Income Per Share (Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share) (Details)	3 Months Ended				9 Months Ended
	Jan. 25, 2013		Jan. 27, 2012		Jan. 25, 2013		Jan. 27, 2012
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Class of warrant or right, exercise price of warrants or rights	50.00				50.00
Stock options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from the computation of earnings per share	23,920	[1]	267,469	[1]	29,951	[1]	294,848	[1]
Common stock warrants [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from the computation of earnings per share			3,012,050	[2]	3,012,050	[2]	3,012,050	[2]

[1] Outstanding options to purchase common shares that are excluded from the computation of earnings per share because to include them would have been anti-dilutive.

[2] In September 2005, in conjunction with the issuance of our Convertible Notes, we sold common stock warrants. The warrants entitled the holder to receive the net value for the purchase of 3,012,050 shares of our common stock at $50.00 per share. The warrants were settled during the quarter ended January 25, 2013. Refer to “Note 9. Warrants” for further information. The warrants were anti-dilutive for the thirty-nine weeks ended January 25, 2012 and the thirteen and thirty-nine weeks ended January 27, 2012, since the exercise price of $50.00 exceeded the average market price of our stock for these periods.