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    <link:label xlink:label="xbit_statement-statement-note-2-significant-accounting-policies-tables-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Note 2 - Significant Accounting Policies</link:label>
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    <link:label xlink:label="us-gaap_SegmentReportingPolicyPolicyTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Segment Reporting, Policy [Policy Text Block]</link:label>
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    <link:label xlink:label="xbit_OtherForeignMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Foreign [Member]</link:label>
    <link:label xlink:label="xbit_OtherForeignMember-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents other foreign countries.</link:label>
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    <link:label xlink:label="xbit_statement-statement-note-5-accrued-expenses-accrued-expenses-details-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Note 5 - Accrued Expenses - Accrued Expenses (Details)</link:label>
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    <link:label xlink:label="xbit_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedInPeriodIntrinsicValueAmountPerShare-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Intrinsic Value, Amount Per Share</link:label>
    <link:label xlink:label="xbit_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedInPeriodIntrinsicValueAmountPerShare-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Per share weighted average intrinsic value of stock options.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="xbit_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedInPeriodIntrinsicValueAmountPerShare" xlink:to="xbit_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedInPeriodIntrinsicValueAmountPerShare-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1</link:label>
    <link:label xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1" xlink:to="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationOptionAndIncentivePlansPolicy" xlink:label="us-gaap_ShareBasedCompensationOptionAndIncentivePlansPolicy" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ShareBasedCompensationOptionAndIncentivePlansPolicy-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-based Payment Arrangement [Policy Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationOptionAndIncentivePlansPolicy" xlink:to="us-gaap_ShareBasedCompensationOptionAndIncentivePlansPolicy-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockholdersEquityNoteDisclosureTextBlock" xlink:label="us-gaap_StockholdersEquityNoteDisclosureTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_StockholdersEquityNoteDisclosureTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Stockholders' Equity Note Disclosure [Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockholdersEquityNoteDisclosureTextBlock" xlink:to="us-gaap_StockholdersEquityNoteDisclosureTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1</link:label>
    <link:label xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Fair Value</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1" xlink:to="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Weighted-average grant date fair value per share (in dollars per share)</link:label>
    <link:label xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue-label" xlink:type="arc"/>
    <link:loc xlink:href="xbit-20191231.xsd#xbit_PropertyPlantAndEquipmentIncludingBuildingConstructionInProcess" xlink:label="xbit_PropertyPlantAndEquipmentIncludingBuildingConstructionInProcess" xlink:type="locator"/>
    <link:label xlink:label="xbit_PropertyPlantAndEquipmentIncludingBuildingConstructionInProcess-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US"/>
    <link:label xlink:label="xbit_PropertyPlantAndEquipmentIncludingBuildingConstructionInProcess-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale including building construction in process. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="xbit_PropertyPlantAndEquipmentIncludingBuildingConstructionInProcess" xlink:to="xbit_PropertyPlantAndEquipmentIncludingBuildingConstructionInProcess-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CommonStockValue" xlink:label="us-gaap_CommonStockValue" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_CommonStockValue-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Common stock, no par value, unlimited shares authorized, 41,519,633 and 35,899,772 shares outstanding at December 31, 2019 and December 31, 2018, respectively</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CommonStockValue" xlink:to="us-gaap_CommonStockValue-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FairValueByMeasurementFrequencyAxis" xlink:label="us-gaap_FairValueByMeasurementFrequencyAxis" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_FairValueByMeasurementFrequencyAxis-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Measurement Frequency [Axis]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValueByMeasurementFrequencyAxis" xlink:to="us-gaap_FairValueByMeasurementFrequencyAxis-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:label="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Adjustments to reconcile net loss to net cash used in operating activities:</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="us-gaap_FairValueMeasurementFrequencyDomain" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_FairValueMeasurementFrequencyDomain-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Measurement Frequency [Domain]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValueMeasurementFrequencyDomain" xlink:to="us-gaap_FairValueMeasurementFrequencyDomain-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice</link:label>
    <link:label xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice-label" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:type="resource" xml:lang="en-US">Options outstanding, exercise price (in dollars per share)</link:label>
    <link:label xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice-label" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:type="resource" xml:lang="en-US">Options outstanding, exercise price (in dollars per share)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FairValueMeasurementsRecurringMember" xlink:label="us-gaap_FairValueMeasurementsRecurringMember" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_FairValueMeasurementsRecurringMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fair Value, Recurring [Member]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValueMeasurementsRecurringMember" xlink:to="us-gaap_FairValueMeasurementsRecurringMember-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CommonStockSharesAuthorizedUnlimited" xlink:label="us-gaap_CommonStockSharesAuthorizedUnlimited" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_CommonStockSharesAuthorizedUnlimited-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Common stock, shares authorized</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CommonStockSharesAuthorizedUnlimited" xlink:to="us-gaap_CommonStockSharesAuthorizedUnlimited-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Forfeitures, exercise price (in dollars per share)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice" xlink:to="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ContractWithCustomerLiabilityCurrent" xlink:label="us-gaap_ContractWithCustomerLiabilityCurrent" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ContractWithCustomerLiabilityCurrent-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Contract liabilities</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ContractWithCustomerLiabilityCurrent" xlink:to="us-gaap_ContractWithCustomerLiabilityCurrent-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CommonStockNoParValue" xlink:label="us-gaap_CommonStockNoParValue" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_CommonStockNoParValue-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Common stock, no par value (in dollars per share)</link:label>
    <link:label xlink:label="us-gaap_CommonStockNoParValue-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Common Stock, No Par Value</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CommonStockNoParValue" xlink:to="us-gaap_CommonStockNoParValue-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount" xlink:label="us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount</link:label>
    <link:label xlink:label="us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount" xlink:to="us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccrualForTaxesOtherThanIncomeTaxesCurrent" xlink:label="us-gaap_AccrualForTaxesOtherThanIncomeTaxesCurrent" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_AccrualForTaxesOtherThanIncomeTaxesCurrent-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other taxes payable</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AccrualForTaxesOtherThanIncomeTaxesCurrent" xlink:to="us-gaap_AccrualForTaxesOtherThanIncomeTaxesCurrent-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Granted, exercise price (in dollars per share)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice" xlink:to="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Exercised, exercise price (in dollars per share)</link:label>
    <link:label xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" xlink:to="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccruedLiabilitiesCurrent" xlink:label="us-gaap_AccruedLiabilitiesCurrent" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_AccruedLiabilitiesCurrent-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accrued expenses</link:label>
    <link:label xlink:label="us-gaap_AccruedLiabilitiesCurrent-label" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AccruedLiabilitiesCurrent" xlink:to="us-gaap_AccruedLiabilitiesCurrent-label" xlink:type="arc"/>
    <link:loc xlink:href="xbit-20191231.xsd#xbit_EscrowReceivable" xlink:label="xbit_EscrowReceivable" xlink:type="locator"/>
    <link:label xlink:label="xbit_EscrowReceivable-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Escrow receivable</link:label>
    <link:label xlink:label="xbit_EscrowReceivable-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the amount of escrow receivable.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="xbit_EscrowReceivable" xlink:to="xbit_EscrowReceivable-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EmployeeRelatedLiabilitiesCurrent" xlink:label="us-gaap_EmployeeRelatedLiabilitiesCurrent" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_EmployeeRelatedLiabilitiesCurrent-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accrued compensation and related expenses</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EmployeeRelatedLiabilitiesCurrent" xlink:to="us-gaap_EmployeeRelatedLiabilitiesCurrent-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxAssetsValuationAllowance" xlink:label="us-gaap_DeferredTaxAssetsValuationAllowance" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_DeferredTaxAssetsValuationAllowance-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_DeferredTaxAssetsValuationAllowance</link:label>
    <link:label xlink:label="us-gaap_DeferredTaxAssetsValuationAllowance-label" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Valuation allowance for deferred tax assets</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredTaxAssetsValuationAllowance" xlink:to="us-gaap_DeferredTaxAssetsValuationAllowance-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeMember" xlink:label="srt_RangeMember" xlink:type="locator"/>
    <link:label xlink:label="srt_RangeMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Statistical Measurement [Domain]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_RangeMember" xlink:to="srt_RangeMember-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_MaximumMember" xlink:label="srt_MaximumMember" xlink:type="locator"/>
    <link:label xlink:label="srt_MaximumMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Maximum [Member]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_MaximumMember" xlink:to="srt_MaximumMember-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_MinimumMember" xlink:label="srt_MinimumMember" xlink:type="locator"/>
    <link:label xlink:label="srt_MinimumMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Minimum [Member]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_MinimumMember" xlink:to="srt_MinimumMember-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_WeightedAverageMember" xlink:label="srt_WeightedAverageMember" xlink:type="locator"/>
