Accrual for manufacturing and development payment liability.

No definition available.

Name:	cers_AccrualForManufacturingAndDevelopmentPaymentLiability
Namespace Prefix:	cers_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Additional co-Investment for collaborative agreement.

+ References

No definition available.

+ Details

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Namespace Prefix:	cers_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Base period maximum funding of collaborative agreement.

+ References

No definition available.

+ Details

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Namespace Prefix:	cers_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Co-investment for collaborative agreement.

+ References

No definition available.

+ Details

Name:	cers_CoInvestmentForCollaborativeAgreement
Namespace Prefix:	cers_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Licenses agreements.

+ References

No definition available.

+ Details

Name:	cers_LicensesAgreementsLineItems
Namespace Prefix:	cers_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Manufacturing and development payment liability.

+ References

No definition available.

+ Details

Name:	cers_ManufacturingAndDevelopmentPaymentLiability
Namespace Prefix:	cers_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Option period maximum funding of collaborative agreement.

+ References

No definition available.

+ Details

Name:	cers_OptionPeriodMaximumFundingOfCollaborativeAgreement
Namespace Prefix:	cers_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Payment for manufacturing of entity products.

+ References

No definition available.

+ Details

Name:	cers_PaymentForManufacturingOfEntityProducts
Namespace Prefix:	cers_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Payments For Manufacturing And Development Cost

+ References

No definition available.

+ Details

Name:	cers_PaymentsForManufacturingAndDevelopmentCost
Namespace Prefix:	cers_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Remaining amount payable for manufacturing and development payment liability.

+ References

No definition available.

+ Details

Name:	cers_RemainingAmountPayableForManufacturingAndDevelopmentPaymentLiability
Namespace Prefix:	cers_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Term of collaborative agreement.

+ References

No definition available.

+ Details

Name:	cers_TermOfCollaborativeAgreement
Namespace Prefix:	cers_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Value of input used to measure alternative investment.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)(2)
-URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258

+ Details

Name:	us-gaap_AlternativeInvestmentMeasurementInput
Namespace Prefix:	us-gaap_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount to be collected within one year of the balance sheet date (or one operating cycle, if longer) from customers in accordance with the contractual provisions of long-term contracts or programs including amounts billed and unbilled as of the balance sheet date.

+ 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 210.5-02.3(c))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Details

Name:	us-gaap_CapitalizedCostsOfUnprovedPropertiesExcludedFromAmortizationByPropertyOrProjectAxis=cers_BiomedicalAdvancedResearchAndDevelopmentAuthorityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=cers_CerusCorporationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=cers_ManufacturingAndSupplyAgreementsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=cers_FreseniusKabiAGMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Development and License Agreements - Additional Information (Detail) € in Millions	1 Months Ended	12 Months Ended
	Aug. 31, 2018 EUR (€)	Dec. 31, 2018 USD ($)	Dec. 31, 2018 EUR (€)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2016 EUR (€)	Dec. 31, 2018 EUR (€)	Dec. 31, 2017 EUR (€)
Licenses Agreements [Line Items]
Payments made relating to the manufacturing of the products		$ 21,300,000		$ 18,100,000	$ 16,100,000
BARDA Agreement
Licenses Agreements [Line Items]
Committed fund receivable		103,200,000
Committed fund receivable		$ 201,200,000
Period of agreement		5 years	5 years
Accounts receivable of billed and unbilled amounts		$ 2,300,000		1,400,000
Cerus Corporation \| BARDA Agreement
Licenses Agreements [Line Items]
Co-investment by the company		5,000,000
Additional co-investment by the company		9,600,000
Manufacturing and Supply Agreement \| Fresenius
Licenses Agreements [Line Items]
Payments made based on the successful achievement of production volumes \| €			€ 8.6
Manufacturing and development payments \| €						€ 3.1
Remaining amount payable for manufacturing and development \| €	€ 5.5
Accrual for manufacturing and development of entity products		$ 5,900,000		$ 5,800,000			€ 5.2	€ 4.8
Manufacturing and Supply Agreement \| Measurement Input, Discount Rate \| Fresenius
Licenses Agreements [Line Items]
Manufacturing and development obligations, discount rate					0.0972	0.0972