Commitments and Contingencies (Details) (USD $)	9 Months Ended		9 Months Ended
	Jan. 25, 2013 state item	Apr. 27, 2012	Jan. 25, 2013 TRD Registry [Member]	Jan. 25, 2013 Zabara Royalty [Member]	Jan. 27, 2012 Zabara Royalty [Member]	Jan. 25, 2013 Other Clinical Studies And Registries [Member]
Commitments And Contingencies [Line Items]
Expected future expense			$ 200,000			$ 2,000,000
Period of future expense, years			3 years			3 years
Rate of royalties paid based on net sales of generators and leads				3.00%
Royalties paid					1,200,000
Deferred Revenue	1,841,361	2,961,837
Date the US District Court for the District of New Jersey unsealed a 'qui tam' action against company	Jul. 24, 2012
Number of different states that have false claim statutes (in States)	21
Date the US Department of Justice declined to intervene in the 'qui tam' action	Mar. 09, 2010
Approval date for treatment-resistant depression ("TRD") by the FDA with post-approval conditions	July 2005
Number of TRD clinical study groups required by the FDA at time of TRD approval (in Groups)	2
Number of TRD clinical study groups receiving VNS Therapy (in Groups)	1
Number of TRD clinical study groups receiving ongoing treatment-as-usual (in Groups)	1
Period required to follow patients in clinical studies required by the FDA for TRD approval	5 years
Calender year in which the TRD registry is expected to be complete	2015
Date that the license agreement expired for U.S. patents covering the method devices of the VNS Therapy System for vagus nerve and other cranial nerve simulation	Jul. 16, 2011
Brussels Office Operating Lease - Future Minimum Payments Due	$ 2,200,000
Length of Brussels Office Operating Lease	9 years
Start Date of Brussels Office Operating Lease	March 2013