Amortizable Intangible Assets (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jul. 31, 2014	Jul. 31, 2013
Finite-Lived Intangible Assets [Line Items]
Net Amount	$ 4,865
ECT and Multitest Acquisition and Credence Merger
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	32,600	27,300
Accumulated Amortization	(27,735)	(25,729)
Net Amount	4,865	1,571
ECT and Multitest Acquisition and Credence Merger | Developed Technology Rights | Asl
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life	6 years	6 years
Gross Carrying Amount	16,000	16,000
Accumulated Amortization	(16,000)	(15,737)
Net Amount		263
ECT and Multitest Acquisition and Credence Merger | Developed Technology Rights | Diamond
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life	9 years	9 years
Gross Carrying Amount	9,400	9,400
Accumulated Amortization	(9,141)	(8,906)
Net Amount	259	494
ECT and Multitest Acquisition and Credence Merger | Developed Technology Rights | Multitest
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life	10 years
Gross Carrying Amount	1,400
Accumulated Amortization	(267)
Net Amount	1,133
ECT and Multitest Acquisition and Credence Merger | Developed Technology Rights | Everett Charles Technologies
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life	10 years
Gross Carrying Amount	600
Accumulated Amortization	(95)
Net Amount	505
ECT and Multitest Acquisition and Credence Merger | Developed Technology Rights | atg Luther & Maelzer
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life	10 years
Gross Carrying Amount	2,000
Accumulated Amortization	(377)
Net Amount	1,623
ECT and Multitest Acquisition and Credence Merger | Maintenance agreements | ASL and Diamond
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life	7 years	7 years
Gross Carrying Amount	1,900	1,900
Accumulated Amortization	(1,357)	(1,086)
Net Amount	543	814
ECT and Multitest Acquisition and Credence Merger | Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	1,300
Accumulated Amortization	(498)
Net Amount	$ 802
ECT and Multitest Acquisition and Credence Merger | Customer relationships | Multitest
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life	2 years
ECT and Multitest Acquisition and Credence Merger | Customer relationships | Everett Charles Technologies
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life	2 years
ECT and Multitest Acquisition and Credence Merger | Customer relationships | atg Luther & Maelzer
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life	2 years