$PRTA
PROTHENA CORP PUBLIC LTD CO Stock $prta

$prta Overview Financials Valuation SEC Filings Company Website

2020 Q4 Form 10-K Financial Statement

#000155905321000008 Filed on February 26, 2021

Income Statement

Concept	2020 Q4	2020 Q1	2019 Q4
Revenue	$360.0K	$141.0K	$256.0K
YoY Change	40.63%	-24.19%	31.96%
Cost Of Revenue
YoY Change
Gross Profit
YoY Change
Gross Profit Margin
Selling, General & Admin	$9.910M	$9.740M	$8.060M
YoY Change	22.95%	-1.72%	0.37%
% of Gross Profit
Research & Development	$20.76M	$15.25M	$15.47M
YoY Change	34.2%	14.68%	-6.3%
% of Gross Profit
Depreciation & Amortization	$360.0K	$384.0K	$400.0K
YoY Change	-10.0%	-0.26%	-51.81%
% of Gross Profit
Operating Expenses	$30.67M	$24.99M	$23.53M
YoY Change	30.34%	7.99%	2.53%
Operating Profit		-$24.85M
YoY Change		8.25%
Interest Expense	$10.00K	$1.140M	$1.570M
YoY Change	-99.36%	-50.43%	80.46%
% of Operating Profit
Other Income/Expense, Net	-$70.00K	$1.113M	$20.00K
YoY Change	-450.0%	-51.33%	-166.67%
Pretax Income	-$30.36M	-$23.74M	-$21.69M
YoY Change	39.97%	14.84%	-1.0%
Income Tax	$350.0K	-$200.0K	-$130.0K
% Of Pretax Income
Net Earnings	-$30.72M	-$23.57M	-$21.55M
YoY Change	42.51%	12.96%	-4.04%
Net Earnings / Revenue	-8532.22%	-16715.6%	-8419.53%
Basic Earnings Per Share	-$0.77	-$0.59	-$0.54
Diluted Earnings Per Share	-$0.77	-$0.59	-$0.54
COMMON SHARES
Basic Shares Outstanding	39.92M shares	39.91M shares	39.90M shares
Diluted Shares Outstanding

Balance Sheet

Concept	2020 Q4	2020 Q1	2019 Q4
SHORT-TERM ASSETS
Cash & Short-Term Investments	$295.4M	$352.7M	$375.7M
YoY Change	-21.37%	-14.0%	-12.16%
Cash & Equivalents	$295.4M	$352.7M	$375.7M
Short-Term Investments
Other Short-Term Assets	$3.900M	$6.800M	$2.584M
YoY Change	50.93%	33.33%	-30.71%
Inventory
Prepaid Expenses
Receivables	$15.00K	$174.0K	$68.00K
Other Receivables	$0.00	$0.00	$0.00
Total Short-Term Assets	$299.3M	$359.7M	$378.4M
YoY Change	-20.9%	-13.37%	-12.29%
LONG-TERM ASSETS
Property, Plant & Equipment	$2.551M	$3.531M	$3.874M
YoY Change	-34.15%	-29.04%	-92.67%
Goodwill
YoY Change
Intangibles
YoY Change
Long-Term Investments
YoY Change
Other Assets	$333.0K	$1.115M	$1.085M
YoY Change	-69.31%	28.46%	33.46%
Total Long-Term Assets	$33.69M	$39.73M	$40.89M
YoY Change	-17.61%	-10.4%	-39.33%
TOTAL ASSETS
Total Short-Term Assets	$299.3M	$359.7M	$378.4M
Total Long-Term Assets	$33.69M	$39.73M	$40.89M
Total Assets	$333.0M	$399.4M	$419.3M
YoY Change	-20.58%	-13.08%	-15.94%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable	$4.117M	$3.297M	$1.242M
YoY Change	231.48%	56.78%	-15.51%
Accrued Expenses	$20.50M	$12.90M	$15.70M
YoY Change	30.57%	10.26%	58.59%
Deferred Revenue
YoY Change
Short-Term Debt	$0.00	$0.00	$0.00
YoY Change
Long-Term Debt Due			$0.00
YoY Change			-100.0%
Total Short-Term Liabilities	$25.85M	$17.09M	$17.71M
YoY Change	45.92%	14.62%	18.68%
LONG-TERM LIABILITIES
Long-Term Debt	$0.00	$0.00	$0.00
YoY Change			-100.0%
Other Long-Term Liabilities	$553.0K	$553.0K	$553.0K
YoY Change	0.0%	0.0%	0.0%
Total Long-Term Liabilities	$123.1M	$127.3M	$128.6M
YoY Change	-4.29%	-3.93%	-20.04%
TOTAL LIABILITIES
Total Short-Term Liabilities	$25.85M	$17.09M	$17.71M
Total Long-Term Liabilities	$123.1M	$127.3M	$128.6M
Total Liabilities	$149.0M	$144.4M	$146.3M
YoY Change	1.79%	-2.05%	-16.75%
SHAREHOLDERS EQUITY
Retained Earnings	-$783.0M	-$695.5M	-$671.9M
YoY Change	16.54%	17.04%	12.36%
Common Stock	$399.0K	$399.0K	$399.0K
YoY Change	0.0%	0.0%	0.0%
Preferred Stock
YoY Change
Treasury Stock (at cost)
YoY Change
Treasury Stock Shares
Shareholders Equity	$184.0M	$255.0M	$272.9M
YoY Change
Total Liabilities & Shareholders Equity	$333.0M	$399.4M	$419.3M
YoY Change	-20.58%	-13.08%	-15.94%

