Intangible Assets (Schedule of Finite-Lived Intangible Assets) (Details) (USD $)	3 Months Ended
	Jul. 26, 2013		Jul. 27, 2012		Apr. 26, 2013
Finite-Lived Intangible Assets [Line Items]
Beginning balance - gross carrying amount	$ 11,363,000		$ 5,785,000
Acquisitions	1,250,000		2,500,000
Impairments	(90,000)
Ending balance - gross carrying amount	12,523,000		8,285,000
Accumulated amortization	(2,399,163)		(1,473,859)
Net	10,123,837		6,811,141		9,219,999
Developed Technology Rights [Member]
Finite-Lived Intangible Assets [Line Items]
Beginning balance - gross carrying amount	10,370,000	[1]	5,660,000	[1]
Acquisitions	1,250,000	[1]	2,500,000	[1]
Impairments	(90,000)	[1]
Ending balance - gross carrying amount	11,530,000	[1]	8,160,000	[1]
Accumulated amortization	(2,316,463)	[1]	(1,454,796)	[1]
Net	9,213,537	[1]	6,705,204	[1]
Other Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Beginning balance - gross carrying amount	993,000	[2]	125,000
Acquisitions		[2]
Impairments		[2]
Ending balance - gross carrying amount	993,000	[2]	125,000
Accumulated amortization	(82,700)	[2]	(19,063)
Net	$ 910,300	[2]	$ 105,937

[1] Developed Technology Rights include acquired patents, licenses and know-how. These assets have finite lives and relate primarily to seizure detection algorithms, wireless communication technology, rechargeable battery technology and an implantable lead with MRI compatibility.

[2] Other Intangible Assets primarily consists of acquired clinical databases.