0001558370-21-010268 | 10-Q | XBRL Viewer

Document and Entity Information - shares	6 Months Ended
Document and Entity Information - shares	Jun. 30, 2021	Jul. 28, 2021
Document and Entity Information
Document Type	10-Q
Document Quarterly Report	true
Document Transition Report	false
Document Period End Date	Jun. 30, 2021
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	111 West Lemon Avenue
Entity Address, City or Town	Monrovia
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	91016
City Area Code	626
Local Phone Number	305-5900
Title of 12(b) Security	Common Stock, par value $0.01 per share
Trading Symbol	XNCR
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		58,323,914
Entity Central Index Key	0001326732
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q2

Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Current assets
Cash and cash equivalents	$ 115,842	$ 163,544
Marketable securities	288,976	434,156
Equity securities	45,230	5,303
Accounts receivable	14,825	11,443
Contract asset	500	12,500
Prepaid expenses and other current assets	15,594	10,726
Total current assets	480,967	637,672
Property and equipment, net	23,132	21,682
Patents, licenses, and other intangible assets, net	16,384	15,977
Marketable securities - long term	153,619	1,030
Equity securities - long term	17,146	16,071
Other assets	4,354	10,812
Total assets	695,602	703,244
Current liabilities
Accounts payable	7,112	8,954
Accrued expenses	17,328	17,603
Lease liabilities	2,322	1,889
Deferred revenue	19,200	92,615
Total current liabilities	45,962	121,061
Lease liabilities, net of current portion	2,702	9,739
Total liabilities	48,664	130,800
Commitments and contingencies
Stockholders' equity
Preferred stock, $0.01 par value: 10,000,000 authorized shares; -0- issued and outstanding shares at June 30, 2021 and December 31, 2020
Common stock, $0.01 par value: 200,000,000 authorized shares at June 30, 2021 and December 31, 2020; 58,315,485 issued and outstanding at June 30, 2021 and 57,873,444 issued and outstanding at December 31, 2020	584	580
Additional paid-in capital	962,343	937,525
Accumulated other comprehensive income (loss)	(15)	74
Accumulated deficit	(315,974)	(365,735)
Total stockholders' equity	646,938	572,444
Total liabilities and stockholders' equity	$ 695,602	$ 703,244

Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Revenue
Collaborations, licenses, milestones, and royalties	$ 67,447	$ 13,089	$ 101,412	$ 45,474
Operating expenses
Research and development	49,497	43,458	90,908	77,401
General and administrative	8,863	7,231	17,090	14,449
Total operating expenses	58,360	50,689	107,998	91,850
Income (loss) from operations	9,087	(37,600)	(6,586)	(46,376)
Other income (expenses)
Interest income, net	147	2,090	362	5,129
Other income (expense), net	(6)	134	(17)	133
Gain (loss) on equity securities, net	43,020	358	56,002	(1,978)
Total other income, net	43,161	2,582	56,347	3,284
Net income (loss)	52,248	(35,018)	49,761	(43,092)
Other comprehensive income (loss)
Net unrealized gain (loss) on marketable securities available-for-sale	(112)	427	(90)	322
Comprehensive income (loss)	$ 52,136	$ (34,591)	$ 49,671	$ (42,770)
Net income (loss) per share attributable to common stockholders:
Basic net income (loss) (in dollars per share)	$ 0.90	$ (0.61)	$ 0.86	$ (0.76)
Diluted net income (loss) (in dollars per share)	$ 0.87	$ (0.61)	$ 0.82	$ (0.76)
Weighted average shares used to compute net income (loss) per share attributable to common stockholders:
Basic (in shares)	58,247,941	57,059,610	58,123,319	57,003,162
Diluted (in shares)	60,335,339	57,059,610	60,503,846	57,003,162

Statements of Stockholders' Equity - USD ($) $ in Thousands	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit	Total
Balance at Dec. 31, 2019	$ 569	$ 887,873	$ 1,161	$ (296,402)	$ 593,201
Balance (in shares) at Dec. 31, 2019	56,902,301
Increase (Decrease) in Stockholders' Equity
Issuance of common stock upon exercise of stock awards	$ 1	1,470			1,471
Issuance of common stock upon exercise of stock awards (in shares)	79,930
Issuance of restricted stock units (in shares)	19,022
Comprehensive income (loss)			(105)	(8,074)	(8,179)
Stock-based compensation		6,512			6,512
Balance at Mar. 31, 2020	$ 570	895,855	1,056	(304,476)	593,005
Balance (in shares) at Mar. 31, 2020	57,001,253
Balance at Dec. 31, 2019	$ 569	887,873	1,161	(296,402)	593,201
Balance (in shares) at Dec. 31, 2019	56,902,301
Increase (Decrease) in Stockholders' Equity
Comprehensive income (loss)					(42,770)
Balance at Jun. 30, 2020	$ 572	908,084	1,483	(339,494)	570,645
Balance (in shares) at Jun. 30, 2020	57,214,253
Balance at Mar. 31, 2020	$ 570	895,855	1,056	(304,476)	593,005
Balance (in shares) at Mar. 31, 2020	57,001,253
Increase (Decrease) in Stockholders' Equity
Issuance of common stock upon exercise of stock awards	$ 2	3,273			3,275
Issuance of common stock upon exercise of stock awards (in shares)	181,856
Issuance of restricted stock units (in shares)	2,800
Issuance of common stock under the Employee Stock Purchase Plan		725			725
Issuance of common stock under the Employee Stock Purchase Plan (in shares)	28,344
Comprehensive income (loss)			427	(35,018)	(34,591)
Stock-based compensation		8,231			8,231
Balance at Jun. 30, 2020	$ 572	908,084	1,483	(339,494)	570,645
Balance (in shares) at Jun. 30, 2020	57,214,253
Balance at Dec. 31, 2020	$ 580	937,525	74	(365,735)	572,444
Balance (in shares) at Dec. 31, 2020	57,873,444
Increase (Decrease) in Stockholders' Equity
Issuance of common stock upon exercise of stock awards	$ 2	5,337			5,339
Issuance of common stock upon exercise of stock awards (in shares)	230,701
Issuance of restricted stock units	$ 1	(1)
Issuance of restricted stock units (in shares)	117,808
Comprehensive income (loss)			23	(2,487)	(2,464)
Stock-based compensation		8,293			8,293
Balance at Mar. 31, 2021	$ 583	951,154	97	(368,222)	583,612
Balance (in shares) at Mar. 31, 2021	58,221,953
Balance at Dec. 31, 2020	$ 580	937,525	74	(365,735)	572,444
Balance (in shares) at Dec. 31, 2020	57,873,444
Increase (Decrease) in Stockholders' Equity
Comprehensive income (loss)					49,671
Balance at Jun. 30, 2021	$ 584	962,343	(15)	(315,974)	646,938
Balance (in shares) at Jun. 30, 2021	58,315,485
Balance at Mar. 31, 2021	$ 583	951,154	97	(368,222)	583,612
Balance (in shares) at Mar. 31, 2021	58,221,953
Increase (Decrease) in Stockholders' Equity
Issuance of common stock upon exercise of stock awards	$ 1	902			903
Issuance of common stock upon exercise of stock awards (in shares)	52,790
Issuance of restricted stock units (in shares)	10,190
Issuance of common stock under the Employee Stock Purchase Plan		937			937
Issuance of common stock under the Employee Stock Purchase Plan (in shares)	30,552
Comprehensive income (loss)			(112)	52,248	52,136
Stock-based compensation		9,350			9,350
Balance at Jun. 30, 2021	$ 584	$ 962,343	$ (15)	$ (315,974)	$ 646,938
Balance (in shares) at Jun. 30, 2021	58,315,485

Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
Statements of Cash Flows - USD ($) $ in Thousands	Jun. 30, 2021	Jun. 30, 2020
Cash flows from operating activities
Net income (loss)	$ 49,761	$ (43,092)
Adjustments to reconcile net income (loss) to net cash used in operating activities:
Depreciation and amortization	3,391	2,816
Amortization of premium (accretion of discount) on marketable securities	1,711	(838)
Stock-based compensation	17,643	14,743
Abandonment of capitalized intangible assets	310	167
Equity received in connection with license agreement		(4,589)
Equity received in connection with sale of financial assets	(3,300)
Change in fair value of equity securities	(37,701)	1,978
Gain (loss) on equity securities, net	56,002	(1,978)
(Gain) loss on disposal of assets	(4)	5
Gain on sale of marketable securities available for sale		(153)
Changes in operating assets and liabilities:
Accounts receivable	(3,382)	12,649
Interest receivable	496	914
Contract asset and deposits	11,938
Prepaid expenses and other current assets	(4,868)	(843)
Accounts payable	(1,842)	324
Accrued expenses	(275)	162
Income taxes		91
Lease liabilities and right of use (ROU) assets	(83)	(110)
Deferred revenue	(73,415)	(2,446)
Net cash used in operating activities	(39,620)	(18,222)
Cash flows from investing activities
Purchase of marketable securities	(231,459)	(302,319)
Proceeds from sale of property and equipment	4
Purchase of intangible assets	(1,324)	(1,467)
Purchase of property and equipment	(4,234)	(2,695)
Proceeds from maturities and sale of marketable securities	221,752	378,454
Net cash (used in) provided by investing activities	(15,261)	71,973
Cash flows from financing activities
Proceeds from issuance of common stock upon exercise of stock awards	6,242	4,746
Proceeds from issuance of common stock from Employee Stock Purchase Plan	937	725
Net cash provided by financing activities	7,179	5,471
Net (decrease) increase in cash and cash equivalents	(47,702)	59,222
Cash and cash equivalents, beginning of year	163,544	50,312
Cash and cash equivalents, end of year	115,842	109,534
Cash paid during the period for:
Interest	9	11
Supplemental disclosures of non-cash investing activities
Unrealized gain (loss) on marketable securities	$ (90)	$ 322

Summary of Significant Accounting Policies

6 Months Ended

Jun. 30, 2021

Summary of Significant Accounting Policies

Summary of Significant Accounting Policies

1. Summary of Significant Accounting Policies

Basis of Presentation

The accompanying unaudited interim financial statements for Xencor, Inc. (the Company, Xencor, we or us) have been prepared in accordance with U.S. generally accepted accounting principles (GAAP) for interim financial information. The financial statements include all adjustments (consisting only of normal recurring adjustments) that the management of the Company believes are necessary for a fair presentation of the periods presented. The preparation of interim financial statements requires the use of management’s estimates and assumptions that affect reported amounts of assets and liabilities at the date of the interim financial statements and the reported revenues and expenditures during the reported periods. These interim financial results are not necessarily indicative of the results expected for the full fiscal year or for any subsequent interim period.

The accompanying unaudited interim financial statements and related notes should be read in conjunction with the audited financial statements and notes thereto included in the Company’s 2020 Annual Report on Form 10-K filed with the Securities and Exchange Commission (SEC) on February 24, 2021.

Use of Estimates

The preparation of interim financial statements in conformity with GAAP requires management to make certain estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses, other comprehensive gain (loss) and the related disclosures. On an ongoing basis, management evaluates its estimates, including estimates related to its accrued clinical trial and manufacturing development expenses, stock-based compensation expense, intangible assets, and related amortization. Significant estimates in these interim financial statements include estimates: made for royalty revenue, accrued research and development expenses, stock-based compensation expenses, intangible assets and related amortization, 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.