Cashflow Statement

Concept	2020 Q4	2020 Q1	2019 Q4
OPERATING ACTIVITIES
Net Income	-$30.72M	-$23.57M	-$21.55M
YoY Change	42.51%	12.96%	-4.04%
Depreciation, Depletion And Amortization	$360.0K	$384.0K	$400.0K
YoY Change	-10.0%	-0.26%	-51.81%
Cash From Operating Activities	-$19.09M	-$23.17M	-$14.49M
YoY Change	31.75%	32.88%	-31.84%
INVESTING ACTIVITIES
Capital Expenditures	-$50.00K	-$20.00K	-$110.0K
YoY Change	-54.55%	-84.62%	-91.79%
Acquisitions
YoY Change
Other Investing Activities	$0.00	$0.00	$0.00
YoY Change		-100.0%	-100.0%
Cash From Investing Activities	-$50.00K	-$22.00K	-$110.0K
YoY Change	-54.55%	-82.11%	-91.54%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net		$0.00
YoY Change
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities	0.000	$151.0K	10.00K
YoY Change	-100.0%	2920.0%	-100.76%
NET CHANGE
Cash From Operating Activities	-19.09M	-$23.17M	-14.49M
Cash From Investing Activities	-50.00K	-$22.00K	-110.0K
Cash From Financing Activities	0.000	$151.0K	10.00K
Net Change In Cash	-19.14M	-$23.04M	-14.59M
YoY Change	31.19%	31.25%	-38.88%
FREE CASH FLOW
Cash From Operating Activities	-$19.09M	-$23.17M	-$14.49M
Capital Expenditures	-$50.00K	-$20.00K	-$110.0K
Free Cash Flow	-$19.04M	-$23.15M	-$14.38M
YoY Change	32.41%	33.76%	-27.81%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
CY2020	dei	Amendment Flag AmendmentFlag	false
CY2020	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2020
CY2020	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	FY
CY2020	dei	Entity Central Index Key EntityCentralIndexKey	0001559053
CY2020	dei	Document Type DocumentType	10-K
CY2020	dei	Document Annual Report DocumentAnnualReport	true
CY2020	dei	Document Period End Date DocumentPeriodEndDate	2020-12-31
CY2020	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-31
CY2020	dei	Document Transition Report DocumentTransitionReport	false
CY2020	dei	Entity File Number EntityFileNumber	001-35676
CY2020	dei	Entity Registrant Name EntityRegistrantName	PROTHENA CORPORATION PUBLIC LIMITED COMPANY
CY2020	dei	Entity Incorporation State Country Code EntityIncorporationStateCountryCode	L2
CY2020	dei	Entity Tax Identification Number EntityTaxIdentificationNumber	98-1111119
CY2020	dei	Entity Address Address Line1 EntityAddressAddressLine1	77 Sir John Rogerson’s Quay, Block C
CY2020	dei	Entity Address Address Line2 EntityAddressAddressLine2	Grand Canal Docklands
CY2020	dei	Entity Address City Or Town EntityAddressCityOrTown	Dublin 2,
CY2020	dei	Entity Address Postal Zip Code EntityAddressPostalZipCode	D02 T804,
CY2020	dei	Entity Address Country EntityAddressCountry	IE
CY2020	dei	Country Region CountryRegion	353
CY2020	dei	City Area Code CityAreaCode	1
CY2020	dei	Local Phone Number LocalPhoneNumber	236-2500
CY2020	dei	Security12b Title Security12bTitle	Ordinary Shares, par value $0.01 per share
CY2020	dei	Trading Symbol TradingSymbol	PRTA
CY2020	dei	Security Exchange Name SecurityExchangeName	NASDAQ
CY2020	dei	Entity Well Known Seasoned Issuer EntityWellKnownSeasonedIssuer	No
CY2020	dei	Entity Voluntary Filers EntityVoluntaryFilers	No
CY2020	dei	Entity Current Reporting Status EntityCurrentReportingStatus	Yes
CY2020	dei	Entity Interactive Data Current EntityInteractiveDataCurrent	Yes
CY2020	dei	Entity Filer Category EntityFilerCategory	Non-accelerated Filer
CY2020	dei	Entity Small Business EntitySmallBusiness	true
CY2020	dei	Entity Emerging Growth Company EntityEmergingGrowthCompany	false
CY2020	dei	Icfr Auditor Attestation Flag IcfrAuditorAttestationFlag	false
CY2020	dei	Entity Shell Company EntityShellCompany	false
CY2020Q2	dei	Entity Public Float EntityPublicFloat	318748731	USD
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CY2020Q4	us-gaap	Restricted Cash Current RestrictedCashCurrent	1352000	USD
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CY2019Q4	us-gaap	Assets Current AssetsCurrent	378375000	USD
CY2020Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	2551000	USD
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CY2020	us-gaap	Increase Decrease In Restructuring Reserve IncreaseDecreaseInRestructuringReserve	0	USD
CY2019	us-gaap	Increase Decrease In Restructuring Reserve IncreaseDecreaseInRestructuringReserve	-461000	USD
CY2018	us-gaap	Increase Decrease In Restructuring Reserve IncreaseDecreaseInRestructuringReserve	461000	USD
CY2020	prta	Increase Decreasein Operating Lease Liability IncreaseDecreaseinOperatingLeaseLiability	5101000	USD
CY2019	prta	Increase Decreasein Operating Lease Liability IncreaseDecreaseinOperatingLeaseLiability	4717000	USD
CY2019	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	228000	USD
CY2018	prta	Increase Decreasein Operating Lease Liability IncreaseDecreaseinOperatingLeaseLiability	0	USD
CY2020	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	-80362000	USD
CY2019	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	-52969000	USD
CY2018	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	-28276000	USD
CY2020	us-gaap	Payments To Acquire Machinery And Equipment PaymentsToAcquireMachineryAndEquipment	196000	USD
CY2019	us-gaap	Payments To Acquire Machinery And Equipment PaymentsToAcquireMachineryAndEquipment	555000	USD
CY2018	us-gaap	Payments To Acquire Machinery And Equipment PaymentsToAcquireMachineryAndEquipment	1768000	USD
CY2020	us-gaap	Proceeds From Sale Of Property Plant And Equipment ProceedsFromSaleOfPropertyPlantAndEquipment	0	USD
CY2019	us-gaap	Proceeds From Sale Of Property Plant And Equipment ProceedsFromSaleOfPropertyPlantAndEquipment	8000	USD
CY2018	us-gaap	Proceeds From Sale Of Property Plant And Equipment ProceedsFromSaleOfPropertyPlantAndEquipment	39000	USD
CY2020	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-196000	USD
CY2019	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-547000	USD
CY2018	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-1729000	USD
CY2020	us-gaap	Proceeds From Issuance Of Private Placement ProceedsFromIssuanceOfPrivatePlacement	0	USD
CY2019	us-gaap	Proceeds From Issuance Of Private Placement ProceedsFromIssuanceOfPrivatePlacement	0	USD
CY2018	us-gaap	Proceeds From Issuance Of Private Placement ProceedsFromIssuanceOfPrivatePlacement	39758000	USD
CY2020	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	215000	USD
CY2018	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	4686000	USD
CY2020	prta	Buildto Suit Leases Increase Decreaseto Obligation BuildtoSuitLeasesIncreaseDecreasetoObligation	0	USD
CY2019	prta	Buildto Suit Leases Increase Decreaseto Obligation BuildtoSuitLeasesIncreaseDecreasetoObligation	0	USD
CY2018	prta	Buildto Suit Leases Increase Decreaseto Obligation BuildtoSuitLeasesIncreaseDecreasetoObligation	4400000	USD
CY2020	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	215000	USD
CY2019	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	228000	USD
CY2018	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	40044000	USD
