Condensed Consolidated Statements of Changes in Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)	Total
Beginning balance (shares) at Dec. 26, 2018	39,009,451
Beginning balance at Dec. 26, 2018	$ 390	$ 375,734	$ (110,888)		$ 265,236
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation		1,797			1,797
Issuance of common stock related to restricted stock	$ 3	(3)
Issuance of common stock related to restricted stock (shares)	292,211
Issuance of common stock upon exercise of stock options		34			34
Issuance of common stock upon exercise of stock options (shares)	6,709
Shares repurchased for employee tax withholdings	$ (1)	(294)			(295)
Shares repurchased for employee tax withholdings (shares)	(29,923)
Repurchase of common stock	$ (43)	(48,221)			(48,264)
Repurchase of common stock (shares)	(4,384,732)
Other comprehensive income (loss), net of taxes				$ 104	104
Net income			21,402		21,402
Ending balance (shares) at Sep. 25, 2019	34,893,716
Ending balance at Sep. 25, 2019	$ 349	329,047	(89,486)	104	240,014
Beginning balance (shares) at Jun. 26, 2019	37,732,948
Beginning balance at Jun. 26, 2019	$ 377	358,335	(95,888)		262,824
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation		668			668
Shares repurchased for employee tax withholdings		(46)			(46)
Shares repurchased for employee tax withholdings (shares)	(4,176)
Forfeiture of common stock related to restricted shares (shares)	(9,160)
Repurchase of common stock	$ (28)	(29,910)			(29,938)
Repurchase of common stock (shares)	(2,825,896)
Other comprehensive income (loss), net of taxes				104	104
Net income			6,402		6,402
Ending balance (shares) at Sep. 25, 2019	34,893,716
Ending balance at Sep. 25, 2019	$ 349	329,047	(89,486)	104	240,014
Beginning balance (shares) at Dec. 25, 2019	35,126,582
Beginning balance at Dec. 25, 2019	$ 351	330,950	(85,988)	253	245,566
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation		2,170			2,170
Issuance of common stock related to restricted stock	$ 4	(4)
Issuance of common stock related to restricted stock (shares)	439,061
Issuance of common stock upon exercise of stock options	$ 10	5,836			$ 5,846
Issuance of common stock upon exercise of stock options (shares)	965,736				965,736
Shares repurchased for employee tax withholdings		(331)			$ (331)
Shares repurchased for employee tax withholdings (shares)	(23,118)
Forfeiture of common stock related to restricted shares	$ (1)	1
Forfeiture of common stock related to restricted shares (shares)	(66,892)				(79,303)
Other comprehensive income (loss), net of taxes				(1,194)	$ (1,194)
Net income			19,019		19,019
Ending balance (shares) at Sep. 23, 2020	36,441,369
Ending balance at Sep. 23, 2020	$ 364	338,622	(66,969)	(941)	271,076
Beginning balance (shares) at Jun. 24, 2020	35,854,122
Beginning balance at Jun. 24, 2020	$ 359	334,088	(76,889)	(999)	256,559
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation		909			909
Issuance of common stock related to restricted stock (shares)	2,798
Issuance of common stock upon exercise of stock options	$ 6	3,675			3,681
Issuance of common stock upon exercise of stock options (shares)	593,180
Shares repurchased for employee tax withholdings		(51)			(51)
Shares repurchased for employee tax withholdings (shares)	(2,925)
Forfeiture of common stock related to restricted shares	$ (1)	1
Forfeiture of common stock related to restricted shares (shares)	(5,806)
Other comprehensive income (loss), net of taxes				58	58
Net income			9,920		9,920
Ending balance (shares) at Sep. 23, 2020	36,441,369
Ending balance at Sep. 23, 2020	$ 364	$ 338,622	$ (66,969)	$ (941)	$ 271,076