XML 65 R55.htm IDEA: XBRL DOCUMENT v3.8.0.1
Goodwill - Additional Information (Detail) - USD ($)
 3 Months Ended
Jun. 25, 2015
Apr. 30, 2018
Apr. 30, 2017
Jan. 31, 2018
Finite Lived Intangible Assets [Line Items]        
Goodwill   $ 26,601,000   $ 26,601,000
Goodwill impairment   $ 0 $ 0  
Vis Lab SRL [Member]        
Finite Lived Intangible Assets [Line Items]        
Business acquisition date Jun. 25, 2015      
Cash paid for business acquisition $ 30,000,000      
Goodwill 25,300,000      
Intangible assets acquired 4,100,000      
Net assets acquired 600,000      
Deferred tax liabilities, intangible assets $ 1,300,000