CY2020	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Excluding Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect	-80343000	USD
CY2019	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Excluding Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect	-53288000	USD
CY2018	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Excluding Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect	10039000	USD
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	378427000	USD
CY2018Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	431715000	USD
CY2017Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	421676000	USD
CY2020Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	298084000	USD
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	378427000	USD
CY2018Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	431715000	USD
CY2020	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	1367000	USD
CY2019	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	1580000	USD
CY2018	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	-995000	USD
CY2020	us-gaap	Noncash Or Part Noncash Acquisition Fixed Assets Acquired1 NoncashOrPartNoncashAcquisitionFixedAssetsAcquired1	0	USD
CY2019	us-gaap	Noncash Or Part Noncash Acquisition Fixed Assets Acquired1 NoncashOrPartNoncashAcquisitionFixedAssetsAcquired1	5000	USD
CY2018	us-gaap	Noncash Or Part Noncash Acquisition Fixed Assets Acquired1 NoncashOrPartNoncashAcquisitionFixedAssetsAcquired1	90000	USD
CY2020	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	0	USD
CY2019	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	28530000	USD
CY2018	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	0	USD
CY2020	prta	Reductionof Buildtosuit Lease Obligation ReductionofBuildtosuitLeaseObligation	0	USD
CY2019	prta	Reductionof Buildtosuit Lease Obligation ReductionofBuildtosuitLeaseObligation	51546000	USD
CY2018	prta	Reductionof Buildtosuit Lease Obligation ReductionofBuildtosuitLeaseObligation	0	USD
CY2020	prta	Reductionof Amounts Capitalized Under Buildtosuit Lease Transaction ReductionofAmountsCapitalizedUnderBuildtosuitLeaseTransaction	0	USD
CY2019	prta	Reductionof Amounts Capitalized Under Buildtosuit Lease Transaction ReductionofAmountsCapitalizedUnderBuildtosuitLeaseTransaction	46760000	USD
CY2018	prta	Reductionof Amounts Capitalized Under Buildtosuit Lease Transaction ReductionofAmountsCapitalizedUnderBuildtosuitLeaseTransaction	0	USD
CY2020	prta	Reductionof Capitalized Interest During Construction Periodfor Buildtosuit Lease Transaction ReductionofCapitalizedInterestDuringConstructionPeriodforBuildtosuitLeaseTransaction	0	USD
CY2019	prta	Reductionof Capitalized Interest During Construction Periodfor Buildtosuit Lease Transaction ReductionofCapitalizedInterestDuringConstructionPeriodforBuildtosuitLeaseTransaction	1099000	USD
CY2018	prta	Reductionof Capitalized Interest During Construction Periodfor Buildtosuit Lease Transaction ReductionofCapitalizedInterestDuringConstructionPeriodforBuildtosuitLeaseTransaction	0	USD
CY2018Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	427659000	USD
CY2020Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	295380000	USD
CY2019Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	375723000	USD
CY2020Q4	us-gaap	Restricted Cash Current RestrictedCashCurrent	1352000	USD
CY2019Q4	us-gaap	Restricted Cash Current RestrictedCashCurrent	0	USD
CY2018Q4	us-gaap	Restricted Cash Current RestrictedCashCurrent	0	USD
CY2020Q4	us-gaap	Restricted Cash Noncurrent RestrictedCashNoncurrent	1352000	USD
CY2019Q4	us-gaap	Restricted Cash Noncurrent RestrictedCashNoncurrent	2704000	USD
CY2018Q4	us-gaap	Restricted Cash Noncurrent RestrictedCashNoncurrent	4056000	USD
CY2020Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	298084000	USD
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	378427000	USD
CY2018Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	431715000	USD
CY2017Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	407189000	USD
CY2018	us-gaap	Stock Issued During Period Value Other StockIssuedDuringPeriodValueOther	39758000	USD
CY2018	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	26062000	USD
CY2018	prta	Adjustmentsto Additional Paidin Capital Share Based Compensation Restructuring AdjustmentstoAdditionalPaidinCapitalShareBasedCompensationRestructuring	948000	USD
CY2018Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	322998000	USD
CY2018	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	4686000	USD
CY2018	us-gaap	Net Income Loss NetIncomeLoss	-155645000	USD
CY2019	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	23585000	USD
CY2019	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	228000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	-77677000	USD
CY2019Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	272921000	USD
CY2020	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	22014000	USD
CY2020	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	215000	USD
CY2020	us-gaap	Net Income Loss NetIncomeLoss	-111144000	USD
CY2020Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	184006000	USD
CY2020Q4	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	-783000000.0	USD
CY2020Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	295400000	USD
CY2020	us-gaap	Use Of Estimates UseOfEstimates	<div style="margin-top:9pt;text-indent:9pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Use of Estimates</span></div><div style="margin-top:10pt;text-align:justify;text-indent:24.75pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The preparation of the Consolidated Financial Statements in conformity with GAAP requires management to make judgments, estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses, and related </span></div>disclosures. On an ongoing basis, management evaluates its estimates, including critical accounting policies or estimates related to revenue recognition, share-based compensation, research and development expenses and leases. The Company bases its estimates on historical experience and on various other market specific and other relevant assumptions that management believes to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Because of the uncertainties inherent in such estimates, actual results may differ materially from these estimates.
CY2020Q4	us-gaap	Restricted Cash RestrictedCash	2700000	USD
CY2020Q4	us-gaap	Restricted Cash Current RestrictedCashCurrent	1400000	USD