    <link:label xlink:label="srt_WeightedAverageMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Weighted Average [Member]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_WeightedAverageMember" xlink:to="srt_WeightedAverageMember-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccountsPayableCurrent" xlink:label="us-gaap_AccountsPayableCurrent" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_AccountsPayableCurrent-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accounts payable</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AccountsPayableCurrent" xlink:to="us-gaap_AccountsPayableCurrent-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ProceedsFromSaleOfProductiveAssets" xlink:label="us-gaap_ProceedsFromSaleOfProductiveAssets" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ProceedsFromSaleOfProductiveAssets-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cash received from Janssen Transaction</link:label>
    <link:label xlink:label="us-gaap_ProceedsFromSaleOfProductiveAssets-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Proceeds from Sale of Productive Assets, Total</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ProceedsFromSaleOfProductiveAssets" xlink:to="us-gaap_ProceedsFromSaleOfProductiveAssets-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber</link:label>
    <link:label xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber-label" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:type="resource" xml:lang="en-US">Options outstanding (in shares)</link:label>
    <link:label xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber-label" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:type="resource" xml:lang="en-US">Options outstanding (in shares)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeAxis" xlink:label="srt_RangeAxis" xlink:type="locator"/>
    <link:label xlink:label="srt_RangeAxis-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Statistical Measurement [Axis]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_RangeAxis" xlink:to="srt_RangeAxis-label" xlink:type="arc"/>
    <link:loc xlink:href="xbit-20191231.xsd#xbit_AdjustmentsToAdditionalPaidInCapitalCollectionOfStockSubscriptionReceivable" xlink:label="xbit_AdjustmentsToAdditionalPaidInCapitalCollectionOfStockSubscriptionReceivable" xlink:type="locator"/>
    <link:label xlink:label="xbit_AdjustmentsToAdditionalPaidInCapitalCollectionOfStockSubscriptionReceivable-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Collection of stock subscription receivable</link:label>
    <link:label xlink:label="xbit_AdjustmentsToAdditionalPaidInCapitalCollectionOfStockSubscriptionReceivable-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Amount of increase to additional paid-in capital (APIC) for collection of stock subscription receivable.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="xbit_AdjustmentsToAdditionalPaidInCapitalCollectionOfStockSubscriptionReceivable" xlink:to="xbit_AdjustmentsToAdditionalPaidInCapitalCollectionOfStockSubscriptionReceivable-label" xlink:type="arc"/>
    <link:loc xlink:href="xbit-20191231.xsd#xbit_MobileFacilityMember" xlink:label="xbit_MobileFacilityMember" xlink:type="locator"/>
    <link:label xlink:label="xbit_MobileFacilityMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Mobile Facility [Member]</link:label>
    <link:label xlink:label="xbit_MobileFacilityMember-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Information pertaining to mobile facility.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="xbit_MobileFacilityMember" xlink:to="xbit_MobileFacilityMember-label" xlink:type="arc"/>
    <link:loc xlink:href="xbit-20191231.xsd#xbit_EquityDistributionAgreementMember" xlink:label="xbit_EquityDistributionAgreementMember" xlink:type="locator"/>
    <link:label xlink:label="xbit_EquityDistributionAgreementMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity Distribution Agreement [Member]</link:label>
    <link:label xlink:label="xbit_EquityDistributionAgreementMember-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the information pertaining to the equity distribution agreement.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="xbit_EquityDistributionAgreementMember" xlink:to="xbit_EquityDistributionAgreementMember-label" xlink:type="arc"/>
    <link:loc xlink:href="xbit-20191231.xsd#xbit_ProceedsFromIssuanceOfCommonStockNet" xlink:label="xbit_ProceedsFromIssuanceOfCommonStockNet" xlink:type="locator"/>
    <link:label xlink:label="xbit_ProceedsFromIssuanceOfCommonStockNet-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">xbit_ProceedsFromIssuanceOfCommonStockNet</link:label>
    <link:label xlink:label="xbit_ProceedsFromIssuanceOfCommonStockNet-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Proceeds from Issuance of Common Stock, Net</link:label>
    <link:label xlink:label="xbit_ProceedsFromIssuanceOfCommonStockNet-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The cash inflow from the additional capital contribution to the entity, net of issuance costs.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="xbit_ProceedsFromIssuanceOfCommonStockNet" xlink:to="xbit_ProceedsFromIssuanceOfCommonStockNet-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PreferredStockValue" xlink:label="us-gaap_PreferredStockValue" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_PreferredStockValue-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Preferred Stock, no par value, unlimited shares authorized, no shares outstanding</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PreferredStockValue" xlink:to="us-gaap_PreferredStockValue-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PreferredStockSharesAuthorizedUnlimited" xlink:label="us-gaap_PreferredStockSharesAuthorizedUnlimited" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_PreferredStockSharesAuthorizedUnlimited-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Preferred stock, shares authorized</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PreferredStockSharesAuthorizedUnlimited" xlink:to="us-gaap_PreferredStockSharesAuthorizedUnlimited-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxAssetsLiabilitiesNet" xlink:label="us-gaap_DeferredTaxAssetsLiabilitiesNet" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_DeferredTaxAssetsLiabilitiesNet-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_DeferredTaxAssetsLiabilitiesNet</link:label>
    <link:label xlink:label="us-gaap_DeferredTaxAssetsLiabilitiesNet-label" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Net deferred tax asset including valuation allowance</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredTaxAssetsLiabilitiesNet" xlink:to="us-gaap_DeferredTaxAssetsLiabilitiesNet-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OtherAccruedLiabilitiesCurrent" xlink:label="us-gaap_OtherAccruedLiabilitiesCurrent" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_OtherAccruedLiabilitiesCurrent-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OtherAccruedLiabilitiesCurrent" xlink:to="us-gaap_OtherAccruedLiabilitiesCurrent-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardPercentageOfOutstandingStockMaximum" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardPercentageOfOutstandingStockMaximum" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardPercentageOfOutstandingStockMaximum-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardPercentageOfOutstandingStockMaximum</link:label>
    <link:label xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardPercentageOfOutstandingStockMaximum-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Percentage of Outstanding Stock Maximum</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardPercentageOfOutstandingStockMaximum" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardPercentageOfOutstandingStockMaximum-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PolicyTextBlockAbstract" xlink:label="us-gaap_PolicyTextBlockAbstract" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_PolicyTextBlockAbstract-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_PolicyTextBlockAbstract</link:label>
    <link:label xlink:label="us-gaap_PolicyTextBlockAbstract-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accounting Policies</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PolicyTextBlockAbstract" xlink:to="us-gaap_PolicyTextBlockAbstract-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PrepaidExpenseCurrent" xlink:label="us-gaap_PrepaidExpenseCurrent" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_PrepaidExpenseCurrent-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_PrepaidExpenseCurrent</link:label>
    <link:label xlink:label="us-gaap_PrepaidExpenseCurrent-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Prepaid Expense, Current, Total</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PrepaidExpenseCurrent" xlink:to="us-gaap_PrepaidExpenseCurrent-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PreferredStockNoParValue" xlink:label="us-gaap_PreferredStockNoParValue" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_PreferredStockNoParValue-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Preferred stock, no par value (in dollars per share)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PreferredStockNoParValue" xlink:to="us-gaap_PreferredStockNoParValue-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ImpairmentOrDisposalOfLongLivedAssetsPolicyTextBlock" xlink:label="us-gaap_ImpairmentOrDisposalOfLongLivedAssetsPolicyTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ImpairmentOrDisposalOfLongLivedAssetsPolicyTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Impairment or Disposal of Long-Lived Assets, Policy [Policy Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ImpairmentOrDisposalOfLongLivedAssetsPolicyTextBlock" xlink:to="us-gaap_ImpairmentOrDisposalOfLongLivedAssetsPolicyTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PropertyPlantAndEquipmentDisclosureTextBlock" xlink:label="us-gaap_PropertyPlantAndEquipmentDisclosureTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_PropertyPlantAndEquipmentDisclosureTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Property, Plant and Equipment Disclosure [Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentDisclosureTextBlock" xlink:to="us-gaap_PropertyPlantAndEquipmentDisclosureTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_StatementGeographicalAxis" xlink:label="srt_StatementGeographicalAxis" xlink:type="locator"/>
    <link:label xlink:label="srt_StatementGeographicalAxis-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Geographical [Axis]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_StatementGeographicalAxis" xlink:to="srt_StatementGeographicalAxis-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTextBlock" xlink:label="us-gaap_PropertyPlantAndEquipmentTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_PropertyPlantAndEquipmentTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Property, Plant and Equipment [Table Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentTextBlock" xlink:to="us-gaap_PropertyPlantAndEquipmentTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxAssetsGross" xlink:label="us-gaap_DeferredTaxAssetsGross" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_DeferredTaxAssetsGross-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_DeferredTaxAssetsGross</link:label>
    <link:label xlink:label="us-gaap_DeferredTaxAssetsGross-label" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total deferred tax assets</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredTaxAssetsGross" xlink:to="us-gaap_DeferredTaxAssetsGross-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_SegmentGeographicalDomain" xlink:label="srt_SegmentGeographicalDomain" xlink:type="locator"/>
    <link:label xlink:label="srt_SegmentGeographicalDomain-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Geographical [Domain]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_SegmentGeographicalDomain" xlink:to="srt_SegmentGeographicalDomain-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredIncomeTaxLiabilities" xlink:label="us-gaap_DeferredIncomeTaxLiabilities" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_DeferredIncomeTaxLiabilities-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_DeferredIncomeTaxLiabilities</link:label>
    <link:label xlink:label="us-gaap_DeferredIncomeTaxLiabilities-label" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total deferred tax liabilities</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredIncomeTaxLiabilities" xlink:to="us-gaap_DeferredIncomeTaxLiabilities-label" xlink:type="arc"/>
    <link:loc xlink:href="xbit-20191231.xsd#xbit_ProceedsFromIssuanceOfCommonStockAndWarrantsNet" xlink:label="xbit_ProceedsFromIssuanceOfCommonStockAndWarrantsNet" xlink:type="locator"/>
    <link:label xlink:label="xbit_ProceedsFromIssuanceOfCommonStockAndWarrantsNet-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Issuance of common stock and warrants, net</link:label>
