Fair Value Measurement (Details) - USD ($) $ in Thousands	Jul. 28, 2018	Apr. 28, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available-for-sale securities:	$ 27,352	$ 34,522
Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available-for-sale securities:	6,189	8,669
U.S. Government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available-for-sale securities:	1,986	992
U.S. Government sponsored entities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available-for-sale securities:	14,971	19,949
Municipal bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available-for-sale securities:	4,206	4,912
Reported Value Measurement [Member] \| Recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash and cash equivalents	15,915	29,727
Restricted cash	26	28
Derivatives - asset position	145	41
Derivatives - liability position	(69)	(236)
Contingent liabilities	(2,309)	(1,000)
Assets (Liabilities), net	41,060	63,082
Reported Value Measurement [Member] \| Recurring Basis \| Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available-for-sale securities:	6,189	8,669
Reported Value Measurement [Member] \| Recurring Basis \| U.S. Government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available-for-sale securities:	1,986	992
Reported Value Measurement [Member] \| Recurring Basis \| U.S. Government sponsored entities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available-for-sale securities:	14,971	19,949
Reported Value Measurement [Member] \| Recurring Basis \| Municipal bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available-for-sale securities:	4,206	4,912
Estimate of Fair Value Measurement [Member] \| Recurring Basis \| Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash and cash equivalents	15,915	29,727
Restricted cash	26	28
Derivatives - asset position	0	0
Derivatives - liability position	0	0
Contingent liabilities	0	0
Assets (Liabilities), net	17,927	30,747
Estimate of Fair Value Measurement [Member] \| Recurring Basis \| Level 1 \| Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available-for-sale securities:	0	0
Estimate of Fair Value Measurement [Member] \| Recurring Basis \| Level 1 \| U.S. Government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available-for-sale securities:	1,986	992
Estimate of Fair Value Measurement [Member] \| Recurring Basis \| Level 1 \| U.S. Government sponsored entities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available-for-sale securities:	0	0
Estimate of Fair Value Measurement [Member] \| Recurring Basis \| Level 1 \| Municipal bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available-for-sale securities:	0	0
Estimate of Fair Value Measurement [Member] \| Recurring Basis \| Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash and cash equivalents	0	0
Restricted cash	0	0
Derivatives - asset position	145	41
Derivatives - liability position	(69)	(236)
Contingent liabilities	0	0
Assets (Liabilities), net	25,442	33,335
Estimate of Fair Value Measurement [Member] \| Recurring Basis \| Level 2 \| Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available-for-sale securities:	6,189	8,669
Estimate of Fair Value Measurement [Member] \| Recurring Basis \| Level 2 \| U.S. Government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available-for-sale securities:	0	0
Estimate of Fair Value Measurement [Member] \| Recurring Basis \| Level 2 \| U.S. Government sponsored entities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available-for-sale securities:	14,971	19,949
Estimate of Fair Value Measurement [Member] \| Recurring Basis \| Level 2 \| Municipal bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available-for-sale securities:	4,206	4,912
Estimate of Fair Value Measurement [Member] \| Recurring Basis \| Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash and cash equivalents	0	0
Restricted cash	0	0
Derivatives - asset position	0	0
Derivatives - liability position	0	0
Contingent liabilities	(2,309)	(1,000)
Assets (Liabilities), net	(2,309)	(1,000)
Estimate of Fair Value Measurement [Member] \| Recurring Basis \| Level 3 \| Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available-for-sale securities:	0	0
Estimate of Fair Value Measurement [Member] \| Recurring Basis \| Level 3 \| U.S. Government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available-for-sale securities:	0	0
Estimate of Fair Value Measurement [Member] \| Recurring Basis \| Level 3 \| U.S. Government sponsored entities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available-for-sale securities:	0	0
Estimate of Fair Value Measurement [Member] \| Recurring Basis \| Level 3 \| Municipal bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available-for-sale securities:	$ 0	$ 0

Restricted Cash and Cash Equivalents, Fair Value Disclosure

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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Amount of liability recognized arising from contingent consideration in a business combination.

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Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Fair value of asset after deduction of liability.

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Fair value portion of asset contracts related to the exchange of different currencies, including, but not limited to, foreign currency options, forward contracts, and swaps.

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Fair value portion of liability contracts related to the exchange of different currencies, including, but not limited to, foreign currency options, forward (delivery or nondelivery) contracts, and swaps entered into.

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