schedule of noncash activities
Net unrealized gain (loss) on marketable securities available-for-sale	8,243	(5,442)	(1,584)
Addition of right-of-use asset	$ 2,462	$ 6,155	$ 24,047

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2023	Dec. 31, 2022
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)	60,998,191	59,997,713
Common stock, shares outstanding (in shares)	60,998,191	59,997,713

Collaboration and Licensing Agreements - Remaining Performance Obligations and Deferred Revenue (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Collaboration and Licensing Agreements
Deferred revenue	$ 0	$ 30,320

Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2023

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 was as follows:


	Year Ended December 31,
(in thousands)	2023		2022		2021
General and administrative	$	19,239	$	17,281	$	12,813
Research and development	34,516		31,632		24,162
	$	53,755	$	48,913	$	36,975


	Year Ended December 31,
(in thousands)	2023		2022		2021
Stock options	$	29,345	$	29,758	$	27,909
ESPP	1,243		1,174		992
RSUs	23,167		17,981		8,074
	$	53,755	$	48,913	$	36,975

Schedule of stock options outstanding

Information with respect to stock options outstanding is as follows:


	December 31,
	2023		2022		2021
Exercisable options	7,761,829		6,679,948		5,576,430
Weighted average exercise price per share of exercisable options	$	28.79	$	26.99	$	24.15
Weighted average grant date fair value per share of options granted during the year	$	15.98	$	15.45	$	21.65
Options available for future grants	6,801,945		3,622,319		3,597,371
Weighted average remaining contractual life	6.03		6.30		6.65

Summary of stock option activity

The following table summarizes stock option activity for the years ended December 31, 2023 and 2022:


	Number of Shares	Weighted- Average Exercise Price (Per Share)(1)		Weighted- Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value (in thousands)(2)
Balances at December 31, 2020	7,751,789	$	26.23	7.00	$	134,941
Options granted	1,827,234	41.22
Options forfeited	(382,454)	36.15
Options exercised(3)	(520,240)	23.61
Balances at December 31, 2021	8,676,329	29.11		6.65	$	100,057
Options granted	2,135,233	29.45
Options forfeited	(533,435)	34.09
Options exercised(3)	(195,485)	18.46
Balances at December 31, 2022	10,082,642	29.12		6.30	$	27,141
Options granted	2,080,732	30.02
Options forfeited	(676,005)	33.19
Options exercised(3)	(344,383)	9.91
Balances at December 31, 2023	11,142,986	$	29.60	6.03	$	9,977
As of December 31, 2023
Options vested and expected to vest	11,142,986	$	29.60	6.03	$	9,977
Exercisable	7,761,829	$	28.79	4.90	$	9,907

______________________________

(1)The weighted average exercise price per share is determined using exercise price per share for stock options.

(2)The aggregate intrinsic value is calculated as the difference between the exercise price of the option and the fair value of our common stock for in-the-money options at December 31, 2023 and 2022.

(3)The total intrinsic value of stock options exercised was $4.8 million, $1.6 million, and $9.2 million for the years ended December 31, 2023, 2022 and 2021 respectively.

Schedule of weighted average assumptions used for estimation of fair value of stock options

The fair value of employee stock options was estimated using the following weighted average assumptions for the years ended December 31, 2023, 2022 and 2021:


	Options
	2023	2022	2021
Common stock fair value per share	$20.14 - 36.02	$19.74- 38.08	$30.65 - 49.47
Expected volatility	49.75% - 52.48%	51.51% - 54.36%	53.91% - 56.82%
Risk-free interest rate	3.50% - 4.55%	1.57% - 4.34%	0.47% - 1.33%
Expected dividend yield	—	—	—
Expected term (in years)	6.00 - 6.59	6.00 - 7.65	6.00 - 7.65

Schedule of weighted average assumptions used for estimation of fair value of ESPP

The fair value of employee stock options was estimated using the following weighted average assumptions for the years ended December 31, 2023, 2022 and 2021:


	ESPP
	2023	2022	2021
Expected term (years)	0.5 - 2.0	0.5 - 2.0	0.5 - 2.0
Expected volatility	38.24% - 55.72%	43.19% - 55.72%	46.08% - 66.37%
Risk-free interest rate	0.13% - 5.39%	0.13% - 4.72%	0.04% - 1.65%
Expected dividend yield	—	—	—

Summary of restricted stock unit activity

The following table summarizes RSU activity for the years ended December 31, 2023:


	Number of Shares	Weighted- Average Grant Date Fair Value (Per Unit)
Unvested at December 31, 2020	358,825	$	33.04
Granted	670,700	39.11
Vested	(151,555)	32.76
Forfeited	(51,822)	36.68
Unvested at December 31, 2021	826,148	$	37.79
Granted	875,330	29.45
Vested	(341,073)	37.37
Forfeited	(127,854)	33.66
Unvested at December 31, 2022	1,232,551	$	32.41
Granted	994,351	30.33
Vested	(558,066)	33.61
Forfeited	(178,796)	31.64
Unvested at December 31, 2023	1,490,040	$	30.66

Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2023

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

Description of Business

Xencor, Inc. (we, us, our, or the Company) was incorporated in California in 1997 and reincorporated in Delaware in September 2004. We are a clinical-stage biopharmaceutical company focused on discovering and developing engineered monoclonal bispecific antibody and cytokine therapeutics to treat patients with cancer and autoimmune diseases who have unmet medical needs. We create our product candidates using our proprietary XmAb technology platforms, which focus on the portion of an antibody that interacts with multiple segments of the immune system, referred to as the Fc domain, which is constant and interchangeable among antibodies. Our engineered Fc domains, the XmAb technology, can increase antibody immune inhibition, improve cytotoxicity, extend half-life and most recently are used to create bispecific antibodies and cytokines.

Our operations are based in Pasadena, California and San Diego, California.

Consolidation and Basis of Presentation

The Consolidated Financial Statements include the accounts of Xencor, Inc. and its subsidiary Gale Therapeutics Inc., which was incorporated in December 2023. 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.

The Company’s consolidated financial statements as of December 31, 2023, 2022, and 2021 and for the years then ended have been prepared in accordance with accounting principles generally accepted in the United States (U.S.).

Use of Estimates

The preparation of 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 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.

Recent Accounting Pronouncements

Pronouncements Not yet Effective

In June 2022, the Financial Accounting Standards Board (FASB) issued ASU No. 2022-03, Fair Value Measurement (Topic 820): Fair Value Measurement of Equity Securities Subject to Contractual Sale Restrictions, which is effective for fiscal years beginning on and after December 15, 2023, and interim periods within those fiscal years. The standard clarifies that a contractual restriction on the sale of an equity security is not considered part of the unit of account of the equity security and is not considered in measuring fair value. The Company does not anticipate that the standard will have a significant impact on its financial statements.

In December 2023, the FASB issued ASU No. 2023-09, Income Taxes (Topic 740) - Improvements to Income Tax Disclosures, which is effective for fiscal years beginning on and after December 15, 2024, and interim periods within those fiscal years. The standard provides more transparency about income tax information through improvements to income tax

disclosures primarily related to the rate reconciliation and income taxes paid information.The Company does not anticipate that the standard will have a significant impact on its financial statements.

Variable Interest Entity

A Variable Interest Entity (VIE) is a legal entity that, by design, 1) has insufficient equity to permit the entity to finance its activities without additional subordinated financial support from other parties, 2) has equity investors that lack the power to direct the entity's activities, 3) has investors with limited obligation to absorb expected losses, or 4) has investors who do not have the right to receive the residual returns of the entity. The primary beneficiary of a VIE is the party with the controlling financial interest and has the power to direct the activities of the VIE that most significantly impact the entity's economic performance and has the obligation to absorb losses of the VIE, or the right to receive benefits of the VIE that could be potentially significant to the VIE.

On December 19, 2023 we entered into the Gale License and Gale Services Agreements. See Note 10, We consolidated Gale's financial statements in which we have direct controlling financial interest based on the VIE model.

We consider all the facts and circumstances, including our role in establishing Gale and our ongoing rights and responsibilities to assess where we have the power to direct the activities of Gale. In general, the parties that make the most significant decisions affecting the VIE and have the right to remove those decision-makers unilaterally or by majority vote are deemed to have the power to direct the activities of a VIE.

At Gale's inception, we determined whether we were the primary beneficiary and if Gale should be consolidated based on facts and circumstances. Under the rules of determining whether an entity is a VIE, we determined that Gale is a VIE and we are the primary beneficiary.

Liability Related to the Sale of Future Royalties

We record a liability related to 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 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 will be 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 expense 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 royalty payments made and changes in the forecasted revenue.

Deferred Income Related to the Sale of Future Royalties

We record a liability related to 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.

Revenue Recognition

We have, to date, earned revenue from research and development collaborations, which may include research and development services, licenses of our internally developed technologies, licenses of our internally developed drug candidates, or combinations of these.

The terms of our license, research and development, and collaboration agreements generally include non-refundable upfront payments, research funding, co-development payments and reimbursements, license fees, and milestone and other contingent payments to us for the achievement of defined collaboration objectives and certain clinical, regulatory and sales-based events, as well as royalties on sales of any commercialized products.

The terms of our licensing agreements include non-refundable upfront fees, annual licensing fees, and contractual payment obligations for the achievement of pre-defined preclinical, clinical, regulatory and sales-based events by our partners. The licensing agreements also include royalties on sales of any commercialized products by our partners.

We recognize revenue through the five-step process in accordance with Accounting Standards Codification (ASC) 606, Revenue from Contracts with Customers, when control of the promised goods or services is transferred to our customers in an amount that reflects the consideration we expect to be entitled to in exchange for those goods or services.

Deferred Revenue

Deferred revenue arises from payments received in advance of the culmination of the earnings process. We have classified deferred revenue for which we stand ready to perform within the next 12 months as a current liability. We recognize deferred revenue as revenue in future periods when the applicable revenue recognition criteria have been met. There was no deferred revenue reported at December 31, 2023. The total amount reported as deferred revenue was $30.3 million at December 31, 2022.

Accounts Receivable

Accounts receivable primarily consists of royalty and milestone revenues receivable from our license and collaboration agreements, as well as receivables arising from cost-sharing development activities. Pursuant to the Ultomiris and Monjuvi Royalty Sale Agreements, a portion of the proceeds we received from the purchasers related to the sale of accounts receivable on royalty and milestone revenue earned at September 30, 2023. Payments for these receivables were paid directly to the purchasers prior to the year-ended December 31, 2023. We did not record an allowance for doubtful accounts at December 31, 2023 or 2022 due to an immaterial allowance as a result of our evaluation of credit risk under ASC 326. We expect to collect all receivables within the terms, which are generally between 30 and 60 days.

Research and Development Expenses

Research and development expenses include costs we incur for our own and for our collaborators’ research and development activities. Research and development costs are expensed as incurred. These costs consist primarily of salaries and benefits, including associated stock-based compensation, laboratory supplies, facility costs, and applicable overhead expenses of personnel directly involved in the research and development of new technology and products, as well as fees paid to other entities that conduct certain research and development activities on our behalf. We estimate preclinical study and clinical trial expenses based on the services performed pursuant to the contracts with research institutions and clinical research organizations that conduct and manage preclinical studies and clinical trials on our behalf based on the actual time and expenses they incurred. Further, we accrue expenses related to clinical trials based on the level of patient enrollment and activity according to the related agreement. We monitor patient enrollment levels and related activity to the extent reasonably possible and adjust estimates accordingly.

We capitalize acquired research and development technology licenses and third-party contract rights where such assets have an alternative use and amortize the costs over the shorter of the license term or the expected useful life. We review the license arrangements and the amortization period on a regular basis and adjust the carrying value or the amortization period of the licensed rights if there is evidence of a change in the carrying value or useful life of the asset.

Cash and Cash Equivalents

We consider cash equivalents to be only those investments which are highly liquid, readily convertible to cash and which mature within three months from the date of purchase.

Restricted Cash

As of December 31, 2023, we had an outstanding letter of credit (LOC) collateralized by a money market account of $0.4 million, to the benefit of the landlord related to the Company’s San Diego facility lease. The terms of the lease provide that the amount of the LOC will be reduced on a ratable basis over the term of the lease. The original amount of the LOC was classified as long-term restricted cash as of December 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 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 and does not intend to sell these securities, and it is not more likely than not the Company will be required to sell the securities before recovery of the amortized cost basis. 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 years ended in December 31, 2023 and 2022, respectively. Accrued interest on marketable debt securities is included in marketable securities’ carrying value. Accrued interest was $2.3 million and $1.3 million at December 31, 2023 and 2022, respectively. 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 years ended December 31, 2023 and 2022, the Company recorded an unrealized gain of $8.2 million and an unrealized loss of $5.4 million, respectively, in its portfolio of marketable debt securities. The unrealized loss was due to the changing interest rate environment and is not due to changes in the credit quality of the underlying securities. The unrealized gain and loss were recorded in other comprehensive income (loss) for the years then ended.

The Company receives equity securities in connection with certain licensing transactions with its partners. These investments in an equity security 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 gains or losses on the sale of the securities will be recognized within other income (expense) in the Statement of Comprehensive Income (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 at their 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. The Company did not record an impairment charge for the year ended December 31, 2023. During the year ended December 31, 2022, the Company recorded an impairment charge of $0.1 million in connection with equity securities without a readily determinable fair value.

During the years ended December 31, 2023 and 2022, the Company recorded a net loss of $0.4 million and net gain of $23.4 million, respectively, in connection with its equity investments.

Concentrations of Risk

Cash, cash equivalents, restricted cash, and marketable debt securities are financial instruments that potentially subject the Company to concentrations of risk. We invest our cash in corporate debt securities and U.S. sponsored agencies with strong credit ratings. We have established guidelines relative to diversification and maturities that are designed to help ensure safety and liquidity. These guidelines are periodically reviewed to take advantage of trends in yields and interest rates.

Cash, cash equivalents, and restricted cash are maintained at financial institutions, and at times, balances may exceed federally insured limits. We have never experienced any losses related to these balances. Amounts on deposit in excess of federally insured limits at December 31, 2023 and 2022 approximated $53.8 million and $53.6 million, respectively.

We have payables with two service providers that represent 38% of our total payables and with two service providers that represented 45% of our total payables at December 31, 2023 and 2022, respectively. We rely on six critical suppliers for the manufacture of our drug product for use in our clinical trials. While we believe that there are alternative vendors available, a change in manufacturing vendors could cause a delay in the availability of drug product and result in a delay of conducting and completing our clinical trials. No other vendor accounted for more than 10% of total payables at December 31, 2023 or 2022.

