Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]
Beginning balance, value at Dec. 26, 2012	$ 64,587	$ 287	$ 239,329	$ (175,029)
Beginning balance, shares at Dec. 26, 2012		28,712,622
Stock based compensation	822		822
Net income (loss)	(16,873)			(16,873)
Ending balance, value at Dec. 25, 2013	48,536	$ 287	240,151	(191,902)
Ending balance, shares at Dec. 25, 2013		28,712,622
Stock based compensation	1,093		1,093
Issuance of common stock for initial public offering, net of offering costs	112,300	$ 82	112,218
Issuance of common stock for initial public offering, net of offering costs, shares		8,214,286
Issuance of common stock upon exercise of stock options, value	$ 2,043	$ 5	2,038
Issuance of common stock upon exercise of stock options, shares	496,944	493,542
Excess income tax benefit related to share-based compensation plans	$ 3,965		3,965
Net income (loss)	42,463			42,463
Ending balance, value at Dec. 31, 2014	210,400	$ 374	359,465	(149,439)
Ending balance, shares at Dec. 31, 2014		37,420,450
Stock based compensation	539		539
Issuance of common stock upon exercise of stock options, value	$ 4,220	$ 9	4,211
Issuance of common stock upon exercise of stock options, shares	863,247	863,985
Excess income tax benefit related to share-based compensation plans	$ 5,420		5,420
Net income (loss)	24,054			24,054
Ending balance, value at Dec. 30, 2015	$ 244,633	$ 383	$ 369,635	$ (125,385)
Ending balance, shares at Dec. 30, 2015		38,284,435