Quarterly report pursuant to Section 13 or 15(d)

Financings - Additional Information (Detail)

v3.10.0.1
Financings - Additional Information (Detail) - USD ($)
 3 Months Ended 6 Months Ended
Jan. 26, 2017
Jun. 30, 2018
Jun. 30, 2017
Jun. 30, 2018
Jun. 30, 2017
Dec. 31, 2017
Financing Activities and Borrowing Arrangements [Line Items]            
Line of credit facility, maximum borrowing amount $ 50,000,000          
Line of credit facility, maturity date Jan. 26, 2020          
Guaranteed borrowing capacity   $ 10,000,000   $ 10,000,000    
Revolving credit facility   42,107,000   42,107,000   $ 38,633,000
Interest Expenses   500,000 $ 500,000 1,000,000 $ 900,000  
Acquisition payable   510,000   510,000   1,796,000
Acquisition payable current   1,326,000   1,326,000   270,000
Maximum            
Financing Activities and Borrowing Arrangements [Line Items]            
Amortization expense of deferred debt issuance costs   100,000 $ 100,000 100,000 $ 200,000  
London Interbank Offered Rate (LIBOR)            
Financing Activities and Borrowing Arrangements [Line Items]            
Debt instrument, basis spread on variable rate 2.75%          
Base Rate            
Financing Activities and Borrowing Arrangements [Line Items]            
Debt instrument, basis spread on variable rate 1.75%          
Other Noncurrent Assets            
Financing Activities and Borrowing Arrangements [Line Items]            
Deferred debt issuance costs   500,000   500,000   600,000
Value Lighting            
Financing Activities and Borrowing Arrangements [Line Items]            
Debt refinance amount       3,700,000    
Acquisition payable   1,800,000   1,800,000   2,100,000
Acquisition payable current   500,000   500,000   $ 1,800,000
Value Lighting | Debt Instrument Due in Twenty Eighteen November Twenty Two            
Financing Activities and Borrowing Arrangements [Line Items]            
Lump sum payment   $ 1,200,000   $ 1,200,000    
Debt instrument maturity date       Nov. 22, 2019