Summary of Significant Accounting Policies - Reconciliation of Changes in Warranty Liability (Details) - USD ($) $ in Thousands	6 Months Ended
	Jul. 01, 2017		Jul. 02, 2016
Reconciliation of the changes in the Company's warranty liability
Balance, beginning of period	$ 603	[1]	$ 603
Accruals for product warranties	203		232
Cost of warranty claims	(140)		(225)
Balance, end of period	$ 666		$ 610

[1] Derived from the audited consolidated financial statements included in the Annual Report on Form 10-K filed with the SEC for the year ended December 31, 2016.