Stockholders' Equity - Stock Options Outstanding, Exercisable and Expected to Vest (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Stock options outstanding, exercisable and expected to vest
Options outstanding, Number of Shares	1,383,552	844,898	857,311
Options outstanding, Weighted Average Exercise Price	$ 6.11	$ 8.84	$ 9.49
Options outstanding, Weighted Average Remaining Contractual Life (years)	5 years 25 days
Options outstanding, Aggregate Intrinsic Value	$ 12
Options vested and expected to vest, Number of Shares	1,233,254
Options vested and expected to vest, Weighted Average Exercise Price	$ 6.27
Options vested and expected to vest, Weighted Average Remaining Contractual Life (years)	4 years 11 months 8 days
Options vested and expected to vest, Aggregate Intrinsic Value	$ 10
Options exercisable, Number of Shares	401,062
Options exercisable, Weighted Average Exercise Price	$ 8.80
Options exercisable, Weighted Average Remaining Contractual Life (years)	2 years 7 months 13 days