Accrued Expenses - Schedule of Accrued Expenses (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Accrued Liabilities Current [Abstract]
Accrued payroll	$ 1,816	$ 1,198
Accrued employee benefits	741	1,317
Accrued bonuses	118	180
Accrued vacation	1,187	1,214
Accrued interest	365	414
Accrued commissions	372	560
Accrued expenses—other	887	2,045
Accrued warranty	1,966	2,030
Accrued income taxes	380
Accrued taxes other than income taxes	971	969
Accrued product liability and workers compensation claims	335	143
Total accrued expenses	$ 9,138	$ 10,070