Condensed Consolidated Statements of Shareholders' (Deficit) (unaudited) - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit
Beginning balance (in shares) at Dec. 29, 2018		30,868
Beginning balance at Dec. 29, 2018	$ (109,550)	$ 309	$ 0	$ (109,859)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	25,418			25,418
Exercise of common stock options (in shares)		151
Exercise of common stock options	2,836	$ 2	2,834
Stock-based compensation (in shares)		364
Stock-based compensation	3,638	$ 3	3,635
Repurchases of common stock (in shares)		(1,170)
Repurchases of common stock	(46,982)	$ (12)	(6,469)	(40,501)
Ending balance (in shares) at Mar. 30, 2019		30,213
Ending balance at Mar. 30, 2019	(124,640)	$ 302	0	(124,942)
Beginning balance (in shares) at Dec. 29, 2018		30,868
Beginning balance at Dec. 29, 2018	(109,550)	$ 309	0	(109,859)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	29,698
Ending balance (in shares) at Jun. 29, 2019		29,323
Ending balance at Jun. 29, 2019	(157,302)	$ 293	0	(157,595)
Beginning balance (in shares) at Mar. 30, 2019		30,213
Beginning balance at Mar. 30, 2019	(124,640)	$ 302	0	(124,942)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	4,280			4,280
Exercise of common stock options (in shares)		115
Exercise of common stock options	2,159	$ 1	2,158
Stock-based compensation (in shares)		99
Stock-based compensation	4,250	$ 1	4,249
Repurchases of common stock (in shares)		(1,104)
Repurchases of common stock	(43,351)	$ (11)	(6,407)	(36,933)
Ending balance (in shares) at Jun. 29, 2019		29,323
Ending balance at Jun. 29, 2019	$ (157,302)	$ 293	0	(157,595)
Beginning balance (in shares) at Dec. 28, 2019	27,961	27,961
Beginning balance at Dec. 28, 2019	$ (159,431)	$ 280	0	(159,711)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	39,140			39,140
Exercise of common stock options (in shares)		167
Exercise of common stock options	3,283	$ 1	3,282
Stock-based compensation (in shares)		396
Stock-based compensation	2,051	$ 4	2,047
Repurchases of common stock (in shares)		(888)
Repurchases of common stock	(40,952)	$ (9)	(5,329)	(35,614)
Ending balance (in shares) at Mar. 28, 2020		27,636
Ending balance at Mar. 28, 2020	$ (155,909)	$ 276	0	(156,185)
Beginning balance (in shares) at Dec. 28, 2019	27,961	27,961
Beginning balance at Dec. 28, 2019	$ (159,431)	$ 280	0	(159,711)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	$ 26,510
Ending balance (in shares) at Jun. 27, 2020	27,725	27,725
Ending balance at Jun. 27, 2020	$ (163,018)	$ 277	5,519	(168,814)
Beginning balance (in shares) at Mar. 28, 2020		27,636
Beginning balance at Mar. 28, 2020	(155,909)	$ 276	0	(156,185)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(12,630)			(12,630)
Exercise of common stock options (in shares)		33
Exercise of common stock options	817		817
Stock-based compensation (in shares)		71
Stock-based compensation	5,033	$ 1	5,032
Repurchases of common stock (in shares)		(15)
Repurchases of common stock	$ (329)		(330)	1
Ending balance (in shares) at Jun. 27, 2020	27,725	27,725
Ending balance at Jun. 27, 2020	$ (163,018)	$ 277	$ 5,519	$ (168,814)