Restructuring and Related Charges by Segment (Detail) - USD ($) $ in Thousands	3 Months Ended
Oct. 31, 2017	Oct. 31, 2016
Restructuring Cost and Reserve [Line Items]
Restructuring and related charges	$ 500	$ 30
Medical Imaging
Restructuring Cost and Reserve [Line Items]
Restructuring and related charges	100	20
Ultrasound
Restructuring Cost and Reserve [Line Items]
Restructuring and related charges	$ 400	$ 10

Amount, after cash payment, of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585

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