We have receivables with three customers and service providers that represent 76% of our total receivables and with four customers and service providers that represent 91% of our total receivables at December 31, 2023 and 2022,

respectively. The receivables are related to cost share reimbursement and royalty revenues from our licensing and collaboration agreements. No other customer accounted for more than 10% of total receivables at December 31, 2023 or 2022.

Fair Value of Financial Instruments

Our financial instruments primarily consist of cash and cash equivalents, marketable debt securities, accounts receivable, accounts payable, and accrued expenses. Marketable debt securities and cash equivalents are carried at fair value. The fair value of a financial instrument is the amount that would be received in an asset sale or paid to transfer a liability in an orderly transaction between unaffiliated market participants. The fair value of the other financial instruments closely approximate their fair value due to their short maturities.

The Company accounts for recurring and non-recurring fair value measurements in accordance with FASB ASC 820, Fair Value Measurements and Disclosures. 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):


	December 31, 2023
	Total Fair Value		Level 1		Level 2

Money Market Funds in Cash and Cash Equivalents	$	25,520	$	25,520	$	—
Corporate Securities	228,723		—		228,723
Government Securities	414,514		—		414,514

	$	668,757	$	25,520	$	643,237


	December 31, 2022
	Total Fair Value		Level 1		Level 2

Money Market Funds in Cash and Cash Equivalents	$	40,967	$	40,967	$	—
Corporate Securities	200,626		—		200,626
Government Securities	329,889		—		329,889

	$	571,482	$	40,967	$	530,515

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 years ended December 31, 2023 and 2022, there were no transfers between Level 1 and Level 2.

Property and Equipment

Property and equipment are recorded at cost and depreciated using the straight-line method over the estimated useful lives of the assets. Expenditures for repairs and maintenance are charged to expense as incurred, while renewals and improvements are capitalized. Useful lives by asset category are as follows:


Computers, software and equipment			3 - 5 years
Furniture and fixtures			5 - 7 years
Leasehold improvements			5 - 7 years or remaining
			lease term, whichever is less

Patents, Licenses, and Other Intangible Assets

The cost of acquiring licenses is capitalized and amortized on the straight-line basis over the shorter of the term of the license or its estimated economic life, ranging from 1 to 20 years. Third-party costs incurred for acquiring patents are capitalized. Capitalized costs are accumulated until the earlier of the period that a patent is issued, or we abandon the patent claims. Cumulative capitalized patent costs are amortized on a straight-line basis from the date of issuance over the shorter of the patent term or the estimated useful economic life of the patent, ranging from 2 to 27 years. Our senior management, with advice from outside patent counsel, assesses three primary criteria to determine if a patent will be capitalized initially: i) technical feasibility, ii) magnitude and scope of new technical function covered by the patent compared to the company’s existing technology and patent portfolio, particularly assessing the value added to our product candidates or licensing business, and iii) legal issues, primarily assessment of patentability and prosecution cost. We review our intellectual property on a regular basis to determine if there are changes in the estimated useful life of issued patents and if any capitalized costs for unissued patents should be abandoned. Capitalized patent costs related to abandoned patent filings are charged off in the period of the decision to abandon. During 2023, 2022, and 2021, we abandoned previously capitalized patent and licensing related charges of $1.3 million, $1.5 million, and $0.9 million, respectively.

The carrying amount and accumulated amortization of patents, licenses, and other intangibles is as follows (in thousands):


	December 31,
	2023		2022
Patents, definite life	$	15,340	$	14,535
Patents, pending issuance	9,723		9,328
Licenses and other amortizable intangible assets	4,007		3,908
Nonamortizable intangible assets (trademarks)	399		399
Total gross carrying amount	29,469		28,170
Accumulated amortization—patents	(8,663)		(7,781)
Accumulated amortization—licenses and other	(2,143)		(1,889)
Total intangible assets, net	$	18,663	$	18,500

Amortization expense for patents, licenses, and other intangible assets was $1.3 million, $1.4 million, and $1.2 million for the years ended December 31, 2023, 2022, and 2021, respectively.

Future amortization expense for patents, licenses, and other intangible assets recorded as of December 31, 2023, and for which amortization has commenced, is as follows:


	Year ended December 31,
	(in thousands)
2024	$	1,076
2025	1,059
2026	961
2027	908
2028	776
Thereafter	3,760
Total	$	8,540

The above amortization expense forecast is an estimate. Actual amounts of amortization expense may differ from estimated amounts due to additional intangible asset acquisitions, impairment of intangible assets, accelerated amortization of intangible assets, and other events. As of December 31, 2023, the Company has $9.7 million of intangible assets which are in-process and have not been placed in service, and accordingly amortization on these assets has not commenced.

Long-Lived Assets

Management reviews long-lived assets which include fixed assets and amortizable intangibles for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset (or asset group) may not be recoverable. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset to undiscounted net cash flows expected to be generated by the asset. If such assets are considered to be impaired, the impairment to be recognized is measured as the amount by which the carrying amount of the assets exceeds the fair value of the assets.

We did not recognize a loss from impairment for the years ended December 31, 2023, 2022, or 2021.

Income Taxes

We account for income taxes in accordance with accounting guidance which requires an asset and liability approach to financial accounting and reporting for income taxes. Deferred income tax assets and liabilities are computed annually for differences between the financial statement and tax bases of assets and liabilities that will result in taxable or deductible amounts in the future based on enacted tax laws and rates applicable to the periods in which the differences are expected to affect taxable income. Valuation allowances are established when necessary to reduce deferred tax assets to the amount expected to be realized. Income tax expense is the tax payable or refundable for the period plus or minus the change during the period in deferred tax assets and liabilities.

We assess our income tax positions and record tax benefits for all years subject to examination based upon our evaluation of the facts, circumstances, and information available at the reporting date. For those tax positions where there is greater than 50% likelihood that a tax benefit will be sustained, we have recorded the largest amount of tax benefit that may potentially be realized upon ultimate settlement with a taxing authority that has full knowledge of all relevant information. For those income tax positions where there is a 50% or less likelihood that a tax benefit will be sustained, no tax benefit has been recognized in the financial statements. We did not have any material uncertain tax positions at December 31, 2023 or 2022.

Our policy is to recognize interest and penalties on taxes, if any, as a component of income tax expense.

The Tax Cuts and Jobs Act of 2017 (TCJA) enacted on December 22, 2017 included several key provisions impacting the accounting for and reporting of income taxes. The most significant provisions reduced the U.S. corporate statutory tax rate from 35% to 21%, eliminated the corporate Alternative Minimum Tax (AMT) system, and made changes to the carryforward of net operating losses beginning on January 1, 2018. The TCJA changed the income tax treatment of research and development expenses requiring such costs to be capitalized and amortized over several years beginning

effective January 1, 2022. We recorded a federal tax expense of $5.8 million and $0.7 million for the years ended December 31, 2023 and 2022, respectively.

Stock-Based Compensation

We recognize compensation expense using a fair-value-based method for costs related to all share-based payments, including stock options, restricted stock units (RSUs), and shares issued under our Employee Stock Purchase Plan (ESPP). Stock-based compensation cost related to employees and directors is measured at the grant date, based on the fair-value-based measurement of the award using the Black-Scholes method, and is recognized as expense over the requisite service period on a straight-line basis. We account for forfeitures when they occur. We recorded stock-based compensation and expense for stock-based awards to employees, directors, and consultants of approximately $53.8 million, $48.9 million, and $37.0 million for the years ended December 31, 2023, 2022, and 2021, respectively.

Net Income (Loss) Per Share

Basic net income (loss) per common share attributable to Xencor 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 attributable to Xencor 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 income (loss) per common share attributable to Xencor is computed as follows:

Basic net income (loss) per common share is computed by dividing the net income or loss attributable to Xencor by the weighted-average number of common shares outstanding during the period.


	Year Ended December 31,
	2023		2022		2021
	(in thousands, except share and per share data)
Basic
Numerator:
Net income (loss) attributable to Xencor, Inc.	$	(126,087)	$	(55,181)	$	82,631
Denominator:
Weighted-average common shares outstanding	60,503,283		59,652,461		58,379,641
Basic net income (loss) per common share attributable to Xencor, Inc.	$	(2.08)	$	(0.93)	$	1.42

Diluted
Numerator:
Net income (loss) attributable to Xencor, Inc.	$	(126,087)	$	(55,181)	$	82,631
Denominator:
Weighted average number of common shares outstanding used in computing basic net income (loss) per common share	60,503,283		59,652,461		58,379,641
Dilutive effect of employee stock options, RSUs, and ESPP	—		—		2,115,814
Weighted-average number of common shares outstanding used in computing diluted net income (loss) per common share	60,503,283		59,652,461		60,495,455
Diluted net income (loss) per common share attributable to Xencor, Inc.	$	(2.08)	$	(0.93)	$	1.37

For the years ended December 31, 2023 and 2022, all outstanding potentially dilutive securities were excluded from the calculation as the effect of including such securities would have been anti-dilutive. For the year ended December 31, 2021, we excluded 1,196,268 shares of options and RSUs from the calculation of diluted net income per common share because the inclusion of such shares would have had an anti-dilutive effect.

Segment Reporting

The Company determines its segment reporting based upon the way the business is organized for making operating decisions and assessing performance. The Company has only one operating segment related to the development of pharmaceutical products.

Leases - Undiscounted Cash Flows (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Leases [Abstract]
2024	$ 6,128
2025	8,022
2026	9,238
2027	9,560
2028	9,076
Thereafter	66,435
Total undiscounted lease payments	108,459
Less: Tenant allowance	(3,252)
Less: Imputed interest	(42,747)
Present value of lease payments	62,460
Lease liabilities - short-term	3,435	$ 4,708
Lease liabilities - long-term	59,025	$ 54,926
Total lease liabilities	$ 62,460

Stock-Based Compensation

12 Months Ended

Dec. 31, 2023

Share-Based Payment Arrangement [Abstract]

Stock-Based Compensation

In 2013 , our Board of Directors and our stockholders approved the 2013 Equity Incentive Plan (the 2013 Plan). The 2013 Plan provides for the grant of incentive stock options, nonstatutory stock options, stock appreciation rights, restricted stock awards, restricted stock unit awards, performance stock awards, performance cash awards, and other stock awards. The 2013 Plan had a ten-year term and would expire on December 3, 2023.

In June 2023, the Board and shareholders approved the 2023 Equity Incentive Plan (the 2023 Plan), which became effective as of June 14, 2023. 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 2013 Plan provided for an automatic increase in the number of shares annually on January 1 by 4% of the total number of issued and outstanding shares of common stock as of December 31 of the immediately preceding year. On January 1, 2023, pursuant to approval by the Board, the total number of shares of common stock available for issuance under the 2013 Plan was increased by 2,399,908 shares. The 2023 Plan does not include a provision for an automatic increase in shares, also known as an Evergreen provision.

As of December 31, 2023, the total number of shares of common stock available for issuance under the 2023 Plan was 19,434,971, which includes 16,932,548 shares of common stock that were available for issuance under the Prior Plans as of the effective date of the 2023 Plan. As of December 31, 2023, a total of 16,616,038 options have been granted under the 2013 Plan and 2023 Plan.

As of December 31, 2023, the Company has awarded 2,994,168 RSUs to certain employees pursuant to the 2013 Plan and 2023 Plan. Vesting of these awards will be annually over equal installments, either a two or three-year vesting period, and is contingent on continued employment terms. 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.

In November 2013, our Board of Directors and stockholders approved the 2013 Employee Stock Purchase Plan (2013 ESPP), which became effective as of December 5, 2013. Under the ESPP our employees may elect to have between 1-15% of their compensation withheld to purchase shares of the Company’s common stock at a discount. The ESPP had an initial two-year term that included four six-month purchase periods, and employee withholding amounts could be used to purchase Company stock during each six-month purchase period. The initial two-year term ended in December 2015 and, pursuant to the provisions of the ESPP, subsequent two-year terms began automatically upon the end of the previous term. The total number of shares that can be purchased with the withholding amounts are based on the lower of 85% of the Company’s common stock price at the initial offering date or 85% of the Company’s stock price at each purchase date.

As of December 31, 2023, the total number of shares of common stock available for issuance under the ESPP is 1,041,340. Under the 2013 ESPP, the total number shares of common stock available for issuance under the ESPP will automatically increase 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. Pursuant to approval by our board, the total number of shares of common stock available for issuance under the ESPP was increased by 599,977 shares on January 1, 2023.

As of December 31, 2023, we have issued a total of 733,478 shares of common stock under the ESPP.

Total employee, director and non-employee stock-based compensation expense recognized was as follows:


	Year Ended December 31,
(in thousands)	2023		2022		2021
General and administrative	$	19,239	$	17,281	$	12,813
Research and development	34,516		31,632		24,162
	$	53,755	$	48,913	$	36,975


	Year Ended December 31,
(in thousands)	2023		2022		2021
Stock options	$	29,345	$	29,758	$	27,909
ESPP	1,243		1,174		992
RSUs	23,167		17,981		8,074
	$	53,755	$	48,913	$	36,975

Information with respect to stock options outstanding is as follows:


	December 31,
	2023		2022		2021
Exercisable options	7,761,829		6,679,948		5,576,430
Weighted average exercise price per share of exercisable options	$	28.79	$	26.99	$	24.15
Weighted average grant date fair value per share of options granted during the year	$	15.98	$	15.45	$	21.65
Options available for future grants	6,801,945		3,622,319		3,597,371
Weighted average remaining contractual life	6.03		6.30		6.65

The following table summarizes stock option activity for the years ended December 31, 2023 and 2022:


	Number of Shares	Weighted- Average Exercise Price (Per Share)(1)		Weighted- Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value (in thousands)(2)
Balances at December 31, 2020	7,751,789	$	26.23	7.00	$	134,941
Options granted	1,827,234	41.22
Options forfeited	(382,454)	36.15
Options exercised(3)	(520,240)	23.61
Balances at December 31, 2021	8,676,329	29.11		6.65	$	100,057
Options granted	2,135,233	29.45
Options forfeited	(533,435)	34.09
Options exercised(3)	(195,485)	18.46
Balances at December 31, 2022	10,082,642	29.12		6.30	$	27,141
Options granted	2,080,732	30.02
Options forfeited	(676,005)	33.19
Options exercised(3)	(344,383)	9.91
Balances at December 31, 2023	11,142,986	$	29.60	6.03	$	9,977
As of December 31, 2023
Options vested and expected to vest	11,142,986	$	29.60	6.03	$	9,977
Exercisable	7,761,829	$	28.79	4.90	$	9,907

______________________________

(1)The weighted average exercise price per share is determined using exercise price per share for stock options.

(3)The total intrinsic value of stock options exercised was $4.8 million, $1.6 million, and $9.2 million for the years ended December 31, 2023, 2022 and 2021 respectively.

