Intangible Assets (Detail) (USD $) In Thousands, unless otherwise specified	6 Months Ended	12 Months Ended
	Jan. 31, 2013	Jul. 31, 2012
Finite-Lived Intangible Assets [Line Items]
Net Amount	$ 2,362
Merger with Credence Systems Corporation (August 29, 2008)
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	38,900	38,900
Accumulated Amortization	36,538	35,747
Net Amount	2,362	3,153
Merger with Credence Systems Corporation (August 29, 2008) | Trade Names
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life	2 years	2 years
Gross Carrying Amount	300	300
Accumulated Amortization	300	300
Net Amount
Merger with Credence Systems Corporation (August 29, 2008) | Distributor relationships
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life	2 years	2 years
Gross Carrying Amount	2,800	2,800
Accumulated Amortization	2,800	2,800
Net Amount
Merger with Credence Systems Corporation (August 29, 2008) | Key customer relationships
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life	3 years	3 years
Gross Carrying Amount	8,500	8,500
Accumulated Amortization	8,500	8,500
Net Amount
Merger with Credence Systems Corporation (August 29, 2008) | 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	15,352	14,965
Net Amount	648	1,035
Merger with Credence Systems Corporation (August 29, 2008) | 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	8,636	8,367
Net Amount	764	1,033
Merger with Credence Systems Corporation (August 29, 2008) | Maintenance agreements
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life	7 years	7 years
Gross Carrying Amount	1,900	1,900
Accumulated Amortization	950	815
Net Amount	$ 950	$ 1,085