Nature of Business and Significant Accounting Policies (Details)	3 Months Ended													12 Months Ended
	Jul. 31, 2015 USD ($) shares		Apr. 30, 2015 shares	[1]	Jan. 31, 2015 shares	[1]	Oct. 31, 2014 shares	Jul. 31, 2014 USD ($) shares		Apr. 30, 2014 shares	Jan. 31, 2014 shares	Oct. 31, 2013 shares	Apr. 30, 2010 USD ($)	Jul. 31, 2015 USD ($) Product Segment shares	Jul. 31, 2014 USD ($) shares	Jul. 31, 2013 USD ($) shares	Jul. 31, 2010 USD ($)	Jan. 31, 2013 USD ($)
Inventory [Abstract]
Inventory reserves																		$ 1,600,000
Deferred Revenue Arrangement [Line Items]
Less: Short-term portion	$ 1,288,000							$ 1,288,000						$ 1,288,000	$ 1,288,000
Long-term portion	$ 11,954,000							$ 13,242,000						$ 11,954,000	13,242,000
Standard Product Warranty Disclosure [Abstract]
Typical warranty period														3 years
Marketing and Advertising Expense [Abstract]
Advertising Expense														$ 278,000	197,000	$ 146,000
Operating Costs and Expenses [Abstract]
Royalty expense														$ 348,000	$ 346,000	$ 331,000
Earnings per share:
Basic weighted average common shares (in shares) | shares	25,372,653	[1]	25,371,764		25,364,574		25,339,983	25,352,326	[2]	25,331,925	25,309,641	25,294,020		25,362,166	25,323,622	25,243,010
Stock options (in shares) | shares														86,861	69,642	94,515
Dilutive weighted average common shares (in shares) | shares	25,505,648	[1]	25,476,336		25,424,835		25,390,181	25,400,341	[2]	25,392,782	25,309,641	25,389,940		25,449,027	25,393,264	25,337,525
Antidilutive securities excluded from computation of earnings per share (in shares) | shares														435,957	650,579	533,079
Segment Reporting [Abstract]
Number of operating segments | Segment														1
Building and improvements [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Useful life														7 years
Building and improvements [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Useful life														39 years
Machinery and equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Useful life														5 years
Machinery and equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Useful life														7 years
Furniture and fixtures [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Useful life														5 years
Furniture and fixtures [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Useful life														7 years
Software [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Useful life														3 years
Software [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Useful life														10 years
Other Intangible Assets [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Useful life														3 years
Other Intangible Assets [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Useful life														15 years
Alcon Settlement [Member]
Deferred Revenue Arrangement [Line Items]
Useful life													15 years	11 years
Deferred revenue	$ 13,242,000							$ 14,530,000						$ 13,242,000	$ 14,530,000
Revenue recognized														$ 1,300,000	$ 1,300,000	$ 1,300,000
Proceeds from confidential settlement and license agreement																	$ 32,000,000
Proceeds from confidential settlement and license agreement, net																	21,400,000
Gain on agreement																	$ 2,400,000
Up-front license fee													$ 19,000,000
Number of products cancelled | Product														2
Estimated earning period													15 years	11 years

[1] The results of Sterimedix are reflected in our results of operations since December 10, 2014, the date of acquisition and reflect the following: Net sales $ 2,342 $ 2,266 $ 1,066 Net income $ 517 $ 320 $ 14

[2] The results of the private OEM Company have been reflected in our results of operations since May 3, 2014, the date of the acquisition.