We estimated the fair value of employee and non-employee awards using the Black-Scholes valuation model. The fair value of employee stock options is being amortized on a straight-line basis over the requisite service period of the awards. Management estimates the probability of non-employee awards being vested based upon an evaluation of the non-employee achieving their specific performance goals.

Options are issued at the fair market value of our stock on the date of grant.

The fair value of employee stock options was estimated using the following weighted average assumptions for the years ended December 31, 2023, 2022 and 2021:


	Options
	2023	2022	2021
Common stock fair value per share	$20.14 - 36.02	$19.74- 38.08	$30.65 - 49.47
Expected volatility	49.75% - 52.48%	51.51% - 54.36%	53.91% - 56.82%
Risk-free interest rate	3.50% - 4.55%	1.57% - 4.34%	0.47% - 1.33%
Expected dividend yield	—	—	—
Expected term (in years)	6.00 - 6.59	6.00 - 7.65	6.00 - 7.65


	ESPP
	2023	2022	2021
Expected term (years)	0.5 - 2.0	0.5 - 2.0	0.5 - 2.0
Expected volatility	38.24% - 55.72%	43.19% - 55.72%	46.08% - 66.37%
Risk-free interest rate	0.13% - 5.39%	0.13% - 4.72%	0.04% - 1.65%
Expected dividend yield	—	—	—

The expected term of stock options represents the average period the stock options are expected to remain outstanding. The expected stock price volatility for our stock options for the years ended December 31, 2023, 2022, and 2021 was determined using a blended volatility by examining the historical volatility for industry peer companies and the volatility of our stock from the effective date that our shares were publicly traded on a national stock exchange.

We determined the average expected life of stock options based on the anticipated time period between the measurement date and the exercise date by examining the option holders’ past exercise patterns.

The risk-free interest rate assumption is based on the U.S. Treasury instruments, for which the term was consistent with the expected term of our stock options.

The expected dividend assumption is based on our history and expectation of dividend payouts. We have not paid dividends and did not have any dividend payout at December 31, 2023.

The following table summarizes RSU activity for the years ended December 31, 2023:


	Number of Shares	Weighted- Average Grant Date Fair Value (Per Unit)
Unvested at December 31, 2020	358,825	$	33.04
Granted	670,700	39.11
Vested	(151,555)	32.76
Forfeited	(51,822)	36.68
Unvested at December 31, 2021	826,148	$	37.79
Granted	875,330	29.45
Vested	(341,073)	37.37
Forfeited	(127,854)	33.66
Unvested at December 31, 2022	1,232,551	$	32.41
Granted	994,351	30.33
Vested	(558,066)	33.61
Forfeited	(178,796)	31.64
Unvested at December 31, 2023	1,490,040	$	30.66

As of December 31, 2023 and 2022, the unamortized compensation expense related to unvested stock options was $49.2 million and $52.6 million, respectively. The remaining unamortized compensation expense will be recognized over the next 2.39 years. At December 31, 2023 and 2022, the unamortized compensation expense was $1.8 million and $1.2 million respectively under our ESPP. The remaining unamortized expense will be recognized over the next 1.94 years. At December 31, 2023 and 2022, the unamortized compensation expense related to unvested restricted stock units was $29.6 million and $28.3 million, respectively. The remaining unamortized compensation expense will be recognized over the next 1.90 years.

Leases (Tables)

12 Months Ended

Dec. 31, 2023

Leases [Abstract]

Schedule of operating lease liabilities maturities

The following table reconciles the undiscounted cash flows for the operating leases at December 31, 2023 to the operating lease liabilities recorded on the balance sheet (in thousands):


Years ending December 31,
2024	$	6,128
2025	8,022
2026	9,238
2027	9,560
2028	9,076
Thereafter	66,435
Total undiscounted lease payments	108,459
Less: Tenant allowance	(3,252)
Less: Imputed interest	(42,747)
Present value of lease payments	$	62,460

Lease liabilities - short-term	$	3,435
Lease liabilities - long-term	59,025
Total lease liabilities	$	62,460

Summary of lease costs and cash disclosures

The following table summarizes lease costs, cash, and other disclosures for the years ended December 31, 2023, 2022, and 2021 (in thousands):


	Year Ended December 31,
	2023			2022			2021

Operating lease cost	$	8,459		$	6,588		$	4,342
Variable lease cost	906			506			58
Total lease costs	$	9,365		$	7,094		$	4,400
Cash paid for amounts included in
the measurement of lease liabilities	$	3,253		$	2,869		$	2,773
Weighted-average remaining lease term
—operating leases (in years)	11.0			12.0			12.3
Weighted-average discount rate
—operating leases	8.9		%	8.9		%	5.8		%

Collaboration and Licensing Agreements - Vir Biotechnology, Inc. (Details) $ in Thousands	1 Months Ended	12 Months Ended
	Oct. 31, 2022 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 target	Jun. 30, 2021 USD ($)
Collaboration research and licensing agreements
Accounts receivable		$ 11,290	$ 28,997
Vir \| Patent License Agreement
Collaboration research and licensing agreements
Number of different target programs \| target					2
Revenue recognized	$ 500	2,200	115,400	$ 52,700
Contract asset						$ 500
Deferred revenue		0
Accounts receivable		600
Vir \| Patent License Agreement \| Royalties
Collaboration research and licensing agreements
Revenue recognized		$ 2,200	$ 114,900	$ 52,200

Summary of Significant Accounting Policies - Restricted Cash (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Accounting Policies [Abstract]
Restricted cash	$ 380	$ 0

Collaboration and Licensing Agreements - Technology License Agreement and Services Agreement with Gale Therapeutics Inc. (Details) $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($)
Gale \| Technology License Agreement
Collaboration research and licensing agreements
Revenue not recognized	$ 1.0

Collaboration and Licensing Agreements

12 Months Ended

Dec. 31, 2023

Collaboration and Licensing Agreements

Collaboration and Licensing Agreements

Following is a summary description of the material revenue arrangements, including arrangements that generated revenue in the period ended December 31, 2023, 2022, and 2021. The revenue reported for each agreement has been adjusted to reflect the adoption of ASC 606 for each period presented.

Alexion Pharmaceuticals, Inc.

In January 2013, the Company entered into an option and license agreement with Alexion Pharmaceuticals, Inc. (Alexion). Under the terms of the agreement, the Company granted to Alexion an exclusive research license, with limited sublicensing rights, to make and use our Xtend technology. Alexion exercised its rights to include our technology in ALXN1210, which is now marketed as Ultomiris.

The Company is eligible to receive royalties based on a percentage of net sales of such products sold by Alexion, its affiliates, or its sub licensees, 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.

In 2022 and 2021, the Company recorded royalty revenue of $29.4 million and $22.2 million, respectively in connection with reported net sales of Ultomiris by Alexion.

In 2023, Alexion completed certain sales milestones for Ultomiris, and the Company received a milestone payment of $20.0 million and recorded royalty revenue of $38.6 million on net sales.

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 in exchange for an upfront payment of $192.5 million. Included in the proceeds is $29.5 million of accounts receivable the Company sold for royalties and milestone receivable recorded at September 30, 2023. For the year ended December 31, 2023, the Company earned and recognized $38.6 million in royalty revenue, $6.2 million of which was non-cash royalty revenue under the Ultomiris Royalty Sale Agreement

The total revenue recognized under this arrangement was $58.6 million, $29.4 million, and $22.2 million for the years ended December 31, 2023, 2022, and 2021, respectively. As of December 31, 2023, there is no receivable and no deferred revenue related to this agreement.

Astellas Pharma Inc.

Effective March 2019, the Company entered into a Research and License Agreement (Astellas Agreement) with Astellas Pharma Inc. (Astellas) pursuant to which the Company and Astellas conducted a discovery program to characterize compounds and products for development and commercialization. Under the Astellas Agreement, Astellas was granted a worldwide exclusive license, with the right to sublicense products in the field created by the research activities.

The Company received an upfront payment and is eligible to receive development, regulatory and sales milestones. If commercialized, the Company is eligible to receive royalties on net sales that range from the high-single to low-double digit percentages.

Astellas has advanced an antibody that was delivered into development, and we received a milestone related to the candidate in 2020. Astellas advanced the candidate into Phase 1 studies in 2022 and we received a $5.0 million milestone. No revenue was recognized for the year ended December 31, 2023 or 2021.The Company recognized $5.0 million of revenue for the year ended December 31, 2022 under the agreement. There is no deferred revenue as of December 31, 2023.

Astria Therapeutics, Inc.

In May 2018, the Company entered into an agreement with Quellis, pursuant to which the Company provided Quellis a non-exclusive license to its Xtend Fc technology. The Company received an equity interest in Quellis and is eligible to receive development, regulatory and sales milestones. The Company is also eligible to receive royalties in the mid-single digit percentage range on net sales of approved products.

In January 2021, Quellis merged into Astria (formerly Catabasis), and the Company received common stock and preferred stock of Aastria in exchange for its equity in Quellis. The Company recognized an increase in the fair value of its equity interest for the exchange of shares, which was recorded as unrealized gain for the three months ended March 31, 2021. In June 2021, a portion of the Company’s preferred stock in Astria was converted to common stock. The remaining Astria preferred stock was converted to common stock in 2023. The Company recorded an impairment charge of $0.1 million and $0.8 million for its investment in Astria preferred stock for the year ended December 31, 2022 and 2021, respectively.

The Company recognized unrealized (loss) gain of $(4.3) million, $6.1 million, and $4.5 million related to its equity interest in Astria for the years ended December 31, 2023, 2022, and 2021 respectively. There is no deferred revenue as of December 31, 2023 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. Hoffman-La Roche Ltd (collectively, Genentech) for the development and commercialization of novel IL-15 collaboration products (Collaboration Products), including XmAb306, 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 determined that the transaction price of the Genentech Agreement at inception was $120.0 million consisting of the upfront payment, and allocated the transaction price to each of the separate performance obligations using the relative standalone selling price with $111.7 million allocated to the license to XmAb306, $4.1 million allocated to the additional program and $4.2 million allocated to the research services.

The Company recognized the $111.7 million allocated to the license when it satisfied its performance obligation and transferred the license to Genentech in March 2019, and the $8.3 million allocated to the research activities was recognized over a period of time through the end of the research term or the time that a program is delivered to Genentech. The research term expired in the first half of 2021, and the balance in deferred revenue related to the Genentech Agreement was recognized as the Company is no longer required to render services.

No revenue was recognized for the years ended December 31, 2023, and 2022. For the year ended December 31, 2021, we recognized $2.5 million of income from the Genentech Agreement. As of December 31, 2023, there was a $3.3

million payable related to cost-sharing development activities during the fourth quarter of 2023. There is no deferred revenue as of December 31, 2023.

Gilead Sciences, Inc.

In January 2020, the Company entered into a Technology License Agreement (the Gilead Agreement) with Gilead Sciences, Inc. (Gilead), in which the Company provided Gilead an exclusive license to its Cytotoxic Fc and Xtend Fc technologies for an initial identified antibody and options for up to three additional antibodies directed to the same molecular target. Gilead is responsible for all development and commercialization activities for all target candidates. The Company received an upfront payment and is eligible to receive development, regulatory and, sales milestones for each product incorporating the antibodies selected. In addition, the Company is eligible to receive royalties in the low-single digit percentage range on net sales of approved products.

The Company recognized $6.0 million in milestone revenue for the year ended December 31, 2023. No revenue was recognized for the years ended December 31, 2022 and 2021. There is no deferred revenue as of December 31, 2023 related to this agreement.

INmune Bio, Inc.

In October 2017, the Company entered into a License Agreement (the INmune Agreement) with INmune. Under the terms of the INmune Agreement, the Company provided INmune with an exclusive license to certain rights to a proprietary protein, XPro1595. In connection with the agreement the Company received shares of INmune common stock and an option to acquire additional shares of INmune. The Company also received a second option to acquire additional shares of INmune common stock with a designee appointed by us serving on the board of directors of INmune.

The Company initially recorded its equity interest in INmune, including its option to acquire additional INmune shares, at cost pursuant to ASC 323.

In June 2021, the Company entered into the First Amendment to License Agreement (the Amended INmune Agreement) and an Option Cancellation Agreement (the Option Agreement) with INmune.The Option Agreement provided for the sale of the initial option to INmune for the total consideration of $18.3 million which includes $15.0 million in cash and additional shares of INmune common stock. The Company recorded a realized gain of $18.3 million according to ASC 860, Transfer and Servicing, and recorded the additional shares of INmune common stock according to ASC 321, Investments – Equity Securities.

During 2021, the Company determined that it should no longer record its investment in INmune under the equity method and recorded its investment in INmune pursuant to ASC 321. The Company adjusted the carrying value of this investment by recognizing an unrealized gain of $27.8 million as other income during 2021.

During 2021, the Company exercised its second to purchase additional shares of INmune common stock for $0.8 million, and the Company recognized an unrealized gain of $2.0 million, which consists of $1.1 million of fair value of the option and $0.9 million gain on the purchase.

For the year ended December 31, 2023, the Company recorded $9.3 million of unrealized gain related to its investment in INmune. For the year ended December 31, 2022, the Company recorded $7.3 million of unrealized loss related to its investment in INmune. For the year ended December 31, 2021, the Company recorded $15.1 million of unrealized gain and $18.3 million of realized gain related to its investment in INmune. No revenue was recognized for the years ended December 31, 2023, 2022, or 2021.

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 Xencor 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 apply its bispecific Fc technology to antibodies targeting prostate cancer provided by J&J. Upon completion of the research activities Janssen will have a candidate selection option to advance an identified candidate for development and commercialization. The activities will be conducted under a research plan agreed to by both parties. J&J will assume full responsibility for development and commercialization of the CD28 bispecific antibody candidate. Pursuant to the J&J Agreement, the Company received an upfront payment and is eligible to receive development, regulatory and, sales milestones. If commercialized, the Company is eligible to receive royalties on net sales that range from the high-single to low-double digit percentages.

Pursuant to the J&J Agreement, upon development of a bispecific candidate by J&J through proof of concept, we have the right to opt-in to fund 20% of development costs and to perform 30% of detailing efforts in the U.S. If we exercise this right, we will be eligible to receive tiered royalties in the low-double digit to mid-teen percentage range.

The Company allocated the transaction price to the single performance obligation, delivery of CD28 bispecific antibodies to J&J.

The Company recognized the $50.0 million transaction price as it satisfied its performance obligation to deliver CD28 bispecific antibodies to J&J. The Company recognized revenue related to the performance obligation over the expected period of time to complete and deliver the CD28 bispecific antibodies to J&J using the expected input method which considers an estimate of the Company’s efforts to complete the research activities outlined in the J&J Agreement.

