Debt - Additional Information (Detail) - Cerus Term Loans		3 Months Ended
Jun. 30, 2014 USD ($) Tranche	Mar. 31, 2017
Line of Credit Facility [Line Items]
Maximum borrowing limit	$ 30,000,000
Term of agreement	5 years
Number of loan tranches \| Tranche	3
Interest rate, description		Term Loan A bears an interest rate of 6.95%. Term Loan B bears an interest rate of 7.01%.
Principal and interest payments	36 months	29 months
Final payment term percent	7.00%
Terms of required periodic payments of interest and principal		The Company was required to make interest only payments through June 2016, followed by thirty-six months of equal principal and interest payments thereafter. On July 28, 2016, the Term Loan Agreement was amended to include an additional interest-only period for all advances under the Term Loan Agreement. As amended, the Company was required to make interest only payments from August 2016 through January 2017, followed by twenty-nine months of equal principal and interest payments thereafter. The Company determined that the amendment to the Term Loan Agreement resulted in a modification. As a result, the accounting treatment for the Term Loan continues under the interest method, with a new effective interest rate based on revised cash flows calculated on a prospective basis upon the execution of the amendment to the Term Loan Agreement. 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.
First Tranche (Term Loan A)
Line of Credit Facility [Line Items]
Loan and security agreement	$ 10,000,000
Interest rate	6.95%
Maturity period		Jun. 01, 2019
Second Tranche (Term Loan B)
Line of Credit Facility [Line Items]
Loan and security agreement	$ 10,000,000
Borrowing conditions		The second tranche of $10.0 million (“Term Loan B”) was drawn on June 15, 2015.
Interest rate		7.01%
Maturity period		Jun. 01, 2019
Securities Pledged as Collateral
Line of Credit Facility [Line Items]
Percentage of investments made in subsidiary	35.00%

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

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Line of credit facility principal and interest repayment additional period.

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Number Of Equal Tranches

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Percentage of investments made in subsidiary.

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- Definition

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

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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.

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- 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 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: 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

Reference 3: 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

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

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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.

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

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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).

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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.

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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.

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