Basis of Presentation and Description of Company (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 26, 2020	Jun. 27, 2020	Mar. 28, 2020	Sep. 28, 2019	Jun. 29, 2019	Mar. 30, 2019	Sep. 26, 2020	Sep. 28, 2019
Basis of Presentation and Description of Company
Net income (loss)	$ 1,385	$ 1,568	$ (978)	$ (1,424)	$ (1,457)	$ (3,581)	$ 1,975	$ (6,461)