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, and we received a milestone of $5.0 million. For the year ended December 31, 2021 the Company recognized as revenue the $50.0 million transaction price in connection with the completion of the research activities and the $5.0 million milestone for selection of an antibody candidate by J&J. No revenue was recognized under this agreement for the year ended December 31, 2022. In 2023, J&J completed filing of regulatory submission for a CD28 candidate and initiated Phase 1 clinical trial, and the Company received $17.5 million in milestone payments. For the year ended December 31, 2023, the Company recognized $17.5 million in milestones under the J&J Agreement. There is no deferred revenue related to the Agreement at December 31, 2023.

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 will conduct research and development activities to discover novel CD28 bispecific antibodies. The parties will conduct joint research activities for up to 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.

Pursuant to the Second J&J Agreement, the Company received an upfront payment of $100.0 million and is eligible to receive up to $1,187.5 million in milestones which include $289.4 million in development milestones, $378.1 million in regulatory milestones and $520.0 million in sales milestones. Under the terms of the Stock Purchase Agreement, Johnson & Johnson Innovation, JJDC, Inc. (JJDC), agreed to purchase $25.0 million of newly issued unregistered shares of the Company’s common stock, priced at a 30-day volume-weighted average price of $33.4197 per share as of October 1, 2021. The Company issued JJDC 748,062 shares of its common stock which had a fair market value of $28.9 million when the shares were transferred.

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.

Under the Second J&J Agreement, the Company granted J&J an exclusive worldwide right to its plamotamab program and the Company will conduct research activities and apply its CD28 bispecific Fc technology to antibodies targeting B-cells. Upon completion of the research activities J&J will have options to advance up to four identified candidates for development and commercialization. The activities will be conducted under a research plan agreed to by both parties. J&J will assume full responsibility for development and commercialization of the CD28 bispecific antibody candidate. If commercialized, the Company is eligible to receive royalties on net sales that range from the high-single to low-double digit percentages.

The Company evaluated the Second J&J Agreement under the provisions of ASC 606. We have determined that J&J is a customer for purposes of the delivery of specific performance obligations under the Second Janssen Agreement and applied the provisions of ASC 606 to the transaction.

The Company identified the following performance obligations under the Second Janssen Agreement:

(i)the license to the plamotamab program, and

(ii)research services during a two-year period to create up to four CD28 bispecific candidates targeting B-cell antigens.

The Company determined that the license and the research services are separate performance obligations because they are capable of being distinct and are distinct in the context of the Second J&J Agreement.

The Company determined the standalone selling price of the license to be $58.5 million using the adjusted market assessment approach considering similar collaboration and license agreements and transactions. The standalone selling price for the research services to be performed during the research term was determined to be $37.6 million using the market approach which was derived from the Company’s experience and information from providing similar research services.

The Company determined that the transaction price of the Second J&J Agreement at inception was $96.1 million consisting of the $100.0 million upfront payment reduced by the $3.9 million discount on the proceeds received from the sale of Company common stock to J&J. The potential milestones are not included in the transaction price as these are contingent on future events and the Company would not recognize these in revenue until it is not probable that these would not result in significant reversal of revenue amounts in future periods. The Company will re-assess the transaction price at each reporting period and when event outcomes are resolved or changes in circumstances occur.

The Company allocated the transaction price to each of the separate performance obligations using the relative standalone selling price with $58.5 million allocated to the license to the plamotamab program and $37.6 million allocated to the research services.

The Company recognized the $58.5 million allocated to the license when it satisfied its performance obligation and transferred the license to J&J in November 2021. The $37.6 million allocated to the research services is being recognized over a period of time through the end of the research term that services are rendered as we determine that the input method is the appropriate approach to recognize income for such services. The Company completed its performance obligations under the research agreement in December 2023.

During 2023, J&J exercised its options on three CD28 candidates developed under the collaboration, and it completed regulatory submissions for a selected candidate and initiated a Phase 1 study for it. During the year ended December 31, 2023, we received $30.0 million in milestone revenue and recognized $30.3 million in revenue related to completion of the research services. A total of $30.3 million, $7.0 million, and $0.3 million of revenue related to the research services was recognized in each of the years ended December 31, 2023, 2022, and 2021, respectively.

The Company recognized $77.8 million, $7.0 million, and $113.8 million of revenue related to the two J&J agreements for the years ended December 31, 2023, 2022, and 2021, respectively. As of December 31, 2023, there was a $2.9 million receivable related to cost-sharing development activities during the fourth quarter of 2023. There is no in deferred revenue as of December 31, 2023 related to our obligation to complete research activities and deliver CD28 bispecific antibodies under the Second J&J Agreement.

MorphoSys AG/Incyte Corporation

In June 2010, the Company entered into a Collaboration and License Agreement with MorphoSys AG (MorphoSys), which was subsequently amended in March 2012 and in 2020. The agreement provides MorphoSys with an exclusive worldwide license to the Company’s patents and know-how to research, develop, and commercialize the Company’s XmAb5574 product candidate (subsequently renamed MOR208 and tafasitamab) with the right to sublicense under certain conditions. 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 in exchange for an upfront payment of $22.5 million. The upfront payment included $2.2 million of accounts receivable we recorded as a royalty receivable at September 30, 2023. The payment for the receivable was received by OMERS.

In February 2024, Incyte Corporation acquired exclusive global development and commercialization rights to tafasitamab.

The Company recognized a total of $8.7 million and $7.8 million of royalty revenue on net sales of Monjuvi for the years ended December 31, 2023 and 2022. Of the $8.7 million royalty revenue earned in 2023, $2.1 million was non-cash royalty revenue from the Monjuvi Royalty Sale Agreement.The Company recognized a total of $12.5 million of milestone revenue related to clinical studies and royalties of $5.9 million on net sales of Monjuvi for the year ended December 31, 2021. As of December 31, 2023, the Company has no deferred revenue related to this agreement and has recorded a receivable of $2.1 million for royalties due.

Novartis Institute for Biomedical Research, Inc.

In June 2016, the Company entered into a Collaboration and License Agreement (Novartis Agreement) with Novartis Institutes for BioMedical Research, Inc. (Novartis), to develop and commercialize bispecific and other Fc engineered antibody drug candidates using the Company’s proprietary XmAb technologies and drug candidates. Pursuant to the Novartis Agreement:

•The Company granted Novartis certain exclusive rights to research, develop and commercialize XmAb14045 (vibecotamab) and,

•The Company will provide Novartis with a non-exclusive license to certain of its Fc technologies to apply against up to ten targets identified by Novartis.

In August 2021, Novartis notified the Company it was terminating its rights with respect to the vibecotamab program, which became effective in February 2022. Under the Novartis Agreement, Novartis is responsible for its share of vibecotamab development costs through August 2022.

We completed delivery of two Global Discovery Programs under the Agreement.

Under ASC 606, revenue is recognized at the time that the Company’s performance obligation for each Global Discovery is completed upon delivery of each discovery program to Novartis. The Company delivered two discovery programs to Novartis and recognized $40.1 million of revenue in the period that each program was delivered. The Company’s obligations to provide research services under the Agreement for additional Global Discovery Programs expired in 2021, and we recognized $40.1 million of research revenue from deferred revenue.

In June 2021, Novartis selected an Fc candidate and received a non-exclusive license to the Company’s Fc technology. Novartis will assume full responsibility for development and commercialization of the licensed Fc product candidate. The Company is eligible to receive development, clinical, and sales milestones and royalties on net sales of approved products for the licensed Fc candidate. During the year ended December 31, 2021, Novartis advanced the Fc candidate into development and initiated clinical studies and the Company recognized $3.0 million of revenue related to the milestones.

No revenue was recognized during the years ended December 31, 2023 and 2022. During the year ended December 31, 2021, the Company recognized $43.1 million of revenue. There is no receivable and no deferred revenue as of December 31, 2023 related to the arrangement.

Omeros Corporation

In August 2020, the Company entered into a Technology License Agreement (the Omeros Agreement) with Omeros Corporation (Omeros), in which the Company provided Omeros a non-exclusive license to its Xtend Fc technology, an exclusive license to apply its Xtend technology to an initial identified antibody and options to apply its Xtend technology to three additional antibodies. Omeros is responsible for all development and commercialization activities for all target candidates. The Company received an upfront payment and is eligible to receive development, regulatory and, sales milestones for each product incorporating the antibodies selected. In addition, the Company is eligible to receive royalties in the mid-single digit percentage range on net sales of approved products.

During 2023, Omeros advanced a candidate that incorporates the Company's Xtend Fc technology into a Phase 2 study, and the Company received a $5.0 million milestone. The Company recognized $5.0 million of revenue related to the Omeros Agreement for the year ended December 31, 2023. There was no revenue recognized for the years ended December 31, 2022 and 2021. There is no deferred revenue as of December 31, 2023 related to this agreement.

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. Under the terms of the Second Vir Agreement, Vir is responsible for all research, development, regulatory and commercial activities for the antibody, 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. In 2023, 2022, and 2021, we recognized royalty revenue of $2.2 million, $114.9 million, and $52.2 million, respectively related to this agreement.

In June 2021, Vir announced its plan to initiate a Phase 2 study for VIR-3434 and subsequently completed dosing of the first patient in such study in July 2021. The Company recorded a $0.5 million contract asset in connection with this milestone event, and the payment was received in August 2021. In October 2022, Vir completed dosing of the first patient in Phase 2 study for VIR-2482, and the Company recorded $0.5 million revenue in connection with this milestone event.

The Company recognized $2.2 million, $115.4 million, and $52.7 million of revenues related to the agreement for the years ended December 31, 2023, 2022, and 2021, respectively. There is no deferred revenue as of December 31, 2023 related to this agreement. As of December 31, 2023, the Company has recorded a receivable of $0.6 million for royalties due related to this agreement.

Viridian Therapeutics, Inc.

In December 2020, we entered into a Technology License Agreement (Viridian Agreement) with Viridian Therapeutics, Inc. (Viridian), in which we provided Viridian a non-exclusive license to our Xtend Fc technology and an exclusive license to apply our Xtend Fc technology to antibodies targeting IGF-1R. We received an upfront payment of shares of Viridian common stock originally valued at $6.0 million and are eligible to receive development, regulatory and sales milestones. We are also eligible to receive royalties in the mid-single digit percentage range on net sales of approved products.

The Company allocated $6.0 million of the transaction price to the licenses to the Xtend Fc technology and recognized income for the licenses at inception of the arrangement when Viridian began benefiting access to it.

During 2023, Viridian terminated the license agreement.

In December 2021, we entered into a second Technology License Agreement (Second Viridian Agreement) with Viridian for a non-exclusive license to certain antibody libraries developed by us. Under the Second Viridian Agreement,

Viridian received a one-year research license to review the antibodies and the right to select up to three antibodies for further development. We received an upfront payment shares of Viridian common stock originally valued at $7.5 million and are eligible to receive up to $24.8 million in milestones, which include $1.8 million in development milestones, $3.0 million in regulatory milestones and $20.0 million in sales milestones in addition to royalties on net sales of approved products under the Second Viridian Agreement.

The Company evaluated the Second Viridian Agreement under the revenue recognition standard ASC 606 and identified the following performance obligation that it deemed to be distinct at the inception of the contract:

•non-exclusive license to certain antibody libraries created by the Company

The Company considered the license as functional intellectual property as Viridian has the right to use the materials and license at the time that the Company transfers such rights.

The total transaction price is $7.5 million, which includes the upfront payment of Viridian common stock at their fair value at the date of the Agreement. The milestone payments are variable consideration to which the Company applied the “most likely amount” method and concluded at inception of the Viridian Agreement it is unlikely that the Company will collect such payments. The milestone payments were not included in the transaction price, and the Company will review this conclusion and update at each reporting period.

The Company allocated $7.5 million of the transaction price to the licenses to the antibody libraries and recognized income for the licenses at inception of the arrangement when Viridian received the materials and began accessing them.

In 2023, the research term under the second Viridian license expired.

No revenue related to the Viridian Agreement was recognized for the years ended December 31, 2023 and 2022. The Company recognized $7.5 million of revenue related to the Viridian Agreement for the year ended December 31, 2021. There is no deferred revenue as of December 31, 2023 related to this agreement.

Zenas BioPharma, Inc.

In November 2020, the Company entered into a License Agreement (Zenas Agreement) with Zenas BioPharma (Cayman) Limited, now Zenas BioPharma, Inc., (Zenas) pursuant to which the Company granted Zenas exclusive worldwide rights to develop and commercialize three preclinical-stage Fc-engineered drug candidates: XmAb6755, Xpro9523, and XmAb10171. The Company received an upfront payment in equity in Zenas with a fair value of $16.1 million and the Company is eligible to receive royalties on net sales of approved products in the mid-single digit to mid-teen percentage range.

In November 2021, the Company entered into a second License Agreement (Second Zenas Agreement) with Zenas, in which we licensed the exclusive worldwide rights to develop and commercialize the Company’s obexelimab (XmAb5871) drug candidate. The Company received a warrant to acquire additional equity in Zenas with a fair value of $14.9 million, and the Company is eligible to receive royalties on net sales of approved products in the mid-single digit to mid-teen percentage range.

The total transaction price is $14.9 million, which includes the upfront payment of a warrant to acquire up to 15% of the equity of Zenas in connection with a future financing at its fair value at the date of the Second Zenas Agreement. The Second Zenas Agreement includes variable consideration for potential future royalties that were contingent on future success factors for the licensed programs. The Company used the “most likely amount” method to determine the variable consideration. None of the royalties were included in the transaction price. The Company will re-evaluate the transaction price in each reporting period as uncertain events are resolved or other changes in circumstances occur.

The Company determined the transaction price at inception of the Second Zenas Agreement and allocated it to the performance obligation, delivery of the obexelimab license.

The Company completed delivery of its performance obligations in December 2021. The licenses to obexelimab were transferred to Zenas at inception of the Second Zenas Agreement, and the related research data and documentation was transferred to Zenas in December 2021.

In 2021, the Company purchased a convertible promissory note from Zenas which would automatically convert to equity in a financing transaction.

In November 2022, Zenas completed a financing transaction, pursuant to which a warrant to purchase Zenas equity that was held by the Company was automatically exercised, and a convertible note issued to the Company by Zenas was automatically converted with both converting into shares of Zenas’ preferred stock. After the financing transaction, we continued to record our investment in Zenas at fair value adjusted at each reporting period for impairment or other evidence of change in value. The equity shares in Zenas received from exercise of the warrant and conversion of the notes have an estimated fair value of $34.5 million and $7.7 million, respectively. As a result of the Zenas financing transaction, the estimated fair value of our investment in equity securities increased by $17.9 million. In 2022, this amount has been recorded in other income.