    <link:label xlink:label="xbit_ProceedsFromIssuanceOfCommonStockAndWarrantsNet-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The cash inflow from issuance of common stock and warrants.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="xbit_ProceedsFromIssuanceOfCommonStockAndWarrantsNet" xlink:to="xbit_ProceedsFromIssuanceOfCommonStockAndWarrantsNet-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccruedProfessionalFeesCurrent" xlink:label="us-gaap_AccruedProfessionalFeesCurrent" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_AccruedProfessionalFeesCurrent-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accrued professional fees</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AccruedProfessionalFeesCurrent" xlink:to="us-gaap_AccruedProfessionalFeesCurrent-label" xlink:type="arc"/>
    <link:loc xlink:href="xbit-20191231.xsd#xbit_CurrentOtherTaxExpenseBenefit" xlink:label="xbit_CurrentOtherTaxExpenseBenefit" xlink:type="locator"/>
    <link:label xlink:label="xbit_CurrentOtherTaxExpenseBenefit-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">xbit_CurrentOtherTaxExpenseBenefit</link:label>
    <link:label xlink:label="xbit_CurrentOtherTaxExpenseBenefit-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Other Foreign</link:label>
    <link:label xlink:label="xbit_CurrentOtherTaxExpenseBenefit-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Amount of other current income tax expense (benefit) pertaining to income (loss) from continuing operations.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="xbit_CurrentOtherTaxExpenseBenefit" xlink:to="xbit_CurrentOtherTaxExpenseBenefit-label" xlink:type="arc"/>
    <link:loc xlink:href="xbit-20191231.xsd#xbit_ProceedsFromSaleOfProductiveAssetsOperatingActivities" xlink:label="xbit_ProceedsFromSaleOfProductiveAssetsOperatingActivities" xlink:type="locator"/>
    <link:label xlink:label="xbit_ProceedsFromSaleOfProductiveAssetsOperatingActivities-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">xbit_ProceedsFromSaleOfProductiveAssetsOperatingActivities</link:label>
    <link:label xlink:label="xbit_ProceedsFromSaleOfProductiveAssetsOperatingActivities-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Proceeds from Sale of Productive Assets, Operating Activities</link:label>
    <link:label xlink:label="xbit_ProceedsFromSaleOfProductiveAssetsOperatingActivities-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The cash inflow from the sale of property, plant and equipment (capital expenditures), software, and other intangible assets as part of operating activities.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="xbit_ProceedsFromSaleOfProductiveAssetsOperatingActivities" xlink:to="xbit_ProceedsFromSaleOfProductiveAssetsOperatingActivities-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxAssetsInProcessResearchAndDevelopment" xlink:label="us-gaap_DeferredTaxAssetsInProcessResearchAndDevelopment" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_DeferredTaxAssetsInProcessResearchAndDevelopment-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Qualifying research and development credits</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredTaxAssetsInProcessResearchAndDevelopment" xlink:to="us-gaap_DeferredTaxAssetsInProcessResearchAndDevelopment-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:label="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_PaymentsToAcquirePropertyPlantAndEquipment</link:label>
    <link:label xlink:label="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment-label" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Purchase of property and equipment</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:to="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ForeignCurrencyTransactionGainLossBeforeTax" xlink:label="us-gaap_ForeignCurrencyTransactionGainLossBeforeTax" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ForeignCurrencyTransactionGainLossBeforeTax-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Foreign exchange gain (loss)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ForeignCurrencyTransactionGainLossBeforeTax" xlink:to="us-gaap_ForeignCurrencyTransactionGainLossBeforeTax-label" xlink:type="arc"/>
    <link:loc xlink:href="xbit-20191231.xsd#xbit_EffectiveIncomeTaxRateReconciliationCapitalGainExclusionPercent" xlink:label="xbit_EffectiveIncomeTaxRateReconciliationCapitalGainExclusionPercent" xlink:type="locator"/>
    <link:label xlink:label="xbit_EffectiveIncomeTaxRateReconciliationCapitalGainExclusionPercent-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Capital gain exclusion</link:label>
    <link:label xlink:label="xbit_EffectiveIncomeTaxRateReconciliationCapitalGainExclusionPercent-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to capital gain exclusion.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="xbit_EffectiveIncomeTaxRateReconciliationCapitalGainExclusionPercent" xlink:to="xbit_EffectiveIncomeTaxRateReconciliationCapitalGainExclusionPercent-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod</link:label>
    <link:label xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod" xlink:to="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LiabilitiesCurrentAbstract" xlink:label="us-gaap_LiabilitiesCurrentAbstract" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_LiabilitiesCurrentAbstract-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Current liabilities:</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LiabilitiesCurrentAbstract" xlink:to="us-gaap_LiabilitiesCurrentAbstract-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsDeferredRent" xlink:label="us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsDeferredRent" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsDeferredRent-label" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Deferred rent</link:label>
    <link:label xlink:label="us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsDeferredRent-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsDeferredRent</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsDeferredRent" xlink:to="us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsDeferredRent-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAccruedLiabilities" xlink:label="us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAccruedLiabilities" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAccruedLiabilities-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accrued liabilities</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAccruedLiabilities" xlink:to="us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAccruedLiabilities-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SupplementalCashFlowInformationAbstract" xlink:label="us-gaap_SupplementalCashFlowInformationAbstract" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_SupplementalCashFlowInformationAbstract-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Supplemental Information:</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SupplementalCashFlowInformationAbstract" xlink:to="us-gaap_SupplementalCashFlowInformationAbstract-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_Assets" xlink:label="us-gaap_Assets" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_Assets-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_Assets</link:label>
    <link:label xlink:label="us-gaap_Assets-label" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total assets</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_Assets" xlink:to="us-gaap_Assets-label" xlink:type="arc"/>
    <link:loc xlink:href="xbit-20191231.xsd#xbit_PercentageOfOutstandingSharesRepurchased" xlink:label="xbit_PercentageOfOutstandingSharesRepurchased" xlink:type="locator"/>
    <link:label xlink:label="xbit_PercentageOfOutstandingSharesRepurchased-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">xbit_PercentageOfOutstandingSharesRepurchased</link:label>
    <link:label xlink:label="xbit_PercentageOfOutstandingSharesRepurchased-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Percentage of Outstanding Shares Repurchased</link:label>
    <link:label xlink:label="xbit_PercentageOfOutstandingSharesRepurchased-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the percentage of outstanding shares repurchased.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="xbit_PercentageOfOutstandingSharesRepurchased" xlink:to="xbit_PercentageOfOutstandingSharesRepurchased-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLife" xlink:label="us-gaap_PropertyPlantAndEquipmentUsefulLife" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_PropertyPlantAndEquipmentUsefulLife-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_PropertyPlantAndEquipmentUsefulLife</link:label>
    <link:label xlink:label="us-gaap_PropertyPlantAndEquipmentUsefulLife-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Property, Plant and Equipment, Useful Life</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentUsefulLife" xlink:to="us-gaap_PropertyPlantAndEquipmentUsefulLife-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PlanNameAxis" xlink:label="us-gaap_PlanNameAxis" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_PlanNameAxis-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Plan Name [Axis]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PlanNameAxis" xlink:to="us-gaap_PlanNameAxis-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PlanNameDomain" xlink:label="us-gaap_PlanNameDomain" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_PlanNameDomain-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Plan Name [Domain]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PlanNameDomain" xlink:to="us-gaap_PlanNameDomain-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions</link:label>
    <link:label xlink:label="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Share-based Payment Arrangement, Nonvested Award, Option, Cost Not yet Recognized, Amount</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions" xlink:to="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ConstructionInProgressMember" xlink:label="us-gaap_ConstructionInProgressMember" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ConstructionInProgressMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Construction in Progress [Member]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ConstructionInProgressMember" xlink:to="us-gaap_ConstructionInProgressMember-label" xlink:type="arc"/>
    <link:loc xlink:href="xbit-20191231.xsd#xbit_TrueHumanAntibodyBermekimabMember" xlink:label="xbit_TrueHumanAntibodyBermekimabMember" xlink:type="locator"/>
    <link:label xlink:label="xbit_TrueHumanAntibodyBermekimabMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">True Human Antibody Bermekimab [Member]</link:label>
    <link:label xlink:label="xbit_TrueHumanAntibodyBermekimabMember-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Information pertaining to the True Human Antibody bermekimab.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="xbit_TrueHumanAntibodyBermekimabMember" xlink:to="xbit_TrueHumanAntibodyBermekimabMember-label" xlink:type="arc"/>
    <link:loc xlink:href="xbit-20191231.xsd#xbit_PercentageOfOutstandingSharesToBeRepurchased" xlink:label="xbit_PercentageOfOutstandingSharesToBeRepurchased" xlink:type="locator"/>
    <link:label xlink:label="xbit_PercentageOfOutstandingSharesToBeRepurchased-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">xbit_PercentageOfOutstandingSharesToBeRepurchased</link:label>
    <link:label xlink:label="xbit_PercentageOfOutstandingSharesToBeRepurchased-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Percentage of Outstanding Shares to be Repurchased</link:label>
    <link:label xlink:label="xbit_PercentageOfOutstandingSharesToBeRepurchased-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the percentage of outstanding shares to be repurchased.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="xbit_PercentageOfOutstandingSharesToBeRepurchased" xlink:to="xbit_PercentageOfOutstandingSharesToBeRepurchased-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Operating activities</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1</link:label>
    <link:label xlink:label="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:to="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1-label" xlink:type="arc"/>
    <link:loc xlink:href="xbit-20191231.xsd#xbit_GainLossOnDispositionOfAssetsExcludingEscrowReceivable" xlink:label="xbit_GainLossOnDispositionOfAssetsExcludingEscrowReceivable" xlink:type="locator"/>
    <link:label xlink:label="xbit_GainLossOnDispositionOfAssetsExcludingEscrowReceivable-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">xbit_GainLossOnDispositionOfAssetsExcludingEscrowReceivable</link:label>
    <link:label xlink:label="xbit_GainLossOnDispositionOfAssetsExcludingEscrowReceivable-label" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Gain from Janssen Transaction</link:label>
    <link:label xlink:label="xbit_GainLossOnDispositionOfAssetsExcludingEscrowReceivable-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Amount of gain (loss) on sale or disposal of assets, including but not limited to property plant and equipment, intangible assets and equity in securities of subsidiaries or equity method investee, excluding escrow receivable.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="xbit_GainLossOnDispositionOfAssetsExcludingEscrowReceivable" xlink:to="xbit_GainLossOnDispositionOfAssetsExcludingEscrowReceivable-label" xlink:type="arc"/>
