<SEC-DOCUMENT>0000939767-18-000197.txt : 20180912
<SEC-HEADER>0000939767-18-000197.hdr.sgml : 20180912
<ACCEPTANCE-DATETIME>20180912200357
ACCESSION NUMBER:		0000939767-18-000197
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20180910
FILED AS OF DATE:		20180912
DATE AS OF CHANGE:		20180912

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			MORRISSEY MICHAEL
		CENTRAL INDEX KEY:			0001202096

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-30235
		FILM NUMBER:		181067752

	MAIL ADDRESS:	
		STREET 1:		C/O EXELIXIS INC
		STREET 2:		170 HARBOR WAY
		CITY:			SAN FRANCISCO
		STATE:			CA
		ZIP:			94083

	FORMER NAME:	
		FORMER CONFORMED NAME:	MORRISSEY MICHAEL M
		DATE OF NAME CHANGE:	20030512

	FORMER NAME:	
		FORMER CONFORMED NAME:	MORRISSEY MICHAEL R
		DATE OF NAME CHANGE:	20021029

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			EXELIXIS, INC.
		CENTRAL INDEX KEY:			0000939767
		STANDARD INDUSTRIAL CLASSIFICATION:	SERVICES-COMMERCIAL PHYSICAL & BIOLOGICAL RESEARCH [8731]
		IRS NUMBER:				043257395
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1228

	BUSINESS ADDRESS:	
		STREET 1:		1851 HARBOR BAY PARKWAY
		CITY:			ALAMEDA
		STATE:			CA
		ZIP:			94502
		BUSINESS PHONE:		6508377000

	MAIL ADDRESS:	
		STREET 1:		1851 HARBOR BAY PARKWAY
		CITY:			ALAMEDA
		STATE:			CA
		ZIP:			94502

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	EXELIXIS INC
		DATE OF NAME CHANGE:	20000207

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	EXELIXIS PHARMACEUTICALS INC
		DATE OF NAME CHANGE:	20000106
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wf-form4_153679701780301.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2018-09-10</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000939767</issuerCik>
        <issuerName>EXELIXIS, INC.</issuerName>
        <issuerTradingSymbol>EXEL</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001202096</rptOwnerCik>
            <rptOwnerName>MORRISSEY MICHAEL</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O EXELIXIS, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>1851 HARBOR BAY PARKWAY</rptOwnerStreet2>
            <rptOwnerCity>ALAMEDA</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94502</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>President and CEO</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable></nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Option (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>18.8</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2018-09-10</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>308365</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2019-09-10</value>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <value>2025-09-09</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>308365.0</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>308365</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Option granted pursuant to the Exelixis, Inc. 2017 Equity Incentive Plan. Option granted will vest as to 1/4th of the original number of shares subject to the option on the one-year anniversary of the Transaction Date, and thereafter as to 1/48th of the original number of shares subject to the option on each monthly anniversary of the Transaction Date.  However, the option will not be exercisable until the closing market price of Exelixis, Inc. common stock is equal to or greater than 125% of the exercise price of the option over a period of at least 30 consecutive calendar days.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Jennifer Drimmer Rokovich, Attorney in Fact</signatureName>
        <signatureDate>2018-09-12</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