In 2023, Zenas initiated a Phase 3 study with obexelimab, and we received additional equity in Zenas as a milestone payment. We recorded milestone revenue of $10.0 million, which is the fair value of the equity shares at the date of issuance.

No revenue was recognized for the year ended December 31, 2022. The Company recognized $10.0 million and $14.9 million of revenue related to the two Zenas Agreements for the years ended December 31, 2023 and 2021, respectively. There is no deferred revenue as of December 31, 2023 related to this agreement.

Technology License Agreement and Services Agreement with Gale Therapeutics Inc.

In the fourth quarter of 2023, the Company formed a subsidiary, Gale Therapuetics Inc. (Gale), to develop novel drug candidates with its Fc technologies. On December 19, 2023, the Company entered into the Gale License Agreement and the Gale Services Agreement with Gale. Under the Gale License Agreement, Gale received an exclusive license to certain preclinical candidates and related Xencor technologies. The Company also has an option on future compounds Gale will develop. Under the Gale Services Agreement, the Company will provide research and development services as well as accounting and administrative support. Pursuant to the Gale Agreement, the Company acquired a majority stake in Gale. The Company is deemed to be the primary beneficiary of Gale, a VIE, and they are under common control; therefore, the assets, liabilities and non-controlling interests of Gale are initially recorded at their previous carrying amounts, with no adjustment to current fair values and no gain or loss is recognized. The value of the preclinical assets and technology had no value on Xencor's financial statements, and the license to Gale at inception had no carrying value. The Company would not recognize license revenue related to the transfer for the year ended December 31, 2023. Total charges under the Services Agreement during 2023 of $1.0 million have been eliminated in consolidation.

Revenue Earned

The $168.3 million, $164.6 million, and $275.1 million of revenue recorded for the years ended December 31, 2023, 2022, and 2021, respectively, were earned principally from the following licensees (in millions):


	Year Ended December 31,
	2023		2022		2021
Alexion	58.6		29.4		22.2
Astellas	—		5.0		—
Genentech	—		—		2.5
Gilead	6.0		—		—
Janssen	77.8		7.0		113.8
MorphoSys	8.7		7.8		18.4
Novartis	—		—		43.1
Omeros	5.0		—		—
Vir	2.2		115.4		52.7
Viridian	—		—		7.5
Zenas	10.0		—		14.9
Total	$	168.3	$	164.6	$	275.1

The table below summarizes the disaggregation of revenue recorded for the years ended December 31, 2023, 2022, and 2021 (in millions):


	Year Ended December 31,
	2023		2022		2021
Research collaboration	$	30.3	$	7.0	$	93.0
Milestone	88.5		5.5		21.0
Licensing	—		—		80.8
Royalties	49.5		152.1		80.3
Total	$	168.3	$	164.6	$	275.1

Remaining Performance Obligations and Deferred Revenue

There is no remaining performance obligation under the Company's arrangements as of December 31, 2023. The Company's performance obligation as of December 31, 2022 was completing research activities pursuant to the Second J&J Agreement. As of December 31, 2022, we have deferred revenue of $30.3 million. All of the deferred revenue was classified as short term as of December 31, 2022, as the Company’s obligations to perform research services are due on demand when requested by J&J under the Second J&J Agreement.

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2023

Income Tax Disclosure [Abstract]

Reconciliation of the federal statutory income tax rate to our effective income tax rate

A reconciliation of the federal statutory income tax to our effective income tax is as follows (in thousands):


	Year Ended December 31,
	2023		2022		2021
Federal statutory income tax	$	(25,258)	$	(11,447)	$	17,352
State and local income taxes	(569)		(615)		783
Research and development credit	(15,821)		(9,366)		(10,492)
Stock-based compensation	3,131		3,384		2,424
Foreign-derived intangible income	(1,188)		(1,449)		—
Other	417		(74)		95
Change in state rate	234		44		2,599
Net change in valuation allowance	44,865		20,196		(12,761)
Income tax provision	$	5,811	$	673	$	—

Schedule of tax effect of temporary differences that give rise to a significant portion of the deferred tax assets and liabilities

The tax effect of temporary differences that give rise to a significant portion of the deferred tax assets and liabilities at December 31, 2023 and 2022 is presented below (in thousands):


	December 31,
	2023		2022
Deferred income tax assets
Net operating loss carryforwards	$	22,466	$	32,898
Research credits	53,198		54,825
Unrealized (gain) loss on securities	(278)		1,573
Capitalized lease assets	6,161		5,564
Accrued compensation	18,172		14,484
Deferred revenue	34,405		3,225
Capitalized research and development costs	45,783		21,338
Gross deferred income tax assets	179,907		133,907
Valuation allowance	(158,099)		(115,010)
Net deferred income tax assets	21,808		18,897
Deferred income tax liabilities
Patent costs	(2,218)		(2,885)
Licensing costs	(136)		(124)
Capitalized legal costs	(6)		(9)
Depreciation	(10,664)		(6,532)
Unrealized gain on securities	(8,784)		(9,347)
Gross deferred income tax liabilities	(21,808)		(18,897)
Net deferred income tax asset	$	—	$	—

Collaboration and Licensing Agreements - Astellas Pharma Inc. (Details) - Astellas - Research and License Agreement - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Collaboration research and licensing agreements
Proceeds from milestone payments		$ 5.0
Revenue recognized	$ 0.0	$ 5.0
Deferred revenue	$ 0.0

Summary of Significant Accounting Policies (Polices)

12 Months Ended

Dec. 31, 2023

Accounting Policies [Abstract]

Consolidation and Basis of Presentation

Use of Estimates

Recent Accounting Pronouncements

Pronouncements Not yet Effective

Variable Interest Entity

Liability Related to the Sale of Future Royalties

Non-Cash Interest Expense on the Liability Related to the Sale of Future Royalties

Deferred Income Related to the Sale of Future Royalties

Revenue Recognition

Deferred Revenue

Accounts Receivable

Research and Development Expenses

Cash and Cash Equivalents

We consider cash equivalents to be only those investments which are highly liquid, readily convertible to cash and which mature within three months from the date of purchase.

Marketable Debt and Equity Securities

During the years ended December 31, 2023 and 2022, the Company recorded a net loss of $0.4 million and net gain of $23.4 million, respectively, in connection with its equity investments.

Concentrations of Risk

Fair Value of Financial Instruments

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

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.

Property and Equipment


Computers, software and equipment			3 - 5 years
Furniture and fixtures			5 - 7 years
Leasehold improvements			5 - 7 years or remaining
			lease term, whichever is less

Patents, Licenses, and Other Intangible Assets

Long-Lived Assets

Income Taxes

Our policy is to recognize interest and penalties on taxes, if any, as a component of income tax expense.

effective January 1, 2022.

Stock-Based Compensation

Net Income (Loss) Per Share

Basic and diluted net income (loss) per common share attributable to Xencor is computed as follows:

Basic net income (loss) per common share is computed by dividing the net income or loss attributable to Xencor by the weighted-average number of common shares outstanding during the period.

For the year ended December 31, 2021, we excluded 1,196,268 shares of options and RSUs from the calculation of diluted net income per common share because the inclusion of such shares would have had an anti-dilutive effect.

Segment Reporting

Collaboration and Licensing Agreements - Omeros Corporation (Details) - Omeros - Technology License Agreement $ in Millions	1 Months Ended	12 Months Ended
	Aug. 31, 2020 antibody	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Collaboration research and licensing agreements
Number of additional antibodies \| antibody	3
Revenue recognized		$ 5.0	$ 0.0	$ 0.0
Deferred revenue		0.0
Proceeds from milestone payments		$ 5.0

Leases

12 Months Ended

Dec. 31, 2023

Leases [Abstract]

Leases

The Company leases office and laboratory space in Monrovia, California under two separate leases; one lease expired in January 2023, and a second lease will expire in December 2025. The second lease includes an option to renew

for an additional five years at then market rates. The initial lease expired in January 2023, and the Company has assessed that it is unlikely to exercise the lease term extension option for the second lease that will expire in December 2025. For the year ended December 31, 2023, there were no ROU assets obtained in exchange for new operating lease liabilities.

The Company leases additional office space in San Diego, California under a lease that expired December 31, 2023.

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. For the year ended December 31, 2023, ROU assets obtained in exchange for new operating lease liabilities were $2.5 million. In connection with the Sublease Agreement, the Company provided a $0.4 million Letter of Credit (LOC) to the landlord. The Letter of Credit will decline ratably over the term of the lease. In connection with the LOC, Company entered into a Cash Collateral Agreement for $0.4 million, which is classified as restricted cash in the Consolidated Balance Sheets.

In June 2021, the Company entered into an 18-month lease for office space in Monrovia, California. The lease began August 1, 2021 and terminated January 31, 2023. For the year ended December 31, 2023, there were no ROU assets obtained in exchange for new operating lease liabilities.

In June 2021, the Company entered into an Agreement of Lease (the Halstead Lease) relating to 129,543 rentable square feet, for laboratory and office space, in Pasadena, California. The term of the Halstead Lease became effective in two phases. The first phase commenced on July 14, 2021 and encompasses 83,083 square feet while the second phase commences no later than July 1, 2025 and encompasses an additional 46,460 square feet. The term of the Halstead Lease is 13 years from the first phase commencement date. The Company received delivery of the first phase premises on July 1, 2021 and completed construction of office, laboratory, and related improvements in 2023. The Company placed the new facility into service in February 2023. The Halstead Lease provides the Company with improvement allowances of up to $17.0 million and $3.3 million in connection with the Phase 1 and Phase 2 building improvements, respectively. The initial base monthly rent is $386,336, or $4.65 per square foot, and includes increases of three percent annually. The Company will also be responsible for its proportionate share of operating expenses, tax expense, and utility costs.

In July 2021, the Halstead Lease was amended to clarify the start date of the new lease to August 1, 2022 and to amend other provisions of the Halstead Lease to reflect the new start date of the lease. In August 2022, the Halstead lease was amended to increase the amount of the tenant allowance by $5.0 million with a corresponding increase in total rental payments. The Company is eligible to receive total tenant allowance under the lease for the phase 1 space of $22.0 million and the initial base rent is increased to $416,246, or $5.01 per square foot. The second phase premises was made available on December 1, 2022. For the year ended December 31, 2023, there were no ROU assets obtained in exchange for new operating lease liabilities.

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 December 31, 2023 to the operating lease liabilities recorded on the balance sheet (in thousands):


Years ending December 31,
2024	$	6,128
2025	8,022
2026	9,238
2027	9,560
2028	9,076
Thereafter	66,435
Total undiscounted lease payments	108,459
Less: Tenant allowance	(3,252)
Less: Imputed interest	(42,747)
Present value of lease payments	$	62,460

Lease liabilities - short-term	$	3,435
Lease liabilities - long-term	59,025
Total lease liabilities	$	62,460

The following table summarizes lease costs, cash, and other disclosures for the years ended December 31, 2023, 2022, and 2021 (in thousands):


	Year Ended December 31,
	2023			2022			2021

Operating lease cost	$	8,459		$	6,588		$	4,342
Variable lease cost	906			506			58
Total lease costs	$	9,365		$	7,094		$	4,400
Cash paid for amounts included in
the measurement of lease liabilities	$	3,253		$	2,869		$	2,773
Weighted-average remaining lease term
—operating leases (in years)	11.0			12.0			12.3
Weighted-average discount rate
—operating leases	8.9		%	8.9		%	5.8		%

Summary of Significant Accounting Policies - Stock-Based Compensation (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Stock-Based Compensation
Stock-based compensation	$ 53.8	$ 48.9	$ 37.0

Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Statement of Comprehensive Income [Abstract]
Consolidated net income (loss)	$ (126,250)	$ (55,181)	$ 82,631
Net unrealized gain (loss) on marketable securities available-for-sale	8,243	(5,442)	(1,584)
Comprehensive income (loss)	(118,007)	(60,623)	81,047
Comprehensive income (loss) attributable non-controlling interest	(163)	0	0
Comprehensive income (loss) attributable to Xencor, Inc.	$ (117,844)	$ (60,623)	$ 81,047

- 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

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

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

Consolidated Statements of Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Revenue
Collaborations, licenses, milestones, and royalties	$ 168,338	$ 164,579	$ 275,111
Operating expenses
Research and development	253,598	199,563	192,507
General and administrative	53,379	47,489	38,837
Total operating expenses	306,977	247,052	231,344
Income (loss) from operations	(138,639)	(82,473)	43,767
Other income (expense)
Interest income, net	18,626	4,817	849
Other expense, net	(31)	(286)	(1,274)
Gain (loss) on equity securities, net	(395)	23,434	39,289
Total other income, net	18,200	27,965	38,864
Income (loss) before income tax	(120,439)	(54,508)	82,631
Income tax expense	5,811	673	0
Net income (loss)	(126,250)	(55,181)	82,631
Net loss attributable to non-controlling interest	(163)	0	0
Net income (loss) attributable to Xencor, Inc.	$ (126,087)	$ (55,181)	$ 82,631
Net income (loss) per common share attributable to Xencor, Inc.:
Basic (in dollars per share)	$ (2.08)	$ (0.93)	$ 1.42
Diluted (in dollars per share)	$ (2.08)	$ (0.93)	$ 1.37
Weighted average common shares used to compute net income (loss) per share attributable to Xencor, Inc.
Basic (in shares)	60,503,283	59,652,461	58,379,641
Diluted (in shares)	60,503,283	59,652,461	60,495,455

Income Taxes - Reconciliation to effective income tax (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Reconciliation of federal statutory income tax to effective income tax
Federal statutory income tax	$ (25,258)	$ (11,447)	$ 17,352
State and local income taxes	(569)	(615)	783
Research and development credit	(15,821)	(9,366)	(10,492)
Stock-based compensation	3,131	3,384	2,424
Foreign-derived intangible income	(1,188)	(1,449)	0
Other	417	(74)	95
Change in state rate	234	44	2,599
Net change in valuation allowance	44,865	20,196	(12,761)
Income tax provision	$ 5,811	$ 673	$ 0

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Current assets
Cash and cash equivalents	$ 53,790	$ 53,942
Marketable debt securities	497,725	526,689
Marketable equity securities	42,210	42,431
Accounts receivable	11,290	28,997
Prepaid expenses and other current assets	18,145	23,283
Total current assets	623,160	675,342
Property and equipment, net	66,124	59,183
Patents, licenses, and other intangible assets, net	18,663	18,500
Restricted cash	380	0
Marketable debt securities - long term	145,512	3,826
Equity securities	64,210	54,383
Right of use asset	33,995	34,419
Other assets	648	613
Total assets	952,692	846,266
Current liabilities
Accounts payable	13,914	10,088
Accrued expenses	23,564	18,728
Income tax payable	5,782	0
Lease liabilities	3,435	4,708
Deferred revenue	0	30,320
Deferred income	31,682	0
Debt	6,332	0
Total current liabilities	84,709	63,844
Lease liabilities, net of current portion	59,025	54,926
Deferred income, net of current portion	125,183	0
Debt, net of current portion	14,642	0
Total liabilities	283,559	118,770
Commitments and contingencies (see note 9)
Stockholders’ equity
Preferred stock, $0.01 par value: 10,000,000 authorized shares; -0- issued and outstanding shares at December 31, 2023 and 2022	0	0
Common stock, $0.01 par value: 200,000,000 authorized shares; 60,998,191 issued and outstanding shares at December 31, 2023 and 59,997,713 issued and outstanding at December 31, 2022	611	601
Additional paid-in capital	1,131,266	1,072,132
Accumulated other comprehensive income	1,291	(6,952)
Accumulated deficit	(464,372)	(338,285)
Total stockholders’ equity attributable to Xencor, Inc.	668,796	727,496
Non-controlling interest	337	0
Total stockholders' equity	669,133	727,496
Total liabilities and stockholders’ equity	$ 952,692	$ 846,266

Property and Equipment

12 Months Ended

Dec. 31, 2023

Property, Plant and Equipment [Abstract]

Property and Equipment

Property and equipment consist of the following:


	December 31,
	2023		2022
	(in thousands)
Computers, software and equipment	$	49,782	$	45,159
Furniture and fixtures	158		539
Leasehold and tenant improvements	52,410		41,774
Total gross carrying amount	102,350		87,472
Less accumulated depreciation and amortization	(36,226)		(28,289)
Total property and equipment, net	$	66,124	$	59,183

Leasehold and tenant improvements consist primarily of leasehold construction at our new Pasadena headquarters.