    <link:loc xlink:href="xbit-20191231.xsd#xbit_AmountHeldInEscrow" xlink:label="xbit_AmountHeldInEscrow" xlink:type="locator"/>
    <link:label xlink:label="xbit_AmountHeldInEscrow-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">xbit_AmountHeldInEscrow</link:label>
    <link:label xlink:label="xbit_AmountHeldInEscrow-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Amount Held in Escrow</link:label>
    <link:label xlink:label="xbit_AmountHeldInEscrow-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the amount held in escrow upon satisfaction of indemnity claims.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="xbit_AmountHeldInEscrow" xlink:to="xbit_AmountHeldInEscrow-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementLineItems" xlink:label="us-gaap_StatementLineItems" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_StatementLineItems-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Statement [Line Items]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StatementLineItems-label" xlink:type="arc"/>
    <link:loc xlink:href="xbit-20191231.xsd#xbit_MilestonePaymentsToBeReceivedNumberOfInstallments" xlink:label="xbit_MilestonePaymentsToBeReceivedNumberOfInstallments" xlink:type="locator"/>
    <link:label xlink:label="xbit_MilestonePaymentsToBeReceivedNumberOfInstallments-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">xbit_MilestonePaymentsToBeReceivedNumberOfInstallments</link:label>
    <link:label xlink:label="xbit_MilestonePaymentsToBeReceivedNumberOfInstallments-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Milestone Payments to be Received, Number of Installments</link:label>
    <link:label xlink:label="xbit_MilestonePaymentsToBeReceivedNumberOfInstallments-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the number of installments for milestone payments to be received.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="xbit_MilestonePaymentsToBeReceivedNumberOfInstallments" xlink:to="xbit_MilestonePaymentsToBeReceivedNumberOfInstallments-label" xlink:type="arc"/>
    <link:loc xlink:href="xbit-20191231.xsd#xbit_MilestonePaymentsToBeReceivedForEachInstallment" xlink:label="xbit_MilestonePaymentsToBeReceivedForEachInstallment" xlink:type="locator"/>
    <link:label xlink:label="xbit_MilestonePaymentsToBeReceivedForEachInstallment-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">xbit_MilestonePaymentsToBeReceivedForEachInstallment</link:label>
    <link:label xlink:label="xbit_MilestonePaymentsToBeReceivedForEachInstallment-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Milestone Payments to be Received for each Installment</link:label>
    <link:label xlink:label="xbit_MilestonePaymentsToBeReceivedForEachInstallment-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the amount of milestone payments to be received for each installment.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="xbit_MilestonePaymentsToBeReceivedForEachInstallment" xlink:to="xbit_MilestonePaymentsToBeReceivedForEachInstallment-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FurnitureAndFixturesMember" xlink:label="us-gaap_FurnitureAndFixturesMember" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_FurnitureAndFixturesMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Furniture and Fixtures [Member]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FurnitureAndFixturesMember" xlink:to="us-gaap_FurnitureAndFixturesMember-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NumberOfOperatingSegments" xlink:label="us-gaap_NumberOfOperatingSegments" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_NumberOfOperatingSegments-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_NumberOfOperatingSegments</link:label>
    <link:label xlink:label="us-gaap_NumberOfOperatingSegments-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of Operating Segments</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NumberOfOperatingSegments" xlink:to="us-gaap_NumberOfOperatingSegments-label" xlink:type="arc"/>
    <link:loc xlink:href="xbit-20191231.xsd#xbit_PeriodOfAmountHeldInEscrow" xlink:label="xbit_PeriodOfAmountHeldInEscrow" xlink:type="locator"/>
    <link:label xlink:label="xbit_PeriodOfAmountHeldInEscrow-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">xbit_PeriodOfAmountHeldInEscrow</link:label>
    <link:label xlink:label="xbit_PeriodOfAmountHeldInEscrow-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Period of Amount Held in Escrow</link:label>
    <link:label xlink:label="xbit_PeriodOfAmountHeldInEscrow-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the period of amount held in escrow upon satisfaction of indemnity claims.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="xbit_PeriodOfAmountHeldInEscrow" xlink:to="xbit_PeriodOfAmountHeldInEscrow-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost" xlink:label="us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Stock based compensation</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost" xlink:to="us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredIncomeTaxAssetsNet" xlink:label="us-gaap_DeferredIncomeTaxAssetsNet" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_DeferredIncomeTaxAssetsNet-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred tax asset</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredIncomeTaxAssetsNet" xlink:to="us-gaap_DeferredIncomeTaxAssetsNet-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BuildingMember" xlink:label="us-gaap_BuildingMember" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_BuildingMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Building [Member]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_BuildingMember" xlink:to="us-gaap_BuildingMember-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock" xlink:label="us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-based Payment Arrangement [Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock" xlink:to="us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTextBlock" xlink:label="us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTextBlock" xlink:to="us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">AOCI Attributable to Parent [Member]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:to="us-gaap_AccumulatedOtherComprehensiveIncomeMember-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockholdersEquityAbstract" xlink:label="us-gaap_StockholdersEquityAbstract" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_StockholdersEquityAbstract-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Shareholders&#8217; equity:</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockholdersEquityAbstract" xlink:to="us-gaap_StockholdersEquityAbstract-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockholdersEquityNoteSubscriptionsReceivable" xlink:label="us-gaap_StockholdersEquityNoteSubscriptionsReceivable" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_StockholdersEquityNoteSubscriptionsReceivable-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_StockholdersEquityNoteSubscriptionsReceivable</link:label>
    <link:label xlink:label="us-gaap_StockholdersEquityNoteSubscriptionsReceivable-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Stockholders' Equity Note, Subscriptions Receivable</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockholdersEquityNoteSubscriptionsReceivable" xlink:to="us-gaap_StockholdersEquityNoteSubscriptionsReceivable-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LandMember" xlink:label="us-gaap_LandMember" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_LandMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Land [Member]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LandMember" xlink:to="us-gaap_LandMember-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LeaseholdImprovementsMember" xlink:label="us-gaap_LeaseholdImprovementsMember" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_LeaseholdImprovementsMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Leasehold Improvements [Member]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LeaseholdImprovementsMember" xlink:to="us-gaap_LeaseholdImprovementsMember-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PropertyPlantAndEquipmentPolicyTextBlock" xlink:label="us-gaap_PropertyPlantAndEquipmentPolicyTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_PropertyPlantAndEquipmentPolicyTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Property, Plant and Equipment, Policy [Policy Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentPolicyTextBlock" xlink:to="us-gaap_PropertyPlantAndEquipmentPolicyTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:label="us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_PropertyPlantAndEquipmentByTypeAxis-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Property, Plant and Equipment, Type [Axis]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:to="us-gaap_PropertyPlantAndEquipmentByTypeAxis-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NonoperatingIncomeExpense" xlink:label="us-gaap_NonoperatingIncomeExpense" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_NonoperatingIncomeExpense-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_NonoperatingIncomeExpense</link:label>
    <link:label xlink:label="us-gaap_NonoperatingIncomeExpense-label" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total other income (loss)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NonoperatingIncomeExpense" xlink:to="us-gaap_NonoperatingIncomeExpense-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:label="us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_PropertyPlantAndEquipmentTypeDomain-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Property, Plant and Equipment, Type [Domain]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:to="us-gaap_PropertyPlantAndEquipmentTypeDomain-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Award Type [Domain]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxAssetsOperatingLossCarryforwards" xlink:label="us-gaap_DeferredTaxAssetsOperatingLossCarryforwards" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_DeferredTaxAssetsOperatingLossCarryforwards-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Noncapital losses</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredTaxAssetsOperatingLossCarryforwards" xlink:to="us-gaap_DeferredTaxAssetsOperatingLossCarryforwards-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OtherNonoperatingIncome" xlink:label="us-gaap_OtherNonoperatingIncome" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_OtherNonoperatingIncome-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other income</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OtherNonoperatingIncome" xlink:to="us-gaap_OtherNonoperatingIncome-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AssetsCurrentAbstract" xlink:label="us-gaap_AssetsCurrentAbstract" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_AssetsCurrentAbstract-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Current assets:</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AssetsCurrentAbstract" xlink:to="us-gaap_AssetsCurrentAbstract-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_InvestmentIncomeNet" xlink:label="us-gaap_InvestmentIncomeNet" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_InvestmentIncomeNet-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Interest income</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InvestmentIncomeNet" xlink:to="us-gaap_InvestmentIncomeNet-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="us-gaap_AwardTypeAxis" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_AwardTypeAxis-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Award Type [Axis]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AwardTypeAxis" xlink:to="us-gaap_AwardTypeAxis-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="us-gaap_NetIncomeLoss" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_NetIncomeLoss-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Net income (loss)</link:label>
    <link:label xlink:label="us-gaap_NetIncomeLoss-label" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Net income (loss)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetIncomeLoss" xlink:to="us-gaap_NetIncomeLoss-label" xlink:type="arc"/>
    <link:loc xlink:href="xbit-20191231.xsd#xbit_SubscriptionReceivable" xlink:label="xbit_SubscriptionReceivable" xlink:type="locator"/>
    <link:label xlink:label="xbit_SubscriptionReceivable-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">xbit_SubscriptionReceivable</link:label>
    <link:label xlink:label="xbit_SubscriptionReceivable-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Subscription receivable</link:label>
