CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY - USD ($) $ in Millions	Total	Redeemable Noncontrolling Interest	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Balance, beginning of period at Dec. 29, 2019		$ 15.0
Redeemable Noncontrolling Interest
Net income (loss)		(0.1)
Balance, end of period at Jun. 28, 2020		14.9
Balance, beginning of period (in shares) at Dec. 29, 2019			106,600,000
Balance, beginning of period at Dec. 29, 2019	$ 574.1		$ 0.0	$ 1,286.5	$ (0.4)	$ (712.0)
Increase (Decrease) in Stockholders' Equity
Stock-based compensation	9.5			9.5
Issuance of common stock for employee stock purchase plan, options and warrants (in shares)			200,000
Issuance of common stock for employee stock purchase plan, options and warrants	2.6			2.6
Restricted stock issued and related taxes (in shares)			200,000
Restricted stock issued and related taxes	(1.2)			(1.2)
Issuance of common stock for cash (in shares)			15,500,000
Issuance of common stock for cash	240.5			240.5
Net income (loss)	(0.9)					(0.9)
Other comprehensive income (loss), net of tax	(0.1)				(0.1)
Balance, end of period (in shares) at Jun. 28, 2020			122,500,000
Balance, end of period at Jun. 28, 2020	824.5		$ 0.0	1,537.9	(0.5)	(712.9)
Balance, beginning of period at Mar. 29, 2020		15.0
Redeemable Noncontrolling Interest
Net income (loss)		(0.1)
Balance, end of period at Jun. 28, 2020		14.9
Balance, beginning of period (in shares) at Mar. 29, 2020			107,000,000.0
Balance, beginning of period at Mar. 29, 2020	580.2		$ 0.0	1,292.6	(0.2)	(712.2)
Increase (Decrease) in Stockholders' Equity
Stock-based compensation	4.8			4.8
Issuance of common stock for cash (in shares)			15,500,000
Issuance of common stock for cash	240.5			240.5
Net income (loss)	(0.7)					(0.7)
Other comprehensive income (loss), net of tax	(0.3)				(0.3)
Balance, end of period (in shares) at Jun. 28, 2020			122,500,000
Balance, end of period at Jun. 28, 2020	$ 824.5		$ 0.0	1,537.9	(0.5)	(712.9)
Balance, beginning of period at Dec. 27, 2020		14.8
Redeemable Noncontrolling Interest
Net income (loss)		(0.2)
Balance, end of period at Jun. 27, 2021		14.6
Balance, beginning of period (in shares) at Dec. 27, 2020	123,047,147		123,000,000.0
Balance, beginning of period at Dec. 27, 2020	$ 925.3		$ 0.0	1,556.3	1.4	(632.4)
Increase (Decrease) in Stockholders' Equity
Stock-based compensation	12.8			12.8
Issuance of common stock for employee stock purchase plan, options and warrants (in shares)			200,000
Issuance of common stock for employee stock purchase plan, options and warrants	2.5			2.5
Restricted stock issued and related taxes (in shares)			600,000
Restricted stock issued and related taxes	(8.5)			(8.5)
Net income (loss)	3.0					3.0
Other comprehensive income (loss), net of tax	$ 0.8				0.8
Balance, end of period (in shares) at Jun. 27, 2021	123,807,616		123,800,000
Balance, end of period at Jun. 27, 2021	$ 935.9		$ 0.0	1,563.1	2.2	(629.4)
Balance, beginning of period at Mar. 28, 2021		14.8
Redeemable Noncontrolling Interest
Net income (loss)		(0.2)
Balance, end of period at Jun. 27, 2021		$ 14.6
Balance, beginning of period (in shares) at Mar. 28, 2021			123,700,000
Balance, beginning of period at Mar. 28, 2021	929.0		$ 0.0	1,557.9	1.6	(630.5)
Increase (Decrease) in Stockholders' Equity
Stock-based compensation	6.6			6.6
Restricted stock issued and related taxes (in shares)			100,000
Restricted stock issued and related taxes	(1.4)			(1.4)
Net income (loss)	1.1					1.1
Other comprehensive income (loss), net of tax	$ 0.6				0.6
Balance, end of period (in shares) at Jun. 27, 2021	123,807,616		123,800,000
Balance, end of period at Jun. 27, 2021	$ 935.9		$ 0.0	$ 1,563.1	$ 2.2	$ (629.4)