Depreciation expense related to property and equipment in 2023, 2022, and 2021 was $10.1 million, $7.4 million, and $6.3 million, respectively.

Pay vs Performance Disclosure - USD ($) $ in Thousands	12 Months Ended
Pay vs Performance Disclosure - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Pay vs Performance Disclosure
Net Income (Loss)	$ (126,087)	$ (55,181)	$ 82,631

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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+ Details

Collaboration and Licensing Agreements - Alexion Pharmaceutical, Inc. (Details) - USD ($) $ in Thousands		12 Months Ended
	Nov. 03, 2023	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Collaboration research and licensing agreements
Accounts receivable		$ 11,290	$ 28,997
Alexion \| Option and license agreement
Collaboration research and licensing agreements
Revenue recognized		58,600	29,400	$ 22,200
Accounts receivable		0
Deferred revenue		0
Alexion \| Royalties \| Option and license agreement
Collaboration research and licensing agreements
Revenue recognized		38,600	$ 29,400	$ 22,200
Proceeds from milestone payments		20,000
Proceeds from upfront payment	$ 192,500
Accounts receivable	$ 29,500
Non-cash revenue recognized		$ 6,200

Cover - USD ($)	12 Months Ended
Cover - USD ($)	Dec. 31, 2023	Feb. 15, 2024	Jun. 30, 2023
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2023
Current Fiscal Year End Date	--12-31
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 Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
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
ICFR Auditor Attestation Flag	true
Document Financial Statement Error Correction [Flag]	false
Entity Shell Company	false
Entity Public Float			$ 1,502,093,347
Entity Common Stock, Shares Outstanding		61,120,272
Documents Incorporated by Reference	Portions of the registrant’s proxy statement to be filed with the Securities and Exchange Commission pursuant to Regulation 14A in connection with the registrant’s 2024 Annual Meeting of Stockholders, which will be filed subsequent to the date hereof, are incorporated by reference into Part III of this Form 10-K. Such proxy statement will be filed with the Securities and Exchange Commission not later than 120 days following the end of the registrant’s fiscal year ended December 31, 2023.
Entity Central Index Key	0001326732
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	FY
Amendment Flag	false

Stock-Based Compensation - Restricted Stock Units (Details) - RSUs - $ / shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Number of Shares
Beginning balance (in shares)	1,232,551	826,148	358,825
Granted (in shares)	994,351	875,330	670,700
Vested (in shares)	(558,066)	(341,073)	(151,555)
Forfeited (in shares)	(178,796)	(127,854)	(51,822)
Ending balance (in shares)	1,490,040	1,232,551	826,148
Weighted- Average Grant Date Fair Value (Per Unit)
Beginning balance (in dollars per share)	$ 32.41	$ 37.79	$ 33.04
Granted (in dollars per share)	30.33	29.45	39.11
Vested (in dollars per share)	33.61	37.37	32.76
Forfeited (in dollars per share)	31.64	33.66	36.68
Ending balance (in dollars per share)	$ 30.66	$ 32.41	$ 37.79

Collaboration and Licensing Agreements - Astria Therapeutics, Inc. (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Collaboration research and licensing agreements
Unrealized (losses) gain recognized on equity securities	$ (395)	$ 23,434	$ 20,988
Astria Common Stock \| Technology License Agreement
Collaboration research and licensing agreements
Impairment charge		100	800
Unrealized (losses) gain recognized on equity securities	(4,300)	$ 6,100	$ 4,500
Deferred revenue	$ 0

Summary of Significant Accounting Policies - Segments (Details)	12 Months Ended
	Dec. 31, 2023 segment
Segment Reporting [Abstract]
Number of operating segments	1

Collaboration and Licensing Agreements - Zenas BioPharma, Inc. (Details) $ in Thousands	1 Months Ended	12 Months Ended
	Nov. 30, 2021 USD ($)	Dec. 31, 2023 USD ($) Agreement	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($) Agreement	Nov. 30, 2022 USD ($)	Nov. 30, 2020 USD ($)
Preferred Stock
Collaboration research and licensing agreements
Equity shares estimated fair value		$ 64,210	$ 54,383
Zenas
Collaboration research and licensing agreements
Increase in estimated fair value of equity securities					$ 17,900
Zenas \| Preferred Stock
Collaboration research and licensing agreements
Equity shares estimated fair value		64,210	54,209
Zenas \| Warrant
Collaboration research and licensing agreements
Equity shares estimated fair value					34,500
Zenas \| Convertible Debt Securities
Collaboration research and licensing agreements
Equity shares estimated fair value					$ 7,700
Zenas \| License Agreement
Collaboration research and licensing agreements
Transaction price	$ 14,900					$ 16,100
Percentage of equity of private company	15.00%
Milestones or royalties in transaction price	$ 0
Revenue recognized		$ 10,000	$ 0	$ 14,900
Number of collaboration and license agreements \| Agreement		2		2
Deferred revenue		$ 0
Zenas \| License Agreement \| Milestone \| Preferred Stock
Collaboration research and licensing agreements
Equity shares estimated fair value		$ 10,000
Zenas \| Second Collaboration And License Agreement
Collaboration research and licensing agreements
Warrants	$ 14,900

Collaboration and Licensing Agreements (Tables)

12 Months Ended

Dec. 31, 2023

Collaboration and Licensing Agreements

Schedule of revenue by licensees


	Year Ended December 31,
	2023		2022		2021
Alexion	58.6		29.4		22.2
Astellas	—		5.0		—
Genentech	—		—		2.5
Gilead	6.0		—		—
Janssen	77.8		7.0		113.8
MorphoSys	8.7		7.8		18.4
Novartis	—		—		43.1
Omeros	5.0		—		—
Vir	2.2		115.4		52.7
Viridian	—		—		7.5
Zenas	10.0		—		14.9
Total	$	168.3	$	164.6	$	275.1

Schedule of disaggregation of revenue

The table below summarizes the disaggregation of revenue recorded for the years ended December 31, 2023, 2022, and 2021 (in millions):


	Year Ended December 31,
	2023		2022		2021
Research collaboration	$	30.3	$	7.0	$	93.0
Milestone	88.5		5.5		21.0
Licensing	—		—		80.8
Royalties	49.5		152.1		80.3
Total	$	168.3	$	164.6	$	275.1

Summary of Significant Accounting Policies - Property and Equipment (Details)	Dec. 31, 2023
Computers, software and equipment \| Minimum
Property and Equipment
Estimated useful lives of the assets	3 years
Computers, software and equipment \| Maximum
Property and Equipment
Estimated useful lives of the assets	5 years
Furniture and fixtures \| Minimum
Property and Equipment
Estimated useful lives of the assets	5 years
Furniture and fixtures \| Maximum
Property and Equipment
Estimated useful lives of the assets	7 years
Leasehold improvements \| Minimum
Property and Equipment
Estimated useful lives of the assets	5 years
Leasehold improvements \| Maximum
Property and Equipment
Estimated useful lives of the assets	7 years

Marketable Debt and Equity Securities - Maturities (Details) $ in Thousands	Dec. 31, 2023 USD ($)
Amortized Cost
Mature in one year or less	$ 497,326
Mature within two years	144,609
Amortized Cost	641,935
Estimated Fair Value
Mature in one year or less	497,725
Mature within two years	145,511
Estimated Fair Value	$ 643,236

Summary of Significant Accounting Policies - Restricted Cash (Details) $ in Millions	Dec. 31, 2023 USD ($)
Accounting Policies [Abstract]
Letter of credit outstanding	$ 0.4

Marketable Debt and Equity Securities - Equity Securities with Readily Determinable Fair Value (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Equity Securities
Equity securities with readily determinable fair value	$ 42,210	$ 42,431
Common Stock
Equity Securities
Equity securities with readily determinable fair value	42,210	42,431
Astria Common Stock \| Common Stock
Equity Securities
Equity securities with readily determinable fair value	5,360	9,529
INmune Common Stock \| Common Stock
Equity Securities
Equity securities with readily determinable fair value	21,231	11,954
Viridian Common Stock \| Common Stock
Equity Securities
Equity securities with readily determinable fair value	$ 15,619	$ 20,948

Stock-Based Compensation - Stock Options Outstanding (Details) - Stock options - $ / shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Aggregate Intrinsic Value (in thousands)
Exercisable options (in shares)	7,761,829	6,679,948	5,576,430
Weighted-average exercise price per share of exercisable options (in dollars per share)	$ 28.79	$ 26.99	$ 24.15
Weighted average grant date fair value per share of options granted during the year (in dollars per share)	$ 15.98	$ 15.45	$ 21.65
Total number of shares of common stock available for issuance (in shares)	6,801,945	3,622,319	3,597,371
Weighted-average remaining contractual life	6 years 10 days	6 years 3 months 18 days	6 years 7 months 24 days	7 years

Commitments and Contingencies	12 Months Ended
Commitments and Contingencies	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies 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. We are obligated to make future payments to third parties under in-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 our balance sheet. We have also entered into agreements with third party vendors which will require us to make future payments upon the delivery of goods and services in future periods. Guarantees In the normal course of business, we indemnify certain employees and other parties, such as collaboration partners and other parties that perform certain work on behalf of, or for the Company or take licenses to our technologies. We have agreed to hold these parties harmless against losses arising from our breach of representations or covenants, intellectual property infringement or other claims made against these parties in performance of their work with us. These agreements typically limit the time within which the party may seek indemnification by us and the amount of the claim. It is not possible to prospectively determine the maximum potential amount of liability under these indemnification agreements since we have not had any prior indemnification claims on which to base the calculation. Further, each potential claim would be based on the unique facts and circumstances of the claim and the particular provisions of each agreement. We are not aware of any potential claims and we did not record a liability as of December 31, 2023 and 2022.

Sales of Future Royalties (Tables)

12 Months Ended

Dec. 31, 2023

Receivables [Abstract]

Debt of Future Royalties

The following table shows the activity within debt for the year ended December 31, 2023 (in thousands):


	December 31, 2023

Beginning balance of debt related to sale of future royalties	$	—
Proceeds from sale of future royalties	20,293
Royalties paid to OMERS	—
Non-cash interest expense recognized	681
Ending balance of debt related to sale of future royalties	$	20,974

Debt - short-term	6,332
Debt - long-term	14,642
Total debt	$	20,974

Income Taxes - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
Income Taxes - Narrative (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Taxes [Line Items]
Income tax expense (benefit)	$ 5,811	$ 673	$ 0
Increase (decrease) in deferred tax asset valuation allowance	43,100
Domestic Tax Authority
Income Taxes [Line Items]
Cumulative net operating loss carryforwards	54,200
Tax credit carryforwards	33,600
State and Local Jurisdiction
Income Taxes [Line Items]
Cumulative net operating loss carryforwards	158,800
Tax credit carryforwards	$ 24,800

- Definition

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

+ References + Details

Collaboration and Licensing Agreements - Revenue Recognition (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Collaboration research and licensing agreements
Revenue recorded	$ 168,338	$ 164,579	$ 275,111
Research collaboration
Collaboration research and licensing agreements
Revenue recorded	30,300	7,000	93,000
Milestone
Collaboration research and licensing agreements
Revenue recorded	88,500	5,500	21,000
Licensing
Collaboration research and licensing agreements
Revenue recorded	0	0	80,800
Royalties
Collaboration research and licensing agreements
Revenue recorded	49,500	152,100	80,300
Alexion
Collaboration research and licensing agreements
Revenue recorded	58,600	29,400	22,200
Astellas
Collaboration research and licensing agreements
Revenue recorded	0	5,000	0
Genentech
Collaboration research and licensing agreements
Revenue recorded	0	0	2,500
Gilead
Collaboration research and licensing agreements
Revenue recorded	6,000	0	0
Janssen
Collaboration research and licensing agreements
Revenue recorded	77,800	7,000	113,800
MorphoSys
Collaboration research and licensing agreements
Revenue recorded	8,700	7,800	18,400
Novartis
Collaboration research and licensing agreements
Revenue recorded	0	0	43,100
Omeros
Collaboration research and licensing agreements
Revenue recorded	5,000	0	0
Vir
Collaboration research and licensing agreements
Revenue recorded	2,200	115,400	52,700
Viridian
Collaboration research and licensing agreements
Revenue recorded	0	0	7,500
Zenas
Collaboration research and licensing agreements
Revenue recorded	$ 10,000	$ 0	$ 14,900

Income Taxes

12 Months Ended

Dec. 31, 2023

Income Tax Disclosure [Abstract]

Income Taxes

Our effective tax rate differs from the statutory federal income tax rate, primarily as a result of the changes in valuation allowance. The provision for current federal income taxes for the years ended December 31, 2023 and 2022 were $5.8 million and $0.7 million, respectively. There was no provision for taxes for the years ended December 31, 2021. There is no state income tax provision for the years ended December 31, 2023, 2022 and 2021, respectively.

