Quarterly Financial Data (unaudited) (Details) - USD ($) $ / shares in Units, shares in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2016	Sep. 24, 2016	Jun. 25, 2016	Mar. 26, 2016	Dec. 26, 2015	Sep. 26, 2015	Jun. 27, 2015	Mar. 28, 2015	Dec. 27, 2014	Sep. 27, 2014	Jun. 28, 2014	Mar. 29, 2014	Dec. 31, 2016	Dec. 26, 2015	Dec. 27, 2014
Quarterly Financial Data (unaudited)
Net revenues	$ 63,365,000	$ 66,529,000	$ 69,263,000	$ 69,855,000	$ 68,664,000	$ 69,865,000	$ 66,422,000	$ 77,607,000	$ 73,746,000.000	$ 72,556,000.000	$ 71,852,000.000	$ 67,509,000.000	$ 269,012,000	$ 282,558,000	$ 285,663,000
Gross profit	5,751,000	7,924,000	10,267,000	8,817,000	7,312,000	8,700,000	8,025,000	(3,700,000)	15,176,000.000	12,926,000.000	13,456,000.000	11,563,000.000	32,759,000	20,337,000	53,121,000
Operating income (loss)	(18,897,000)	(1,266,000)	1,774,000	708,000	(1,645,000)	(533,000)	(2,192,000)	(22,129,000)	5,980,000.000	5,356,000.000	4,432,000.000	3,165,000.000	(17,681,000)	(26,499,000)	18,933,000
Net loss	$ (26,389,000)	$ (2,564,000)	$ (278,000)	$ (1,018,000)	$ (2,460,000)	$ (1,737,000)	$ (1,951,000)	$ (14,635,000)	$ 3,408,000.000	$ 3,084,000.000	$ 2,472,000.000	$ 1,597,000.000	$ (30,249,000)	$ (20,783,000)	$ 10,561,000
Income (loss) per common share:
Basic (in dollars per share)	$ (1.34)	$ (0.13)	$ (0.01)	$ (0.05)	$ (0.13)	$ (0.09)	$ (0.10)	$ (0.75)	$ 0.17	$ 0.16	$ 0.13	$ 0.08	$ (1.54)	$ (1.06)	$ 0.54
Diluted (in dollars per share)	$ (1.34)	$ (0.13)	$ (0.01)	$ (0.05)	$ (0.13)	$ (0.09)	$ (0.10)	$ (0.75)	$ 0.17	$ 0.15	$ 0.12	$ 0.08	$ (1.54)	$ (1.06)	$ 0.53
Weighted average number of common shares:
Basic (in shares)	19,672	19,671	19,628	19,603	19,610	19,594	19,566	19,581	19,564	19,530	19,468	19,437	19,644	19,588	19,500
Diluted (in shares)	19,672	19,671	19,628	19,603	19,610	19,594	19,566	19,581	20,062	20,014	19,960	19,924	19,644	19,588	19,990