Intangible Assets

The Company maintains definite-lived intangible assets related to certain capitalized costs of acquired licenses and third-party costs incurred in establishing and maintaining its intellectual property rights to its platform technologies and development candidates. These assets are amortized over their useful lives, which are estimated to be the remaining patent life or the contractual term of the license. The straight-line method is used to record amortization expense. The Company assesses its intangible assets for impairment if indicators are present or changes in circumstances suggest that impairment may exist. There were no impairment charges recorded for the three and six months ended June 30, 2021 and 2020.

The Company capitalizes certain in-process intangible assets that are then abandoned when they are no longer pursued or used in current research activities. There was no material abandonment of in-process intangible assets during the three and six months ended June 30, 2021 and 2020.

Marketable 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 because it is not more likely than not that the Company will be required to sell the securities before recovery of the amortized cost. These assets are carried at fair value and any impairment losses and recoveries related to the underlying issuer’s credit standing are recognized within other income (expense), while non-credit related impairment losses and recoveries are recognized within accumulated other comprehensive income (loss). There were no impairment losses or recoveries recorded for the three and six months ended June 30, 2021 and 2020. Accrued interest on marketable debt securities is included in the marketable securities’ carrying value. Each reporting period, the Company reviews its portfolio of marketable debt securities, using both quantitative and qualitative factors, to determine if each security’s fair value has declined below its amortized cost basis.

The Company receives equity securities in connection with certain licensing transactions with its partners. These investments in equity securities are carried at fair value with changes in fair value recognized each period and reported within other income (expense). For equity securities with a readily determinable fair value, the Company re-measures these equity investments at each reporting period until such time that the investment is sold or disposed. If the Company sells an investment, any realized gain or loss on the sale of the securities will be recognized within other income (expense) in the Statements of Comprehensive Income (Loss) in the period of sale.

The Company also has investments in equity securities without readily determinable fair values, where the Company elects the measurement alternative to record at its initial cost minus impairment, plus or minus changes resulting from observable price changes in orderly transactions for the identical or a similar investment of the same issuer.

Recent Accounting Pronouncements

Pronouncements Adopted in 2021

Effective January 1, 2021, the Company adopted ASU No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes, which removes specific exceptions to the general principles in Topic 740 and simplifies the accounting for income taxes. The adoption of this standard did not have a significant impact on the Company’s financial statements.

Effective January 1, 2021, the Company adopted ASU No. 2020-01, which clarifies that a company should consider observable transactions that require a company to either apply or discontinue the equity method of accounting under Topic 323, Investment – Equity Method and Joint Ventures, for the purposes of applying the measurement alternative in accordance with Topic 321, Investments – Equity Securities immediately before applying or upon discontinuing the equity method. The adoption of this standard did not have a significant impact on the Company’s financial statements.

Effective January 1, 2021, the Company adopted ASU No. 2020-10, Codification Improvements, which amends a variety of topics in the Accounting Standards Codification to improve consistency and clarify guidance. The adoption of this standard did not have a significant impact on the Company’s financial statements.

There have been no other material changes to the significant accounting policies previously disclosed in the Company’s 2020 Annual Report on Form 10-K.

Fair Value of Financial Instruments

6 Months Ended

Jun. 30, 2021

Fair Value of Financial Instruments

Fair Value of Financial Instruments

2. Fair Value of Financial Instruments

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

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

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

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

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

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


	June 30, 2021
	(unaudited)								December 31, 2020
	Total								Total
	Fair Value		Level 1		Level 2		Level 3		Fair Value		Level 1		Level 2		Level 3
Available-for-Sale Debt Securities:
Money Market Funds	$	71,703	$	71,703	$	—	$	—	$	158,937	$	158,937	$	—	$	—
Corporate Securities		104,957		—		104,957		—		119,833		—		119,833		—
Government Securities		337,638		—		337,638		—		315,353		—		315,353		—
Equity Securities:
Securities with Readily Determinable Fair Value		45,230		45,230		—		—		5,303		5,303		—		—
Securities without Readily Determinable Fair Value		17,146		—		—		17,146		16,071		—		—		16,071
	$	576,674	$	116,933	$	442,595	$	17,146	$	615,497	$	164,240	$	435,186	$	16,071

Our policy is to record transfers of assets between Level 1 and Level 2 at their fair values as of the end of each reporting period, consistent with the date of the determination of fair value. During the three and six months ended June 30, 2021 and 2020, there were no transfers between Level 1 and Level 2. During the three and six months ended June 30, 2021, an equity investment without a readily determinable fair value was transferred to Level 1 from Level 3.

The following table provides a rollforward for recurring Level 3 fair value measurements (in thousands):


	Securities without Readily Determinable Fair Value
Balance at December 31, 2020	$	16,071
Issuance		12,148
Transfer out of Level 3		(11,073)
Balance at June 30, 2021	$	17,146

The Company held equity securities without readily determinable fair value at June 30, 2021 and December 31, 2020, respectively. The Company elects the measurement alternative to record at its initial cost minus impairment, plus or minus changes resulting from observable price changes in orderly transactions for the identical or a similar investment of the same issuer.

- Definition

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

+ References + Details

Net Income (Loss) Per Common Share

6 Months Ended

Jun. 30, 2021

Net Income (Loss) Per Common Share

Net Income (Loss) Per Common Share

3. Net Income (Loss) Per Common Share

Basic net income (loss) per common share is computed by dividing the net income (loss) attributable to common stockholders by the weighted-average number of common shares outstanding during the period without consideration of common stock equivalents. Diluted net income (loss) per common share is computed by dividing the net income (loss) attributable to common stockholders 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 is computed as follows:


	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2021		2020		2021		2020

	(in thousands, except share and per share data)
Numerator:
Net income (loss) attributable to common stockholders	$	52,248	$	(35,018)	$	49,761	$	(43,092)
Denominator:
Weighted-average common shares outstanding used in computing basic net income (loss)		58,247,941		57,059,610		58,123,319		57,003,162
Effect of dilutive securities		2,087,398		—		2,380,527		—
Weighted-average common shares outstanding used in computing diluted net income (loss)		60,335,339		57,059,610		60,503,846		57,003,162
Basic net income (loss) per common share	$	0.90	$	(0.61)	$	0.86	$	(0.76)
Diluted net income (loss) per common share	$	0.87	$	(0.61)	$	0.82	$	(0.76)

For the three and six months ended June 30, 2021, we excluded 1,374,608 and 698,917 shares of stock issuable pursuant to outstanding options and RSUs from the calculation, respectively, because the inclusion of such shares would have had an antidilutive effect. For the three and six months ended June 30, 2020, all outstanding potentially dilutive securities have been excluded from the calculation of diluted net income (loss) per common share as the effect of including such securities would have been anti-dilutive.

Marketable Securities

6 Months Ended

Jun. 30, 2021

Marketable Securities

Marketable Securities

5. Marketable and Equity Securities

The Company’s marketable debt securities held as of June 30, 2021 and December 31, 2020 are summarized below:


			Gross		Gross
	Amortized		Unrealized		Unrealized
June 30, 2021	Cost		Gains		Losses		Fair Value
(in thousands)
Money Market Funds	$	71,703	$	—	$	—	$	71,703
Corporate Securities		104,975		13		(31)		104,957
Government Securities		337,625		36		(23)		337,638
	$	514,303	$	49	$	(54)	$	514,298

Reported as
Cash and cash equivalents							$	71,703
Marketable securities								442,595
Total investments							$	514,298



			Gross		Gross
	Amortized		Unrealized		Unrealized
December 31, 2020	Cost		Gains		Losses		Fair Value
(in thousands)
Money Market Funds	$	158,937	$	—	$	—	$	158,937
Corporate Securities		119,782		57		(6)		119,833
Government Securities		315,319		37		(3)		315,353
	$	594,038	$	94	$	(9)	$	594,123

Reported as
Cash and cash equivalents							$	158,937
Marketable securities								435,186
Total investments							$	594,123

The maturities of the Company’s marketable debt securities as of June 30, 2021 are as follows:


	Amortized		Estimated
June 30, 2021	Cost		Fair Value
(in thousands)
Mature in one year or less	$	288,935	$	288,976
Mature within two years		153,665		153,619
	$	442,600	$	442,595

The unrealized losses on available-for-sale investments and their related fair values as of June 30, 2021 and December 31, 2020 are as follows:


	Less than 12 months				12 months or greater
			Unrealized				Unrealized
June 30, 2021	Fair value		losses		Fair value		losses
(in thousands)
Corporate Securities	$	11,721	$	(4)	$	24,876	$	(27)
Government Securities		—		—		84,888		(23)
	$	11,721	$	(4)	$	109,764	$	(50)



	Less than 12 months				12 months or greater
			Unrealized				Unrealized
December 31, 2020	Fair value		losses		Fair value		losses
(in thousands)
Corporate Securities	$	15,843	$	(6)	$	—	$	—
Government Securities		40,802		(3)		—		—
	$	56,645	$	(9)	$	—	$	—

The unrealized losses from the listed securities are primarily 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 June 30, 2021 and December 31, 2020 are as follows:


	Fair Value		Fair Value
	June 30, 2021		December 31, 2020
Catabasis Common Stock	$	8,102	$	—
INmune Common Stock		31,231		—
Viridian Common Stock		5,897		5,303
	$	45,230	$	5,303

The Company also has investments in equity securities without a readily determinable fair value. The Company elects the measurement alternative to record these investments at their initial cost and evaluate such investments at each reporting period for evidence of impairment. Equity securities without a readily determinable fair value and their carrying values (in thousands) as of June 30, 2021 and December 31, 2020 are as follows:


	Carrying Value		Carrying Value
	June 30, 2021		December 31, 2020
Catabasis Preferred Stock	$	1,075	$	—
Zenas Preferred Stock		16,071		16,071
	$	17,146	$	16,071

In 2018, the Company received equity shares in Quellis Biosciences, Inc. (Quellis), in connection with a licensing transaction. The Company recorded the Quellis equity as securities not having a readily determinable fair value, and the investment was recorded at its original cost. In 2021, Quellis merged into Catabasis Pharmaceuticals, Inc. (Catabasis), and the Company received 259,206 shares of common stock and 3,928 shares of preferred stock in Catabasis in exchange for its Quellis equity. During the three months ended June 30, 2021, 3,581 shares of the Catabasis preferred stock were exchanged for 3,580,539 shares of Catabasis common stock. The 3,839,745 shares of the Catabasis common stock have a readily determinable fair value. The adjustment in the fair value of the Catabasis common stock has been recorded in gain (loss) on equity securities for the three and six months ended June 30, 2021.

The Company records its investment in the shares of Catabasis preferred stock as an equity interest without a readily determinable fair value. The Company elected to record the shares of preferred stock at their initial cost and reviews the carrying value for impairment or other changes in carrying value at each reporting period.

In 2017, the Company received 1,585,000 shares of common stock of INmune Bio, Inc. and an option to acquire an additional 10% of INmune’s outstanding shares of common stock in connection with a licensing transaction. The Company initially recorded its equity interest, including its option to acquire additional equity in INmune, at cost pursuant to ASC 323, Investments – Equity Method and Joint Ventures. In June 2021, the Company entered into an Option Cancellation Agreement with INmune and received an additional 192,533 shares of INmune common stock. During the period ended June 30, 2021, the Company determined that it should no longer account for its investment in INmune under the equity method. The 1,777,533 shares of INmune common stock have a readily determinable fair value and the adjustment in the fair value of the shares of INmune common stock has been recorded in gain (loss) on equity securities for the three and six months ended June 30, 2021.

