Debt instrument, available amount upon condition.

No definition available.

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- Definition

Debt instrument, final payment percentage of principal drawn at maturity.

+ References

No definition available.

+ Details

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- Definition

Debt instrument, principal and interest repayment additional period.

+ References

No definition available.

+ Details

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- Definition

Expiration date to draw second tranche.

+ References

No definition available.

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- Definition

Number of equal tranches.

+ References

No definition available.

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- Definition

Percentage of investments made in subsidiary.

+ References

No definition available.

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- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

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- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

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-Publisher FASB
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Balance Type:	credit
Period Type:	instant

- Definition

Description of the frequency of periodic payments (monthly, quarterly, annual).

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- Definition

Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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Period Type:	instant

- Definition

Description of the interest rate as being fixed or variable, and, if variable, identification of the index or rate on which the interest rate is based and the number of points or percentage added to that index or rate to set the rate, and other pertinent information, such as frequency of rate resets.

+ References

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- 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

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- 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/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
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-Subparagraph (SX 210.5-02.22(a)(2))
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- Definition

Description of the payment terms of the debt instrument (for example, whether periodic payments include principal and frequency of payments) and discussion about any contingencies associated with the payment.

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- 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

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- Definition

The interest rate applicable to the portion of the carrying amount of long-term borrowings outstanding as of the balance sheet date, including current maturities, which accrues interest at a rate subject to change from time to time.

+ References

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- Definition

The cash outflow during the period from the repayment of aggregate short-term and long-term debt. Excludes payment of capital lease obligations.

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Debt - Additional Information (Detail)			1 Months Ended	12 Months Ended
Debt - Additional Information (Detail)	Apr. 27, 2017	Dec. 30, 2016 USD ($)	Jul. 31, 2017 USD ($) Tranche	Dec. 31, 2018
Cerus Term Loans
Debt Instrument [Line Items]
Term loan, face amount		$ 20,000,000
Term of agreement		5 years
Maturity period				Jun. 01, 2019
Principal and interest payments	18 months
Terms of required periodic payments of interest and principal				On April 27, 2017, the Term Loan Agreement was amended to include an additional interest-only period under the Term Loan Agreement. As amended, the Company was required to make interest only payments from May 2017 through December 2017, followed by eighteen months of equal principal and interest payments thereafter. The Company was also required to make a final payment equal to 7% of the principal amounts drawn payable on the earlier to occur of maturity or prepayment.
Final payment term percent	7.00%
Cerus Amended Credit Agreement \| 2017 Term Loans
Debt Instrument [Line Items]
Term loan, face amount			$ 40,000,000
Percentage of investments made in subsidiary			35.00%
Number of loan tranches \| Tranche			2
Repay in full all of outstanding term loans			$ 1,400,000
Terms of required periodic payments of interest and principal				The Amended Credit Agreement provided for secured growth capital term loans of up to $40.0 million (the “2017 Term Loans”). All of the Company’s current and future assets, excluding its intellectual property and 35% of the Company’s investment in Cerus Europe B.V., are secured for its borrowings under the Amended Credit Agreement. The 2017 Term Loans were available in two tranches. The first tranche of $30.0 million (“2017 Term Loan A”) was drawn by the Company on July 31, 2017, with the proceeds used in part to repay in full all of the outstanding term loans under the Term Loan Agreement of $17.6 million and the final payment of the Term Loan Agreement of $1.4 million. The availability of the second tranche of $10.0 million (“2017 Term Loan B”) expired on May 14, 2018, and the Company did not elect to draw the 2017 Term Loan B.
Interest rate, description				The 2017 Term Loan A bears interest at a rate equal to the greater of (i) 8.01% and (ii) the three-month U.S. LIBOR rate plus 6.72%. The interest rate on the 2017 Term Loan A at December 31, 2018 was approximately 9.53%. The Company will also be required to make a final payment fee of 8.00% of the principal amounts of the 2017 Term Loan A. The Amended Credit Agreement contains certain nonfinancial covenants, with which the Company was in compliance at December 31, 2018
Cerus Amended Credit Agreement \| 2017 Term Loans \| Three-month U.S. LIBOR
Debt Instrument [Line Items]
Debt, applicable margin			6.72%
First Tranche (Term Loan A) \| Cerus Amended Credit Agreement \| 2017 Term Loans
Debt Instrument [Line Items]
Term loan, face amount			$ 30,000,000
Final payment term percent			8.00%
Repay in full all of outstanding term loans			$ 17,600,000
Interest rate				9.53%
First Tranche (Term Loan A) \| Cerus Amended Credit Agreement \| 2017 Term Loans \| Minimum
Debt Instrument [Line Items]
Debt instrument floating interest rate percentage			8.01%
Second Tranche (Term Loan B) \| Cerus Amended Credit Agreement \| 2017 Term Loans
Debt Instrument [Line Items]
Loan and security agreement available upon revenue achievement			$ 10,000,000
Expiration date to draw second tranche			May 14, 2018