Derivatives (Details) (USD $)	3 Months Ended			9 Months Ended			3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended
	Jan. 25, 2013	Oct. 26, 2012	Jan. 27, 2012	Jan. 25, 2013	Jan. 27, 2012	Sep. 27, 2005 Convertible Subordinated Debt [Member]	Jan. 25, 2013 Euro forward contracts [Member]	Jan. 27, 2012 Euro forward contracts [Member]	Jan. 25, 2013 Euro forward contracts [Member]	Jan. 27, 2012 Euro forward contracts [Member]	Jan. 25, 2013 Common stock warrants [Member]	Jan. 27, 2012 Common stock warrants [Member]	Jan. 25, 2013 Common stock warrants [Member]	Jan. 27, 2012 Common stock warrants [Member]
Derivatives, Fair Value [Line Items]
Gain (Loss) on Derivative Instruments, Net, Pretax							$ 0	$ 824,550	$ 0	$ 1,194,550	$ (2,112)	$ 0	$ 1,325,574	$ 0
Senior Notes						125,000,000
Proceeds from Issuance of Warrants				25,200,000
Number of common stock a warrant entitles holder to purchase	3,012,050			3,012,050
Class of warrant or right, exercise price of warrants or rights	50.00			50.00
Liabilities Assumed				3,649,637
Warrants' liability revalued		2,321,951
Derivative, Gain (Loss) on Derivative, Net	$ (2,112)	$ 2,321,951	$ 0	$ 1,325,574	$ 0