Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Other Liabilities Disclosure [Abstract]
Accrued compensation and benefits	$ 24,545	$ 17,348
Accrued warranty	4,510	4,835	$ 3,142	$ 3,335
Contract liabilities, current portion	4,165	4,790
Other	13,075	16,341
Total	$ 46,295	$ 43,314