XML 90 R79.htm IDEA: XBRL DOCUMENT v3.19.1
Restructuring and Severance - Additional Information (Detail) - USD ($)
$ in Thousands
3 Months Ended
Feb. 14, 2018
Mar. 31, 2019
Mar. 31, 2018
Dec. 31, 2018
Restructuring Cost And Reserve [Line Items]        
Restructuring and severance expenses   $ (12) $ 110  
Restructuring accrual   $ 129   $ 129
3VR        
Restructuring Cost And Reserve [Line Items]        
Date of acquisition completed Feb. 14, 2018 Feb. 14, 2018    
3VR | Facility Rental        
Restructuring Cost And Reserve [Line Items]        
Restructuring and severance expenses   $ 100