CY2020	us-gaap	Concentration Risk Credit Risk ConcentrationRiskCreditRisk	<div style="margin-top:10pt;text-align:justify;text-indent:24.75pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Financial instruments that potentially subject the Company to concentration of credit risk consist of cash and cash equivalents and accounts receivable. The Company places its cash equivalents with high credit quality financial institutions and, by policy, limits the amount of credit exposure with any one financial institution. Deposits held with banks may exceed the amount of insurance provided on such deposits. The Company has not experienced any losses on its deposits of cash and cash equivalents and its credit risk exposure is up to the extent recorded on the Company's Consolidated Balance Sheet.</span></div><div style="margin-top:10pt;text-align:justify;text-indent:24.75pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The receivables recorded in the Consolidated Balance Sheets include amounts due from a Roche entity located in Switzerland. Collaboration revenue recorded in the Consolidated Statements of Operations consists of reimbursement from Roche for research and development services. The Company's credit risk exposure is up to the extent recorded on the Company's Consolidated Balance Sheet.</span></div><div style="margin-top:10pt;text-align:justify;text-indent:24.75pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"> As of December 31, 2020 and 2019, $2.6 million and $3.9 million, respectively, of the Company’s property and equipment, net were held in the U.S. and none were in Ireland. </span></div><div style="margin-top:10pt;text-align:justify;text-indent:24.75pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The Company does not own or operate facilities for the manufacture, packaging, labeling, storage, testing or distribution of nonclinical or clinical supplies of any of its drug candidates. The Company instead contracts with and relies on third-parties to manufacture, package, label, store, test and distribute all preclinical development and clinical supplies of our drug candidates, and it plans to continue to do so for the foreseeable future. The Company also relies on third-party consultants to assist in managing these third-parties and assist with its manufacturing strategy.</span></div>
CY2020Q4	us-gaap	Machinery And Equipment Gross MachineryAndEquipmentGross	9343000	USD
CY2019Q4	us-gaap	Machinery And Equipment Gross MachineryAndEquipmentGross	9312000	USD
CY2020Q4	us-gaap	Leasehold Improvements Gross LeaseholdImprovementsGross	1278000	USD
CY2019Q4	us-gaap	Leasehold Improvements Gross LeaseholdImprovementsGross	1261000	USD
CY2020Q4	us-gaap	Capitalized Computer Software Gross CapitalizedComputerSoftwareGross	1423000	USD
CY2019Q4	us-gaap	Capitalized Computer Software Gross CapitalizedComputerSoftwareGross	1308000	USD
CY2020Q4	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	12044000	USD
CY2019Q4	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	11881000	USD
CY2020Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	9493000	USD
CY2019Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	8007000	USD
CY2020Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	2551000	USD
CY2019Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	3874000	USD
CY2020	us-gaap	Depreciation Depreciation	1500000	USD
CY2019	us-gaap	Depreciation Depreciation	1600000	USD
CY2018	us-gaap	Depreciation Depreciation	3200000	USD
CY2020Q4	us-gaap	Employee Related Liabilities Current EmployeeRelatedLiabilitiesCurrent	5927000	USD
CY2019Q4	us-gaap	Employee Related Liabilities Current EmployeeRelatedLiabilitiesCurrent	4818000	USD
CY2020Q4	us-gaap	Accrued Professional Fees Current AccruedProfessionalFeesCurrent	696000	USD
CY2019Q4	us-gaap	Accrued Professional Fees Current AccruedProfessionalFeesCurrent	400000	USD
CY2020Q4	us-gaap	Other Sundry Liabilities Current OtherSundryLiabilitiesCurrent	516000	USD
CY2019Q4	us-gaap	Other Sundry Liabilities Current OtherSundryLiabilitiesCurrent	322000	USD
CY2020Q4	us-gaap	Other Liabilities Current OtherLiabilitiesCurrent	7139000	USD
CY2019Q4	us-gaap	Other Liabilities Current OtherLiabilitiesCurrent	5540000	USD
CY2020	us-gaap	Net Income Loss NetIncomeLoss	-111144000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	-77677000	USD
CY2018	us-gaap	Net Income Loss NetIncomeLoss	-155645000	USD
CY2020	us-gaap	Weighted Average Number Of Share Outstanding Basic And Diluted WeightedAverageNumberOfShareOutstandingBasicAndDiluted	39915000	shares
CY2019	us-gaap	Weighted Average Number Of Share Outstanding Basic And Diluted WeightedAverageNumberOfShareOutstandingBasicAndDiluted	39882000	shares
CY2018	us-gaap	Weighted Average Number Of Share Outstanding Basic And Diluted WeightedAverageNumberOfShareOutstandingBasicAndDiluted	39559000	shares
CY2020	us-gaap	Earnings Per Share Basic And Diluted EarningsPerShareBasicAndDiluted	-2.78
CY2019	us-gaap	Earnings Per Share Basic And Diluted EarningsPerShareBasicAndDiluted	-1.95
CY2018	us-gaap	Earnings Per Share Basic And Diluted EarningsPerShareBasicAndDiluted	-3.93
CY2020	us-gaap	Operating Lease Cost OperatingLeaseCost	6300000	USD
CY2019	us-gaap	Operating Lease Cost OperatingLeaseCost	6400000	USD
CY2020	us-gaap	Operating Lease Payments OperatingLeasePayments	6000000.0	USD
CY2019	us-gaap	Operating Lease Payments OperatingLeasePayments	5800000	USD
CY2018	us-gaap	Operating Leases Rent Expense Net OperatingLeasesRentExpenseNet	700000	USD
CY2016Q1	prta	Operating Lease Area OperatingLeaseArea	128751	sqft
CY2020Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P3Y
CY2016Q2	us-gaap	Capital Leases Future Minimum Payments Due CapitalLeasesFutureMinimumPaymentsDue	39200000	USD
CY2016	prta	Operating Leases Improvement Allowance OperatingLeasesImprovementAllowance	14200000	USD
CY2018Q4	prta	Builtto Suit Leases At Cost BuilttoSuitLeasesAtCost	52300000	USD
CY2018Q4	prta	Buildtosuit Lease Obligation Currentand Noncurrent BuildtosuitLeaseObligationCurrentandNoncurrent	51500000	USD
CY2018Q4	prta	Buildtosuit Lease Obligation Current BuildtosuitLeaseObligationCurrent	1600000	USD
CY2020Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	17800000	USD
CY2018Q4	prta	Buildtosuitleaseobligationnoncurrent Buildtosuitleaseobligationnoncurrent	49900000	USD
CY2020Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	17800000	USD
CY2020Q4	us-gaap	Restricted Cash RestrictedCash	2700000	USD
CY2018Q3	prta	Operating Leases Sublease Rentals Areaof Sublease Rental OperatingLeasesSubleaseRentalsAreaofSubleaseRental	46641	sqft
CY2020	us-gaap	Sublease Income SubleaseIncome	2900000	USD
CY2019	us-gaap	Sublease Income SubleaseIncome	2900000	USD
CY2018	us-gaap	Sublease Income SubleaseIncome	800000	USD
CY2018Q3	prta	Subleaserentals Annual Base Rent Initial Amount SubleaserentalsAnnualBaseRentInitialAmount	2700000	USD
CY2018Q3	prta	Operating Leases Sublease Rentals Percent Annual Rent Increase OperatingLeasesSubleaseRentalsPercentAnnualRentIncrease	0.035
CY2018Q3	prta	Operating Leases Sublease Rentals Termof Contract OperatingLeasesSubleaseRentalsTermofContract	P5Y2M12D
CY2018Q3	prta	Operating Leases Sublease Rentals Percentof Rental Gain Attributableto Sublandlord OperatingLeasesSubleaseRentalsPercentofRentalGainAttributabletoSublandlord	0.50
