Subsequent Event - Additional Information (Detail) - USD ($)	Jul. 31, 2018	Dec. 23, 2016
Revolving Credit Facility [Member]
Subsequent Event [Line Items]
Loan agreement, maturity date		Dec. 23, 2021
Loans maximum borrowing capacity		$ 300,000,000
Counsyl Inc [Member] \| Amendment to Credit Agreement [Member] \| Revolving Credit Facility [Member] \| JPMorgan Chase Bank, N.A. [Member]
Subsequent Event [Line Items]
Loans maximum borrowing capacity		$ 300,000,000
Subsequent Event [Member] \| Counsyl Inc [Member] \| Agreement and Plan of Merger [Member]
Subsequent Event [Line Items]
Effective date of business acquisition	Jul. 31, 2018
Business acquisition consideration	$ 407,800,000
Cash payment on business acquisition	$ 280,400,000
Subsequent Event [Member] \| Counsyl Inc [Member] \| Agreement and Plan of Merger [Member] \| Common Stock [Member]
Subsequent Event [Line Items]
Business acquisition, shares issued	2,994,251
Business acquisition, shares issued, value	$ 127,300,000
Subsequent Event [Member] \| Counsyl Inc [Member] \| Amendment to Credit Agreement [Member] \| Revolving Credit Facility [Member] \| JPMorgan Chase Bank, N.A. [Member]
Subsequent Event [Line Items]
Loan agreement, maturity date	Jul. 31, 2023
Loans maximum borrowing capacity	$ 350,000,000

Date when the acquirer obtains control of the acquiree, in CCYY-MM-DD format.

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Value of equity interests (such as common shares, preferred shares, or partnership interest) issued or issuable to acquire the entity.

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Number of shares of equity interests issued or issuable to acquire entity.

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Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

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

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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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The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

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Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

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