XML 53 R38.htm IDEA: XBRL DOCUMENT v3.8.0.1
Stock Option Plans - Additional Information (Detail) - shares
3 Months Ended 9 Months Ended
May 20, 2015
Sep. 30, 2017
Sep. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Effective date for stock options plan May 20, 2015    
Minimum [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Vesting period for options     1 year
Maximum      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Vesting period for options     4 years
Employee Stock Option [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Minimum period for expiration of options in case of employee termination     60 days
Maximum period for expiration of options in case of employee termination     90 days
Employee Stock Option [Member] | Minimum [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Minimum expiration period for options     5 years
Employee Stock Option [Member] | Maximum      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Vesting period for options     4 years
Minimum expiration period for options     10 years
Restricted Stock Units (RSUs) [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Restricted stock units granted   79,300  
Two Thousand Fifteen Plan [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Shares reserved for issuance in different forms 3,100,000    
Share based compensation arrangement shares available for grant   895,418 895,418