Early exercised stock options.

No definition available.

Name:	pcvx_EarlyExercisedStockOptions
Namespace Prefix:	pcvx_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Exercise price expire in years form the date of grant.

+ References

No definition available.

+ Details

Name:	pcvx_ExercisePriceExpireInYearsFormTheDateOfGrant
Namespace Prefix:	pcvx_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Incentive stock option granted to Employees Owning percentage of shares of common stock.

+ References

No definition available.

+ Details

Name:	pcvx_IncentiveStockOptionGrantedToEmployeesOwningPercentageOfSharesOfCommonStock
Namespace Prefix:	pcvx_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of options exercised, excludes options exercised from NPLN.

+ References

No definition available.

+ Details

Name:	pcvx_NumberOfOptionsExercisedExcludesOptionsExercisedFromNpln
Namespace Prefix:	pcvx_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Offering period.

+ References

No definition available.

+ Details

Name:	pcvx_OfferingPeriod
Namespace Prefix:	pcvx_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of fair value per share on the grant date.

+ References

No definition available.

+ Details

Name:	pcvx_PercentageOfFairValuePerShareOnTheGrantDate
Namespace Prefix:	pcvx_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of provisions subject to stockholders.

+ References

No definition available.

+ Details

Name:	pcvx_PercentageOfProvisionsSubjectToStockholders
Namespace Prefix:	pcvx_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Purchase period.

+ References

No definition available.

+ Details

Name:	pcvx_PurchasePeriod
Namespace Prefix:	pcvx_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Remaining liabilities related to early exercised shares.

+ References

No definition available.

+ Details

Name:	pcvx_RemainingLiabilitiesRelatedToEarlyExercisedShares
Namespace Prefix:	pcvx_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Share based Compensation Arrangement By Share based Payment Award Award Vesting Rights Six Months Thereafter Percentage

+ References

No definition available.

+ Details

Name:	pcvx_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingRightsSixMonthsThereafterPercentage
Namespace Prefix:	pcvx_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Share based compensation arrangement by share based payment award number of shares increase in available for grant.

+ References

No definition available.

+ Details

Name:	pcvx_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesIncreaseInAvailableForGrant
Namespace Prefix:	pcvx_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Stock options granted term.

+ References

No definition available.

+ Details

Name:	pcvx_StockOptionsGrantedTerm
Namespace Prefix:	pcvx_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

+ References

+ Details

Name:	us-gaap_AllocatedShareBasedCompensationExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Aggregate number of common shares reserved for future issuance.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.29)
-URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_CommonStockCapitalSharesReservedForFutureIssuance
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

+ References

+ Details

Name:	us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

+ Details

Name:	us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of cost to be recognized for option under share-based payment arrangement.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (i)
-URI https://asc.fasb.org/extlink&oid=128089324&loc=d3e5070-113901

+ Details

Name:	us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI https://asc.fasb.org/extlink&oid=128089324&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The highest percentage of annual salary that an employee is permitted to utilize with respect to the plan.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-URI https://asc.fasb.org/extlink&oid=128089324&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumEmployeeSubscriptionRate
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

+ References

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

+ References

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Gross number of share options (or share units) granted during the period.

+ References

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

+ References

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of options outstanding, including both vested and non-vested options.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(ii)
-URI https://asc.fasb.org/extlink&oid=128089324&loc=d3e5070-113901

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(i)
-URI https://asc.fasb.org/extlink&oid=128089324&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Maximum number of shares that may be issued in accordance with the plan as a proportion of outstanding capital stock.

+ References

No definition available.

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardPercentageOfOutstandingStockMaximum
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of shares purchased for issuance under share-based payment arrangement.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (l)
-URI https://asc.fasb.org/extlink&oid=128089324&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesPurchasedForAward
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Weighted average price at which option holders acquired shares when converting their stock options into shares.

+ References

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of vesting of award under share-based payment arrangement.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI https://asc.fasb.org/extlink&oid=128089324&loc=d3e5070-113901

+ Details

Name:	us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(2)
-URI https://asc.fasb.org/extlink&oid=128089324&loc=d3e5070-113901

+ Details

Name:	us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of options vested.

+ References

No definition available.

+ Details

Name:	us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedNumberOfShares
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Purchase price of common stock expressed as a percentage of its fair value.

+ References

No definition available.

+ Details

Name:	us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_AwardTypeAxis=us-gaap_PerformanceSharesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsidiarySaleOfStockAxis=us-gaap_IPOMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardTypeAxis=us-gaap_RestrictedStockUnitsRSUMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardTypeAxis=pcvx_OtherRestrictedStockUnitsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PlanNameAxis=pcvx_TwoThousandTwentyEquityIncentivePlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PlanNameAxis=pcvx_TwoThousandFourteenEquityIncentivePlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PlanNameAxis=pcvx_TwoThousandTwentyEmployeeStockPurchasePlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BalanceSheetLocationAxis=us-gaap_OtherNoncurrentLiabilitiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Equity Incentive Plans - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions			3 Months Ended	12 Months Ended
	Jan. 01, 2023	Jun. 11, 2020	Jun. 30, 2020	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting percentage for stock options granted		25.00%
Vesting period for stock options granted		4 years
Early exercised stock options				3,705	7,410
Options granted				36,710
Exercise of stock options (in shares)				1,153,285	926,514	358,264
Weighted-average price per share				$ 4.25	$ 3.25	$ 1.88
Weighted-average grant date fair value of options granted				$ 18.88	$ 14.65	$ 9.62
Intrinsic value of the stock options exercised				$ 34.0	$ 18.9	$ 7.8
Unrecognized stock-based compensation expense				$ 87.7
Unrecognized share-based compensation expense, expected to be recognized				2 years 10 months 24 days
Performance-based Awards
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense			$ 0.3
Performance-based Awards \| IPO
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares vested			362,935
Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting percentage for stock options granted		25.00%
Vesting percentage for stock options granted, Six months thereafter		12.50%
Vesting period for stock options granted		4 years
Other Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting percentage for stock options granted, Six months thereafter		12.50%
Vesting period for stock options granted		3 years 6 months
Weighted-average grant date fair value of options granted				$ 26.25
Unrecognized stock-based compensation cost				$ 10.8
Unrecognized share-based compensation expense, expected to be recognized				3 years
2020 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Exercise price expire in years form the date of grant		5 years
Stock options granted term		10 years
Percentage of provisions subject to stockholders		10.00%
Shares reserved for issuance		10,150,000
Term of plan		10 years
Percentage of outstanding number of shares		5.00%
Aggregate number of shares available for issuance					4,679,598
Available for issuance of shares increased				3,973,533
2020 Equity Incentive Plan \| Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares outstanding				5,596,099
2014 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares outstanding				2,576,161
2020 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares reserved for issuance		650,000
Term of plan		10 years
Percentage of outstanding number of shares		1.00%
Employees purchase shares of common stock of lower of fair market value		85.00%
Offering period		2 years
Purchase period		6 months
Percentage of payroll deductions of eligible compensation		15.00%
Employees acquired shares of common stock				61,709	62,546	27,465
2020 Employee Stock Purchase Plan \| Subsequent Event
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Available for issuance of shares increased	794,706
Minimum \| 2020 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Incentive stock option granted to employees owning percentage of shares of common stock		10.00%
Maximum \| Other Liabilities
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Remaining liabilities related to early exercised shares				$ 0.1	$ 0.1
Maximum \| 2020 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of fair value per share on the grant date		110.00%