Shareholders' Equity - Summary of Restricted Stock Awards and Restricted Stock Units Activity (Details) - shares	12 Months Ended
Apr. 28, 2018	Apr. 29, 2017	Apr. 30, 2016	Apr. 28, 2012	May 01, 2011
2014 Incentive Plan \| RSAs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested and unissued - beginning balance (in shares)	1,168,500	1,161,000	0
Awarded (in shares)	152,738	99,000	1,185,000
Vested (in shares)	(24,000)	(27,000)	(24,000)
Forfeited and cancelled (in shares)	(126,000)	(64,500)	0
Unvested and unissued - ending balance (in shares)	1,171,238	1,168,500	1,161,000
2014 Incentive Plan \| RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested and unissued - beginning balance (in shares)	568,000	576,000	0
Awarded (in shares)	30,925	32,000	576,000
Vested (in shares)	(160,553)	(11,333)	0
Forfeited and cancelled (in shares)	(56,000)	(28,667)	0
Unvested and unissued - ending balance (in shares)	382,372	568,000	576,000
2010 Stock Plan \| RSAs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested and unissued - beginning balance (in shares)	0	33,334	66,667
Awarded (in shares)	0	0	0	100,000	320,000
Vested (in shares)	0	(33,334)	(33,333)
Forfeited and cancelled (in shares)	0	0	0
Unvested and unissued - ending balance (in shares)	0	0	33,334

The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(3)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

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- Definition

The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(1)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

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- Definition

The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(i)-(ii)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

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- Definition

The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(2)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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