Annual report pursuant to Section 13 and 15(d)

Goodwill and Intangible Assets - Additional Information (Detail)

v3.7.0.1
Goodwill and Intangible Assets - Additional Information (Detail) - USD ($)
 1 Months Ended 3 Months Ended 9 Months Ended 12 Months Ended
Aug. 01, 2016
Jan. 31, 2017
Jan. 31, 2017
Jan. 31, 2016
Jan. 31, 2017
Jan. 31, 2017
Jan. 31, 2016
Jan. 31, 2015
Jul. 31, 2016
May 05, 2016
Goodwill And Intangible Assets [Line Items]                    
Goodwill   $ 23,287,000 $ 23,287,000 $ 40,175,000 $ 23,287,000 $ 23,287,000 $ 40,175,000      
Loss on impairment of long-lived assets   $ 500,000 $ 23,500,000 $ 21,500,000   23,772,000 21,464,000      
Amortization of intangible assets           $ 3,300,000 $ 4,800,000 $ 5,200,000    
DCC Labs [Member]                    
Goodwill And Intangible Assets [Line Items]                    
Goodwill $ 45,800,000                 $ 7,255,000
Fair value of reporting unit less than carrying value 102,500,000                  
Estimated implied fair value 22,300,000                  
Loss on impairment of long-lived assets $ 23,500,000       $ 3,400,000          
DCC Labs [Member] | Minimum [Member]                    
Goodwill And Intangible Assets [Line Items]                    
Excess fair value amount over and above the carrying value of the net assets                 $ 15,400,000  
Excess fair value percentage over and above the carrying value of the net assets                 15.00%  
DCC Labs [Member] | Maximum [Member]                    
Goodwill And Intangible Assets [Line Items]                    
Excess fair value amount over and above the carrying value of the net assets                 $ 25,000,000  
Excess fair value percentage over and above the carrying value of the net assets                 24.40%