Condensed Consolidating Financial Statements - Statement of Operations and Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended
	Apr. 01, 2018	Mar. 26, 2017
Condensed Financial Statements, Captions [Line Items]
Service revenues	$ 46.0	$ 49.2
Product sales	97.0	82.8
Total revenues	143.0	132.0
Cost of service revenues	32.9	35.0
Cost of product sales	69.3	60.9
Total costs	102.2	95.9
Gross profit	40.8	36.1
Selling, general and administrative expenses	30.2	30.3
Research and development expenses	3.6	4.4
Operating income from continuing operations	7.0	1.4
Other income (expense):
Interest income (expense), net	(5.1)	(8.2)
Loss on extinguishment of debt	0.0	(2.1)
Other income (expense), net	0.3	0.2
Total other expense, net	(4.8)	(10.1)
Income (loss) from continuing operations before income taxes	2.2	(8.7)
Provision for income taxes from continuing operations	0.9	1.4
Income (loss) from continuing operations	1.3	(10.1)
Income (loss) from discontinued operations	(3.5)	0.1
Equity in net income (loss) of subsidiaries	0.0	0.0
Net loss	(2.2)	(10.0)
Comprehensive income (loss)	(2.3)	(9.9)
Eliminations
Condensed Financial Statements, Captions [Line Items]
Service revenues	0.0	0.0
Product sales	(4.9)	(3.2)
Total revenues	(4.9)	(3.2)
Cost of service revenues	0.0	0.0
Cost of product sales	(4.9)	(3.2)
Total costs	(4.9)	(3.2)
Gross profit	0.0	0.0
Selling, general and administrative expenses	0.0	0.0
Research and development expenses	0.0	0.0
Operating income from continuing operations	0.0	0.0
Other income (expense):
Interest income (expense), net	0.0	0.0
Loss on extinguishment of debt		0.0
Other income (expense), net	0.0	0.0
Total other expense, net	0.0	0.0
Income (loss) from continuing operations before income taxes	0.0	0.0
Provision for income taxes from continuing operations	0.0	0.0
Income (loss) from continuing operations	0.0	0.0
Income (loss) from discontinued operations	0.0	0.0
Equity in net income (loss) of subsidiaries	(7.0)	(2.3)
Net loss	(7.0)	(2.3)
Comprehensive income (loss)	(6.9)	(2.4)
Parent Company
Condensed Financial Statements, Captions [Line Items]
Service revenues	0.0	0.0
Product sales	0.0	0.0
Total revenues	0.0	0.0
Cost of service revenues	0.0	0.0
Cost of product sales	0.0	0.0
Total costs	0.0	0.0
Gross profit	0.0	0.0
Selling, general and administrative expenses	0.4	2.1
Research and development expenses	0.0	0.0
Operating income from continuing operations	(0.4)	(2.1)
Other income (expense):
Interest income (expense), net	(5.2)	(8.2)
Loss on extinguishment of debt		(2.1)
Other income (expense), net	(0.8)	0.0
Total other expense, net	(6.0)	(10.3)
Income (loss) from continuing operations before income taxes	(6.4)	(12.4)
Provision for income taxes from continuing operations	0.1	0.1
Income (loss) from continuing operations	(6.5)	(12.5)
Income (loss) from discontinued operations	0.0	(0.1)
Equity in net income (loss) of subsidiaries	4.3	2.6
Net loss	(2.2)	(10.0)
Comprehensive income (loss)	(2.3)	(9.9)
Subsidiary Guarantors on a Combined Basis
Condensed Financial Statements, Captions [Line Items]
Service revenues	42.7	46.6
Product sales	85.5	73.3
Total revenues	128.2	119.9
Cost of service revenues	30.4	33.1
Cost of product sales	63.2	54.0
Total costs	93.6	87.1
Gross profit	34.6	32.8
Selling, general and administrative expenses	26.7	25.1
Research and development expenses	3.2	4.0
Operating income from continuing operations	4.7	3.7
Other income (expense):
Interest income (expense), net	0.1	0.0
Loss on extinguishment of debt		0.0
Other income (expense), net	0.8	0.0
Total other expense, net	0.9	0.0
Income (loss) from continuing operations before income taxes	5.6	3.7
Provision for income taxes from continuing operations	0.5	1.0
Income (loss) from continuing operations	5.1	2.7
Income (loss) from discontinued operations	(3.5)	0.2
Equity in net income (loss) of subsidiaries	2.7	(0.3)
Net loss	4.3	2.6
Comprehensive income (loss)	4.3	2.6
Non-Guarantors on a Combined Basis
Condensed Financial Statements, Captions [Line Items]
Service revenues	3.3	2.6
Product sales	16.4	12.7
Total revenues	19.7	15.3
Cost of service revenues	2.5	1.9
Cost of product sales	11.0	10.1
Total costs	13.5	12.0
Gross profit	6.2	3.3
Selling, general and administrative expenses	3.1	3.1
Research and development expenses	0.4	0.4
Operating income from continuing operations	2.7	(0.2)
Other income (expense):
Interest income (expense), net	0.0	0.0
Loss on extinguishment of debt		0.0
Other income (expense), net	0.3	0.2
Total other expense, net	0.3	0.2
Income (loss) from continuing operations before income taxes	3.0	0.0
Provision for income taxes from continuing operations	0.3	0.3
Income (loss) from continuing operations	2.7	(0.3)
Income (loss) from discontinued operations	0.0	0.0
Equity in net income (loss) of subsidiaries	0.0	0.0
Net loss	2.7	(0.3)
Comprehensive income (loss)	$ 2.6	$ (0.2)