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Next Twelve Months LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths	6192000	USD
CY2020Q4	us-gaap	Lessor Operating Lease Payments To Be Received Next Twelve Months LessorOperatingLeasePaymentsToBeReceivedNextTwelveMonths	2944000	USD
CY2020Q4	us-gaap	Purchase Obligation Due In Third Year PurchaseObligationDueInThirdYear	0	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Two LesseeOperatingLeaseLiabilityPaymentsDueYearTwo	6350000	USD
CY2020Q4	us-gaap	Lessor Operating Lease Payments To Be Received Two Years LessorOperatingLeasePaymentsToBeReceivedTwoYears	3047000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Three LesseeOperatingLeaseLiabilityPaymentsDueYearThree	6535000	USD
CY2020Q4	us-gaap	Lessor Operating Lease Payments To Be Received Three Years LessorOperatingLeasePaymentsToBeReceivedThreeYears	3019000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Four LesseeOperatingLeaseLiabilityPaymentsDueYearFour	0	USD
CY2020Q4	us-gaap	Lessor Operating Lease Payments To Be Received Four Years LessorOperatingLeasePaymentsToBeReceivedFourYears	0	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	19077000	USD
CY2020Q4	us-gaap	Lessor Operating Lease Payments To Be Received LessorOperatingLeasePaymentsToBeReceived	9010000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Undiscounted Excess Amount LesseeOperatingLeaseLiabilityUndiscountedExcessAmount	1212000	USD
CY2020Q4	prta	Lessee Operating Lease Liability Nominal Payments LesseeOperatingLeaseLiabilityNominalPayments	27000	USD
CY2020Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	17838000	USD
CY2020Q4	us-gaap	Purchase Obligation PurchaseObligation	10900000	USD
CY2020Q4	us-gaap	Contractual Obligation ContractualObligation	800000	USD
CY2020Q4	us-gaap	Purchase Obligation PurchaseObligation	10900000	USD
CY2020Q4	us-gaap	Purchase Obligation Due In Next Twelve Months PurchaseObligationDueInNextTwelveMonths	10900000	USD
CY2020Q4	us-gaap	Purchase Obligation Due In Second Year PurchaseObligationDueInSecondYear	0	USD
CY2020Q4	us-gaap	Purchase Obligation Due In Fourth Year PurchaseObligationDueInFourthYear	0	USD
CY2020Q4	us-gaap	Purchase Obligation Due In Fifth Year PurchaseObligationDueInFifthYear	0	USD
CY2020Q4	us-gaap	Purchase Obligation Due After Fifth Year PurchaseObligationDueAfterFifthYear	0	USD
CY2020Q4	prta	Purchaseand Contractual Obligation Total PurchaseandContractualObligationTotal	11685000	USD
CY2020Q4	prta	Purchaseand Contractual Obligation Due Next Fiscal Year PurchaseandContractualObligationDueNextFiscalYear	11080000	USD
CY2020Q4	prta	Purchaseand Contractual Obligation Duein Second Year PurchaseandContractualObligationDueinSecondYear	70000	USD
CY2020Q4	prta	Purchaseand Contractual Obligation Duein Third Year PurchaseandContractualObligationDueinThirdYear	70000	USD
CY2020Q4	prta	Purchaseand Contractual Obligation Duein Fourth Year PurchaseandContractualObligationDueinFourthYear	60000	USD
CY2020Q4	prta	Purchaseand Contractual Obligation Duein Fifth Year PurchaseandContractualObligationDueinFifthYear	60000	USD
CY2020Q4	prta	Purchaseand Contractual Obligation Due After Fifth Year PurchaseandContractualObligationDueAfterFifthYear	345000	USD
CY2020Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	100000000	shares
CY2020Q4	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	0.01
CY2020Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	39921413	shares
CY2020Q4	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	39921413	shares
CY2020	prta	Numberof Votes NumberofVotes	1	vote
CY2020Q4	prta	Deferred Shares Shares Authorized DeferredSharesSharesAuthorized	10000	shares
CY2020Q4	prta	Deferred Shares Par Value DeferredSharesParValue	22
CY2020Q4	prta	Deferred Shares Shares Outstanding DeferredSharesSharesOutstanding	0	shares
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Gross ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross	2108950	shares
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Gross ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross	1315975	shares
CY2018	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Gross ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross	4140800	shares
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Award Vesting Period1 ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1	P4Y
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	8744765	shares
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	20.42
CY2020Q4	us-gaap	Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized Stock Options EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions	32700000	USD
CY2020	us-gaap	Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized Period For Recognition1 EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1	P2Y4M20D
CY2020	us-gaap	Share Based Compensation ShareBasedCompensation	22014000	USD
CY2019	us-gaap	Share Based Compensation ShareBasedCompensation	23585000	USD
CY2018	us-gaap	Share Based Compensation ShareBasedCompensation	27010000	USD
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Volatility Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate	0.809
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Volatility Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate	0.814
CY2018	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Volatility Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate	0.795
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Risk Free Interest Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate	0.009
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Risk Free Interest Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate	0.023
CY2018	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Risk Free Interest Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate	0.028
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Dividend Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate	0
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Dividend Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate	0
CY2018	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Dividend Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate	0
CY2020	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Fair Value Assumptions Expected Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1	P6Y
CY2019	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Fair Value Assumptions Expected Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1	P6Y
CY2018	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Fair Value Assumptions Expected Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1	P6Y
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Weighted Average Grant Date Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue	8.12
