Annual report pursuant to Section 13 and 15(d)

Goodwill and intangible assets (Details)

v2.4.0.8
Goodwill and intangible assets (Details) (USD $)
1 Months Ended 3 Months Ended 12 Months Ended 1 Months Ended 3 Months Ended 12 Months Ended
May 31, 2013
Jul. 31, 2012
Jul. 31, 2013
Jul. 31, 2012
Jul. 31, 2011
Jul. 31, 2012
Enzo Life Sciences [Member]
May 31, 2012
Trademarks [Member]
Jul. 31, 2012
Trademarks [Member]
Jul. 31, 2013
Trademarks [Member]
Jul. 31, 2012
Trademarks [Member]
Jul. 31, 2013
Intangible Assets, Amortization Period [Member]
Goodwill and intangible assets (Details) [Line Items]                      
Percentage Of Stock Price Result Of Decline Market Capitalization   44.00%                  
Asset Impairment Charges       $ 24,540,000   $ 18,800,000   $ 5,700,000      
Asset Impairment Charges Net of Taxes       22,400,000   18,000,000   4,400,000      
Finite-Lived Intangible Asset, Useful Life     10 years       5 years   5 years   6 years
Amortization of Intangible Assets     1,990,000 1,660,000 1,507,000         600,000  
Finite-Lived Intangible Assets, Period Increase (Decrease)             5,700,000        
Goodwill, Impairment Loss $ 0     $ (18,838,000)   $ (18,838,000)