Income Taxes - Additional Information (Detail) (USD $)	12 Months Ended
Apr. 28, 2012	Apr. 30, 2011	Apr. 24, 2010
Income Taxes [Line Items]
Valuation allowance	$ 4,800,000
Net operating loss carryforwards	7,656,000	9,431,000
Undistributed earnings subject to federal income tax	228,000,000
Gross unrecognized tax benefits	18,099,000	18,963,000	18,685,000
Deferred tax assets, net	5,000,000	4,900,000
Interest and penalties	2,600,000	2,900,000
Increase in interest and penalties expense	700,000
Mobilis Healthcare Group
Income Taxes [Line Items]
Foreign net operating loss carryforwards	$ 31,500,000

The sum of the tax effects as of the balance sheet date of the amount of excesses of tax deductions over gross income in a year which cannot be used on the tax returns in the current year but can be carried forward to reduce taxable income or income taxes payable in a future year, for which there must be sufficient tax-basis income to utilize a portion or all of the carryforward amount to realize the deferred tax asset.

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The tax effect as of the balance sheet date of the amount of excess of tax deductions over gross income in a year which cannot be used on the tax return of a country outside the country of domicile in the current year but can be carried forward to reduce taxable income or income taxes payable in a future year, for which there must be sufficient tax-basis income to utilize a portion or all of the carryforward amount to realize the deferred tax asset.

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- Definition

The amount as of the balance sheet date of the estimated future tax effects attributable to undistributed earnings of subsidiaries and other recognized entities in countries outside the country of domicile which will increase future taxable income when such earnings are distributed into the country of domicile.

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- Definition

This element represents the total of accruals as of the date of the statement of financial position for interest recognized for an underpayment of income taxes computed by applying the applicable statutory rate of interest to the difference between a tax position recognized for financial reporting purposes and the amount previously taken or expected to be taken in a tax return of the entity and the amount of statutory penalties for a tax position claimed or expected to be claimed by the entity, in its tax return, that does not meet the minimum statutory threshold to avoid payment of penalties.

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- Definition

This element represents the total of interest expense recognized for an underpayment of income taxes computed by applying the applicable statutory rate of interest to the difference between a tax position recognized for financial reporting purposes and the amount previously taken or expected to be taken in a tax return of the entity and the amount of statutory penalties in the period in which the entity claims or expects to claim a tax position, in its tax return, that does not meet the minimum statutory threshold to avoid payment of penalties.

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- Definition

The amount of the valuation allowance recorded as of the balance sheet date pertaining to the specified deferred tax asset for which an assessment was made that it is more likely than not that all or a portion of such deferred tax asset will not be realized through related deductions on future tax returns.

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