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Weighted Average Grant Date Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue	8.55
CY2018	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Weighted Average Grant Date Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue	13.70
CY2019Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	7008403	shares
CY2019Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	23.34
CY2019	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Outstanding Weighted Average Remaining Contractual Term2 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2	P7Y2M26D
CY2019Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue	11901000	USD
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Gross ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross	2108950	shares
CY2020	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Grants In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice	11.81
CY2020	us-gaap	Stock Issued During Period Shares Stock Options Exercised StockIssuedDuringPeriodSharesStockOptionsExercised	22852	shares
CY2020	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Exercises In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice	9.42
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod	54543	shares
CY2020	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Forfeitures In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice	14.65
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Expirations In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationsInPeriod	295193	shares
CY2020	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Expirations In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExpirationsInPeriodWeightedAverageExercisePrice	30.13
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	8744765	shares
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	20.42
CY2020	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Outstanding Weighted Average Remaining Contractual Term2 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2	P7Y2M8D
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue	4656000	USD
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Vested And Expected To Vest Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingNumber	8370141	shares
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Vested And Expected To Vest Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageExercisePrice	20.75
CY2020	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Vested And Expected To Vest Exercisable Weighted Average Remaining Contractual Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestExercisableWeightedAverageRemainingContractualTerm1	P7Y1M13D
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Vested And Expected To Vest Outstanding Aggregate Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingAggregateIntrinsicValue	4512000	USD
CY2020	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Vested Number Of Shares SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedNumberOfShares	4884436	shares
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice	25.45
CY2020	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Weighted Average Remaining Contractual Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1	P6Y1M2D
CY2020Q4	prta	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Intrinsic Value Related To Vested Options ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValueRelatedToVestedOptions	3444000	USD
CY2020	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	-111427000	USD
CY2019	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	-77298000	USD
CY2018	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	-156115000	USD
CY2020	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	1405000	USD
CY2019	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	1628000	USD
CY2018	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	1119000	USD
CY2020	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-1688000	USD
CY2019	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-1249000	USD
CY2018	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-1589000	USD
CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	-283000	USD
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	379000	USD
CY2018	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	-470000	USD
CY2020	prta	Sharebased Compensation Net Tax Shortfall Excess Tax Benefit Amount Bookedto Income Tax Provision SharebasedCompensationNetTaxShortfallExcessTaxBenefitAmountBookedtoIncomeTaxProvision	1000000.0	USD
CY2019	prta	Sharebased Compensation Net Tax Shortfall Excess Tax Benefit Amount Bookedto Income Tax Provision SharebasedCompensationNetTaxShortfallExcessTaxBenefitAmountBookedtoIncomeTaxProvision	2600000	USD
CY2018	prta	Sharebased Compensation Net Tax Shortfall Excess Tax Benefit Amount Bookedto Income Tax Provision SharebasedCompensationNetTaxShortfallExcessTaxBenefitAmountBookedtoIncomeTaxProvision	1700000	USD
CY2020	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	-13928000	USD
CY2019	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	-9662000	USD
CY2018	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	-19514000	USD
CY2020	us-gaap	Income Tax Reconciliation Foreign Income Tax Rate Differential IncomeTaxReconciliationForeignIncomeTaxRateDifferential	-3402000	USD
CY2019	us-gaap	Income Tax Reconciliation Foreign Income Tax Rate Differential IncomeTaxReconciliationForeignIncomeTaxRateDifferential	-1202000	USD
CY2018	us-gaap	Income Tax Reconciliation Foreign Income Tax Rate Differential IncomeTaxReconciliationForeignIncomeTaxRateDifferential	-458000	USD
CY2020	us-gaap	Income Tax Reconciliation Change In Deferred Tax Assets Valuation Allowance IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance	16266000	USD
CY2019	us-gaap	Income Tax Reconciliation Change In Deferred Tax Assets Valuation Allowance IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance	8248000	USD
CY2018	us-gaap	Income Tax Reconciliation Change In Deferred Tax Assets Valuation Allowance IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance	26747000	USD
CY2020	us-gaap	Income Tax Reconciliation Nondeductible Expense Share Based Compensation Cost IncomeTaxReconciliationNondeductibleExpenseShareBasedCompensationCost	3409000	USD
CY2019	us-gaap	Income Tax Reconciliation Nondeductible Expense Share Based Compensation Cost IncomeTaxReconciliationNondeductibleExpenseShareBasedCompensationCost	4518000	USD
CY2018	us-gaap	Income Tax Reconciliation Nondeductible Expense Share Based Compensation Cost IncomeTaxReconciliationNondeductibleExpenseShareBasedCompensationCost	2215000	USD
CY2020	us-gaap	Income Tax Reconciliation Tax Credits Research IncomeTaxReconciliationTaxCreditsResearch	2786000	USD
CY2019	us-gaap	Income Tax Reconciliation Tax Credits Research IncomeTaxReconciliationTaxCreditsResearch	1470000	USD
