Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)	3 Months Ended		6 Months Ended		12 Months Ended
	Jan. 31, 2015	Jan. 31, 2014	Jan. 31, 2015	Jan. 31, 2014	Jul. 31, 2014	Aug. 29, 2008
Significant Accounting Policies [Line Items]
Inventory reserves	$ 48,100,000		$ 48,100,000		45,300,000
Estimated weighted average useful life of acquired intangible assets			3 years 9 months 18 days
Indefinite lived trademarks	6,700,000		6,700,000
Warranty for Products			The Company generally offers a warranty for most of its products, the standard terms and conditions of which are based on the product sold and the customer.
Unrecognized income tax benefits	5,900,000		5,900,000		6,600,000
Unrecognized income tax benefits that would impact income tax rate if recognized	2,400,000		2,400,000		3,000,000
Uncertain tax positions accrued interest and penalties	900,000		900,000		1,000,000
Ownership percentage that trigger limitation on NOL carryforward utilization						50.00%
Operating loss carryforwards, limitations on use			As a result of the Company's merger with Credence on August 29, 2008, a greater than 50% cumulative ownership change in both entities triggered a significant limitation on net operating loss carryforward utilization. The Company's ability to use acquired U.S. net operating loss and credit carryforwards is subject to annual limitation as defined in sections 382 and 383 of the Internal Revenue Code.
Estimated annual limitation on use of net operating loss						10,100,000
Amount of net operating loss available for utilization						202,000,000
Share-based compensation	1,900,000	1,300,000	3,844,000	2,425,000
Maturity period of highly liquid investments to be considered cash equivalent			3 months
Other temporary impairment losses	0	0	0	0
Minimum
Significant Accounting Policies [Line Items]
Property plant and equipment estimated useful life			3 years		3 years
Maximum
Significant Accounting Policies [Line Items]
Property plant and equipment estimated useful life			7 years		7 years
Other Income, Net
Significant Accounting Policies [Line Items]
Foreign currency remeasurement and transaction gains	$ 1,400,000	$ 100,000	$ 1,800,000	$ 100,000
Stock Option
Significant Accounting Policies [Line Items]
Anti-dilutive securities excluded from computation of earnings per share			100,000	600,000
Restricted stock units (RSU's)
Significant Accounting Policies [Line Items]
Restricted stock unit awards granted	61,400
Anti-dilutive securities excluded from computation of earnings per share		2,000,000		2,000,000
Restricted stock units (RSU's) | Vest Over Next Twelve Months
Significant Accounting Policies [Line Items]
Restricted stock unit awards granted	60,000
Restricted stock unit award granted, vesting period	12 months
Restricted stock units (RSU's) | Vest 25% Per Year For Four Years
Significant Accounting Policies [Line Items]
Restricted stock unit awards granted	1,400
Restricted stock unit award granted, vesting period	4 years
Restricted stock unit award granted, vesting percentage	25.00%