In 2020, the Company received 322,407 shares of common stock of Viridian in connection with the Viridian Agreement (defined below). The shares of Viridian common stock are classified as equity securities with a readily determinable fair value at June 30, 2021.

In 2020, the Company received an equity interest in Zenas BioPharma 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 the identical or a similar investment of the same issuer. During the three and six months ended June 30, 2021, there has not been any impairment or observable price changes related to this investment.

Net gains and losses recognized on equity securities during the three and six months ended June 30, 2021 and 2020 consist of the following:


	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2021		2020		2021		2020
Net gains (losses) recognized on equity securities	$	43,020	$	358	$	56,002	$	(1,978)
Less: net gains recognized on sale of equity securities		(18,300)		—		(18,301)		—
Unrealized gains (losses) recognized on equity securities	$	24,720	$	358	$	37,701	$	(1,978)

Stock-Based Compensation

6 Months Ended

Jun. 30, 2021

Stock-Based Compensation

Stock-Based Compensation

6. Stock Based Compensation

Our Board of Directors (the Board) and the requisite stockholders previously approved the 2010 Equity Incentive Plan (the 2010 Plan). In October 2013, the Board approved the 2013 Equity Incentive Plan (the 2013 Plan), and in November 2013, our stockholders approved the 2013 Plan, which became effective as of December 3, 2013. As of December 2, 2013, we suspended the 2010 Plan, and no additional awards may be granted under the 2010 Plan. Any shares of common stock covered by awards granted under the 2010 Plan that terminate after December 2, 2013 by expiration, forfeiture, cancellation, or other means without the issuance of such shares will be added to the 2013 Plan reserve.

As of June 30, 2021, the total number of shares of common stock available for issuance under the 2013 Plan is 13,382,544, which includes 2,684,456 shares of common stock that were available for issuance under the 2010 Plan as of the effective date of the 2013 Plan. Unless otherwise determined by the Board, beginning January 1, 2014, and continuing until the expiration of the 2013 Plan, the total number of shares of common stock available for issuance under the 2013 Plan will automatically increase annually on January 1 of each year by 4% of the total number of issued and outstanding shares of common stock as of December 31 of the immediately preceding year. Pursuant to approval by the Board, the total number of shares of common stock available for issuance under the 2013 Plan was increased by 2,314,937 shares on January 1, 2021. As of June 30, 2021, a total of 12,061,415 options have been granted under the 2013 Plan.

In November 2013, the Board and our stockholders approved the ESPP, which became effective as of December 5, 2013. We have reserved a total of 581,286 shares of common stock for issuance under the ESPP. Unless otherwise determined by the Board, beginning on January 1, 2014, and continuing until the expiration of the ESPP, the total number of 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, there was no increase in the number of authorized shares in the ESPP from 2015 to 2020. As of June 30, 2021, we have issued a total of 498,147 shares of common stock under the ESPP.

During the six months ended June 30, 2021, the Company awarded 266,726 RSUs to certain employees. The standard vesting of these awards is generally in three equal annual installments and is contingent on continued service to the Company. The fair value of these awards is determined based on the intrinsic value of the stock on the date of grant and will be recognized as stock-based compensation expense over the requisite service period. As of June 30, 2021, we have granted a total of 720,513 shares of common stock issuable upon the vesting of RSUs.

Total employee, director and non-employee stock-based compensation expense recognized for the three and six months ended June 30, 2021 and 2020 are as follows (in thousands):


	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2021		2020		2021		2020
General and administrative	$	3,193	$	2,804	$	5,930	$	5,095
Research and development		6,157		5,427		11,713		9,648
	$	9,350	$	8,231	$	17,643	$	14,743

	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2021		2020		2021		2020
Stock options	$	7,355	$	6,667	$	13,885	$	12,549
ESPP		253		213		501		407
RSUs		1,742		1,351		3,257		1,787
	$	9,350	$	8,231	$	17,643	$	14,743

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


		Weighted		Weighted
		Average		Average
	Number of	Exercise		Remaining		Aggregate
	Shares Subject	Price		Contractual		Intrinsic
	to Outstanding	(Per		Term		Value
	Options	Share)		(in years)		(in thousands)
Balance at December 31, 2020	7,751,789	$	26.23		7.00	$	134,941
Options granted	1,488,576	$	42.73
Options forfeited	(197,440)	$	35.34
Options exercised	(283,491)	$	22.02
Balance at June 30, 2021	8,759,434	$	28.97		6.94	$	65,388
Exercisable	5,265,826	$	23.37		5.68	$	61,080

We calculate the intrinsic value as the difference between the exercise price of the options and the closing price of common stock of $34.49 per share as of June 30, 2021.

The weighted-average fair value of options granted during the six-month periods ended June 30, 2021 and 2020 were $22.54 and $16.44 per share, respectively. There were 1,433,699 options granted during the six-month period ended June 30, 2020. We estimated the fair value of each stock option using the Black-Scholes option-pricing model based on the date of grant of such stock option with the following weighted average assumptions for the three and six months ended June 30, 2021 and 2020:


	Options				Options
	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2021		2020		2021		2020
Expected term (years)	6.2		5.7		6.2		6.2
Expected volatility	55.3	%	56.1	%	55.6	%	54.3	%
Risk-free interest rate	1.03	%	0.41	%	1.02	%	0.84	%
Expected dividend yield	—	%	—	%	—	%	—	%


	ESPP				ESPP
	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2021		2020		2021		2020
Expected term (years)	0.5 - 2.0		0.5 - 2.0		0.5 - 2.0		0.5 - 2.0
Expected volatility	46.1 - 66.4	%	50.8 - 62.6	%	46.1 - 66.4	%	50.8 - 62.6	%
Risk-free interest rate	0.04 - 1.65	%	0.18 - 1.65	%	0.04 - 1.65	%	0.18 - 1.65	%
Expected dividend yield	—	%	—	%	—	%	—	%

As of June 30, 2021, the unamortized compensation expense related to unvested stock options was $65.0 million. The remaining unamortized compensation expense will be recognized over the next 2.8 years. As of June 30, 2021, the unamortized compensation expense under our ESPP was $0.5 million. The remaining unamortized expense will be recognized over the next 0.4 years.

The following table summarizes the RSU activity for the six-month period ended June 30, 2021:


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

Unvested RSUs at December 31, 2020	358,825	$	33.04
Granted	266,726		42.85
Vested	(127,998)		31.71
Forfeited	(28,086)		36.16
Unvested RSUs at June 30, 2021	469,467	$	38.79

As of June 30, 2021, the unamortized compensation expense related to unvested RSUs was $15.7 million. The remaining unamortized expense will be recognized over the next 2.3 years.

Leases

6 Months Ended

Jun. 30, 2021

Leases

Leases

7. Leases

The Company leases office and laboratory space in Monrovia, California under a lease that expires in December 2025 with an option to renew for an additional five years at then market rates. In July 2017, under a separate lease agreement, the Company entered into a lease for additional space in the same building with a lease that continues through September 2022, also with an option to renew for an additional five years. The Company has assessed that it is unlikely to exercise either of the lease term extension options.

The Company leases additional office space in San Diego, California through August 2022, with an option to extend for an additional five years. The Company has assessed that it is unlikely to exercise the option to extend the lease term.

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

In June 2021, the Company entered into an Agreement of Lease (465 Halstead), (the “Halstead Lease”) relating to 129,543 rentable square feet, for laboratory and office space, in Pasadena, California, where the Company intends to move its corporate headquarters in the second half of 2022. The term of the Halstead Lease will become effective in two phases. The first phase commences on July 1, 2022 and encompasses 83,083 square feet while the second phase commences no later than September 30, 2026 and encompasses an additional 46,460 square feet. The term of the Halstead Lease is 13 years from July 1, 2022. The Company received delivery of the premise on July 1, 2021 and is scheduled to complete construction of office, laboratory, and related improvements in the second half of 2022. The Halstead Lease provides the Company with improvement allowances of up to $17,032,015 and $3,252,000 in connection with the Phase 1 and Phase 2 building improvements, respectively. The initial base monthly rent is $386,335.95, 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 as August 1, 2021 and amends other provisions of the Halstead Lease to reflect the new start date of the lease.

In June 2021, the Company entered into an 18-month lease for a 7,020-square-foot office space in Monrovia, California. The lease begins on August 1, 2021 and the initial base monthly rent is $15,000. The Company received delivery of the premises on July 19, 2021.

The following table reconciles the undiscounted cash flows for the operating leases at June 30, 2021 to the operating lease liabilities recorded on the balance sheet (in thousands):


Years ending December 31,
For the remainder of 2021	$	1,117
2022		2,093
2023		707
2024		729
2025		688
Total undiscounted lease payments		5,334
Less: Imputed interest		(310)
Present value of lease payments	$	5,024

Lease liabilities - short-term	$	2,322
Lease liabilities - long-term		2,702
Total lease liabilities	$	5,024

The following table summarizes lease costs and cash payments for the three and six months ended June 30, 2021 and 2020 (in thousands):


	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2021		2020		2021		2020

Operating lease cost	$	614	$	648	$	1,228	$	1,297
Variable lease cost		18		38		28		59
Total lease costs	$	632	$	686	$	1,256	$	1,356

Cash paid for amounts included in
the measurement of lease liabilities	$	548	$	566	$	1,047	$	1,123

As of June 30, 2021, the weighted-average remaining lease term for operating leases is 3.1 years, and the weighted-average discount rate for operating leases is 4.0%

Collaboration and Licensing Agreements

6 Months Ended

Jun. 30, 2021

Collaboration and Licensing Agreements

Collaboration and Licensing Agreements

9. Collaboration and Licensing Agreements

The following is a summary description of the material revenue arrangements, including arrangements that generated revenue in the three and six months ended June 30, 2021 and 2020.

Aimmune Therapeutics, Inc.

On February 4, 2020, the Company entered into a License, Development and Commercialization Agreement (the Aimmune Agreement) with Aimmune pursuant to which the Company granted Aimmune an exclusive worldwide license to XmAb7195, which was renamed AIMab7195. The Company received an upfront payment of $5.0 million and 156,238 shares of Aimmune common stock with an aggregate value of $4.6 million on the closing date. Under the Aimmune Agreement, the Company is also eligible to receive up to $385.0 million in milestones, which includes $22.0 million in development milestones, $53.0 million in regulatory milestones and $310.0 million in sales milestones, and tiered royalties on net sales of approved products from high-single to mid-teen percentage range.

No revenue was recognized in the three and six months ended June 30, 2021, or the three months ended June 30, 2020. The Company recognized $9.6 million of revenue related to the agreement for the six months ended June 30, 2020. There is no deferred revenue as of June 30, 2021 related to this agreement.

Alexion Pharmaceuticals, Inc.

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

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

At December 31, 2020, the Company recorded a contract asset of $10.0 million related to a contractual sales milestone; the Company received payment for this milestone during the three-month period ended March 31, 2021.

Under ASC 606, Revenue from Contracts with Customers (ASC 606), the Company recognizes revenue for sales-based royalties upon the subsequent sale of the product. The Company recognized $5.2 million and $3.8 million of royalty revenue under this arrangement for the three months ended June 30, 2021 and 2020, respectively. The Company recognized $10.5 million and $7.2 million of revenue for the six months ended June 30, 2021 and 2020, respectively. As of June 30, 2021, there is a receivable of $10.2 million related to royalties due under the arrangement. There is no deferred revenue related to this agreement.

Amgen Inc.

