Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Accrued Expenses and Other Current Liabilities
Payroll and related costs	$ 8,731	$ 8,927
Employee benefits	5,179	4,113
Accrued warranty	3,535	7,423
Amounts due to sellers	5,487
Other	4,393	5,086
Accrued expenses and other current liabilities	$ 27,325	$ 25,549