CY2018	us-gaap	Income Tax Reconciliation Tax Credits Research IncomeTaxReconciliationTaxCreditsResearch	10351000	USD
CY2020	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	158000	USD
CY2019	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	-53000	USD
CY2018	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	891000	USD
CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	-283000	USD
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	379000	USD
CY2018	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	-470000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards DeferredTaxAssetsOperatingLossCarryforwards	118976000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards DeferredTaxAssetsOperatingLossCarryforwards	101897000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Tax Credit Carryforwards Research DeferredTaxAssetsTaxCreditCarryforwardsResearch	14804000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Tax Credit Carryforwards Research DeferredTaxAssetsTaxCreditCarryforwardsResearch	16434000	USD
CY2020Q4	prta	Deferred Tax Assets Lease Liabilities DeferredTaxAssetsLeaseLiabilities	4199000	USD
CY2019Q4	prta	Deferred Tax Assets Lease Liabilities DeferredTaxAssetsLeaseLiabilities	5319000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals DeferredTaxAssetsTaxDeferredExpenseReservesAndAccruals	2936000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals DeferredTaxAssetsTaxDeferredExpenseReservesAndAccruals	2501000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Share Based Compensation Cost DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost	13048000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Share Based Compensation Cost DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost	11186000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	153963000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	137337000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	137809000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	121633000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	16154000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	15704000	USD
CY2020Q4	prta	Deferred Tax Liabilities Operating Lease Rightof Use Assets DeferredTaxLiabilitiesOperatingLeaseRightofUseAssets	4192000	USD
CY2019Q4	prta	Deferred Tax Liabilities Operating Lease Rightof Use Assets DeferredTaxLiabilitiesOperatingLeaseRightofUseAssets	5397000	USD
CY2020Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	318000	USD
CY2019Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	351000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Liabilities Net DeferredTaxAssetsLiabilitiesNet	11644000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Liabilities Net DeferredTaxAssetsLiabilitiesNet	9956000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	137800000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Liabilities Net DeferredTaxAssetsLiabilitiesNet	11600000	USD
CY2020	us-gaap	Valuation Allowance Deferred Tax Asset Change In Amount ValuationAllowanceDeferredTaxAssetChangeInAmount	16200000	USD
CY2019Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	6601000	USD
CY2018Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	6855000	USD
CY2020	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	703000	USD
CY2019	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	371000	USD
CY2020	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	124000	USD
CY2019	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	0	USD
CY2020	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions	176000	USD
CY2019	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions	625000	USD
CY2020Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	7252000	USD
CY2019Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	6601000	USD
CY2020Q4	us-gaap	Restructuring And Related Cost Cost Incurred To Date1 RestructuringAndRelatedCostCostIncurredToDate1	16100000	USD
CY2019	us-gaap	Restructuring Costs RestructuringCosts	-61000	USD
CY2020	us-gaap	Restructuring Costs RestructuringCosts	0	USD
CY2019	us-gaap	Restructuring Costs RestructuringCosts	-61000	USD
CY2018	us-gaap	Restructuring Costs RestructuringCosts	16145000	USD
CY2020Q4	us-gaap	Net Income Loss NetIncomeLoss	-30716000	USD
CY2020Q3	us-gaap	Net Income Loss NetIncomeLoss	-30577000	USD
CY2020Q1	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	141000	USD
CY2020Q2	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	195000	USD
CY2020Q3	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	157000	USD
CY2020Q4	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	360000	USD
CY2020Q1	us-gaap	Operating Expenses OperatingExpenses	24989000	USD
CY2020Q2	us-gaap	Operating Expenses OperatingExpenses	26927000	USD
CY2020Q3	us-gaap	Operating Expenses OperatingExpenses	31003000	USD
CY2020Q4	us-gaap	Operating Expenses OperatingExpenses	30668000	USD
CY2020Q1	us-gaap	Net Income Loss NetIncomeLoss	-23569000	USD
CY2020Q2	us-gaap	Net Income Loss NetIncomeLoss	-26282000	USD
CY2020Q1	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-0.59
CY2020Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-0.66
CY2020Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-0.77
CY2020Q4	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-0.77
CY2020Q1	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-0.59
CY2020Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-0.66
CY2020Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-0.77
CY2020Q4	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-0.77
CY2019Q1	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	186000	USD
CY2019Q2	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	167000	USD
CY2019Q3	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	205000	USD
CY2019Q4	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	256000	USD
CY2019Q1	us-gaap	Operating Expenses OperatingExpenses	23140000	USD
CY2019Q2	us-gaap	Operating Expenses OperatingExpenses	18664000	USD
CY2019Q3	us-gaap	Operating Expenses OperatingExpenses	21177000	USD
CY2019Q4	us-gaap	Operating Expenses OperatingExpenses	23530000	USD
CY2019Q1	us-gaap	Net Income Loss NetIncomeLoss	-20865000	USD
CY2019Q2	us-gaap	Net Income Loss NetIncomeLoss	-15810000	USD
CY2019Q3	us-gaap	Net Income Loss NetIncomeLoss	-19448000	USD
CY2019Q4	us-gaap	Net Income Loss NetIncomeLoss	-21554000	USD
CY2019Q1	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-0.52
CY2019Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-0.40
CY2019Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-0.49
CY2019Q4	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-0.54
CY2019Q1	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-0.52
CY2019Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-0.40
CY2019Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-0.49
CY2019Q4	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-0.54

