Quarterly report pursuant to Section 13 or 15(d)

Employee Benefit Plan - Additional Information (Detail)

v3.8.0.1
Employee Benefit Plan - Additional Information (Detail) - Employee Savings Plan - USD ($)
3 Months Ended 6 Months Ended
Nov. 30, 2017
Nov. 30, 2016
Nov. 30, 2017
Nov. 30, 2016
Defined Contribution Plan Disclosure [Line Items]        
Qualified non-elective contribution     3.00%  
Qualified non-elective contribution expense $ 10,800 $ 9,800 $ 21,500 $ 18,600