Reportable Segment Information (Detail) (USD $)	3 Months Ended
	Oct. 31, 2013		Oct. 31, 2012	Jul. 31, 2013
Product revenue:
Product revenue	$ 108,454,000		$ 112,547,000
Engineering revenue:
Engineering revenue	1,628,000		7,320,000
Net revenue:
Total net revenue	110,082,000		119,867,000
Income (loss) from continuing operations
Income (loss) from continuing operations	(5,365,000)		7,435,000
Total other expense, net	(400,000)		(900,000)
(Loss) income before income taxes	(5,786,000)		6,529,000
Identifiable assets
Assets	578,024,000			587,784,000
Goodwill by segment:
Goodwill	56,978,000			50,073,000
Reportable segment assets
Identifiable assets
Assets	453,600,000			488,900,000
Corporate assets
Identifiable assets
Assets	124,400,000	[1]		98,900,000	[1]
Goodwill by segment:
Goodwill	6,900,000	[2]
Medical Imaging
Product revenue:
Product revenue	59,200,000		72,100,000
Engineering revenue:
Engineering revenue	1,000,000		3,900,000
Net revenue:
Total net revenue	60,200,000		76,000,000
Income (loss) from continuing operations
Income (loss) from continuing operations	(500,000)		7,400,000
Medical Imaging | Reportable segment assets
Identifiable assets
Assets	207,500,000			217,100,000
Goodwill by segment:
Goodwill	1,900,000			1,900,000
Ultrasound
Product revenue:
Product revenue	34,700,000		31,700,000
Net revenue:
Total net revenue	34,700,000		31,700,000
Income (loss) from continuing operations
Income (loss) from continuing operations	(4,000,000)		(800,000)
Ultrasound | Reportable segment assets
Identifiable assets
Assets	209,700,000			218,400,000
Goodwill by segment:
Goodwill	48,200,000			48,200,000
Security Technology
Product revenue:
Product revenue	14,600,000		8,800,000
Engineering revenue:
Engineering revenue	600,000		3,400,000
Net revenue:
Total net revenue	15,200,000		12,200,000
Income (loss) from continuing operations
Income (loss) from continuing operations	(900,000)		800,000
Security Technology | Reportable segment assets
Identifiable assets
Assets	$ 36,400,000			$ 53,400,000

[1] Includes cash and cash equivalents of $62.4 million and $57.4 million as of October 31, 2013 and July 31, 2013, respectively.

[2] Includes goodwill related to the acquisition of PocketSonics.