    <link:label xlink:label="xbit_SubscriptionReceivable-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The amount of subscription receivable.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="xbit_SubscriptionReceivable" xlink:to="xbit_SubscriptionReceivable-label" xlink:type="arc"/>
    <link:loc xlink:href="xbit-20191231.xsd#xbit_EffectiveIncomeTaxRateReconciliationPriorYearTrueupsPercent" xlink:label="xbit_EffectiveIncomeTaxRateReconciliationPriorYearTrueupsPercent" xlink:type="locator"/>
    <link:label xlink:label="xbit_EffectiveIncomeTaxRateReconciliationPriorYearTrueupsPercent-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Prior year true-ups</link:label>
    <link:label xlink:label="xbit_EffectiveIncomeTaxRateReconciliationPriorYearTrueupsPercent-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations applicable to prior year true-ups.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="xbit_EffectiveIncomeTaxRateReconciliationPriorYearTrueupsPercent" xlink:to="xbit_EffectiveIncomeTaxRateReconciliationPriorYearTrueupsPercent-label" xlink:type="arc"/>
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    <link:label xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivities-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_NetCashProvidedByUsedInFinancingActivities</link:label>
    <link:label xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivities-label" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Net cash provided by financing activities</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="us-gaap_NetCashProvidedByUsedInFinancingActivities-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_Liabilities" xlink:label="us-gaap_Liabilities" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_Liabilities-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_Liabilities</link:label>
    <link:label xlink:label="us-gaap_Liabilities-label" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total liabilities</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_Liabilities" xlink:to="us-gaap_Liabilities-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SubsidiarySaleOfStockAxis" xlink:label="us-gaap_SubsidiarySaleOfStockAxis" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_SubsidiarySaleOfStockAxis-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sale of Stock [Axis]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SubsidiarySaleOfStockAxis" xlink:to="us-gaap_SubsidiarySaleOfStockAxis-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SaleOfStockNameOfTransactionDomain" xlink:label="us-gaap_SaleOfStockNameOfTransactionDomain" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_SaleOfStockNameOfTransactionDomain-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sale of Stock [Domain]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SaleOfStockNameOfTransactionDomain" xlink:to="us-gaap_SaleOfStockNameOfTransactionDomain-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingIncomeLoss" xlink:label="us-gaap_OperatingIncomeLoss" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_OperatingIncomeLoss-label" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Loss from operations</link:label>
    <link:label xlink:label="us-gaap_OperatingIncomeLoss-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_OperatingIncomeLoss</link:label>
    <link:label xlink:label="us-gaap_OperatingIncomeLoss-label" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Loss from operations</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingIncomeLoss" xlink:to="us-gaap_OperatingIncomeLoss-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EmployeeStockOptionMember" xlink:label="us-gaap_EmployeeStockOptionMember" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_EmployeeStockOptionMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-based Payment Arrangement, Option [Member]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EmployeeStockOptionMember" xlink:to="us-gaap_EmployeeStockOptionMember-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivities-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_NetCashProvidedByUsedInOperatingActivities</link:label>
    <link:label xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivities-label" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Net cash used in operating activities</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="us-gaap_NetCashProvidedByUsedInOperatingActivities-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivities-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_NetCashProvidedByUsedInInvestingActivities</link:label>
    <link:label xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivities-label" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Net cash provided by investing activities</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:to="us-gaap_NetCashProvidedByUsedInInvestingActivities-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_WarrantMember" xlink:label="us-gaap_WarrantMember" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_WarrantMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Warrant [Member]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_WarrantMember" xlink:to="us-gaap_WarrantMember-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PrepaidExpenseAndOtherAssetsCurrent" xlink:label="us-gaap_PrepaidExpenseAndOtherAssetsCurrent" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_PrepaidExpenseAndOtherAssetsCurrent-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Prepaid expenses and other current assets</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PrepaidExpenseAndOtherAssetsCurrent" xlink:to="us-gaap_PrepaidExpenseAndOtherAssetsCurrent-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTextBlock" xlink:label="us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTextBlock" xlink:to="us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EffectOfExchangeRateOnCashAndCashEquivalents" xlink:label="us-gaap_EffectOfExchangeRateOnCashAndCashEquivalents" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_EffectOfExchangeRateOnCashAndCashEquivalents-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Effect of foreign exchange rate on cash and cash equivalents</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EffectOfExchangeRateOnCashAndCashEquivalents" xlink:to="us-gaap_EffectOfExchangeRateOnCashAndCashEquivalents-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease" xlink:label="us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease</link:label>
    <link:label xlink:label="us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease-label" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Net change in cash and cash equivalents</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease" xlink:to="us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:label="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Antidilutive Securities [Axis]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:to="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AntidilutiveSecuritiesNameDomain" xlink:label="us-gaap_AntidilutiveSecuritiesNameDomain" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_AntidilutiveSecuritiesNameDomain-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Antidilutive Securities, Name [Domain]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AntidilutiveSecuritiesNameDomain" xlink:to="us-gaap_AntidilutiveSecuritiesNameDomain-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:label="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment</link:label>
    <link:label xlink:label="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment-label" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Accumulated depreciation</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:to="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="us-gaap_PropertyPlantAndEquipmentNet" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_PropertyPlantAndEquipmentNet-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Property and equipment, net</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentNet" xlink:to="us-gaap_PropertyPlantAndEquipmentNet-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccountingStandardsUpdate201602Member" xlink:label="us-gaap_AccountingStandardsUpdate201602Member" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_AccountingStandardsUpdate201602Member-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accounting Standards Update 2016-02 [Member]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AccountingStandardsUpdate201602Member" xlink:to="us-gaap_AccountingStandardsUpdate201602Member-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PropertyPlantAndEquipmentGross" xlink:label="us-gaap_PropertyPlantAndEquipmentGross" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_PropertyPlantAndEquipmentGross-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Property, plant, and equipment, gross</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentGross" xlink:to="us-gaap_PropertyPlantAndEquipmentGross-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_TypeOfAdoptionMember" xlink:label="us-gaap_TypeOfAdoptionMember" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_TypeOfAdoptionMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Type of Adoption [Domain]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TypeOfAdoptionMember" xlink:to="us-gaap_TypeOfAdoptionMember-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CanadaRevenueAgencyMember" xlink:label="us-gaap_CanadaRevenueAgencyMember" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_CanadaRevenueAgencyMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Canada Revenue Agency [Member]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CanadaRevenueAgencyMember" xlink:to="us-gaap_CanadaRevenueAgencyMember-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ConcentrationRiskCreditRisk" xlink:label="us-gaap_ConcentrationRiskCreditRisk" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ConcentrationRiskCreditRisk-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Concentration Risk, Credit Risk, Policy [Policy Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ConcentrationRiskCreditRisk" xlink:to="us-gaap_ConcentrationRiskCreditRisk-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment" xlink:label="us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment</link:label>
    <link:label xlink:label="us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment-label" xlink:role="http://www.xbrl.org/2009/role/netLabel" xlink:type="resource" xml:lang="en-US">Depreciation</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment" xlink:to="us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxLiabilitiesPrepaidExpenses" xlink:label="us-gaap_DeferredTaxLiabilitiesPrepaidExpenses" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_DeferredTaxLiabilitiesPrepaidExpenses-label" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Prepaid assets</link:label>
    <link:label xlink:label="us-gaap_DeferredTaxLiabilitiesPrepaidExpenses-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_DeferredTaxLiabilitiesPrepaidExpenses</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredTaxLiabilitiesPrepaidExpenses" xlink:to="us-gaap_DeferredTaxLiabilitiesPrepaidExpenses-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AdjustmentsForNewAccountingPronouncementsAxis" xlink:label="us-gaap_AdjustmentsForNewAccountingPronouncementsAxis" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_AdjustmentsForNewAccountingPronouncementsAxis-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Adjustments for New Accounting Pronouncements [Axis]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AdjustmentsForNewAccountingPronouncementsAxis" xlink:to="us-gaap_AdjustmentsForNewAccountingPronouncementsAxis-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxLiabilitiesAbstract" xlink:label="us-gaap_DeferredTaxLiabilitiesAbstract" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_DeferredTaxLiabilitiesAbstract-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred tax liabilities:</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredTaxLiabilitiesAbstract" xlink:to="us-gaap_DeferredTaxLiabilitiesAbstract-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Investing activities</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:to="us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract-label" xlink:type="arc"/>
    <link:loc xlink:href="xbit-20191231.xsd#xbit_CommonStockShareSubscribedValueIssuance" xlink:label="xbit_CommonStockShareSubscribedValueIssuance" xlink:type="locator"/>
    <link:label xlink:label="xbit_CommonStockShareSubscribedValueIssuance-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Subscription receivable</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CurrentIncomeTaxExpenseBenefit" xlink:to="us-gaap_CurrentIncomeTaxExpenseBenefit-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncreaseDecreaseInAccountsPayable" xlink:label="us-gaap_IncreaseDecreaseInAccountsPayable" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_IncreaseDecreaseInAccountsPayable-label" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Accounts payable</link:label>
