Quarterly report pursuant to Section 13 or 15(d)

Stock-based Compensation Expense - Additional Information (Detail)

v3.19.2
Stock-based Compensation Expense - Additional Information (Detail) - USD ($)
$ in Millions
1 Months Ended 3 Months Ended 6 Months Ended 24 Months Ended 42 Months Ended
Feb. 28, 2019
Jul. 31, 2019
Jul. 31, 2019
Jul. 31, 2018
Jan. 31, 2017
Jul. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Options granted     995,000      
Stock-based compensation expense, modification of awards   $ 0.2 $ 0.2      
Deferred Stock Units [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Awards granted     236,688      
Market Based Options [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Options granted           0
Market Based Options [Member] | Former CEO [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Options granted         800,000  
Fair value of options outstanding     $ 2.1      
Service period required to be fulfilled     3 years      
Reversal of stock-based compensation expense $ 0.5          
Options and Deferred Stock Units [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Share-based awards fair value     $ 1.1      
Stock Options [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Employee service share-based compensation, nonvested awards, total compensation cost not yet recognized   1.6 $ 1.6     $ 1.6
Share based compensation arrangement by share based payment award expected weighted average recognition period     2 years 4 months 24 days      
Restricted Stock Units and Deferred Stock Units [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Employee service share-based compensation, nonvested awards, total compensation cost not yet recognized   1.2 $ 1.2     1.2
Share based compensation arrangement by share based payment award expected weighted average recognition period     1 year 8 months 12 days      
Performance Stock Units (PSUs) [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Employee service share-based compensation, nonvested awards, total compensation cost not yet recognized   $ 0.1 $ 0.1     $ 0.1
Share based compensation arrangement by share based payment award expected weighted average recognition period     1 year 1 month 6 days      
2011 Compensation and Incentive Plan [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
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      
2011 Compensation and Incentive Plan [Member] | Minimum [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Share-based compensation arrangement by Share-based payment award, vesting period     1 year      
2011 Compensation and Incentive Plan [Member] | Maximum [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Share-based compensation arrangement by Share-based payment award, vesting period     3 years      
2011 Compensation and Incentive Plan [Member] | Stock Compensation Plan            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Share-based compensation arrangement by share-based payment award, number of shares authorized   9,300,000 9,300,000     9,300,000
Share-based compensation arrangement by share-based payment award, number of shares available for grant   2,523,690 2,523,690     2,523,690
2011 Compensation and Incentive Plan [Member] | Deferred Stock Units [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Share-based compensation arrangement by Share-based payment award, vesting period     1 year      
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, number of shares available for grant   1,086,964 1,086,964     1,086,964
Share-based compensation arrangement by share-based payment award, Description     On each purchase date, eligible employees can 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.      
Percentage of stock to be purchased under the plan     85.00%      
Shares purchased under ESPP     7,819 9,421    
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 1,150,000     1,150,000