Condensed Consolidating Statement of Operations and Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 25, 2017	Jun. 26, 2016	Jun. 25, 2017	Jun. 26, 2016
Condensed Financial Statements, Captions [Line Items]
Service revenues	$ 91.6	$ 88.2	$ 176.6	$ 170.8
Product sales	94.1	80.0	176.9	150.4
Total revenues	185.7	168.2	353.5	321.2
Cost of service revenues	67.0	64.4	128.8	124.7
Cost of product sales	71.3	58.6	132.2	115.4
Total costs	138.3	123.0	261.0	240.1
Gross profit	47.4	45.2	92.5	81.1
Selling, general and administrative expenses	40.7	41.2	79.7	84.4
Research and development expenses	4.1	4.0	8.5	6.9
Operating income (loss) from continuing operations	2.6	0.0	4.3	(10.2)
Other income (expense):
Interest income (expense), net	(7.2)	(8.7)	(15.4)	(17.4)
Loss on extinguishment of debt	0.0	0.0	(2.1)	0.0
Other income (expense), net	0.2	0.2	0.4	0.5
Total other expense, net	(7.0)	(8.5)	(17.1)	(16.9)
Loss from continuing operations before income taxes	(4.4)	(8.5)	(12.8)	(27.1)
Provision for income taxes from continuing operations	1.8	1.8	3.3	5.4
Loss from continuing operations	(6.2)	(10.3)	(16.1)	(32.5)
Loss from discontinued operations	0.0	(0.1)	(0.1)	(0.1)
Equity in net income (loss) of subsidiaries	0.0	0.0	0.0	0.0
Net loss	(6.2)	(10.4)	(16.2)	(32.6)
Comprehensive income (loss)	(6.2)	(10.5)	(16.1)	(32.7)
Eliminations
Condensed Financial Statements, Captions [Line Items]
Service revenues	0.0	0.0	0.0	0.0
Product sales	(3.0)	(1.9)	(6.2)	(3.6)
Total revenues	(3.0)	(1.9)	(6.2)	(3.6)
Cost of service revenues	0.0	0.0	0.0	0.0
Cost of product sales	(3.0)	(1.9)	(6.2)	(3.6)
Total costs	(3.0)	(1.9)	(6.2)	(3.6)
Gross profit	0.0	0.0	0.0	0.0
Selling, general and administrative expenses	0.0	0.0	0.0	0.0
Research and development expenses	0.0	0.0	0.0	0.0
Operating income (loss) from continuing operations	0.0	0.0	0.0	0.0
Other income (expense):
Interest income (expense), net	0.0	0.0	0.0	0.0
Loss on extinguishment of debt			0.0
Other income (expense), net	0.0	0.0	0.0	0.0
Total other expense, net	0.0	0.0	0.0	0.0
Loss from continuing operations before income taxes	0.0	0.0	0.0	0.0
Provision for income taxes from continuing operations	0.0	0.0	0.0	0.0
Loss from continuing operations	0.0	0.0	0.0	0.0
Loss from discontinued operations		0.0	0.0	0.0
Equity in net income (loss) of subsidiaries	(2.0)	(2.5)	(4.3)	7.8
Net loss	(2.0)	(2.5)	(4.3)	7.8
Comprehensive income (loss)	(2.0)	(2.4)	(4.4)	7.9
Parent Company
Condensed Financial Statements, Captions [Line Items]
Service revenues	0.0	0.0	0.0	0.0
Product sales	0.0	0.0	0.0	0.0
Total revenues	0.0	0.0	0.0	0.0
Cost of service revenues	0.0	0.0	0.0	0.0
Cost of product sales	0.0	0.0	0.0	0.0
Total costs	0.0	0.0	0.0	0.0
Gross profit	0.0	0.0	0.0	0.0
Selling, general and administrative expenses	1.4	2.5	3.5	3.8
Research and development expenses	0.0	0.0	0.0	0.0
Operating income (loss) from continuing operations	(1.4)	(2.5)	(3.5)	(3.8)
