COMMON STOCK AND STOCK-BASED COMPENSATION - Stock Options Outstanding and Exercisable (Details) (Stock options, USD $) In Thousands, except Share data, unless otherwise specified	6 Months Ended
Oct. 26, 2013
2010 Stock Plan
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding - Average Exercise Price (in dollars per share)	$ 11.46
Options Outstanding - Shares	480,000
Options Exercisable - Average Exercise Price (in dollars per share)	$ 9.63
Options Exercisable - Shares	240,000
Outstanding options - intrinsic value	$ 8,711
2010 Stock Plan \| Average Exercise Price $9.24
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding - Average Exercise Price (in dollars per share)	$ 9.24
Options Outstanding - Shares	120,000
Options Outstanding - Avg. Remaining Life (Years)	7 years 0 months 25 days
Options Exercisable - Average Exercise Price (in dollars per share)	$ 9.24
Options Exercisable - Shares	120,000
Options Exercisable - Avg. Remaining Life (Years)	7 years 0 months 25 days
2010 Stock Plan \| Average Exercise Price $10.70
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding - Average Exercise Price (in dollars per share)	$ 10.70
Options Outstanding - Shares	120,000
Options Outstanding - Avg. Remaining Life (Years)	7 years 9 months 26 days
Options Exercisable - Average Exercise Price (in dollars per share)	$ 10.70
Options Exercisable - Shares	80,000
Options Exercisable - Avg. Remaining Life (Years)	7 years 9 months 26 days
2010 Stock Plan \| Average Exercise Price $8.64
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding - Average Exercise Price (in dollars per share)	$ 8.64
Options Outstanding - Shares	120,000
Options Outstanding - Avg. Remaining Life (Years)	8 years 9 months 21 days
Options Exercisable - Average Exercise Price (in dollars per share)	$ 8.64
Options Exercisable - Shares	40,000
Options Exercisable - Avg. Remaining Life (Years)	8 years 9 months 21 days
2010 Stock Plan \| Average Exercise Price $17.27
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding - Average Exercise Price (in dollars per share)	$ 17.27
Options Outstanding - Shares	120,000
Options Outstanding - Avg. Remaining Life (Years)	9 years 9 months 25 days
2007 Stock Plan
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding - Average Exercise Price (in dollars per share)	$ 5.87
Options Outstanding - Shares	650,002
Options Exercisable - Average Exercise Price (in dollars per share)	$ 4.80
Options Exercisable - Shares	561,669
Outstanding options - intrinsic value	$ 15,431
2007 Stock Plan \| Average Exercise Price $8.64
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding - Average Exercise Price (in dollars per share)	$ 8.64
Options Outstanding - Shares	30,001
Options Outstanding - Avg. Remaining Life (Years)	8 years 9 months 21 days
Options Exercisable - Average Exercise Price (in dollars per share)	$ 8.64
Options Exercisable - Shares	1,668
Options Exercisable - Avg. Remaining Life (Years)	8 years 9 months 21 days
2007 Stock Plan \| Average Exercise Price $2.72
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding - Average Exercise Price (in dollars per share)	$ 2.72
Options Outstanding - Shares	279,000
Options Outstanding - Avg. Remaining Life (Years)	5 years 5 months 17 days
Options Exercisable - Average Exercise Price (in dollars per share)	$ 2.72
Options Exercisable - Shares	279,000
Options Exercisable - Avg. Remaining Life (Years)	5 years 5 months 17 days
2007 Stock Plan \| Average Exercise Price $6.46
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding - Average Exercise Price (in dollars per share)	$ 6.46
Options Outstanding - Shares	246,000
Options Outstanding - Avg. Remaining Life (Years)	5 years 9 months 12 days
Options Exercisable - Average Exercise Price (in dollars per share)	$ 6.46
Options Exercisable - Shares	246,000
Options Exercisable - Avg. Remaining Life (Years)	5 years 9 months 12 days
2007 Stock Plan \| Average Exercise Price $10.55
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding - Average Exercise Price (in dollars per share)	$ 10.55
Options Outstanding - Shares	20,000
Options Outstanding - Avg. Remaining Life (Years)	6 years 9 months 22 days
Options Exercisable - Average Exercise Price (in dollars per share)	$ 10.55
Options Exercisable - Shares	20,000
Options Exercisable - Avg. Remaining Life (Years)	6 years 9 months 22 days
2007 Stock Plan \| Average Exercise Price $8.10
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding - Average Exercise Price (in dollars per share)	$ 8.10
Options Outstanding - Shares	32,501
Options Outstanding - Avg. Remaining Life (Years)	8 years 0 months 0 days
Options Exercisable - Average Exercise Price (in dollars per share)	$ 8.10
Options Exercisable - Shares	15,001
Options Exercisable - Avg. Remaining Life (Years)	8 years 0 months 0 days
2007 Stock Plan \| Average Exercise Price $17.27
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding - Average Exercise Price (in dollars per share)	$ 17.27
Options Outstanding - Shares	42,500
Options Outstanding - Avg. Remaining Life (Years)	9 years 9 months 25 days

Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of options outstanding.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph d(1)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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- Definition

Weighted average exercise price as of the balance sheet date for those equity-based payment arrangements exercisable and outstanding.

+ References

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- Definition

Weighted average remaining contractual term of exercisable stock options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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- Definition

The number of shares reserved for issuance pertaining to the outstanding exercisable stock options as of the balance sheet date in the customized range of exercise prices for which the market and performance vesting condition has been satisfied.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph b(1)(c)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(iii)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

The number of shares reserved for issuance pertaining to the outstanding stock options as of the balance sheet date for all option plans in the customized range of exercise prices.

+ 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)(1)(i)-(ii)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph b(1)(a, b)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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- Definition

The weighted average price as of the balance sheet date at which grantees could acquire the underlying shares with respect to all outstanding stock options which are in the customized range of exercise prices.

+ References

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- Definition

Weighted average remaining contractual term of outstanding stock options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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