Income Taxes - Additional Information (Detail) (USD $)	12 Months Ended
	Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2012	Jul. 31, 2011	Aug. 31, 2008	Aug. 29, 2008
Income Taxes [Line Items]
Cumulative unremitted earnings considered to be indefinitely reinvested outside of U.S. taxes	$ 8,300,000	$ 100,000
Valuation allowance	211,925,000	204,484,000
Deferred Tax Benefit	500,000
Ownership percentage that trigger limitation on NOL carryforward utilization					50.00%	50.00%
Estimated annual limitation on use of net operating loss					10,100,000	10,100,000
Net operating loss subject to limitation	202,000,000					202,000,000
Unrecognized tax benefits	6,590,000	6,788,000	8,009,000	9,094,000
unrecognized tax benefit that would impact on effective income tax rate, if recognized	3,000,000	3,200,000
Accrued interest and penalties related to uncertain tax positions	1,000,000	900,000
Net cash paid for income taxes	1,100,000	200,000	100,000
Federal
Income Taxes [Line Items]
Net operating loss carry forwards	367,100,000	356,400,000
Tax credit carryforwards including research and development	8,000,000	6,900,000
Federal | Minimum
Income Taxes [Line Items]
Net operating loss carry forwards expiration year	2019	2017
Tax credit carryforwards expiration year	2018	2018
Federal | Maximum
Income Taxes [Line Items]
Net operating loss carry forwards expiration year	2034	2033
Tax credit carryforwards expiration year	2034	2033
State
Income Taxes [Line Items]
Net operating loss carry forwards	255,400,000	247,200,000
Tax credit carryforwards including research and development	34,800,000	33,400,000
State | Minimum
Income Taxes [Line Items]
Net operating loss carry forwards expiration year	2015	2014
Tax credit carryforwards expiration year	2015	2014
State | Maximum
Income Taxes [Line Items]
Net operating loss carry forwards expiration year	2034	2033
Tax credit carryforwards expiration year	2029	2028
Foreign
Income Taxes [Line Items]
Net operating loss carry forwards	$ 16,100,000	$ 16,100,000