Other income (expense):
Interest income (expense), net	(7.3)	(8.7)	(15.5)	(17.3)
Loss on extinguishment of debt			(2.1)
Other income (expense), net	0.0	0.0	0.0	0.0
Total other expense, net	(7.3)	(8.7)	(17.6)	(17.3)
Loss from continuing operations before income taxes	(8.7)	(11.2)	(21.1)	(21.1)
Provision for income taxes from continuing operations	0.0	0.0	0.1	0.1
Loss from continuing operations	(8.7)	(11.2)	(21.2)	(21.2)
Loss from discontinued operations		(0.1)	(0.1)	(0.1)
Equity in net income (loss) of subsidiaries	2.5	0.9	5.1	(11.3)
Net loss	(6.2)	(10.4)	(16.2)	(32.6)
Comprehensive income (loss)	(6.2)	(10.5)	(16.1)	(32.7)
Subsidiary Guarantors on a Combined Basis
Condensed Financial Statements, Captions [Line Items]
Service revenues	86.3	82.3	168.7	159.7
Product sales	84.0	69.0	157.3	128.0
Total revenues	170.3	151.3	326.0	287.7
Cost of service revenues	62.7	60.0	122.6	116.7
Cost of product sales	63.0	50.2	117.0	98.2
Total costs	125.7	110.2	239.6	214.9
Gross profit	44.6	41.1	86.4	72.8
Selling, general and administrative expenses	36.3	36.2	70.1	75.8
Research and development expenses	3.7	3.9	7.7	6.8
Operating income (loss) from continuing operations	4.6	1.0	8.6	(9.8)
Other income (expense):
Interest income (expense), net	0.1	0.0	0.1	(0.1)
Loss on extinguishment of debt			0.0
Other income (expense), net	0.1	(0.2)	0.1	(0.2)
Total other expense, net	0.2	(0.2)	0.2	(0.3)
Loss from continuing operations before income taxes	4.8	0.8	8.8	(10.1)
Provision for income taxes from continuing operations	1.8	1.5	2.9	4.7
Loss from continuing operations	3.0	(0.7)	5.9	(14.8)
Loss from discontinued operations		0.0	0.0	0.0
Equity in net income (loss) of subsidiaries	(0.5)	1.6	(0.8)	3.5
Net loss	2.5	0.9	5.1	(11.3)
Comprehensive income (loss)	2.5	0.9	5.1	(11.3)
Non-Guarantors on a Combined Basis
Condensed Financial Statements, Captions [Line Items]
Service revenues	5.3	5.9	7.9	11.1
Product sales	13.1	12.9	25.8	26.0
Total revenues	18.4	18.8	33.7	37.1
Cost of service revenues	4.3	4.4	6.2	8.0
Cost of product sales	11.3	10.3	21.4	20.8
Total costs	15.6	14.7	27.6	28.8
Gross profit	2.8	4.1	6.1	8.3
Selling, general and administrative expenses	3.0	2.5	6.1	4.8
Research and development expenses	0.4	0.1	0.8	0.1
Operating income (loss) from continuing operations	(0.6)	1.5	(0.8)	3.4
Other income (expense):
Interest income (expense), net	0.0	0.0	0.0	0.0
Loss on extinguishment of debt			0.0
Other income (expense), net	0.1	0.4	0.3	0.7
Total other expense, net	0.1	0.4	0.3	0.7
Loss from continuing operations before income taxes	(0.5)	1.9	(0.5)	4.1
Provision for income taxes from continuing operations	0.0	0.3	0.3	0.6
Loss from continuing operations	(0.5)	1.6	(0.8)	3.5
Loss from discontinued operations		0.0	0.0	0.0
Equity in net income (loss) of subsidiaries	0.0	0.0	0.0	0.0
Net loss	(0.5)	1.6	(0.8)	3.5
Comprehensive income (loss)	$ (0.5)	$ 1.5	$ (0.7)	$ 3.4