Investments (Schedule of Long-term Investments) (Details) (USD $)	Jul. 26, 2013		Apr. 26, 2013
Investment [Line Items]
Carrying amount - long-term investments	$ 10,588,202		$ 10,588,202
Im Thera Medical Inc [Member]
Investment [Line Items]
Carrying amount - long-term investments	8,000,002	[1]	8,000,002	[1]
Cerbomed GmbH [Member]
Investment [Line Items]
Carrying amount - long-term investments	$ 2,588,200	[2]	$ 2,588,200	[2]

[1] ImThera Medical, Inc. (“ImThera”) is a privately-held company focused on developing a neurostimulation device system for the treatment of obstructive sleep apnea. See “Note 14. Fair Value Measurements” for further details regarding this investment.

[2] Cerbomed GmbH (“Cerbomed”) is a privately-held German company focused on developing a transcutaneous vagus nerve stimulation device for the treatment of epilepsy. This investment provides us with less than 20% ownership and no significant influence over the entity involved. See “Note 14. Fair Value Measurements” for further details regarding this investment.