    <link:label xlink:label="us-gaap_IncreaseDecreaseInAccountsPayable-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_IncreaseDecreaseInAccountsPayable</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncreaseDecreaseInAccountsPayable" xlink:to="us-gaap_IncreaseDecreaseInAccountsPayable-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign" xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign-label" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">United States</link:label>
    <link:label xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign" xlink:to="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest</link:label>
    <link:label xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest-label" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Income before income taxes</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:to="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic" xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic-label" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Canada</link:label>
    <link:label xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic" xlink:to="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingExpenses" xlink:label="us-gaap_OperatingExpenses" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_OperatingExpenses-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_OperatingExpenses</link:label>
    <link:label xlink:label="us-gaap_OperatingExpenses-label" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total operating expenses</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingExpenses" xlink:to="us-gaap_OperatingExpenses-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_GeneralAndAdministrativeExpense" xlink:label="us-gaap_GeneralAndAdministrativeExpense" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_GeneralAndAdministrativeExpense-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">General and administrative</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_GeneralAndAdministrativeExpense" xlink:to="us-gaap_GeneralAndAdministrativeExpense-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_CashAndCashEquivalentsAtCarryingValue-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cash and cash equivalents</link:label>
    <link:label xlink:label="us-gaap_CashAndCashEquivalentsAtCarryingValue-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Cash and Cash Equivalents, at Carrying Value, Ending Balance</link:label>
    <link:label xlink:label="us-gaap_CashAndCashEquivalentsAtCarryingValue-label" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:type="resource" xml:lang="en-US">Cash and cash equivalents, beginning of period</link:label>
    <link:label xlink:label="us-gaap_CashAndCashEquivalentsAtCarryingValue-label" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:type="resource" xml:lang="en-US">Cash and cash equivalents, end of period</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:to="us-gaap_CashAndCashEquivalentsAtCarryingValue-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_VehiclesMember" xlink:label="us-gaap_VehiclesMember" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_VehiclesMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Vehicles [Member]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_VehiclesMember" xlink:to="us-gaap_VehiclesMember-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeTaxAuthorityNameAxis" xlink:label="us-gaap_IncomeTaxAuthorityNameAxis" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_IncomeTaxAuthorityNameAxis-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income Tax Authority, Name [Axis]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncomeTaxAuthorityNameAxis" xlink:to="us-gaap_IncomeTaxAuthorityNameAxis-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeTaxAuthorityNameDomain" xlink:label="us-gaap_IncomeTaxAuthorityNameDomain" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_IncomeTaxAuthorityNameDomain-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income Tax Authority, Name [Domain]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncomeTaxAuthorityNameDomain" xlink:to="us-gaap_IncomeTaxAuthorityNameDomain-label" xlink:type="arc"/>
    <link:loc xlink:href="xbit-20191231.xsd#xbit_StockRepurchaseProgramMaximumPurchasePricePerShare" xlink:label="xbit_StockRepurchaseProgramMaximumPurchasePricePerShare" xlink:type="locator"/>
    <link:label xlink:label="xbit_StockRepurchaseProgramMaximumPurchasePricePerShare-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">xbit_StockRepurchaseProgramMaximumPurchasePricePerShare</link:label>
    <link:label xlink:label="xbit_StockRepurchaseProgramMaximumPurchasePricePerShare-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Stock Repurchase Program, Maximum Purchase Price Per Share</link:label>
    <link:label xlink:label="xbit_StockRepurchaseProgramMaximumPurchasePricePerShare-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the maximum purchase price per share under stock repurchase plan.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="xbit_StockRepurchaseProgramMaximumPurchasePricePerShare" xlink:to="xbit_StockRepurchaseProgramMaximumPurchasePricePerShare-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_InternalRevenueServiceIRSMember" xlink:label="us-gaap_InternalRevenueServiceIRSMember" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_InternalRevenueServiceIRSMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Internal Revenue Service (IRS) [Member]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InternalRevenueServiceIRSMember" xlink:to="us-gaap_InternalRevenueServiceIRSMember-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeTaxAuthorityAxis" xlink:label="us-gaap_IncomeTaxAuthorityAxis" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_IncomeTaxAuthorityAxis-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income Tax Authority [Axis]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncomeTaxAuthorityAxis" xlink:to="us-gaap_IncomeTaxAuthorityAxis-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncreaseDecreaseInPropertyAndOtherTaxesPayable" xlink:label="us-gaap_IncreaseDecreaseInPropertyAndOtherTaxesPayable" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_IncreaseDecreaseInPropertyAndOtherTaxesPayable-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_IncreaseDecreaseInPropertyAndOtherTaxesPayable</link:label>
    <link:label xlink:label="us-gaap_IncreaseDecreaseInPropertyAndOtherTaxesPayable-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Other taxes payable</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncreaseDecreaseInPropertyAndOtherTaxesPayable" xlink:to="us-gaap_IncreaseDecreaseInPropertyAndOtherTaxesPayable-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeTaxAuthorityDomain" xlink:label="us-gaap_IncomeTaxAuthorityDomain" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_IncomeTaxAuthorityDomain-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income Tax Authority [Domain]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncomeTaxAuthorityDomain" xlink:to="us-gaap_IncomeTaxAuthorityDomain-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DomesticCountryMember" xlink:label="us-gaap_DomesticCountryMember" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_DomesticCountryMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Domestic Tax Authority [Member]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DomesticCountryMember" xlink:to="us-gaap_DomesticCountryMember-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense" xlink:label="us-gaap_AllocatedShareBasedCompensationExpense" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_AllocatedShareBasedCompensationExpense-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_AllocatedShareBasedCompensationExpense</link:label>
    <link:label xlink:label="us-gaap_AllocatedShareBasedCompensationExpense-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Share-based compensation expense</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AllocatedShareBasedCompensationExpense" xlink:to="us-gaap_AllocatedShareBasedCompensationExpense-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ForeignCountryMember" xlink:label="us-gaap_ForeignCountryMember" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ForeignCountryMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Foreign Tax Authority [Member]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ForeignCountryMember" xlink:to="us-gaap_ForeignCountryMember-label" xlink:type="arc"/>
    <link:loc xlink:href="xbit-20191231.xsd#xbit_StockRepurchasedDuringPeriodPricePerShare" xlink:label="xbit_StockRepurchasedDuringPeriodPricePerShare" xlink:type="locator"/>
    <link:label xlink:label="xbit_StockRepurchasedDuringPeriodPricePerShare-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">xbit_StockRepurchasedDuringPeriodPricePerShare</link:label>
    <link:label xlink:label="xbit_StockRepurchasedDuringPeriodPricePerShare-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Stock Repurchased During Period, Price Per Share</link:label>
    <link:label xlink:label="xbit_StockRepurchasedDuringPeriodPricePerShare-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the price per share for stock repurchased during the period.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="xbit_StockRepurchasedDuringPeriodPricePerShare" xlink:to="xbit_StockRepurchasedDuringPeriodPricePerShare-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OfficeEquipmentMember" xlink:label="us-gaap_OfficeEquipmentMember" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_OfficeEquipmentMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Office Equipment [Member]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OfficeEquipmentMember" xlink:to="us-gaap_OfficeEquipmentMember-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EquipmentMember" xlink:label="us-gaap_EquipmentMember" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_EquipmentMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equipment [Member]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EquipmentMember" xlink:to="us-gaap_EquipmentMember-label" xlink:type="arc"/>
    <link:loc xlink:href="xbit-20191231.xsd#xbit_ReclassificationOfPropertyPlantAndEquipment" xlink:label="xbit_ReclassificationOfPropertyPlantAndEquipment" xlink:type="locator"/>
    <link:label xlink:label="xbit_ReclassificationOfPropertyPlantAndEquipment-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other non-cash adjustments</link:label>
    <link:label xlink:label="xbit_ReclassificationOfPropertyPlantAndEquipment-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the amount of PPE that was reclassified.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="xbit_ReclassificationOfPropertyPlantAndEquipment" xlink:to="xbit_ReclassificationOfPropertyPlantAndEquipment-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncreaseDecreaseInDeferredLiabilities" xlink:label="us-gaap_IncreaseDecreaseInDeferredLiabilities" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_IncreaseDecreaseInDeferredLiabilities-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_IncreaseDecreaseInDeferredLiabilities</link:label>
    <link:label xlink:label="us-gaap_IncreaseDecreaseInDeferredLiabilities-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Deferred rent</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncreaseDecreaseInDeferredLiabilities" xlink:to="us-gaap_IncreaseDecreaseInDeferredLiabilities-label" xlink:type="arc"/>
    <link:loc xlink:href="xbit-20191231.xsd#xbit_UnderwritersCommissionAttributableToIssuanceOfCommonStock" xlink:label="xbit_UnderwritersCommissionAttributableToIssuanceOfCommonStock" xlink:type="locator"/>
    <link:label xlink:label="xbit_UnderwritersCommissionAttributableToIssuanceOfCommonStock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">xbit_UnderwritersCommissionAttributableToIssuanceOfCommonStock</link:label>
    <link:label xlink:label="xbit_UnderwritersCommissionAttributableToIssuanceOfCommonStock-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Underwriter's Commission Attributable to Issuance of Common Stock</link:label>
    <link:label xlink:label="xbit_UnderwritersCommissionAttributableToIssuanceOfCommonStock-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the amount of underwriter's commission related to the issuance of common stock.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="xbit_UnderwritersCommissionAttributableToIssuanceOfCommonStock" xlink:to="xbit_UnderwritersCommissionAttributableToIssuanceOfCommonStock-label" xlink:type="arc"/>
    <link:loc xlink:href="xbit-20191231.xsd#xbit_OtherRelatedFeeAttributableToIssuanceOfCommonStock" xlink:label="xbit_OtherRelatedFeeAttributableToIssuanceOfCommonStock" xlink:type="locator"/>
