Consolidated Statements of Equity Statement (USD $) In Thousands, except Share data, unless otherwise specified		Total	Common Stock [Member]		Treasury Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Loss [Member]	Retained Earnings (Accumulated Deficit) [Member]
Temporary equity, beginning balance at Dec. 28, 2010		$ 2,572
Beginning balance at Dec. 28, 2010		(494)	232	[1],[2]	0	4,897	(274)	(5,349)
Beginning balance, shares at Dec. 28, 2010			23,237,169	[2]	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options		16	0	[2]		16
Exercise of stock options, shares	[2]		1,815
Tax benefit on exercise of stock options		109				109
Stock-based compensation expenses		1,402				1,402
2010 Merger-transaction expenses		(133)				(133)
Unrealized income on cash flow hedges, net of tax		222					222
Net income		3,829						3,829
Temporary equity, ending balance at Jan. 03, 2012		2,572
Ending balance at Jan. 03, 2012		4,951	232	[1],[2]	0	6,291	(52)	(1,520)
Ending balance, shares at Jan. 03, 2012			23,238,984	[2]	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Tax benefit on exercise of stock options		27				27
Stock-based compensation expenses		1,315				1,315
2010 Merger-transaction expenses		(48)				(48)
Temporary equity related to put options		(1,029)						(1,029)
Unrealized income on cash flow hedges, net of tax		28					28
Net income		5,163						5,163
Increase (Decrease) in Temporary Equity [Roll Forward]
Temporary equity related to put options		1,029
Temporary equity, ending balance at Jan. 01, 2013		3,601
Ending balance at Jan. 01, 2013		10,407	232	[1],[2]	0	7,585	(24)	2,614
Beginning balance, shares at Jan. 01, 2013			23,238,984	[2]	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock in connection with IPO, net of transaction expenses		100,069	62	[2]		100,007
Issuance of common stock, net of transaction expenses, shares	[2]		6,160,714
Tax benefit on exercise of stock options		201				201
Stock-based compensation expenses		1,098				1,098
Stock-based compensation expense related to acceleration of vesting		3,203				3,203
Elimination of temporary equity at IPO		3,601				2,572		1,029
Proceeds from exercise of stock options, warrants and employee stock purchase plan		1,982	1	[2]		1,981
Proceeds from exercise of stock options, warrants and employee stock purchase plan, shares	[2]		144,907
Treasury shares acquired		(2,777)			(2,777)
Treasury shares acquired, shares					65,478
Other		24					24
Other, shares			(48)
Net income		6,665						6,665
Increase (Decrease) in Temporary Equity [Roll Forward]
Elimination of temporary equity at IPO		(3,601)
Temporary equity, ending balance at Dec. 31, 2013		0
Ending balance at Dec. 31, 2013		$ 124,473	$ 295	[1],[2]	$ (2,777)	$ 116,647	$ 0	$ 10,308
Ending balance, shares at Dec. 31, 2013			29,544,557	[2]	65,478

[1] Includes 6,292,640 shares of Class B common stock in all years presented and one share of Class C common stock

[2] Unless otherwise noted, activity relates to Class A common stock