A reconciliation of the federal statutory income tax to our effective income tax is as follows (in thousands):


	Year Ended December 31,
	2023		2022		2021
Federal statutory income tax	$	(25,258)	$	(11,447)	$	17,352
State and local income taxes	(569)		(615)		783
Research and development credit	(15,821)		(9,366)		(10,492)
Stock-based compensation	3,131		3,384		2,424
Foreign-derived intangible income	(1,188)		(1,449)		—
Other	417		(74)		95
Change in state rate	234		44		2,599
Net change in valuation allowance	44,865		20,196		(12,761)
Income tax provision	$	5,811	$	673	$	—

The tax effect of temporary differences that give rise to a significant portion of the deferred tax assets and liabilities at December 31, 2023 and 2022 is presented below (in thousands):


	December 31,
	2023		2022
Deferred income tax assets
Net operating loss carryforwards	$	22,466	$	32,898
Research credits	53,198		54,825
Unrealized (gain) loss on securities	(278)		1,573
Capitalized lease assets	6,161		5,564
Accrued compensation	18,172		14,484
Deferred revenue	34,405		3,225
Capitalized research and development costs	45,783		21,338
Gross deferred income tax assets	179,907		133,907
Valuation allowance	(158,099)		(115,010)
Net deferred income tax assets	21,808		18,897
Deferred income tax liabilities
Patent costs	(2,218)		(2,885)
Licensing costs	(136)		(124)
Capitalized legal costs	(6)		(9)
Depreciation	(10,664)		(6,532)
Unrealized gain on securities	(8,784)		(9,347)
Gross deferred income tax liabilities	(21,808)		(18,897)
Net deferred income tax asset	$	—	$	—

The Tax Cuts and Jobs Act of 2017 (TCJA) was enacted in December 2017 and made substantial changes in the U.S. tax system. The significant changes made by the TCJA include a reduction in the maximum corporate income tax rate and the requirement that research and development costs incurred after December 31, 2021 to be capitalized and amortized over several years. We have recorded a deferred asset for each year ended December 31, 2023 and 2022, respectively. for such capitalized research and development costs. We have net deferred tax assets relating primarily to capitalized research and development costs, net operating loss carryforwards and research and development tax credit carryforwards. Due to the uncertainty surrounding the realization of the benefits of our deferred tax assets in future tax periods, we have placed a valuation allowance against our deferred tax assets at December 31, 2023 and 2022. The Company recognizes valuation allowances to reduce deferred tax assets to the amount that is more likely than not to be realized. The Company’s net deferred income tax asset is not more likely than not to be realized due to the lack of sufficient sources of future taxable

income and cumulative losses that have resulted over the years. During the year ended December 31, 2023, the valuation allowance increased by $43.1 million. The Company’s tax years starting in 2019 through 2022 remain open to potential examination by the U.S. and state taxing authorities due to carryforwards of net operating losses and income tax credits.

As of December 31, 2023, we had cumulative net operating loss carryforwards for federal and state income tax purposes of $54.2 million and $158.8 million, respectively, and available tax credit carryforwards of approximately $33.6 million for federal income tax purposes and $24.8 million for state income tax purposes, which can be carried forward to offset future taxable income, if any. All of the federal net operating loss carryforwards were incurred prior to January 1, 2018, which are subject to carryforward limitations. To the extent allowed by law, taxing authorities may examine prior periods where net operating losses were carried forwards and were claimed and offset against current year taxable income, and make adjustments up to the amount of the net operating loss carryforward amount.

Our federal net operating loss carryforwards expire starting in 2027, state net operating loss carryforwards expire starting in 2035, and federal tax credit carryforwards begin to expire in 2034. Utilization of our net operating loss and tax credit carryforwards are subject to a substantial annual limitation under Section 382 of the Code due to the fact that we have experienced ownership changes. As a result of these changes, certain of our net operating loss and tax credit carryforwards may expire before we can use them.

- 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
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(h)(2))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1

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

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 14
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-14

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 21
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-21

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 270
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482526/740-270-50-1

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 17
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-17

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 6.I.5.Q1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479360/740-10-S99-1

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 11.C)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479360/740-10-S99-2

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482603/740-30-50-2

+ Details

Collaboration and Licensing Agreements - Janssen Biotech, Inc., a Johnson & Johnson company (Details) $ / shares in Units, $ in Thousands		1 Months Ended		12 Months Ended
	Oct. 01, 2021 USD ($) d candidate agreement $ / shares shares	Dec. 31, 2021 USD ($)	Nov. 30, 2021 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Nov. 30, 2020 USD ($)
Collaboration research and licensing agreements
Sale of common stock						$ 28,920
Accounts receivable				$ 11,290	$ 28,997
Janssen \| Second Collaboration And License Agreement
Collaboration research and licensing agreements
Transaction price	$ 96,100
Research license term	2 years
Nonrefundable upfront payment	$ 100,000
Revenue Recognition Milestone Method Pending	1,187,500
Sale of common stock	$ 28,900
Share development percentage	80.00%
Percentage of responsibility for development costs	20.00%
Number of candidates for which option to advance for development and commercialization \| candidate	4
Number of drug candidates \| candidate	4
Discount on proceeds from sale	$ 3,900
Janssen \| Second Collaboration And License Agreement \| Development-based
Collaboration research and licensing agreements
Revenue Recognition Milestone Method Pending	289,400
Janssen \| Second Collaboration And License Agreement \| Regulatory-based
Collaboration research and licensing agreements
Revenue Recognition Milestone Method Pending	378,100
Janssen \| Second Collaboration And License Agreement \| Sales-based
Collaboration research and licensing agreements
Revenue Recognition Milestone Method Pending	520,000
Janssen \| Second Collaboration And License Agreement \| Licensing
Collaboration research and licensing agreements
Revenue recognized	58,500		$ 58,500
Standalone selling price	58,500
Janssen \| Second Collaboration And License Agreement \| Research service
Collaboration research and licensing agreements
Revenue recognized				30,300	7,000	300
Standalone selling price	37,600
Performance obligation	$ 37,600		$ 37,600
Proceeds from milestone payments				30,000
Janssen \| Collaboration and License Agreements
Collaboration research and licensing agreements
Revenue recognized				77,800	7,000	113,800
Janssen \| Collaboration and License Agreement
Collaboration research and licensing agreements
Percentage of funding for development costs							20.00%
Percentage of co-detailing activities							30.00%
Transaction price							$ 50,000
Revenue recognized		$ 5,000		17,500	$ 0
Deferred revenue				0
Research license term	2 years
Number of collaboration and license agreements \| agreement	2
Janssen \| Collaboration and License Agreement \| Cost-Sharing Development
Collaboration research and licensing agreements
Accounts receivable				$ 2,900
Janssen \| Collaboration and License Agreement \| Research collaboration
Collaboration research and licensing agreements
Revenue recognized						$ 50,000
Johnson & Johnson Innovation, JJDC, Inc. \| Second Collaboration And License Agreement \| Common Stock
Collaboration research and licensing agreements
Sale of common stock	$ 25,000
Weighted average price (in dollars per share) \| $ / shares	$ 33.4197
Number of trading days \| d	30
Sale of common stock (in shares) \| shares	748,062

Marketable Debt and Equity Securities (Tables)

12 Months Ended

Dec. 31, 2023

Marketable Securities [Abstract]

Schedule of marketable securities

The Company’s marketable debt securities held as of December 31, 2023 and 2022 are summarized below:


	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


	December 31, 2022
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
(in thousands)
Money Market Funds	$	40,967	$	—	$	—	$	40,967
Corporate Securities	201,752		—		(1,126)		200,626
Government Securities	335,705		3		(5,819)		329,889
	$	578,424	$	3	$	(6,945)	$	571,482

Reported as
Cash and cash equivalents							$	40,967
Marketable securities							530,515
Total investments							$	571,482

Schedule of maturities of marketable securities

The maturities of the Company’s marketable debt securities as of December 31, 2023 are as follows:


	Amortized Cost		Estimated Fair Value
(in thousands)
Mature in one year or less	$	497,326	$	497,725
Mature within two years	144,609		145,511
	$	641,935	$	643,236

Debt Securities, Available-for-Sale, Unrealized Loss Position, Fair Value

The unrealized losses on available-for-sale investments and their related fair values as of December 31, 2023 and 2022 are as follows:


	December 31, 2023
	Less than 12 months				12 months or greater
	Fair value		Unrealized losses		Fair value		Unrealized losses
(in thousands)
Corporate Securities	$	8,073	$	(1)	$	—	$	—
Government Securities	66,546		(77)		—		—
	$	74,619	$	(78)	$	—	$	—


	December 31, 2022
	Less than 12 months				12 months or greater
	Fair value		Unrealized losses		Fair value		Unrealized losses
(in thousands)
Corporate Securities	$	132,658	$	(1,121)	$	3,826	$	(5)
Government Securities	324,933		(5,819)		—		—
	$	457,591	$	(6,940)	$	3,826	$	(5)

Schedule of equity securities with readily determinable fair value

Equity securities with a readily determinable fair value and their fair values (in thousands) as of December 31, 2023 and 2022 are as follows:


	Fair Value December 31, 2023		Fair Value December 31, 2022
Astria Common Stock	$	5,360	$	9,529
INmune Common Stock	21,231		11,954
Viridian Common Stock	15,619		20,948
	$	42,210	$	42,431

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 December 31, 2023 and 2022 are as follows:


	Carrying Value December 31, 2023		Carrying Value December 31, 2022
Astria Preferred Stock	$	—	$	174
Zenas Preferred Stock	64,210		54,209
	$	64,210	$	54,383

Schedule of net gains and losses

Unrealized gains and losses recognized on equity securities (in thousands) during the year ended December 31, 2023 and 2022 consist of the following:


	Year Ended December 31,
	2023		2022		2021

Net (losses) gains recognized on equity securities	$	(395)	$	23,434	$	39,289
Less: net gains recognized on equity securities redeemed	—		—		18,301
Unrealized (losses) gain recognized on equity securities	$	(395)	$	23,434	$	20,988

Stock-Based Compensation - Employee Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Total employee, director and non-employee stock-based compensation expense	$ 53,755	$ 48,913	$ 36,975
Stock options
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Total employee, director and non-employee stock-based compensation expense	29,345	29,758	27,909
ESPP
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Total employee, director and non-employee stock-based compensation expense	1,243	1,174	992
RSUs
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Total employee, director and non-employee stock-based compensation expense	23,167	17,981	8,074
General and administrative
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Total employee, director and non-employee stock-based compensation expense	19,239	17,281	12,813
Research and development
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Total employee, director and non-employee stock-based compensation expense	$ 34,516	$ 31,632	$ 24,162

- 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 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 35
-Paragraph 1D
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480483/718-10-35-1D

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 35
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480483/718-10-35-3

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)(3)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(i)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
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+ Details

Summary of Significant Accounting Policies - Concentrations of Risk (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Concentrations of risk
Amounts on deposit in excess of federally insured limits approximately	$ 53.8	$ 53.6
Accounts Payable \| Supplier Concentration Risk \| Two Suppliers
Concentrations of risk
Concentration risk percentage	38.00%	45.00%
Accounts Receivable \| Customer Concentration Risk \| Major Customers
Concentrations of risk
Concentration risk percentage	76.00%	91.00%

Marketable Debt and Equity Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Schedule of Available-for-sale Securities
Money Market Funds in Cash and Cash Equivalents	$ 53,790	$ 53,942
Amortized Cost	641,935
Amortized Cost	667,455	578,424
Gross Unrealized Gains	1,379	3
Gross Unrealized Losses	(77)	(6,945)
Marketable securities	643,236
Total investments	668,757	571,482
Money Market Funds in Cash and Cash Equivalents
Schedule of Available-for-sale Securities
Money Market Funds in Cash and Cash Equivalents	25,520	40,967
Corporate Securities
Schedule of Available-for-sale Securities
Amortized Cost	228,382	201,752
Gross Unrealized Gains	342	0
Gross Unrealized Losses	(1)	(1,126)
Marketable securities	228,723	200,626
Government Securities
Schedule of Available-for-sale Securities
Amortized Cost	413,553	335,705
Gross Unrealized Gains	1,037	3
Gross Unrealized Losses	(76)	(5,819)
Marketable securities	414,514	329,889
Cash and cash equivalents
Schedule of Available-for-sale Securities
Money Market Funds in Cash and Cash Equivalents	25,520	40,967
Marketable securities
Schedule of Available-for-sale Securities
Marketable securities	$ 643,237	$ 530,515

Summary of Significant Accounting Policies - Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Fair Value of Financial Instruments
Money Market Funds in Cash and Cash Equivalents	$ 53,790	$ 53,942
Marketable securities	643,236
Money Market Funds in Cash and Cash Equivalents
Fair Value of Financial Instruments
Money Market Funds in Cash and Cash Equivalents	25,520	40,967
Corporate Securities
Fair Value of Financial Instruments
Marketable securities	228,723	200,626
Government Securities
Fair Value of Financial Instruments
Marketable securities	414,514	329,889
Fair Value, Recurring
Fair Value of Financial Instruments
Total Fair Value	668,757	571,482
Fair Value, Recurring \| Money Market Funds in Cash and Cash Equivalents
Fair Value of Financial Instruments
Money Market Funds in Cash and Cash Equivalents	25,520	40,967
Fair Value, Recurring \| Corporate Securities
Fair Value of Financial Instruments
Marketable securities	228,723	200,626
Fair Value, Recurring \| Government Securities
Fair Value of Financial Instruments
Marketable securities	414,514	329,889
Level 1 \| Fair Value, Recurring
Fair Value of Financial Instruments
Total Fair Value	25,520	40,967
Level 1 \| Fair Value, Recurring \| Money Market Funds in Cash and Cash Equivalents
Fair Value of Financial Instruments
Money Market Funds in Cash and Cash Equivalents	25,520	40,967
Level 1 \| Fair Value, Recurring \| Corporate Securities
Fair Value of Financial Instruments
Marketable securities	0	0
Level 1 \| Fair Value, Recurring \| Government Securities
Fair Value of Financial Instruments
Marketable securities	0	0
Level 2 \| Fair Value, Recurring
Fair Value of Financial Instruments
Total Fair Value	643,237	530,515
Level 2 \| Fair Value, Recurring \| Money Market Funds in Cash and Cash Equivalents
Fair Value of Financial Instruments
Money Market Funds in Cash and Cash Equivalents	0	0
Level 2 \| Fair Value, Recurring \| Corporate Securities
Fair Value of Financial Instruments
Marketable securities	228,723	200,626
Level 2 \| Fair Value, Recurring \| Government Securities
Fair Value of Financial Instruments
Marketable securities	$ 414,514	$ 329,889

