Fair Value Measurements (Details 3) (USD $)	3 Months Ended
	Oct. 31, 2013	Jul. 31, 2013	Apr. 30, 2013	Jan. 31, 2013	Oct. 31, 2012	Oct. 31, 2013 Byrne Medical Business Three-year price floor	Jul. 31, 2013 Byrne Medical Business Three-year price floor	Apr. 30, 2013 Byrne Medical Business Three-year price floor	Jan. 31, 2013 Byrne Medical Business Three-year price floor	Oct. 31, 2012 Byrne Medical Business Three-year price floor	Jan. 31, 2013 Contingent consideration liability Byrne Medical Business	Jul. 31, 2012 Contingent consideration liability Byrne Medical Business
Reconciliation of liability measured and recorded at fair value on a recurring basis using Level 3
Beginning balance	$ 45,000	$ 255,000	$ 314,000	$ 2,224,000	$ 2,537,000	$ 45,000	$ 255,000	$ 314,000	$ 724,000	$ 1,037,000	$ 1,500,000	$ 1,500,000
Total net unrealized gains included in general and administrative expense in earnings	(44,000)	(210,000)	(59,000)	(1,910,000)	(313,000)	(44,000)	(210,000)	(59,000)	(410,000)	(313,000)	(1,500,000)
Ending balance	$ 1,000	$ 45,000	$ 255,000	$ 314,000	$ 2,224,000	$ 1,000	$ 45,000	$ 255,000	$ 314,000	$ 724,000		$ 1,500,000