In September 2015, the Company entered into a research and license agreement (the Amgen Agreement) with Amgen Inc. (Amgen) to develop and commercialize bispecific antibody product candidates using the Company’s proprietary XmAb bispecific Fc technology. Under the Amgen Agreement, the Company granted an exclusive license to Amgen to the rights to our CD38 x CD3 preclinical program and developed AMG 424. Amgen also applied our bispecific Fc technology to create AMG 509, a STEAP1 x CD3 XmAb 2+1 bispecific antibody.

In May 2020, Amgen notified the Company that it was terminating its rights with respect to the AMG 424 program, (now XmAb968). Under the terms of the Amgen Agreement, the rights to the AMG 424 program reverted to the Company in connection with the termination. Pursuant to the termination agreement, the Company entered into a supply agreement with Amgen pursuant to which Amgen will provide drug product of AMG 424 to the Company to enable it to conduct additional studies of XmAb968.

There is an obligation of $0.9 million due to Amgen in connection with the drug supply agreement. No revenue was recognized under the Amgen Agreement during the three and six months ended June 30, 2021 or 2020. As of June 30, 2021, there is no deferred revenue related to the arrangement.

Astellas Pharma Inc.

Effective March 29, 2019, the Company entered into a Research and License Agreement (the Astellas Agreement) with Astellas Pharma Inc. (Astellas).

Pursuant to the Astellas Agreement, the Company applied its bispecific Fc technology to research antibodies provided by Astellas to generate bispecific antibody candidates and returned the candidates to Astellas for further development and commercialization. Pursuant to the Astellas Agreement, the Company received an upfront payment of $15.0 million and is eligible to receive up to $240.0 million in milestones, which include $32.5 million in development milestones, $57.5 million in regulatory milestones and $150.0 million in sales milestones.

The Company recognized the $13.6 million allocated to the bispecific antibodies when it satisfied its performance obligation and transferred the bispecific antibodies to Astellas in June 2019. The $1.4 million allocated to the research activities was recognized as the research services were completed. The Company completed the remaining activities under the research plan during the second quarter of 2020.

At December 31, 2020, the Company recorded a contract asset of $2.5 million related to a development milestone; the Company received payment for this milestone in the three-month period ended March 31, 2021.

The Company did not recognize revenue related to the arrangement for the three and six months ended June 30, 2021. The Company recognized $0.7 million and $0.9 million revenue for the three and six months ended June 30, 2020, respectively. There is no deferred revenue as of June 30, 2021 related to the arrangement.

Catabasis Pharmaceuticals, Inc. / Quellis Biosciences, 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 to apply to an identified antibody. Quellis is responsible for all development and commercialization activities. The Company received an equity interest in Quellis and is eligible to receive up to $66.0 million in milestones, which include $6.0 million in development milestones, $30.0 million in regulatory milestones and $30.0 million in sales milestones. In addition, the Company is eligible to receive royalties in the mid-single digit percentage range on net sales of approved products.

In January 2021, Quellis merged into Catabasis, and the Company received common stock and preferred stock of Catabasis stock 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 Catabasis was converted to common stock, which was recorded at its fair value as of June 30, 2021. The remaining Catabasis preferred stock is carried at its original cost and is reviewed for impairment or other changes at each reporting period. The Company recognized a decrease in the fair value of its Catabasis common stock, which was recorded as unrealized loss for the three months ended June 30, 2021.

The Company recognized unrealized loss of $3.7 million and unrealized gain of $9.2 million related to its equity interest in Catabasis for the three and six months ended June 30, 2021. There is no deferred revenue as of June 30, 2021 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 (also named RG6323), the Company’s IL-15/IL-15Ra candidate.

Pursuant to the Genentech Agreement, XmAb306 is designated as a development program and all costs incurred for developing XmAb306 from March 8, 2019, the effective date of the Genentech Agreement, are being shared with Genentech under the initial cost-sharing percentage of 45%. In October 2020, a second candidate, a targeted IL-15 candidate, was designated as a development candidate, and all development costs incurred from the date of designation are being shared with Genentech under the initial cost-sharing percentage of 45%.

Pursuant to the Genentech Agreement, the Company and Genentech conducted joint research activities for a two-year period to identify and discover additional IL-15 candidates developed from the Company’s cytokine and bispecific technologies. The two-year research term expired in March 2021. The Company is eligible for clinical milestone payments for new Collaboration Products identified from the research efforts.

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. A total of $8.3 million of the transaction price was allocated to the research activities and is being recognized over a period of time through the end of the research term that services are rendered. 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.

For the three months ended June 30, 2021 and 2020, the Company recognized $2.3 million and $0.8 million of revenue, respectively. For the six months ended June 30, 2021, and 2020, the Company recognized $2.5 million and $1.5 million of revenue, respectively from the Genentech Agreement. As of June 30, 2021, there is a $2.3 million payable related to cost-sharing development activities during the second quarter of 2021 for the XmAb306 and the targeted IL-15 programs. There is no deferred revenue as of June 30, 2021, as the obligation to perform research activities has expired.

Gilead Sciences, Inc.

In January 2020, the Company entered into a Technology License Agreement (the Gilead Agreement) with Gilead Sciences, Inc. (Gilead), pursuant to which the Company provided 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. The Company retains the right to grant licenses for other antibodies directed to the target, subject to the Company’s approval. Gilead is responsible for all development and commercialization activities for all target candidates. The Company received an upfront payment of $6.0 million and is eligible to receive up to $67.0 million in milestones, which includes $10.0 million in development milestones, $27.0 million in regulatory milestones and $30.0 million in 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 did not recognize any revenue related to the Gilead Agreement for the three and six months ended June 30, 2021. The Company recognized $7.5 million and $13.5 million of revenue related to the Gilead Agreement for the three and six months ended June 30, 2020, respectively. There is no deferred revenue as of June 30, 2021 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 1,585,000 shares of INmune common stock and an option to acquire additional shares of INmune.

The option had a six-year term from the date of the INmune Agreement and provided the Company the option to purchase up to 10% of the fully diluted outstanding shares of INmune common stock for $10.0 million. 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 Amended INmune Agreement modified certain diligence provisions in the INmune Agreement with no change in total consideration or performance obligations. The Option Agreement provided for the sale of the option to INmune for a total consideration of $18.3 million which includes $15.0 million in cash and $3.3 million in additional shares of INmune common stock, which represented an additional 192,533 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 investment of 192,533 shares of INmune common stock according to ASC 321, Investments – Equity Securities (ASC 321). For the three and six months ended June 30, 2021, the Company recorded $27.9 million of unrealized gain and $18.3 million of realized gain related to its investment in INmune.

During the period ended June 30, 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 for the three and six months ended June 30, 2021.

At the inception of the INmune agreement in 2017, INmune was a related party as a result of the Company's significant influence with respect to its investment in INmune, as determined under ASC 323. The Company did not have any amounts due to or from INmune at June 30, 2021 or December 31, 2020. At June 30, 2021, the Company determined that it no longer has a significant influence in INmune and INmune is no longer a related party.

Janssen Biotech, Inc.

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

Under the Janssen Agreement, the Company will conduct research activities and apply its bispecific Fc technology to antibodies targeting prostate cancer provided by Janssen. 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. Janssen will assume full responsibility for development and commercialization of the CD28 bispecific antibody candidate. Pursuant to the Janssen Agreement, the Company received an upfront payment of $50.0 million and is eligible to receive up to $662.5 million in milestones which includes $161.9 million in development milestones, $240.6 million in regulatory milestones and $260.0 million in 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.

The Company evaluated the Janssen Agreement under ASC 606 and identified the performance obligation under the Agreement to be delivery of CD28 bispecific antibodies to Janssen from the research activities outlined in the research plan. The Company determined that the license to the bispecific antibodies is not a separate performance obligation because it is not capable of being distinct; the license to the antibodies cannot be separated from the underlying antibodies.

The Company determined that the transaction price of the Janssen Agreement at inception was $50.0 million consisting of the upfront payment. 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 candidate selection option payment is substantive and is a separate performance obligation. 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 the single performance obligation, delivery of CD28 bispecific antibodies to Janssen.

The Company is recognizing the $50.0 million transaction price as it satisfies its performance obligation to deliver CD28 bispecific antibodies to Janssen. The Company is using the expected input method, which considers an estimate of the Company’s efforts to complete the research activities outlined in the Janssen Agreement.

The Company recognized $16.2 million and $30.8 million of revenue under this arrangement for the three and six months ended June 30, 2021, and there is $19.2 million in deferred revenue as of June 30, 2021 related to our obligation to complete research activities and deliver CD28 bispecific antibodies under the Janssen Agreement.

MorphoSys AG

In June 2010, the Company entered into a Collaboration and License Agreement with MorphoSys AG (MorphoSys), which was subsequently amended. Under the agreement, we granted MorphoSys an exclusive worldwide license to the Company’s patents and know-how to research, develop and commercialize the XmAb5574 product candidate (subsequently renamed MOR208 and tafasitamab) with the right to sublicense under certain conditions. If certain developmental, regulatory and sales milestones are achieved, the Company is eligible to receive future milestone payments and royalties.

In February 2020, the U.S. Food and Drug Administration (FDA) accepted MorphoSys’ Biologics License Application (BLA) for tafasitamab and the Company received a milestone payment of $12.5 million. The Company recognized the payment as revenue in the period that the milestone event occurred.

On July 31, 2020, the FDA granted accelerated approval to MorphoSys’ BLA for tafasitamab (now Monjuvi®) for marketing in the United States. In connection with the approval, the Company received a milestone payment of $25.0 million.

During the three months ended March 31, 2021, MorphoSys reported to us its plans to initiate additional clinical studies of Monjuvi, and the Company recorded a contract asset of $12.5 million as an adjustment to the total transaction price. In April 2021, MorphoSys and Incyte Corporation (Incyte) announced the dosing of the first patient in one of their planned Phase 3 clinical studies and the contract asset was recorded as a receivable. The Company received payment for this receivable in the three months ended June 30, 2021.

The Company is eligible to receive royalties in the high-single to low-double digit percentage range on approved sales of Monjuvi. Under ASC 606, the Company recognizes revenue for sales-based royalties upon the subsequent sale of the product. The Company recorded royalties for Monjuvi based on an estimate of sales to be reported by MorphoSys for the three and six months ended June 30, 2021.

The Company recognized $1.2 million and $2.6 million of royalty revenue during the three and six months ended June 30, 2021, respectively. The Company also recognized $12.5 million of milestone revenue under this arrangement for each of the six months ended June 30, 2021 and June 30, 2020. As of June 30, 2021, there is a receivable of $1.5 million related to estimated royalties due under the arrangement. As of June 30, 2021, there is no deferred revenue related to this agreement.

Novartis Institute for Biomedical Research, Inc.

In June 2016, the Company entered into a Collaboration and License Agreement (the 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 and Novartis are co-developing vibecotamab worldwide and sharing development costs;

●

the Company will apply its bispecific technology in up to four target pair antibodies identified by Novartis (each a Global Discovery Program) during the research term; 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 during the research term.

We completed delivery of separate Global Discovery Programs in 2017 and in 2018. The research term expired in June 2021 without delivery of additional Global Discovery Programs.

In June 2021, Novartis selected an Fc candidate and received a non-exclusive license to the Company’s Fc technology under the Novartis Agreement. 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 three and six months ended June 30, 2021, Novartis advanced the Fc candidate into investigational new drug (IND) - enabling studies and the Company recognized a milestone of $1.0 million.