Collaboration and Licensing Agreements - Novartis Institute for Biomedical Research, Inc. (Details) $ in Thousands	1 Months Ended	12 Months Ended
	Jun. 30, 2016 target	Dec. 31, 2023 USD ($) program Agreement	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($) Agreement	Dec. 31, 2018 USD ($)
Collaboration research and licensing agreements
Accounts receivable		$ 11,290	$ 28,997
Novartis \| Collaboration and License Agreement
Collaboration research and licensing agreements
Revenue recognized		0	0	$ 43,100
Accounts receivable		0
Deferred revenue		$ 0
Novartis \| Research and License Agreement \| Milestone
Collaboration research and licensing agreements
Revenue recognized			3,000
Zenas \| License Agreement
Collaboration research and licensing agreements
Number of collaboration and license agreements \| Agreement		2		2
Revenue recognized		$ 10,000	$ 0	$ 14,900
Deferred revenue		$ 0
FC Licenses \| Novartis \| Maximum \| Collaboration and License Agreement
Collaboration research and licensing agreements
Number of targets against which non-exclusive license is provided \| target	10
Global Discovery Program \| Novartis \| Collaboration and License Agreement
Collaboration research and licensing agreements
Number of programs delivered \| program		2
Revenue recognized				$ 40,100	$ 40,100

Sales of Future Royalties - Debt of Future Royalties (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($)
Sale of Future Royalty [Roll Forward]
Beginning balance of debt related to sale of future royalties	$ 0
Proceeds from sale of future royalties	20,293
Royalties paid to OMERS	0
Non-cash interest expense recognized	681
Ending balance of debt related to sale of future royalties	20,974
Debt - short-term	6,332
Debt - long-term	14,642
Total debt	$ 20,974

Leases - Lease Costs (Details) - USD ($) $ in Thousands	12 Months Ended
Leases - Lease Costs (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Leases [Abstract]
Operating lease cost	$ 8,459	$ 6,588	$ 4,342
Variable lease cost	906	506	58
Total lease costs	9,365	7,094	4,400
Cash paid for amounts included in the measurement of lease liabilities	$ 3,253	$ 2,869	$ 2,773
Weighted-average remaining lease term	11 years	12 years	12 years 3 months 18 days
Weighted-average discount rate	8.90%	8.90%	5.80%

Sale of Additional Common Stock	12 Months Ended
Sale of Additional Common Stock	Dec. 31, 2023
Equity [Abstract]
Sale of Additional Common Stock	Sale of Additional Common Stock Under the terms of the Stock Purchase Agreement (defined below), Johnson & Johnson Innovation, JJDC, Inc. (JJDC), purchased $25.0 million of newly issued unregistered shares of the Company’s common stock, priced at a 30-day volume-weighted average price of $33.4197 per share as of October 1, 2021. The Company issued 748,062 shares of common stock to JJDC on November 12, 2021. The issued shares are subject to customary resale restrictions pursuant to Rule 144 of the Securities Act of 1933.

401(k) Plan	12 Months Ended
401(k) Plan	Dec. 31, 2023
Retirement Benefits [Abstract]
401(k) Plan	401(k) Plan We have a 401(k) plan covering all full-time employees. Employees may make pre-tax contributions up to the maximum allowable by the Internal Revenue Code. Effective March 31, 2020, the Company contributes 100% of the first 1% of participating employees’ contribution and 50% of the next 6% of participating employees’ contribution, for a maximum of 4.0% of employer contribution. Participants are immediately vested in their employee contributions; employer contributions are vested over a three-year period with one-third for each year of a participating employee’s service. Employer contributions made for the years ended December 31, 2023, 2022, and 2021 were $1.7 million, $1.4 million, and $1.1 million, respectively.

- Definition

The entire disclosure for retirement benefits.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
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-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480794/715-70-50-1

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 715
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-Name Accounting Standards Codification
-Section 55
-Paragraph 17
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
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-Name Accounting Standards Codification
-Section 50
-Paragraph 1
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-URI https://asc.fasb.org//1943274/2147480506/715-20-50-1

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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-Publisher FASB
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
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-URI https://asc.fasb.org//715/tableOfContent

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
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-Name Accounting Standards Codification
-Section 50
-Paragraph 1
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-URI https://asc.fasb.org//1943274/2147480506/715-20-50-1

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
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-Section 50
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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
-Topic 715
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-Name Accounting Standards Codification
-Section 50
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Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
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Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480126/715-20-S99-2

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 60
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480266/715-60-50-3

+ Details

Insider Trading Arrangements	3 Months Ended
Insider Trading Arrangements	Dec. 31, 2023
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Collaboration and Licensing Agreements - INmune Bio, Inc. (Details) - USD ($) $ in Thousands	1 Months Ended		12 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Collaboration research and licensing agreements
Realized gain on investment			$ 0	$ 0	$ 18,301
Unrealized (losses) gain recognized on equity securities			(395)	23,434	20,988
Net gain (loss) recognized on equity securities			(395)	23,434	39,289
INmune Common Stock \| License Agreement
Collaboration research and licensing agreements
Consideration on sale of option		$ 18,300
Cash consideration on sale of option		15,000
Realized gain on investment		18,300			18,300
Unrealized (losses) gain recognized on equity securities			9,300	(7,300)	15,100
INmune Common Stock \| License Agreement \| Common Stock
Collaboration research and licensing agreements
Cash consideration on sale of option		$ 15,000
Unrealized (losses) gain recognized on equity securities					2,000
Purchase amount of share options or equity in noncash transaction					800
Gain on fair value of option					1,100
Net gain (loss) recognized on equity securities	$ 900
INmune Common Stock \| License Agreement \| Other Income
Collaboration research and licensing agreements
Unrealized (losses) gain recognized on equity securities					27,800
INmune Common Stock \| License Agreement \| Other Income \| Common Stock
Collaboration research and licensing agreements
Net gain (loss) recognized on equity securities					900
INmune Common Stock \| Licensing Agreements
Collaboration research and licensing agreements
Revenue recognized			$ 0	$ 0	$ 0

Collaboration and Licensing Agreements - Viridian Therapeutics, Inc. (Details) - Viridian - Technology License Agreement $ in Millions	1 Months Ended		12 Months Ended
	Dec. 31, 2021 USD ($) candidate	Dec. 31, 2020 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Collaboration research and licensing agreements
Purchase amount of share options or equity in noncash transaction	$ 7.5	$ 6.0
Research license term	1 year
Number of antibodies \| candidate	3
Revenue recognized			$ 0.0	$ 0.0	$ 7.5
Deferred revenue			$ 0.0
Development-based
Collaboration research and licensing agreements
Potential milestone payment	$ 1.8				1.8
Regulatory-based
Collaboration research and licensing agreements
Potential milestone payment	3.0				3.0
Sales-based
Collaboration research and licensing agreements
Potential milestone payment	20.0				20.0
Maximum
Collaboration research and licensing agreements
Potential milestone payment	24.8				24.8
Xtend Fc Technology
Collaboration research and licensing agreements
Transaction price		$ 6.0
Antibody Libraries
Collaboration research and licensing agreements
Transaction price	$ 7.5				$ 7.5

Summary of Significant Accounting Policies - Net Income (Loss) Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Numerator:
Net income (loss) attributable to Xencor, Inc.	$ (126,087)	$ (55,181)	$ 82,631
Denominator:
Weighted-average common shares outstanding, basic (in shares)	60,503,283	59,652,461	58,379,641
Net income (loss) per common share, basic (in dollars per share)	$ (2.08)	$ (0.93)	$ 1.42
Numerator:
Net income (loss) attributable to Xencor, Inc.	$ (126,087)	$ (55,181)	$ 82,631
Denominator:
Weighted-average common shares outstanding, basic (in shares)	60,503,283	59,652,461	58,379,641
Dilutive effect of employee stock options and ESPP (in shares)	0	0	2,115,814
Weighted-average common shares outstanding, diluted (in shares)	60,503,283	59,652,461	60,495,455
Net income (loss) per common share, diluted (in dollars per share)	$ (2.08)	$ (0.93)	$ 1.37
Securities excluded in calculation of EPS (in shares)		1,196,268

Comprehensive Income (Loss)	12 Months Ended
Comprehensive Income (Loss)	Dec. 31, 2023
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 the years ended December 31, 2023, 2022, and 2021, 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 loss during the year ended December 31, 2023.

Sale of Additional Common Stock (Details) $ / shares in Units, $ in Thousands		12 Months Ended
	Oct. 01, 2021 USD ($) d $ / shares shares	Dec. 31, 2021 USD ($) shares
Investment Company, Change in Net Assets [Line Items]
Proceeds from sale of common stock		$ 28,920
Second Collaboration And License Agreement \| Common Stock \| Johnson & Johnson Innovation, JJDC, Inc.
Investment Company, Change in Net Assets [Line Items]
Proceeds from sale of common stock	$ 25,000
Number of trading days \| d	30
Weighted average price (in dollars per share) \| $ / shares	$ 33.4197
Total equity shares (in shares) \| shares	748,062
Common Stock
Investment Company, Change in Net Assets [Line Items]
Proceeds from sale of common stock		$ 7
Total equity shares (in shares) \| shares		748,062

- 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 + Details

- Definition

Equity impact of the value of new stock issued during the period. Includes shares issued in an initial public offering or a secondary public offering.

+ References + Details

Summary of Significant Accounting Policies - Accounts Receivable (Details)	12 Months Ended
	Dec. 31, 2023
Minimum
Accounts Receivable Collection Period [Line Items]
Collection period	30 days
Maximum
Accounts Receivable Collection Period [Line Items]
Collection period	60 days

Stock-Based Compensation - Stock Option Activity (Details) - Stock options - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Number of Shares
Balance at the beginning of the period (in shares)	10,082,642	8,676,329	7,751,789
Options granted (in shares)	2,080,732	2,135,233	1,827,234
Options forfeited (in shares)	(676,005)	(533,435)	(382,454)
Options exercised (in shares)	(344,383)	(195,485)	(520,240)
Balance at the end of the period (in shares)	11,142,986	10,082,642	8,676,329	7,751,789
Options vested and expected to vest (in shares)	11,142,986
Exercisable (in shares)	7,761,829	6,679,948	5,576,430
Weighted-Average Exercise Price (Per Share)
Balance at the beginning of the period (in dollars per share)	$ 29.12	$ 29.11	$ 26.23
Options granted (in dollars per share)	30.02	29.45	41.22
Options forfeited (in dollars per share)	33.19	34.09	36.15
Options exercised (in dollars per share)	9.91	18.46	23.61
Balance at the end of the period (in dollars per share)	29.60	29.12	29.11	$ 26.23
Options vested and expected to vest (in dollars per share)	29.60
Exercisable (in dollars per share)	$ 28.79	$ 26.99	$ 24.15
Aggregate Intrinsic Value (in thousands)
Weighted-average remaining contractual term, balance outstanding	6 years 10 days	6 years 3 months 18 days	6 years 7 months 24 days	7 years
Weighted-average remaining contractual term, options vested and expected to vest	6 years 10 days
Weighted-average remaining contractual term, exercisable	4 years 10 months 24 days
Aggregate intrinsic value, balance outstanding	$ 9,977	$ 27,141	$ 100,057	$ 134,941
Aggregate intrinsic value, options vested and expected to vest	9,977
Aggregate intrinsic value, exercisable	9,907
Intrinsic value of options exercised	$ 4,800	$ 1,600	$ 9,200

Sales of Future Royalties

12 Months Ended

Dec. 31, 2023

Receivables [Abstract]

Sales of Future Royalties

Sale of Future Royalties

Ultomiris Royalty Sale Agreement

On November 3, 2023, the Company and OMERS entered into the Ultomiris Royalty Sale Agreement. Pursuant to the Ultomiris Royalty Sale Agreement, OMERS acquired the rights to a portion of royalties and milestones earned after July 1, 2023 associated with the existing license relating to Ultomiris® (ravulizumab) in exchange for an upfront payment of $192.5 million.

Pursuant to the Ultomiris Royalty Sale Agreement and subject to the Company’s existing license with Alexion, OMERS has acquired the right to receive: (i) 100% of royalties payable on past and potential sales related to Ultomiris® that occur from July 1, 2023 through December 31, 2025; (ii) up to $35.0 million annually in royalties on potential sales

related to Ultomiris® that occur from January 1, 2026 through December 31, 2028 with any royalties in excess of $35.0 million reverting to the Company; (iii) up to $12.0 million annually in royalties on potential sales related to Ultomiris® that occur from and after January 1, 2029, with any royalties in excess of $12.0 million reverting to the Company; and (iv) $18.0 million of a certain potential sales based milestone payment pursuant to the existing license with Alexion. OMERS will pay an additional $12.0 million in 2024 to the Company if certain potential sales based milestones have been reached.

The Company determined that $29.5 million of the upfront payment is for a recorded receivable for royalties and a milestone earned in the third quarter of 2023 and $163.0 million is for the sale of future royalties. 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 had been met in accordance with ASC 470. The Company records the non-cash royalty revenue under the “units-of-revenue” method in the consolidated statements of income (loss). For the year ended December 31, 2023, the Company recognized $6.2 million of non-cash royalty revenue.

Monjuvi Royalty Sale Agreement

On November 3, 2023, the Company and OMERS entered into the Monjuvi Royalty Sale Agreement. Pursuant to the Monjuvi Royalty Sale Agreement, OMERS acquired the rights to a portion of royalties earned after July 1, 2023 associated with the existing license relating to Monjuvi®/Minjuvi® (tafasitamab-cxix) in exchange for an upfront payment of $22.5 million.

Pursuant to the Monjuvi Royalty Sale Agreement and subject to the Company’s existing license with MorphoSys, OMERS has acquired the right to receive up to $29.3 million in royalties earned after July 1, 2023 related to sales of Monjuvi®/Minjuvi®, with any royalties in excess of $29.3 million paid to OMERS reverting to the Company.

The Company determined that $2.2 million of the upfront payment is for a recorded receivable for royalties earned in the third quarter of 2023 and $20.3 million is from the sale of future royalties. 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. As of December 31, 2023, the estimated effective rate under the agreement was 21.1%. The Company will 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 year ended December 31, 2023, the Company recognized $2.1 million of non-cash royalty revenue and $0.7 million of non-cash interest expense.

The following table shows the activity within debt for the year ended December 31, 2023 (in thousands):


	December 31, 2023

Beginning balance of debt related to sale of future royalties	$	—
Proceeds from sale of future royalties	20,293
Royalties paid to OMERS	—
Non-cash interest expense recognized	681
Ending balance of debt related to sale of future royalties	$	20,974

Debt - short-term	6,332
Debt - long-term	14,642
Total debt	$	20,974

Summary of Significant Accounting Policies - Deferred Revenue (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Accounting Policies [Abstract]
Deferred revenue	$ 0	$ 30,320