Line of Credit Facility Final Payment Percentage of Principal Drawn at Maturity

No definition available.

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Namespace Prefix:	cers_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Line of credit facility principal and interest repayment additional period.

+ References

No definition available.

+ Details

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

- Definition

Number Of Equal Tranches

+ References

No definition available.

+ Details

Name:	cers_NumberOfEqualTranches
Namespace Prefix:	cers_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of investments made in subsidiary.

+ References

No definition available.

+ Details

Name:	cers_PercentageOfInvestmentsMadeInSubsidiary
Namespace Prefix:	cers_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of the fee that accompanies borrowing money under the debt instrument.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22(b))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Definition

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22(a)(2))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentMaturityDate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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

- Definition

The amount of expense provided in the period for legal costs incurred on or before the balance sheet date pertaining to resolved, pending or threatened litigation, including arbitration and mediation proceedings.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.3)

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

+ Details

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

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.16)

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 20, 22

-Article 5

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.16)

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

+ Details

Name:	us-gaap_LineOfCredit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Description of the conditions for borrowing under the credit facility including the nature of any restrictions.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.19(b),22(b))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 22

-Article 5

+ Details

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

- Definition

Description of the frequency of the required periodic payments of interest, principal, or both, and the amount, if set, or a description of a formula upon which payment is based.

+ References

+ Details

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

- Definition

The effective interest rate at the end of the reporting period.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityInterestRateAtPeriodEnd
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Description of the interest rate for the amounts borrowed under the credit facility, including the terms and the method for determining the interest rate (for example, fixed or variable, LIBOR plus a percentage, increasing rate, timing of interest rate resets, remarketing provisions).

+ References

+ Details

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

- Details

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

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Debt - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended		0 Months Ended	9 Months Ended				9 Months Ended		9 Months Ended
	Sep. 30, 2014 Revolving Credit Facility	May 31, 2014 Revolving Credit Facility	Jun. 30, 2014 Loan and Security Agreement Tranche	Sep. 30, 2014 Loan and Security Agreement	Jun. 30, 2014 Loan and Security Agreement	Jun. 30, 2014 Loan and Security Agreement Securities Pledged as Collateral	Jun. 30, 2014 First Tranche (Term Loan A) Loan and Security Agreement	Sep. 30, 2014 Second Tranche (Term Loan B) Loan and Security Agreement	Jun. 30, 2014 Second Tranche (Term Loan B) Loan and Security Agreement	Sep. 30, 2014 Third Tranche (Term Loan C) Loan and Security Agreement	Jun. 30, 2014 Third Tranche (Term Loan C) Loan and Security Agreement
Line of Credit Facility [Line Items]
Maximum borrowing limit	$ 7.0				$ 30.0
Term of agreement			5 years
Number of loan tranches			3
Loan and security agreement		3.4					10.0		10.0		10.0
Borrowing conditions								The second tranche of $10.0 million ("Term Loan B") is contingent upon the approval, if it occurs, by the U.S. Food and Drug Administration ("FDA") of the Company's premarket approval application for either the plasma or platelet system (the "PMA Approval"). The availability of Term Loan B expires at the earlier of (i) six months after receiving PMA Approval or (ii) June 30, 2015.		The third tranche of $10.0 million ("Term Loan C") will be available from July 1, 2015 through December 31, 2015, contingent upon both (i) obtaining PMA Approval and (ii) the Company achieving trailing six months' revenue at a specified threshold (the "Revenue Event").
Interest rate							6.95%
Interest rate, description				Term Loan A bears an interest rate of 6.95%. Term Loan B and Term Loan C will bear an interest rate calculated at the greater of 6.95% or 6.72% plus the three month U.S. LIBOR rate in effect three business days prior to the applicable Term Loan funding date.
Maturity period	Jun. 30, 2014			Jun. 01, 2019
Principal and interest payments			42 months
Final payment term percent			7.00%
Terms of required periodic payments of interest and principal				The Company is required to make interest only payments through December 2015 followed by forty-two months of equal principal and interest payments thereafter; however, if the Revenue Event is achieved no later than November 30, 2015, then the interest-only period may be extended through December 31, 2016, and the amortization period will be reduced to thirty months. The Company is also required to make a final payment equal to 7% of the principal amounts of the Term Loans drawn payable on the earlier to occur of maturity or prepayment.
Commitment fee					0.2
Lender legal fees			$ 0.1
Percentage of investments made in subsidiary						35.00%