The Company recognized $40.1 million of revenue during the three and six months ended June 30, 2021, as a result of the expiration of the research term under the Novartis Agreement. The Company also recognized $1.0 million of milestone revenue during the three and six months ended June 30, 2021. No revenue was recognized during the three and six months ended June 30, 2020. As of June 30, 2021, there is a receivable of $1.0 million related to milestones revenue and $0.8 million related to cost-sharing of development activities for the second quarter of 2021 for the vibecotamab program. There is no deferred revenue as of June 30, 2021 as the research term to deliver additional Global Discovery Programs to Novartis under the arrangement has expired.

Vir Biotechnology, Inc.

In the third quarter of 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 two novel antibodies Vir is investigating 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 antibodies, and the Company is eligible to receive royalties on the net sales of approved products in the mid-single digit percentage range. In May 2021, the FDA granted emergency use authorization (EUA) to Vir’s COVID-19 antibody, sotrovimab (VIR-7831), for the treatment of mild-to-moderate COVID-19 in high-risk adults and patients.

In February 2021, the Company entered into the Vir Amendment No. 1 to the Vir Agreement and the Vir Amendment No. 1 to the Second Vir Agreement (collectively, the Vir Amendments), in each case, pursuant to which the Company provided a non-exclusive license to additional Fc technology for the targets previously identified in the Vir Agreement and the Second Vir Agreement, respectively. If Vir incorporates additional Fc technologies in the identified targets, the Company is eligible to receive additional royalties on net sales of approved products from low to mid-single digit range.

The Company determined that the Second Vir Agreement and the Vir Amendments were modifications of the original Vir Agreement, and that the transfer of the license occurred at inception of the Vir Agreement. The total consideration under the arrangement did not change with the Second Vir Agreement or the Amendments as the Company will potentially receive additional royalty revenue which is variable consideration and is not included in the transaction price.

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.

The Company recognized $0.9 million of royalty revenue and $0.5 million of milestone revenue for the three and six months ended June 30, 2021. The Company recognized $0.3 million of milestone revenue for the three and six months ended June 30, 2020. There is no deferred revenue as of June 30, 2021 related to this agreement.

Viridian Therapeutics, Inc.

In December 2020, the Company entered into a Technology License Agreement (Viridian Agreement) with Viridian Therapeutics, Inc. (Viridian, formerly MiRagen Therapeutics, Inc.), pursuant to which the Company provided Viridian a non-exclusive license to its Xtend Fc technology and an exclusive license to apply its Xtend Fc technology to antibodies targeting IGF-1R. Viridian is responsible for all development and commercialization activities. The Company received an upfront payment of 322,407 shares of Viridian common stock valued at $6.0 million and is eligible to receive up to $55.0 million in milestones, which includes $10.0 million in development milestones, $20.0 million in regulatory milestones and $25.0 million in sales milestones. If commercialized, the Company is eligible to receive royalties on net sales in the mid-single digit percentage range.

The Company recognized revenue of $6.0 million from the Viridian Agreement in 2020, which includes the upfront payment of 322,407 shares of Viridian common stock at their fair value at the date of the Viridian Agreement. At inception of the Viridian Agreement, these shares were recorded at their fair value and are adjusted to their fair value at the end of each reporting period. The Company reported unrealized gain in other income of $0.5 million and $0.6 million for the three and six months ended June 30, 2021 related to the Viridian shares.

The Company did not recognize revenue for the three and six months ended June 30, 2021, and there is no deferred revenue as of June 30, 2021 related to this agreement.

Zenas BioPharma Limited

In November 2020, the Company entered into a License Agreement (the Zenas Agreement) with 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. Under the Zenas Agreement, Zenas will be responsible for all further development and commercialization activities for the drug candidates. The Company received a 15% equity interest 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.

The total transaction price is $16.1 million, which includes the upfront payment of 15% of the equity of Zenas at its fair value using the measurement alternative under ASC 321 as of the date of the Zenas Agreement. The Company recorded licensing revenue of $16.1 million for the Zenas Agreement for the three months ended December 31, 2020. The equity in Zenas is recorded at the fair value as of the date of the Zenas Agreement and is reviewed each reporting period for impairment or other evidence of change in value. The Company did not record an impairment or change in the value of the Zenas equity at June 30, 2021.

The Company did not recognize any revenue related to the Zenas Agreement for the three and six months ended June 30, 2021. There is no deferred revenue as of June 30, 2021 related to this agreement.

Revenue earned

The revenues recorded for the three and six months ended June 30, 2021 and 2020 were earned principally from the following licensees (in millions):


	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2021		2020		2021		2020

Aimmune	$	—	$	—	$	—	$	9.6
Alexion		5.2		3.8		10.5		7.2
Astellas		—		0.7		—		0.9
Genentech		2.3		0.8		2.5		1.5
Gilead		—		7.5		—		13.5
Janssen		16.2		—		30.8		—
MorphoSys		1.2		—		15.1		12.5
Novartis		41.1		—		41.1		—
Vir		1.4		0.3		1.4		0.3
Total	$	67.4	$	13.1	$	101.4	$	45.5

The table below summarizes the disaggregation of revenue recorded for the three and six months ended June 30, 2021 and 2020 (in millions):


	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2021		2020		2021		2020

Research collaboration	$	58.6	$	1.5	$	73.4	$	2.4
Milestone		1.5		0.3		14.0		12.8
Licensing		—		7.5		—		23.1
Royalties		7.3		3.8		14.0		7.2
Total	$	67.4	$	13.1	$	101.4	$	45.5

Remaining Performance Obligations and Deferred Revenue

The Company’s remaining performance obligation as of June 30, 2021 is conducting research activities pursuant to research plans under the Janssen Agreement. The Company completed its performance obligations for research activities pursuant to the Astellas Agreement in the second quarter of 2020. The Company’s obligation to perform research services for Genentech and to deliver additional Global Discovery Programs under the Novartis Agreement ended upon expiration of the respective research terms for each agreement in the second quarter of 2021. As of June 30, 2021 and 2020, the Company has deferred revenue of $19.2 million and $44.7 million, respectively. All deferred revenue as of June 30, 2021 is classified as current liabilities as the Company’s obligations to perform services are due on demand when requested by Janssen under the Janssen Agreement.

Summary of Significant Accounting Policies (Polices)	6 Months Ended
Summary of Significant Accounting Policies (Polices)	Jun. 30, 2021
Summary of Significant Accounting Policies
Basis of Presentation	Basis of Presentation The accompanying unaudited interim financial statements for Xencor, Inc. (the Company, Xencor, we or us) have been prepared in accordance with U.S. generally accepted accounting principles (GAAP) for interim financial information. The financial statements include all adjustments (consisting only of normal recurring adjustments) that the management of the Company believes are necessary for a fair presentation of the periods presented. The preparation of interim financial statements requires the use of management’s estimates and assumptions that affect reported amounts of assets and liabilities at the date of the interim financial statements and the reported revenues and expenditures during the reported periods. These interim financial results are not necessarily indicative of the results expected for the full fiscal year or for any subsequent interim period. The accompanying unaudited interim financial statements and related notes should be read in conjunction with the audited financial statements and notes thereto included in the Company’s 2020 Annual Report on Form 10-K filed with the Securities and Exchange Commission (SEC) on February 24, 2021.
Use of Estimates	Use of Estimates The preparation of interim financial statements in conformity with GAAP requires management to make certain estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses, other comprehensive gain (loss) and the related disclosures. On an ongoing basis, management evaluates its estimates, including estimates related to its accrued clinical trial and manufacturing development expenses, stock-based compensation expense, intangible assets, and related amortization. Significant estimates in these interim financial statements include estimates: made for royalty revenue, accrued research and development expenses, stock-based compensation expenses, intangible assets and related amortization, 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.
Intangible Assets	Intangible Assets The Company maintains definite-lived intangible assets related to certain capitalized costs of acquired licenses and third-party costs incurred in establishing and maintaining its intellectual property rights to its platform technologies and development candidates. These assets are amortized over their useful lives, which are estimated to be the remaining patent life or the contractual term of the license. The straight-line method is used to record amortization expense. The Company assesses its intangible assets for impairment if indicators are present or changes in circumstances suggest that impairment may exist. There were no impairment charges recorded for the three and six months ended June 30, 2021 and 2020. The Company capitalizes certain in-process intangible assets that are then abandoned when they are no longer pursued or used in current research activities. There was no material abandonment of in-process intangible assets during the three and six months ended June 30, 2021 and 2020.
Marketable and Equity Securities	Marketable 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 because it is not more likely than not that the Company will be required to sell the securities before recovery of the amortized cost. These assets are carried at fair value and any impairment losses and recoveries related to the underlying issuer’s credit standing are recognized within other income (expense), while non-credit related impairment losses and recoveries are recognized within accumulated other comprehensive income (loss). There were no impairment losses or recoveries recorded for the three and six months ended June 30, 2021 and 2020. Accrued interest on marketable debt securities is included in the marketable securities’ carrying value. Each reporting period, the Company reviews its portfolio of marketable debt securities, using both quantitative and qualitative factors, to determine if each security’s fair value has declined below its amortized cost basis. The Company receives equity securities in connection with certain licensing transactions with its partners. These investments in equity securities are carried at fair value with changes in fair value recognized each period and reported within other income (expense). For equity securities with a readily determinable fair value, the Company re-measures these equity investments at each reporting period until such time that the investment is sold or disposed. If the Company sells an investment, any realized gain or loss on the sale of the securities will be recognized within other income (expense) in the Statements of Comprehensive Income (Loss) in the period of sale. The Company also has investments in equity securities without readily determinable fair values, where the Company elects the measurement alternative to record at its initial cost minus impairment, plus or minus changes resulting from observable price changes in orderly transactions for the identical or a similar investment of the same issuer.
Recent Accounting Pronouncements	Recent Accounting Pronouncements Pronouncements Adopted in 2021 Effective January 1, 2021, the Company adopted ASU No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes, which removes specific exceptions to the general principles in Topic 740 and simplifies the accounting for income taxes. The adoption of this standard did not have a significant impact on the Company’s financial statements. Effective January 1, 2021, the Company adopted ASU No. 2020-01, which clarifies that a company should consider observable transactions that require a company to either apply or discontinue the equity method of accounting under Topic 323, Investment – Equity Method and Joint Ventures, for the purposes of applying the measurement alternative in accordance with Topic 321, Investments – Equity Securities immediately before applying or upon discontinuing the equity method. The adoption of this standard did not have a significant impact on the Company’s financial statements. Effective January 1, 2021, the Company adopted ASU No. 2020-10, Codification Improvements, which amends a variety of topics in the Accounting Standards Codification to improve consistency and clarify guidance. The adoption of this standard did not have a significant impact on the Company’s financial statements. There have been no other material changes to the significant accounting policies previously disclosed in the Company’s 2020 Annual Report on Form 10-K.

