Annual report pursuant to Section 13 and 15(d)

Annual report pursuant to Section 13 and 15(d)

Retirement Plan - Additional Information (Detail)

v3.8.0.1
Retirement Plan - Additional Information (Detail) - USD ($)
12 Months Ended
Jan. 01, 2017
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Defined Contribution Plan Disclosure [Line Items]        
Percentage of employees contribution 100.00% 75.00%    
Employee's contribution to retirement plan 3.00% 4.00%    
Additional percentage of employees contribution 50.00%      
Additional employee's contribution to retirement plan 2.00%      
Employers contribution   $ 2,470,000 $ 1,660,000 $ 493,000
Maximum [Member]        
Defined Contribution Plan Disclosure [Line Items]        
Percentage of company match   3.00%    
Percentage of company match 4.00%