Quarterly report pursuant to Section 13 or 15(d)

Selected Balance Sheet Data - Schedule of Other Assets (Parenthetical) (Detail)

v3.8.0.1
Selected Balance Sheet Data - Schedule of Other Assets (Parenthetical) (Detail) - USD ($)
$ in Thousands
 3 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Dec. 31, 2017
Other Assets [Line Items]      
Allowance of doubtful accounts $ 337   $ 494
(Recovery) provision for bad debt expense (106) $ (44)  
Write-off receivables $ 51 $ 16  
Minimum [Member]      
Other Assets [Line Items]      
Notes receivable due period 1 year    
Maximum [Member]      
Other Assets [Line Items]      
Notes receivable due period 5 years