Quarterly report pursuant to Section 13 or 15(d)

Stockholders' Equity - Additional Information (Detail)

v3.8.0.1
Stockholders' Equity - Additional Information (Detail) - USD ($)
$ in Millions
1 Months Ended 9 Months Ended 12 Months Ended
Jul. 13, 2017
Apr. 06, 2016
Jun. 30, 2016
Jul. 31, 2015
Oct. 31, 2017
Jan. 31, 2016
CEO [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Market based options granted   600,000     800,000  
Chief Operating Officer [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Market based options granted     200,000      
Officer [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Share-based compensation arrangement by share-based payment award, options, vested in period, fair value         $ 2.1  
Employee service share-based compensation, nonvested awards, total compensation cost not yet recognized         $ 0.4  
Share-based compensation arrangement by share-based payment award, options, vested in period         1 year 8 months 13 days  
Compensation and Incentive Plan 2011 [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Share-based compensation arrangement by share-based payment award, number of additional shares authorized 4,000,000          
Share-based compensation arrangement by share-based payment award, Description         Option awards may be granted to employees at an exercise price per share of not less than 100% of the fair market value per common share on the date of the grant  
Share-based Compensation Arrangement by Share-based Payment Award, Purchase Price of Common Stock, Percent         100.00%  
Share-based compensation arrangement by share based payment award, Option award expiration period         10 years  
Compensation and Incentive Plan 2011 [Member] | Minimum [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Share-based compensation arrangement by Share-based payment award, Option award vesting period         1 year  
Compensation and Incentive Plan 2011 [Member] | Maximum [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Share-based compensation arrangement by Share-based payment award, Option award vesting period         4 years  
Compensation and Incentive Plan 2011 [Member] | Stock Compensation Plan [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Share-based compensation arrangement by share-based payment award, number of shares available for grant         3,989,268  
Long Term Incentive Program [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Share-based compensation arrangement by Share-based payment award, Option award vesting period           3 years
2015 Employee Stock Purchase Plan [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Share-based compensation arrangement by share-based payment award, Description         On each purchase date, eligible employees will purchase our stock at a price per share equal to 85% of the closing price of our common stock on the exercise date, but no less than par value  
Maximum payroll deductions at base compensation under employee stock purchase plan       15.00%    
Minimum payroll deductions at base compensation under employee stock purchase plan       1.00%    
Offering period commence date       Oct. 01, 2015    
Percentage of stock to be purchased under the plan       85.00%    
2015 Employee Stock Purchase Plan [Member] | Maximum [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Share-based compensation arrangement by share-based payment award, number of shares authorized         1,150,000