Subsequent Event (Details) (Acquisition [Member], Hologic [Member], USD $) In Millions, except Per Share data, unless otherwise specified	0 Months Ended
Apr. 29, 2012
Acquisition [Member] \| Hologic [Member]
Subsequent Event [Line Items]
Subsequent event, date	Apr. 29, 2012
Sale of stock offered price, per share	$ 82.75
Merger agreement termination fee	$ 128.0
Reimbursed transaction costs	20.0
Financing failure fee	$ 200.0

Date of subsequent event occurrence or of indication that subsequent event occurred.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 855

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6842918&loc=SL6314017-165662

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