CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY - USD ($) $ in Millions	Total	Redeemable Noncontrolling Interest	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Loss	Accumulated Deficit
Balance, beginning of period at Dec. 30, 2018		$ 0.0
Redeemable Noncontrolling Interest
Net income (loss)		0.5
Changes in noncontrolling interest	$ 0.0	15.0
Balance, end of period at Sep. 29, 2019		15.5
Balance, beginning of period (in shares) at Dec. 30, 2018			103,800,000
Balance, beginning of period at Dec. 30, 2018	519.3		$ 0.0	$ 1,244.5	$ (0.7)	$ (724.5)
Increase (Decrease) in Stockholders' Equity
Stock-based compensation	8.2			8.2
Issuance of common stock for employee stock purchase plan, options and warrants (in shares)			500,000
Issuance of common stock for employee stock purchase plan, options and warrants	3.9			3.9
Restricted stock issued and related taxes (in shares)			200,000
Restricted stock issued and related taxes	(0.9)			(0.9)
Issuance of common stock for acquisitions (in shares)			1,800,000
Issuance of common stock for acquisitions	27.0			27.0
Net income (loss)	9.5					9.5
Other comprehensive income (loss), net of tax	(0.3)				(0.3)
Changes in noncontrolling interest	0.0	15.0
Balance, end of period (in shares) at Sep. 29, 2019			106,300,000
Balance, end of period at Sep. 29, 2019	566.7		$ 0.0	1,282.7	(1.0)	(715.0)
Balance, beginning of period at Jun. 30, 2019		15.4
Redeemable Noncontrolling Interest
Net income (loss)		0.1
Balance, end of period at Sep. 29, 2019		15.5
Balance, beginning of period (in shares) at Jun. 30, 2019			105,900,000
Balance, beginning of period at Jun. 30, 2019	559.5		$ 0.0	1,277.8	(0.8)	(717.5)
Increase (Decrease) in Stockholders' Equity
Stock-based compensation	2.8			2.8
Issuance of common stock for employee stock purchase plan, options and warrants (in shares)			300,000
Issuance of common stock for employee stock purchase plan, options and warrants	2.2			2.2
Restricted stock issued and related taxes (in shares)			100,000
Restricted stock issued and related taxes	(0.1)			(0.1)
Net income (loss)	2.5					2.5
Other comprehensive income (loss), net of tax	(0.2)				(0.2)
Balance, end of period (in shares) at Sep. 29, 2019			106,300,000
Balance, end of period at Sep. 29, 2019	$ 566.7		$ 0.0	1,282.7	(1.0)	(715.0)
Balance, beginning of period at Dec. 29, 2019		15.0
Redeemable Noncontrolling Interest
Net income (loss)		(0.1)
Balance, end of period at Sep. 27, 2020		14.9
Balance, beginning of period (in shares) at Dec. 29, 2019	106,635,508		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	$ 14.5			14.5
Issuance of common stock for employee stock purchase plan, options and warrants (in shares)	400,000
Issuance of common stock for employee stock purchase plan, options and warrants	$ 5.3			5.3
Restricted stock issued and related taxes (in shares)			200,000
Restricted stock issued and related taxes	$ (1.3)			(1.3)
Issuance of common stock for cash	15,500,000
Issuance of common stock for cash	$ 240.4			240.4
Net income (loss)	1.5			0.0		1.5
Other comprehensive income (loss), net of tax	$ 0.8			0.0
Balance, end of period (in shares) at Sep. 27, 2020	122,755,405		122,700,000
Balance, end of period at Sep. 27, 2020	$ 835.3		$ 0.0	1,545.4	0.4	(710.5)
Balance, beginning of period at Jun. 28, 2020		14.9
Balance, end of period at Sep. 27, 2020		$ 14.9
Balance, beginning of period (in shares) at Jun. 28, 2020			122,500,000
Balance, beginning of period at Jun. 28, 2020	824.5		$ 0.0	1,537.9	(0.5)	(712.9)
Increase (Decrease) in Stockholders' Equity
Stock-based compensation	5.0			5.0
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	2.7			2.7
Restricted stock issued and related taxes (in shares)			0
Restricted stock issued and related taxes	(0.1)			(0.1)
Issuance of common stock for cash	(0.1)			(0.1)
Net income (loss)	2.4					2.4
Other comprehensive income (loss), net of tax	$ 0.9				0.9
Balance, end of period (in shares) at Sep. 27, 2020	122,755,405		122,700,000
Balance, end of period at Sep. 27, 2020	$ 835.3		$ 0.0	$ 1,545.4	$ 0.4	$ (710.5)