Fair Value of Financial Instruments (Tables)

6 Months Ended

Jun. 30, 2021

Fair Value of Financial Instruments

Schedule of assets recorded at fair value


	June 30, 2021
	(unaudited)								December 31, 2020
	Total								Total
	Fair Value		Level 1		Level 2		Level 3		Fair Value		Level 1		Level 2		Level 3
Available-for-Sale Debt Securities:
Money Market Funds	$	71,703	$	71,703	$	—	$	—	$	158,937	$	158,937	$	—	$	—
Corporate Securities		104,957		—		104,957		—		119,833		—		119,833		—
Government Securities		337,638		—		337,638		—		315,353		—		315,353		—
Equity Securities:
Securities with Readily Determinable Fair Value		45,230		45,230		—		—		5,303		5,303		—		—
Securities without Readily Determinable Fair Value		17,146		—		—		17,146		16,071		—		—		16,071
	$	576,674	$	116,933	$	442,595	$	17,146	$	615,497	$	164,240	$	435,186	$	16,071

Summary of rollforward of recurring Level 3 fair value measurements


	Securities without Readily Determinable Fair Value
Balance at December 31, 2020	$	16,071
Issuance		12,148
Transfer out of Level 3		(11,073)
Balance at June 30, 2021	$	17,146

- Definition

Tabular disclosure of financial instruments measured at fair value, including those classified in shareholders' equity measured on a recurring or nonrecurring basis. Disclosures include, but are not limited to, fair value measurements recorded and the reasons for the measurements, level within the fair value hierarchy in which the fair value measurements are categorized and transfers between levels 1 and 2. Nonrecurring fair value measurements are those that are required or permitted in the statement of financial position in particular circumstances.

+ References + Details

Marketable Securities (Tables)

6 Months Ended

Jun. 30, 2021

Marketable Securities

Schedule of marketable securities


			Gross		Gross
	Amortized		Unrealized		Unrealized
June 30, 2021	Cost		Gains		Losses		Fair Value
(in thousands)
Money Market Funds	$	71,703	$	—	$	—	$	71,703
Corporate Securities		104,975		13		(31)		104,957
Government Securities		337,625		36		(23)		337,638
	$	514,303	$	49	$	(54)	$	514,298

Reported as
Cash and cash equivalents							$	71,703
Marketable securities								442,595
Total investments							$	514,298



			Gross		Gross
	Amortized		Unrealized		Unrealized
December 31, 2020	Cost		Gains		Losses		Fair Value
(in thousands)
Money Market Funds	$	158,937	$	—	$	—	$	158,937
Corporate Securities		119,782		57		(6)		119,833
Government Securities		315,319		37		(3)		315,353
	$	594,038	$	94	$	(9)	$	594,123

Reported as
Cash and cash equivalents							$	158,937
Marketable securities								435,186
Total investments							$	594,123

Schedule of maturities of marketable securities


	Amortized		Estimated
June 30, 2021	Cost		Fair Value
(in thousands)
Mature in one year or less	$	288,935	$	288,976
Mature within two years		153,665		153,619
	$	442,600	$	442,595

Schedule of unrealized losses on available-for-sale investments

The unrealized losses on available-for-sale investments and their related fair values as of June 30, 2021 and December 31, 2020 are as follows:


	Less than 12 months				12 months or greater
			Unrealized				Unrealized
June 30, 2021	Fair value		losses		Fair value		losses
(in thousands)
Corporate Securities	$	11,721	$	(4)	$	24,876	$	(27)
Government Securities		—		—		84,888		(23)
	$	11,721	$	(4)	$	109,764	$	(50)



	Less than 12 months				12 months or greater
			Unrealized				Unrealized
December 31, 2020	Fair value		losses		Fair value		losses
(in thousands)
Corporate Securities	$	15,843	$	(6)	$	—	$	—
Government Securities		40,802		(3)		—		—
	$	56,645	$	(9)	$	—	$	—

Schedule of equity securities with readily determinable fair value


	Fair Value		Fair Value
	June 30, 2021		December 31, 2020
Catabasis Common Stock	$	8,102	$	—
INmune Common Stock		31,231		—
Viridian Common Stock		5,897		5,303
	$	45,230	$	5,303

Schedule of equity securities without readily determinable fair value


	Carrying Value		Carrying Value
	June 30, 2021		December 31, 2020
Catabasis Preferred Stock	$	1,075	$	—
Zenas Preferred Stock		16,071		16,071
	$	17,146	$	16,071

Schedule of net gains and losses


	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2021		2020		2021		2020
Net gains (losses) recognized on equity securities	$	43,020	$	358	$	56,002	$	(1,978)
Less: net gains recognized on sale of equity securities		(18,300)		—		(18,301)		—
Unrealized gains (losses) recognized on equity securities	$	24,720	$	358	$	37,701	$	(1,978)

Stock-Based Compensation (Tables)

6 Months Ended

Jun. 30, 2021

Stock-Based Compensation

Schedule of total employee, director and non-employee stock-based compensation expense recognized


	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2021		2020		2021		2020
General and administrative	$	3,193	$	2,804	$	5,930	$	5,095
Research and development		6,157		5,427		11,713		9,648
	$	9,350	$	8,231	$	17,643	$	14,743

	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2021		2020		2021		2020
Stock options	$	7,355	$	6,667	$	13,885	$	12,549
ESPP		253		213		501		407
RSUs		1,742		1,351		3,257		1,787
	$	9,350	$	8,231	$	17,643	$	14,743

Summary of stock option activity


		Weighted		Weighted
		Average		Average
	Number of	Exercise		Remaining		Aggregate
	Shares Subject	Price		Contractual		Intrinsic
	to Outstanding	(Per		Term		Value
	Options	Share)		(in years)		(in thousands)
Balance at December 31, 2020	7,751,789	$	26.23		7.00	$	134,941
Options granted	1,488,576	$	42.73
Options forfeited	(197,440)	$	35.34
Options exercised	(283,491)	$	22.02
Balance at June 30, 2021	8,759,434	$	28.97		6.94	$	65,388
Exercisable	5,265,826	$	23.37		5.68	$	61,080

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


	Options				Options
	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2021		2020		2021		2020
Expected term (years)	6.2		5.7		6.2		6.2
Expected volatility	55.3	%	56.1	%	55.6	%	54.3	%
Risk-free interest rate	1.03	%	0.41	%	1.02	%	0.84	%
Expected dividend yield	—	%	—	%	—	%	—	%

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


	ESPP				ESPP
	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2021		2020		2021		2020
Expected term (years)	0.5 - 2.0		0.5 - 2.0		0.5 - 2.0		0.5 - 2.0
Expected volatility	46.1 - 66.4	%	50.8 - 62.6	%	46.1 - 66.4	%	50.8 - 62.6	%
Risk-free interest rate	0.04 - 1.65	%	0.18 - 1.65	%	0.04 - 1.65	%	0.18 - 1.65	%
Expected dividend yield	—	%	—	%	—	%	—	%

Summary of restricted stock unity activity


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

Unvested RSUs at December 31, 2020	358,825	$	33.04
Granted	266,726		42.85
Vested	(127,998)		31.71
Forfeited	(28,086)		36.16
Unvested RSUs at June 30, 2021	469,467	$	38.79

Leases (Tables)

6 Months Ended

Jun. 30, 2021

Leases

Schedule of operating lease liabilities maturities

The following table reconciles the undiscounted cash flows for the operating leases at June 30, 2021 to the operating lease liabilities recorded on the balance sheet (in thousands):


Years ending December 31,
For the remainder of 2021	$	1,117
2022		2,093
2023		707
2024		729
2025		688
Total undiscounted lease payments		5,334
Less: Imputed interest		(310)
Present value of lease payments	$	5,024

Lease liabilities - short-term	$	2,322
Lease liabilities - long-term		2,702
Total lease liabilities	$	5,024

Summary of lease costs and cash disclosures


	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2021		2020		2021		2020

Operating lease cost	$	614	$	648	$	1,228	$	1,297
Variable lease cost		18		38		28		59
Total lease costs	$	632	$	686	$	1,256	$	1,356

Cash paid for amounts included in
the measurement of lease liabilities	$	548	$	566	$	1,047	$	1,123

Collaboration and Licensing Agreements (Tables)

6 Months Ended

Jun. 30, 2021

Collaboration and Licensing Agreements

Schedule of revenue by licensees

The revenues recorded for the three and six months ended June 30, 2021 and 2020 were earned principally from the following licensees (in millions):


	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2021		2020		2021		2020

Aimmune	$	—	$	—	$	—	$	9.6
Alexion		5.2		3.8		10.5		7.2
Astellas		—		0.7		—		0.9
Genentech		2.3		0.8		2.5		1.5
Gilead		—		7.5		—		13.5
Janssen		16.2		—		30.8		—
MorphoSys		1.2		—		15.1		12.5
Novartis		41.1		—		41.1		—
Vir		1.4		0.3		1.4		0.3
Total	$	67.4	$	13.1	$	101.4	$	45.5

Schedule of disaggregation of revenue

The table below summarizes the disaggregation of revenue recorded for the three and six months ended June 30, 2021 and 2020 (in millions):


	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2021		2020		2021		2020

Research collaboration	$	58.6	$	1.5	$	73.4	$	2.4
Milestone		1.5		0.3		14.0		12.8
Licensing		—		7.5		—		23.1
Royalties		7.3		3.8		14.0		7.2
Total	$	67.4	$	13.1	$	101.4	$	45.5

Net Income (Loss) Per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Numerator:
Net income (loss) attributable to common stockholders	$ 52,248	$ (35,018)	$ 49,761	$ (43,092)
Denominator:
Weighted average common shares outstanding, basic	58,247,941	57,059,610	58,123,319	57,003,162
Effect of dilutive securities	2,087,398		2,380,527
Weighted average common shares outstanding, diluted	60,335,339	57,059,610	60,503,846	57,003,162
Basic net income (loss) (in dollars per share)	$ 0.90	$ (0.61)	$ 0.86	$ (0.76)
Diluted net income (loss) (in dollars per share)	$ 0.87	$ (0.61)	$ 0.82	$ (0.76)

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=109234566&loc=d3e22583-107794

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- Definition

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

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

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+ Details

Stock-Based Compensation - Option activity (Details) - USD ($) $ / shares in Units, $ in Thousands		6 Months Ended		91 Months Ended
	Dec. 31, 2020	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021
Employee stock options
Number of Shares subject to outstanding options
Balance at the beginning of the period (in shares)		7,751,789
Options granted (in shares)		1,488,576	1,433,699
Options forfeited (in shares)		(197,440)
Options exercised (in shares)		(283,491)
Balance at the end of the period (in shares)	7,751,789	8,759,434		8,759,434
Exercisable options (in shares)		5,265,826		5,265,826
Weighted Average Exercise Price (Per Share)
Balance at the beginning of the period (in dollars per share)		$ 26.23
Options granted (in dollars per share)		42.73
Options forfeited (in dollars per share)		35.34
Options exercised (in dollars per share)		22.02
Balance at the end of the period (in dollars per share)	$ 26.23	28.97		$ 28.97
Exercisable (in dollars per share)		$ 23.37		$ 23.37
Weighted-average remaining contractual life	7 years	6 years 11 months 8 days
Weighted-average remaining contractual life of awards exercisable		5 years 8 months 4 days
Aggregate intrinsic value of options outstanding	$ 134,941	$ 65,388		$ 65,388
Aggregate intrinsic value of options exercisable		$ 61,080		$ 61,080
Closing price of common stock (in dollars per share)		$ 34.49		$ 34.49
Weighted average fair value of options granted (in dollars per share)		$ 22.54	$ 16.44
The 2013 Plan
Number of Shares subject to outstanding options
Options granted (in shares)				12,061,415