    <link:label xlink:label="xbit_OtherRelatedFeeAttributableToIssuanceOfCommonStock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">xbit_OtherRelatedFeeAttributableToIssuanceOfCommonStock</link:label>
    <link:label xlink:label="xbit_OtherRelatedFeeAttributableToIssuanceOfCommonStock-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Other Related Fee Attributable to Issuance of Common Stock</link:label>
    <link:label xlink:label="xbit_OtherRelatedFeeAttributableToIssuanceOfCommonStock-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the amount of other related fee attributable to the issuance of common stock.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="xbit_OtherRelatedFeeAttributableToIssuanceOfCommonStock" xlink:to="xbit_OtherRelatedFeeAttributableToIssuanceOfCommonStock-label" xlink:type="arc"/>
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    <link:label xlink:label="us-gaap_CashAndCashEquivalentsPolicyTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cash and Cash Equivalents, Policy [Policy Text Block]</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_UnrecognizedTaxBenefits" xlink:to="us-gaap_UnrecognizedTaxBenefits-label" xlink:type="arc"/>
    <link:loc xlink:href="xbit-20191231.xsd#xbit_EffectiveIncomeTaxRateReconciliationStockCompensationAndOtherPercent" xlink:label="xbit_EffectiveIncomeTaxRateReconciliationStockCompensationAndOtherPercent" xlink:type="locator"/>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_GeneralAndAdministrativeExpenseMember" xlink:to="us-gaap_GeneralAndAdministrativeExpenseMember-label" xlink:type="arc"/>
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    <link:label xlink:label="us-gaap_AccountingPoliciesAbstract-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accounting Policies [Abstract]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AccountingPoliciesAbstract" xlink:to="us-gaap_AccountingPoliciesAbstract-label" xlink:type="arc"/>
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    <link:label xlink:label="us-gaap_SignificantAccountingPoliciesTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Significant Accounting Policies [Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SignificantAccountingPoliciesTextBlock" xlink:to="us-gaap_SignificantAccountingPoliciesTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="xbit-20191231.xsd#xbit_DeferredTaxAssetsAbstract" xlink:label="xbit_DeferredTaxAssetsAbstract" xlink:type="locator"/>
    <link:label xlink:label="xbit_DeferredTaxAssetsAbstract-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred tax assets:</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="xbit_DeferredTaxAssetsAbstract" xlink:to="xbit_DeferredTaxAssetsAbstract-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ComprehensiveIncomeNetOfTax" xlink:label="us-gaap_ComprehensiveIncomeNetOfTax" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ComprehensiveIncomeNetOfTax-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_ComprehensiveIncomeNetOfTax</link:label>
    <link:label xlink:label="us-gaap_ComprehensiveIncomeNetOfTax-label" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Comprehensive income (loss)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ComprehensiveIncomeNetOfTax" xlink:to="us-gaap_ComprehensiveIncomeNetOfTax-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BasisOfAccountingPolicyPolicyTextBlock" xlink:label="us-gaap_BasisOfAccountingPolicyPolicyTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_BasisOfAccountingPolicyPolicyTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Basis of Accounting, Policy [Policy Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_BasisOfAccountingPolicyPolicyTextBlock" xlink:to="us-gaap_BasisOfAccountingPolicyPolicyTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_UseOfEstimates" xlink:label="us-gaap_UseOfEstimates" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_UseOfEstimates-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Use of Estimates, Policy [Policy Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_UseOfEstimates" xlink:to="us-gaap_UseOfEstimates-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock" xlink:label="us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">New Accounting Pronouncements, Policy [Policy Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock" xlink:to="us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="xbit-20191231.xsd#xbit_DeferredTaxLiabilitiesSharesIssuanceCosts" xlink:label="xbit_DeferredTaxLiabilitiesSharesIssuanceCosts" xlink:type="locator"/>
    <link:label xlink:label="xbit_DeferredTaxLiabilitiesSharesIssuanceCosts-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share issuance costs</link:label>
    <link:label xlink:label="xbit_DeferredTaxLiabilitiesSharesIssuanceCosts-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Amount of deferred tax liability attributable to taxable temporary differences fro shares issuance costs.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="xbit_DeferredTaxLiabilitiesSharesIssuanceCosts" xlink:to="xbit_DeferredTaxLiabilitiesSharesIssuanceCosts-label" xlink:type="arc"/>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityInteractiveDataCurrent" xlink:label="dei_EntityInteractiveDataCurrent" xlink:type="locator"/>
    <link:label xlink:label="dei_EntityInteractiveDataCurrent-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Entity Interactive Data Current</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntityInteractiveDataCurrent" xlink:to="dei_EntityInteractiveDataCurrent-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromSettlementsWithTaxingAuthorities" xlink:label="us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromSettlementsWithTaxingAuthorities" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromSettlementsWithTaxingAuthorities-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Settlements</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromSettlementsWithTaxingAuthorities" xlink:to="us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromSettlementsWithTaxingAuthorities-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption" xlink:label="us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption</link:label>
    <link:label xlink:label="us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Cumulative Effect of New Accounting Principle in Period of Adoption</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption" xlink:to="us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption-label" xlink:type="arc"/>
    <link:loc xlink:href="xbit-20191231.xsd#xbit_DeferredTaxAssetsShareIssuanceCosts" xlink:label="xbit_DeferredTaxAssetsShareIssuanceCosts" xlink:type="locator"/>
    <link:label xlink:label="xbit_DeferredTaxAssetsShareIssuanceCosts-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share issue costs</link:label>
    <link:label xlink:label="xbit_DeferredTaxAssetsShareIssuanceCosts-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from share issuance costs.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="xbit_DeferredTaxAssetsShareIssuanceCosts" xlink:to="xbit_DeferredTaxAssetsShareIssuanceCosts-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SharesOutstanding" xlink:label="us-gaap_SharesOutstanding" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_SharesOutstanding-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_SharesOutstanding</link:label>
    <link:label xlink:label="us-gaap_SharesOutstanding-label" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:type="resource" xml:lang="en-US">Balance (in shares)</link:label>
    <link:label xlink:label="us-gaap_SharesOutstanding-label" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:type="resource" xml:lang="en-US">Balance (in shares)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SharesOutstanding" xlink:to="us-gaap_SharesOutstanding-label" xlink:type="arc"/>
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    <link:label xlink:label="us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Additions for tax positions of prior years</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions" xlink:to="us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncreaseDecreaseInContractWithCustomerLiability" xlink:label="us-gaap_IncreaseDecreaseInContractWithCustomerLiability" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_IncreaseDecreaseInContractWithCustomerLiability-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_IncreaseDecreaseInContractWithCustomerLiability</link:label>
    <link:label xlink:label="us-gaap_IncreaseDecreaseInContractWithCustomerLiability-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Contract liabilities</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncreaseDecreaseInContractWithCustomerLiability" xlink:to="us-gaap_IncreaseDecreaseInContractWithCustomerLiability-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CommonStockSharesOutstanding" xlink:label="us-gaap_CommonStockSharesOutstanding" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_CommonStockSharesOutstanding-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Common stock, shares outstanding (in shares)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CommonStockSharesOutstanding" xlink:to="us-gaap_CommonStockSharesOutstanding-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions" xlink:label="us-gaap_UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Reductions for tax positions of prior years</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions" xlink:to="us-gaap_UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions-label" xlink:type="arc"/>
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    <link:label xlink:label="us-gaap_PreferredStockSharesOutstanding-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Preferred stock, shares outstanding (in shares)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PreferredStockSharesOutstanding" xlink:to="us-gaap_PreferredStockSharesOutstanding-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions" xlink:label="us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Additions based on tax positions related to the current year</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions" xlink:to="us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions-label" xlink:type="arc"/>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_Security12bTitle" xlink:label="dei_Security12bTitle" xlink:type="locator"/>
    <link:label xlink:label="dei_Security12bTitle-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Title of 12(b) Security</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_Security12bTitle" xlink:to="dei_Security12bTitle-label" xlink:type="arc"/>
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    <link:label xlink:label="dei_CurrentFiscalYearEndDate-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Current Fiscal Year End Date</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_CurrentFiscalYearEndDate" xlink:to="dei_CurrentFiscalYearEndDate-label" xlink:type="arc"/>
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    <link:label xlink:label="us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets-label" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Prepaid expenses and other current</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets" xlink:to="us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets-label" xlink:type="arc"/>
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    <link:label xlink:label="us-gaap_ResearchAndDevelopmentExpenseMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Research and Development Expense [Member]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ResearchAndDevelopmentExpenseMember" xlink:to="us-gaap_ResearchAndDevelopmentExpenseMember-label" xlink:type="arc"/>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_DocumentFiscalPeriodFocus" xlink:label="dei_DocumentFiscalPeriodFocus" xlink:type="locator"/>
    <link:label xlink:label="dei_DocumentFiscalPeriodFocus-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Document Fiscal Period Focus</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:label="us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_WeightedAverageNumberOfSharesOutstandingBasic-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Shares used to compute basic net income (loss) per share (in shares)</link:label>
