Stock Based Compensation - Summary of Stock Options Outstanding, Vested and Expected to Vest and Exercisable (Details) (USD $) In Thousands, except Share data, unless otherwise specified	9 Months Ended
	Sep. 27, 2014	Dec. 28, 2013
Stock options outstanding, exercisable and expected to vest
Options outstanding, Number of Shares	914,826	1,102,842
Options vested and expected to vest, Number of Shares	855,313
Options exercisable, Number of Shares	513,636
Options outstanding, Weighted Average Exercise Price	$ 4.60	$ 3.97
Options vested and expected to vest, Weighted Average Exercise Price	$ 4.48
Options exercisable, Weighted Average Exercise Price	$ 3.62
Options outstanding, Weighted Average Remaining Contractual Life (years)	4 years 1 month 2 days
Options vested and expected to vest, Weighted Average Remaining Contractual Life (years)	3 years 11 months 19 days
Options exercisable, Weighted Average Remaining Contractual Life (years)	2 years 10 months 28 days
Options outstanding, Aggregate Intrinsic Value	$ 2,535
Options vested and expected to vest, Aggregate Intrinsic Value	2,448
Options exercisable, Aggregate Intrinsic Value	$ 1,815