Files In Submission

Name	View Source	Status
0001559053-21-000008-index-headers.html	Edgar Link	pending
0001559053-21-000008-index.html	Edgar Link	pending
0001559053-21-000008.txt	Edgar Link	pending
0001559053-21-000008-xbrl.zip	Edgar Link	pending
FilingSummary.xml	Edgar Link	unprocessable
Financial_Report.xlsx	Edgar Link	pending
MetaLinks.json	Edgar Link	pending
prta-20201231.htm	Edgar Link	pending
prta-20201231.xsd	Edgar Link	pending
prta-20201231_cal.xml	Edgar Link	unprocessable
prta-20201231_def.xml	Edgar Link	unprocessable
prta-20201231_g1.jpg	Edgar Link	pending
prta-20201231_g2.gif	Edgar Link	pending
prta-20201231_htm.xml	Edgar Link	completed
prta-20201231_lab.xml	Edgar Link	unprocessable
prta-20201231_pre.xml	Edgar Link	unprocessable
prta202010-kxex311.htm	Edgar Link	pending
prta202010-kxex312.htm	Edgar Link	pending
prta202010-kxex321.htm	Edgar Link	pending
prta2020ex211listofsubsidi.htm	Edgar Link	pending
prta2020xex1017firstthroug.htm	Edgar Link	pending
prta2020xex1035selkoeconsu.htm	Edgar Link	pending
prta2020xex231consentofind.htm	Edgar Link	pending
prta2020xex42descriptionof.htm	Edgar Link	pending
R1.htm	Edgar Link	pending
R10.htm	Edgar Link	pending
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R61.htm	Edgar Link	pending
R7.htm	Edgar Link	pending
R8.htm	Edgar Link	pending
R9.htm	Edgar Link	pending
report.css	Edgar Link	pending
Show.js	Edgar Link	pending

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$PRTA
PROTHENA CORP PUBLIC LTD CO Stock $prta

2020 Q4 Form 10-K Financial Statement

#000155905321000008 Filed on February 26, 2021

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$PRTA PROTHENA CORP PUBLIC LTD CO Stock $prta

2020 Q4 Form 10-K Financial Statement

#000155905321000008 Filed on February 26, 2021

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$PRTA
PROTHENA CORP PUBLIC LTD CO Stock $prta