Stock-Based Compensation - FV of employee stock options (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Employee stock options
Weighted average assumptions for estimated fair value of employee stock options
Expected volatility (as a percent)	55.30%	56.10%	55.60%	54.30%
Risk-free interest rate (as a percent)	1.03%	0.41%	1.02%	0.84%
Expected term (years)	6 years 2 months 12 days	5 years 8 months 12 days	6 years 2 months 12 days	6 years 2 months 12 days
Compensation expense
Unamortized compensation expense related to unvested options	$ 65.0		$ 65.0
Period to recognize unamortized compensation expense			2 years 9 months 18 days
ESPP
Weighted average assumptions for estimated fair value of employee stock options
Expected volatility, low end of range (as a percent)	46.10%		46.10%	50.80%
Expected volatility, high end of range (as a percent)	66.40%		66.40%	62.60%
Risk-free interest rate, low end of range (as a percent)	0.04%	0.18%	0.04%	0.18%
Risk-free interest rate, high end of range (as a percent)	1.65%	1.65%	1.65%	1.65%
Compensation expense
Unamortized compensation expense related to unvested options	$ 0.5		$ 0.5
Period to recognize unamortized compensation expense			4 months 24 days
ESPP \| Minimum
Weighted average assumptions for estimated fair value of employee stock options
Expected term (years)	6 months	6 months	6 months	6 months
ESPP \| Maximum
Weighted average assumptions for estimated fair value of employee stock options
Expected term (years)	2 years	2 years	2 years	2 years

Stock Based Compensation - Restricted stock units (Details) - Restricted stock units $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 30, 2021 USD ($) $ / shares shares
Stock-based compensation
Beginning balance \| shares	358,825
Granted \| shares	266,726
Vested \| shares	(127,998)
Forfeited \| shares	(28,086)
Ending balance \| shares	469,467
Weighted Average Grant Date Fair Value, Beginning Balance \| $ / shares	$ 33.04
Weighted Average Grant Date Fair Value, Granted \| $ / shares	42.85
Weighted Average Grant Date Fair Value, Vested \| $ / shares	31.71
Weighted Average Grant Date Fair Value, Forfeited \| $ / shares	36.16
Weighted Average Grant Date Fair Value, Ending Balance \| $ / shares	$ 38.79
Compensation expense
Unamortized compensation expense related to unvested restricted stock units \| $	$ 15,700
Period to recognize unamortized compensation expense	2 years 3 months 18 days

Leases (Details)		1 Months Ended	6 Months Ended
Leases (Details)	Jul. 01, 2022 USD ($) ft²	Jun. 30, 2021 USD ($) ft² item	Jun. 30, 2021 USD ($) ft²	Sep. 30, 2026 USD ($) ft²	Nov. 30, 2020	Jul. 31, 2017
Lessee, Lease, Description [Line Items]
Option to extend			true
For the remainder of 2021		$ 1,117,000	$ 1,117,000
2022		2,093,000	2,093,000
2023		707,000	707,000
2024		729,000	729,000
2025		688,000	688,000
Total undiscounted lease payments		5,334,000	5,334,000
Less: Imputed interest		(310,000)	(310,000)
Present value of lease payments		$ 5,024,000	$ 5,024,000
Monrovia, CA - office and laboratory space
Lessee, Lease, Description [Line Items]
Area of property \| ft²		7,020	7,020
Initial base monthly rent		$ 15,000	$ 15,000
Lease term		18 months	18 months
Renewal term					5 years
Monrovia, CA - office and laboratory space with additional space
Lessee, Lease, Description [Line Items]
Renewal term						5 years
San Diego, CA - office space
Lessee, Lease, Description [Line Items]
Renewal term		5 years	5 years
Pasadena, CA - office and laboratory space
Lessee, Lease, Description [Line Items]
Area of property \| ft²		129,543	129,543
Phases of lease term \| item		2
Forecast \| Pasadena, CA - office and laboratory space
Lessee, Lease, Description [Line Items]
Area of property \| ft²	83,083			46,460
Improvement allowance	$ 17,032,015			$ 3,252,000
Initial base monthly rent	$ 386,335.95
Rent expense per square foot	4.65
Rent increase (as a percentage)	3.00%
Lease term	13 years

Collaboration and Licensing Agreements (Details)				1 Months Ended											3 Months Ended					6 Months Ended		12 Months Ended
Collaboration and Licensing Agreements (Details)	Feb. 04, 2020 USD ($) shares	Mar. 29, 2019 USD ($)	Mar. 08, 2019	Jun. 30, 2021 USD ($) shares	Dec. 31, 2020 USD ($) shares	Nov. 30, 2020 USD ($) item	Jul. 31, 2020 USD ($)	Mar. 31, 2020 item	Feb. 29, 2020 USD ($)	Jan. 31, 2020 USD ($) item	Jun. 30, 2019 USD ($)	Feb. 28, 2019	Oct. 31, 2017 USD ($) shares	Jan. 31, 2013 Program	Jun. 30, 2021 USD ($)	Mar. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Jun. 30, 2020 USD ($)	Sep. 30, 2019 item	Jun. 30, 2021 USD ($) item	Jun. 30, 2020 USD ($)	Dec. 31, 2020 USD ($) shares	Dec. 31, 2017 shares	Mar. 31, 2019 USD ($)	May 31, 2018 USD ($)
Collaboration research and licensing agreements
Other income															$ (6,000)			$ 134,000		$ (17,000)	$ 133,000
Proceeds from sale of equity securities															18,300,000					18,301,000
Unrealized gains (losses) recognized on equity securities															24,720,000			358,000		37,701,000	(1,978,000)
Deferred revenue				$ 19,200,000											19,200,000			44,700,000		19,200,000	44,700,000
Receivable				14,825,000	$ 11,443,000										14,825,000		$ 11,443,000			14,825,000		$ 11,443,000
Genentech \| Collaboration and License Agreement
Collaboration research and licensing agreements
Revenue recognized																				2,500,000	1,500,000
License, Development, and Commercialization Agreement \| Aimmune
Collaboration research and licensing agreements
Nonrefundable upfront payment	$ 5,000,000.0
Revenue recognized															0			0		0	9,600,000
Shares received in noncash transaction \| shares	156,238
Purchase amount of share options or equity in noncash transaction	$ 4,600,000
Deferred revenue				0											0					0
License, Development, and Commercialization Agreement \| Aimmune \| Maximum
Collaboration research and licensing agreements
Potential milestone payment	385,000,000.0
Option and License Agreement \| Alexion
Collaboration research and licensing agreements
Revenue recognized																				10,500,000	7,200,000
Deferred revenue				0											0					0
Receivable				10,200,000											10,200,000					10,200,000
Number of different target programs \| Program														1
Option and License Agreement \| Alexion \| Royalty
Collaboration research and licensing agreements
Revenue recognized															5,200,000			3,800,000
Option and License Agreement \| Alexion \| Milestone
Collaboration research and licensing agreements
Contract asset					10,000,000.0												10,000,000.0					10,000,000.0
Research and License Agreement \| Amgen, Inc.
Collaboration research and licensing agreements
Performance obligation				900,000											900,000					900,000
Revenue recognized															0			0		0	0
Deferred revenue				0											0					0
Research and License Agreement \| Astellas
Collaboration research and licensing agreements
Nonrefundable upfront payment		$ 15,000,000.0
Potential milestone payment		240,000,000.0
Revenue recognized															0			700,000		0	900,000
Deferred revenue				0											0					0
Research and License Agreement \| Astellas \| Bispecific
Collaboration research and licensing agreements
Revenue recognized											$ 13,600,000
Research and License Agreement \| Astellas \| Research service
Collaboration research and licensing agreements
Performance obligation		1,400,000
Research and License Agreement \| Astellas \| Milestone
Collaboration research and licensing agreements
Contract asset					2,500,000												2,500,000					2,500,000
Research and License Agreement \| Novartis
Collaboration research and licensing agreements
Revenue recognized															1,000,000.0	$ 1,000,000.0
Collaboration and License Agreement \| Genentech
Collaboration research and licensing agreements
Initial cost-sharing percentage			45.00%
Research license term												2 years
Revenue recognized															2,300,000			800,000
Collaboration and License Agreement \| Genentech \| XmAb24306
Collaboration research and licensing agreements
Cost sharing receivable (payable)				(2,300,000)											(2,300,000)					(2,300,000)
Collaboration and License Agreement \| Genentech \| Research service
Collaboration research and licensing agreements
Performance obligation																								$ 8,300,000
Deferred revenue				0											0					0
Collaboration and License Agreement \| Genentech \| Licensing
Collaboration research and licensing agreements
Performance obligation																								$ 111,700,000
Collaboration and License Agreement \| Janssen Biotech, Inc
Collaboration research and licensing agreements
Performance obligation						$ 50,000,000.0
Nonrefundable upfront payment						50,000,000.0
Potential milestone payment						662,500,000
Revenue recognized															16,200,000					30,800,000
Deferred revenue				19,200,000											19,200,000					19,200,000
Collaboration and License Agreement \| MorphoSys
Collaboration research and licensing agreements
Revenue recognized							$ 25,000,000.0
Contract asset																$ 12,500,000
Deferred revenue				0											0					0
Collaboration and License Agreement \| MorphoSys \| Royalty
Collaboration research and licensing agreements
Revenue recognized															1,200,000					2,600,000
Receivable				1,500,000											1,500,000					1,500,000
Collaboration and License Agreement \| MorphoSys \| Milestone
Collaboration research and licensing agreements
Revenue recognized									$ 12,500,000											12,500,000	12,500,000
Collaboration and License Agreement \| Novartis
Collaboration research and licensing agreements
Revenue recognized																		0		40,100,000	0
Deferred revenue				0											0					$ 0
Number of antibody targets for which bispecific technology applied \| item																				4
Number of targets against which non-exclusive license is provided \| item																				10
Collaboration and License Agreement \| Novartis \| Milestone
Collaboration research and licensing agreements
Revenue recognized															1,000,000.0					$ 1,000,000.0
Cost sharing receivable (payable)				1,000,000.0											1,000,000.0					1,000,000.0
Collaboration and License Agreement \| Novartis \| Development
Collaboration research and licensing agreements
Cost sharing receivable (payable)				800,000											800,000					800,000
Technology License Agreement \| Quellis \| Maximum
Collaboration research and licensing agreements
Potential milestone payment																									$ 66,000,000.0
Technology License Agreement \| Catabasis
Collaboration research and licensing agreements
Unrealized gains (losses) recognized on equity securities															(3,700,000)					9,200,000
Deferred revenue				0											0					0
Technology License Agreement \| Gilead
Collaboration research and licensing agreements
Nonrefundable upfront payment										$ 6,000,000.0
Potential milestone payment										$ 67,000,000.0
Revenue recognized															0			7,500,000		0	13,500,000
Deferred revenue				0											0					0
Number of compounds \| item										3
Technology License Agreement \| MiRagen/Viridian
Collaboration research and licensing agreements
Potential milestone payment					$ 55,000,000.0												55,000,000.0					55,000,000.0
Revenue recognized																				0		$ 6,000,000.0
Shares received in noncash transaction \| shares					322,407																	322,407
Purchase amount of share options or equity in noncash transaction					$ 6,000,000.0
Unrealized gains (losses) recognized on equity securities															500,000					600,000
Deferred revenue				0											0					0
License Agreement \| INmune
Collaboration research and licensing agreements
Shares received in noncash transaction \| shares													1,585,000										1,585,000
Purchase amount of share options or equity in noncash transaction													$ 10,000,000.0
Consideration on sale of option				18,300,000
Cash consideration on sale of option				15,000,000.0
Shares issues on sale of option value				$ 3,300,000
Shares issued upon conversion \| shares				192,533
Proceeds from sale of equity securities				$ 18,300,000																18,300,000
Unrealized gains (losses) recognized on equity securities															27,900,000
Additional equity interests (as a percentage)																							10.00%
Option term													6 years
License Agreement \| INmune \| Maximum
Collaboration research and licensing agreements
Additional equity interests (as a percentage)													10.00%
License Agreement \| INmune \| Other Income
Collaboration research and licensing agreements
Unrealized gains (losses) recognized on equity securities															27,800,000					27,800,000
License Agreement \| Zenas Bio Pharma Limited
Collaboration research and licensing agreements
Performance obligation						16,100,000
Revenue recognized															0					0
Purchase amount of share options or equity in noncash transaction						$ 16,100,000
Deferred revenue				0											0					0
Percentage of equity of private company						15.00%
Number of drug candidates \| item						3
License Agreement \| Zenas Bio Pharma Limited \| Licensing
Collaboration research and licensing agreements
Revenue recognized																	16,100,000
Patent License Agreement \| Vir
Collaboration research and licensing agreements
Revenue recognized																		$ 300,000			$ 300,000
Contract asset				500,000											500,000					500,000
Deferred revenue				$ 0											0					0
Number of different target programs \| item								2											2
Patent License Agreement \| Vir \| Royalty
Collaboration research and licensing agreements
Revenue recognized															$ 900,000
Patent License Agreement \| Vir \| Milestone
Collaboration research and licensing agreements
Revenue recognized																				$ 500,000
Development-based \| License, Development, and Commercialization Agreement \| Aimmune
Collaboration research and licensing agreements
Potential milestone payment	22,000,000.0
Development-based \| Research and License Agreement \| Astellas
Collaboration research and licensing agreements
Potential milestone payment		32,500,000
Development-based \| Collaboration and License Agreement \| Janssen Biotech, Inc
Collaboration research and licensing agreements
Potential milestone payment						$ 161,900,000
Development-based \| Technology License Agreement \| Quellis
Collaboration research and licensing agreements
Potential milestone payment																									6,000,000.0
Development-based \| Technology License Agreement \| Gilead
Collaboration research and licensing agreements
Potential milestone payment										$ 10,000,000.0
Development-based \| Technology License Agreement \| MiRagen/Viridian
Collaboration research and licensing agreements
Potential milestone payment					10,000,000.0												10,000,000.0					$ 10,000,000.0
Regulatory-based \| License, Development, and Commercialization Agreement \| Aimmune
Collaboration research and licensing agreements
Potential milestone payment	53,000,000.0
Regulatory-based \| Research and License Agreement \| Astellas
Collaboration research and licensing agreements
Potential milestone payment		57,500,000
Regulatory-based \| Collaboration and License Agreement \| Janssen Biotech, Inc
Collaboration research and licensing agreements
Potential milestone payment						240,600,000
Regulatory-based \| Technology License Agreement \| Quellis
Collaboration research and licensing agreements
Potential milestone payment																									30,000,000.0
Regulatory-based \| Technology License Agreement \| Gilead
Collaboration research and licensing agreements
Potential milestone payment										27,000,000.0
Regulatory-based \| Technology License Agreement \| MiRagen/Viridian
Collaboration research and licensing agreements
Potential milestone payment					20,000,000.0												20,000,000.0					20,000,000.0
Sales-based \| License, Development, and Commercialization Agreement \| Aimmune
Collaboration research and licensing agreements
Potential milestone payment	$ 310,000,000.0
Sales-based \| Research and License Agreement \| Astellas
Collaboration research and licensing agreements
Potential milestone payment		$ 150,000,000.0
Sales-based \| Collaboration and License Agreement \| Janssen Biotech, Inc
Collaboration research and licensing agreements
Potential milestone payment						$ 260,000,000.0
Sales-based \| Technology License Agreement \| Quellis
Collaboration research and licensing agreements
Potential milestone payment																									$ 30,000,000.0
Sales-based \| Technology License Agreement \| Gilead
Collaboration research and licensing agreements
Potential milestone payment										$ 30,000,000.0
Sales-based \| Technology License Agreement \| MiRagen/Viridian
Collaboration research and licensing agreements
Potential milestone payment					$ 25,000,000.0												$ 25,000,000.0					$ 25,000,000.0

Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2021	Dec. 31, 2020
Balance Sheets
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	58,315,485	57,873,444
Common stock, shares outstanding	58,315,485	57,873,444

Marketable Securities - Maturities (Details) $ in Thousands	Jun. 30, 2021 USD ($)
Amortized Cost
Maturing in one year or less	$ 288,935
Maturing within two years	153,665
Total amortized cost	442,600
Estimate Fair Value
Maturing in one year or less	288,976
Maturing within two years	153,619
Total estimated fair value	$ 442,595

Marketable Securities - Equity Securities with Readily Determinable Fair Value (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Equity Securities
Equity Securities with Readily Determinable Fair Value	$ 45,230	$ 5,303
Common Stock
Equity Securities
Equity Securities with Readily Determinable Fair Value	45,230	5,303
Catabasis \| Common Stock
Equity Securities
Equity Securities with Readily Determinable Fair Value	8,102
INmune \| Common Stock
Equity Securities
Equity Securities with Readily Determinable Fair Value	31,231
MiRagen/Viridian \| Common Stock
Equity Securities
Equity Securities with Readily Determinable Fair Value	$ 5,897	$ 5,303

Marketable Securities - Equity Securities without Readily Determinable Fair Value (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Equity securities without readily determinable fair value
Equity Securities without Readily Determinable Fair Value	$ 17,146	$ 16,071
Preferred Stock
Equity securities without readily determinable fair value
Equity Securities without Readily Determinable Fair Value	17,146	16,071
Preferred Stock \| Catabasis
Equity securities without readily determinable fair value
Equity Securities without Readily Determinable Fair Value	1,075
Preferred Stock \| Zenas Bio Pharma Limited
Equity securities without readily determinable fair value
Equity Securities without Readily Determinable Fair Value	$ 16,071	$ 16,071

Fair Value of Financial Instruments - Level 3 (Details) - Level 3 - Equity Securities $ in Thousands	6 Months Ended
	Jun. 30, 2021 USD ($)
Fair Value of Financial Instruments
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value, Beginning Balance	$ 16,071
Issuance	12,148
Transfer out of Level 3	(11,073)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value, Ending Balance	$ 17,146

Marketable Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Schedule of Available-for-sale Securities
Cash and cash equivalents	$ 115,842	$ 163,544
Investments, amortized cost	514,303	594,038
Investments	514,298	594,123
Total amortized cost	442,600
Gross unrealized gains	49	94
Gross unrealized losses	(54)	(9)
Marketable Securities	442,595
Marketable securities
Schedule of Available-for-sale Securities
Marketable Securities	442,595	435,186
Money Market Funds
Schedule of Available-for-sale Securities
Cash and cash equivalents	71,703	158,937
Corporate Securities
Schedule of Available-for-sale Securities
Total amortized cost	104,975	119,782
Gross unrealized gains	13	57
Gross unrealized losses	(31)	(6)
Marketable Securities	104,957	119,833
Government Securities
Schedule of Available-for-sale Securities
Total amortized cost	337,625	315,319
Gross unrealized gains	36	37
Gross unrealized losses	(23)	(3)
Marketable Securities	337,638	315,353
Cash and Cash Equivalents
Schedule of Available-for-sale Securities
Cash and cash equivalents	$ 71,703	$ 158,937

Marketable Securities - Unrealized losses (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Fair value
Fair value, less than 12 months	$ 11,721	$ 56,645
Fair value, 12 months or greater	109,764
Unrealized losses
Unrealized losses, Less than 12 months	(4)	(9)
Unrealized losses, 12 months or greater	(50)
Corporate Securities
Fair value
Fair value, less than 12 months	11,721	15,843
Fair value, 12 months or greater	24,876
Unrealized losses
Unrealized losses, Less than 12 months	(4)	(6)
Unrealized losses, 12 months or greater	(27)
Government Securities
Fair value
Fair value, less than 12 months		40,802
Fair value, 12 months or greater	84,888
Unrealized losses
Unrealized losses, Less than 12 months		$ (3)
Unrealized losses, 12 months or greater	$ (23)

Marketable Securities - Equity Securities Transactions (Details) - shares	1 Months Ended			3 Months Ended	6 Months Ended	12 Months Ended
	Jun. 30, 2021	Dec. 31, 2020	Oct. 31, 2017	Jun. 30, 2021	Jun. 30, 2021	Dec. 31, 2020	Dec. 31, 2017
Catabasis \| Common Stock
Equity Securities
Shares received in noncash transaction	259,206
Total common equity shares				3,839,745
Number of preferred stock converted (in shares)				3,580,539
Catabasis \| Preferred Stock
Equity Securities
Shares received in noncash transaction	3,928
Number of preferred stock converted (in shares)				3,581
INmune \| Common Stock
Equity Securities
Total common equity shares					1,777,533
Shares issued upon conversion	192,533
Technology License Agreement \| MiRagen/Viridian
Equity Securities
Shares received in noncash transaction		322,407				322,407
License Agreement \| INmune
Equity Securities
Shares received in noncash transaction			1,585,000				1,585,000
Additional equity interests (as a percentage)							10.00%
Shares issued upon conversion	192,533

Stock Based Compensation (Details)		6 Months Ended		91 Months Ended
Stock Based Compensation (Details)	Dec. 02, 2013 shares	Jun. 30, 2021 item shares	Jun. 30, 2020 shares	Jun. 30, 2021 shares	Jan. 01, 2021 shares
Employee stock options
Stock-based compensation
Options granted (in shares)		1,488,576	1,433,699
ESPP
Stock-based compensation
Total number of shares of common stock available for issuance		581,286		581,286
Awards issued under the plan (in shares)				498,147
Increase in shares of common stock available for issuance (in shares)		0
ESPP \| Maximum
Stock-based compensation
Annual percentage increase in shares of common stock available for issuance		1.00%
Annual increase in shares of common stock available for issuance (in shares)		621,814
Restricted stock units
Stock-based compensation
Awards issued under the plan (in shares)				720,513
Granted		266,726
Annual installment vesting periods \| item		3
The 2013 Plan
Stock-based compensation
Total number of shares of common stock available for issuance		13,382,544		13,382,544	2,314,937
Annual percentage increase in shares of common stock available for issuance		4.00%
Increase in shares of common stock available for issuance (in shares)		2,314,937
Options granted (in shares)				12,061,415
The 2010 Plan
Stock-based compensation
Total number of shares of common stock available for issuance		2,684,456		2,684,456
Options granted (in shares)	0

Leases - Operating lease liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Leases
Lease liability - short-term	$ 2,322	$ 1,889
Lease liability - long-term	2,702	$ 9,739
Operating lease liabilities	$ 5,024

Leases - Lease costs (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
Leases - Lease costs (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Leases
Operating lease cost	$ 614	$ 648	$ 1,228	$ 1,297
Variable lease cost	18	38	28	59
Total lease costs	632	686	1,256	1,356
Cash paid for amounts included in the measurement of lease liabilities	$ 548	$ 566	$ 1,047	$ 1,123
Remaining lease term	3 years 1 month 6 days		3 years 1 month 6 days
Discount rate	4.00%		4.00%

Income Taxes (Details) - USD ($)	3 Months Ended		6 Months Ended
Income Taxes (Details) - USD ($)	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Reconciliation of federal statutory income tax to effective income tax
Income tax expense	$ 0	$ 0	$ 0	$ 0