Marketable Securities - Available-for-sale Securities (Details) - USD ($) $ in Thousands	May 02, 2020	Apr. 27, 2019
Schedule of Available-for-sale Securities
Amortized Cost	$ 1,230	$ 26,379
Unrealized Losses	0	(35)
Fair Value	1,230	26,344
Certificates of deposit
Schedule of Available-for-sale Securities
Amortized Cost	1,230	3,464
Unrealized Losses	0	0
Fair Value	$ 1,230	3,464
U.S. Government securities
Schedule of Available-for-sale Securities
Amortized Cost		10,779
Unrealized Losses		(5)
Fair Value		10,774
U.S. Government sponsored entities
Schedule of Available-for-sale Securities
Amortized Cost		10,510
Unrealized Losses		(28)
Fair Value		10,482
Municipal bonds
Schedule of Available-for-sale Securities
Amortized Cost		1,626
Unrealized Losses		(2)
Fair Value		$ 1,624

Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27161-111563

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=118942338&loc=SL82898722-210454

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

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