    <link:label xlink:label="us-gaap_WeightedAverageNumberOfSharesOutstandingBasic-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Weighted-average number of common shares&#8212;basic (in shares)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:to="us-gaap_WeightedAverageNumberOfSharesOutstandingBasic-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccountsPayableAndAccruedLiabilitiesDisclosureTextBlock" xlink:label="us-gaap_AccountsPayableAndAccruedLiabilitiesDisclosureTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_AccountsPayableAndAccruedLiabilitiesDisclosureTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accounts Payable and Accrued Liabilities Disclosure [Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AccountsPayableAndAccruedLiabilitiesDisclosureTextBlock" xlink:to="us-gaap_AccountsPayableAndAccruedLiabilitiesDisclosureTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:label="us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_EffectiveIncomeTaxRateContinuingOperations-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_EffectiveIncomeTaxRateContinuingOperations</link:label>
    <link:label xlink:label="us-gaap_EffectiveIncomeTaxRateContinuingOperations-label" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:to="us-gaap_EffectiveIncomeTaxRateContinuingOperations-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationChangeInEnactedTaxRate" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationChangeInEnactedTaxRate" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationChangeInEnactedTaxRate-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Impacts of US tax reform</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EffectiveIncomeTaxRateReconciliationChangeInEnactedTaxRate" xlink:to="us-gaap_EffectiveIncomeTaxRateReconciliationChangeInEnactedTaxRate-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EarningsPerShareBasic" xlink:label="us-gaap_EarningsPerShareBasic" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_EarningsPerShareBasic-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Net income (loss) per share&#8212;basic (in dollars per share)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EarningsPerShareBasic" xlink:to="us-gaap_EarningsPerShareBasic-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Change in valuation allowance</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance" xlink:to="us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockRepurchasedDuringPeriodShares" xlink:label="us-gaap_StockRepurchasedDuringPeriodShares" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_StockRepurchasedDuringPeriodShares-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_StockRepurchasedDuringPeriodShares</link:label>
    <link:label xlink:label="us-gaap_StockRepurchasedDuringPeriodShares-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Stock Repurchased During Period, Shares</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockRepurchasedDuringPeriodShares" xlink:to="us-gaap_StockRepurchasedDuringPeriodShares-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementOfCashFlowsAbstract" xlink:label="us-gaap_StatementOfCashFlowsAbstract" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_StatementOfCashFlowsAbstract-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Statement of Cash Flows [Abstract]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StatementOfCashFlowsAbstract" xlink:to="us-gaap_StatementOfCashFlowsAbstract-label" xlink:type="arc"/>
    <link:loc xlink:href="xbit-20191231.xsd#xbit_DeferredTaxAssetsNetBeforeValuationAllowance" xlink:label="xbit_DeferredTaxAssetsNetBeforeValuationAllowance" xlink:type="locator"/>
    <link:label xlink:label="xbit_DeferredTaxAssetsNetBeforeValuationAllowance-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">xbit_DeferredTaxAssetsNetBeforeValuationAllowance</link:label>
    <link:label xlink:label="xbit_DeferredTaxAssetsNetBeforeValuationAllowance-label" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Net deferred tax asset</link:label>
    <link:label xlink:label="xbit_DeferredTaxAssetsNetBeforeValuationAllowance-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Amount before allocation of valuation allowances of deferred tax assets net of deferred tax liabilities attributable to deductible temporary differences and carryforwards.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="xbit_DeferredTaxAssetsNetBeforeValuationAllowance" xlink:to="xbit_DeferredTaxAssetsNetBeforeValuationAllowance-label" xlink:type="arc"/>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityCommonStockSharesOutstanding" xlink:label="dei_EntityCommonStockSharesOutstanding" xlink:type="locator"/>
    <link:label xlink:label="dei_EntityCommonStockSharesOutstanding-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Entity Common Stock, Shares Outstanding (in shares)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntityCommonStockSharesOutstanding" xlink:to="dei_EntityCommonStockSharesOutstanding-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementOfStockholdersEquityAbstract" xlink:label="us-gaap_StatementOfStockholdersEquityAbstract" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_StatementOfStockholdersEquityAbstract-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Statement of Stockholders' Equity [Abstract]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StatementOfStockholdersEquityAbstract" xlink:to="us-gaap_StatementOfStockholdersEquityAbstract-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockRepurchasedDuringPeriodValue" xlink:label="us-gaap_StockRepurchasedDuringPeriodValue" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_StockRepurchasedDuringPeriodValue-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_StockRepurchasedDuringPeriodValue</link:label>
    <link:label xlink:label="us-gaap_StockRepurchasedDuringPeriodValue-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Stock Repurchased During Period, Value</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockRepurchasedDuringPeriodValue" xlink:to="us-gaap_StockRepurchasedDuringPeriodValue-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeStatementAbstract" xlink:label="us-gaap_IncomeStatementAbstract" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_IncomeStatementAbstract-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income Statement [Abstract]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncomeStatementAbstract" xlink:to="us-gaap_IncomeStatementAbstract-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis" xlink:label="us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Disposal Group Name [Axis]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis" xlink:to="us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain" xlink:label="us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Disposal Group Name [Domain]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain" xlink:to="us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfAccruedLiabilitiesTableTextBlock" xlink:label="us-gaap_ScheduleOfAccruedLiabilitiesTableTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ScheduleOfAccruedLiabilitiesTableTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Accrued Liabilities [Table Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfAccruedLiabilitiesTableTextBlock" xlink:to="us-gaap_ScheduleOfAccruedLiabilitiesTableTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ProfessionalFees" xlink:label="us-gaap_ProfessionalFees" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ProfessionalFees-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_ProfessionalFees</link:label>
    <link:label xlink:label="us-gaap_ProfessionalFees-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Professional Fees</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ProfessionalFees" xlink:to="us-gaap_ProfessionalFees-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsDisclosureTextBlock" xlink:label="us-gaap_DisposalGroupsIncludingDiscontinuedOperationsDisclosureTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_DisposalGroupsIncludingDiscontinuedOperationsDisclosureTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Disposal Groups, Including Discontinued Operations, Disclosure [Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DisposalGroupsIncludingDiscontinuedOperationsDisclosureTextBlock" xlink:to="us-gaap_DisposalGroupsIncludingDiscontinuedOperationsDisclosureTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_TradingSymbol" xlink:label="dei_TradingSymbol" xlink:type="locator"/>
    <link:label xlink:label="dei_TradingSymbol-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Trading Symbol</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_TradingSymbol" xlink:to="dei_TradingSymbol-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfQuarterlyFinancialInformationTableTextBlock" xlink:label="us-gaap_ScheduleOfQuarterlyFinancialInformationTableTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ScheduleOfQuarterlyFinancialInformationTableTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Quarterly Financial Information [Table Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfQuarterlyFinancialInformationTableTextBlock" xlink:to="us-gaap_ScheduleOfQuarterlyFinancialInformationTableTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlock" xlink:label="us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlock" xlink:to="us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="xbit-20191231.xsd#xbit_ThePlanMember" xlink:label="xbit_ThePlanMember" xlink:type="locator"/>
    <link:label xlink:label="xbit_ThePlanMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">The Plan [Member]</link:label>
    <link:label xlink:label="xbit_ThePlanMember-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents a stock option plan ("the Plan").</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="xbit_ThePlanMember" xlink:to="xbit_ThePlanMember-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfIncomeBeforeIncomeTaxDomesticAndForeignTableTextBlock" xlink:label="us-gaap_ScheduleOfIncomeBeforeIncomeTaxDomesticAndForeignTableTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ScheduleOfIncomeBeforeIncomeTaxDomesticAndForeignTableTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Income before Income Tax, Domestic and Foreign [Table Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfIncomeBeforeIncomeTaxDomesticAndForeignTableTextBlock" xlink:to="us-gaap_ScheduleOfIncomeBeforeIncomeTaxDomesticAndForeignTableTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfUnrecognizedTaxBenefitsRollForwardTableTextBlock" xlink:label="us-gaap_ScheduleOfUnrecognizedTaxBenefitsRollForwardTableTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ScheduleOfUnrecognizedTaxBenefitsRollForwardTableTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Unrecognized Tax Benefits Roll Forward [Table Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfUnrecognizedTaxBenefitsRollForwardTableTextBlock" xlink:to="us-gaap_ScheduleOfUnrecognizedTaxBenefitsRollForwardTableTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="xbit-20191231.xsd#xbit_AnyOnePersonMember" xlink:label="xbit_AnyOnePersonMember" xlink:type="locator"/>
    <link:label xlink:label="xbit_AnyOnePersonMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Any One Person [Member]</link:label>
    <link:label xlink:label="xbit_AnyOnePersonMember-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents any one person.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="xbit_AnyOnePersonMember" xlink:to="xbit_AnyOnePersonMember-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock" xlink:label="us-gaap_ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock" xlink:to="us-gaap_ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfDeferredTaxAssetsAndLiabilitiesTableTextBlock" xlink:label="us-gaap_ScheduleOfDeferredTaxAssetsAndLiabilitiesTableTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ScheduleOfDeferredTaxAssetsAndLiabilitiesTableTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Deferred Tax Assets and Liabilities [Table Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfDeferredTaxAssetsAndLiabilitiesTableTextBlock" xlink:to="us-gaap_ScheduleOfDeferredTaxAssetsAndLiabilitiesTableTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfEffectiveIncomeTaxRateReconciliationTableTextBlock" xlink:label="us-gaap_ScheduleOfEffectiveIncomeTaxRateReconciliationTableTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ScheduleOfEffectiveIncomeTaxRateReconciliationTableTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfEffectiveIncomeTaxRateReconciliationTableTextBlock" xlink:to="us-gaap_ScheduleOfEffectiveIncomeTaxRateReconciliationTableTextBlock-label" xlink:type="arc"/>
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    <link:label xlink:label="us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Issuance of common stock under stock option plan</link:label>
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    <link:label xlink:label="us-gaap_DeferredRentCreditNoncurrent-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred rent</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredRentCreditNoncurrent" xlink:to="us-gaap_DeferredRentCreditNoncurrent-label" xlink:type="arc"/>
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    <link:label xlink:label="us-gaap_StockholdersEquity-label" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total shareholders&#8217; equity</link:label>
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