Accrued Expenses - Components of Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 30, 2017	Dec. 31, 2016
Components of accrued expenses
Customer deposits	$ 509	$ 496
Earn-out – short term	337	305
Distributor commission	293	171
Sales and use tax payable	57	94
Royalties payable	82	66
Other accrued expenses	875	1,003
Total accrued expenses	$ 2,153	$ 2,135