Condensed Consolidating Statement of Operations and Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Oct. 01, 2017	Sep. 25, 2016	Oct. 01, 2017	Sep. 25, 2016
Condensed Financial Statements, Captions [Line Items]
Service revenues	$ 86.7	$ 87.2	$ 263.3	$ 258.0
Product sales	109.5	78.2	286.4	228.6
Total revenues	196.2	165.4	549.7	486.6
Cost of service revenues	60.8	64.7	189.6	189.4
Cost of product sales	87.3	74.8	219.5	190.2
Total costs	148.1	139.5	409.1	379.6
Gross profit	48.1	25.9	140.6	107.0
Selling, general and administrative expenses	40.8	35.7	120.5	120.1
Research and development expenses	4.2	3.2	12.7	10.1
Operating income (loss) from continuing operations	3.1	(13.0)	7.4	(23.2)
Other income (expense):
Interest income (expense), net	(7.7)	(8.7)	(23.1)	(26.1)
Loss on extinguishment of debt	0.0	0.0	(2.1)	0.0
Other income (expense), net	0.6	0.1	1.0	0.6
Total other expense, net	(7.1)	(8.6)	(24.2)	(25.5)
Loss from continuing operations before income taxes	(4.0)	(21.6)	(16.8)	(48.7)
Provision for income taxes from continuing operations	0.2	1.9	3.5	7.3
Loss from continuing operations	(4.2)	(23.5)	(20.3)	(56.0)
Loss from discontinued operations	(0.1)	(0.1)	(0.2)	(0.2)
Equity in net income (loss) of subsidiaries	0.0	0.0	0.0	0.0
Net loss	(4.3)	(23.6)	(20.5)	(56.2)
Comprehensive income (loss)	(4.5)	(23.7)	(20.6)	(56.4)
Eliminations
Condensed Financial Statements, Captions [Line Items]
Service revenues	0.0	0.0	0.0	0.0
Product sales	(4.8)	(2.0)	(11.0)	(5.6)
Total revenues	(4.8)	(2.0)	(11.0)	(5.6)
Cost of service revenues	0.0	0.0	0.0	0.0
Cost of product sales	(4.8)	(2.0)	(11.0)	(5.6)
Total costs	(4.8)	(2.0)	(11.0)	(5.6)
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	0.0
Equity in net income (loss) of subsidiaries	(7.3)	12.6	(11.6)	20.4
Net loss	(7.3)	12.6	(11.6)	20.4
Comprehensive income (loss)	(7.1)	12.7	(11.5)	20.6
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	2.3	0.2	5.8	4.0
Research and development expenses	0.0	0.0	0.0	0.0
Operating income (loss) from continuing operations	(2.3)	(0.2)	(5.8)	(4.0)
Other income (expense):
Interest income (expense), net	(7.7)	(8.7)	(23.2)	(26.0)
Loss on extinguishment of debt			(2.1)
Other income (expense), net	0.0	0.0	0.0	0.0
Total other expense, net	(7.7)	(8.7)	(25.3)	(26.0)
Loss from continuing operations before income taxes	(10.0)	(8.9)	(31.1)	(30.0)
Provision for income taxes from continuing operations	0.3	0.1	0.4	0.2
Loss from continuing operations	(10.3)	(9.0)	(31.5)	(30.2)
Loss from discontinued operations	(0.1)	0.0	(0.2)	(0.1)
Equity in net income (loss) of subsidiaries	6.1	(14.6)	11.2	(25.9)
Net loss	(4.3)	(23.6)	(20.5)	(56.2)
Comprehensive income (loss)	(4.5)	(23.7)	(20.6)	(56.4)
Subsidiary Guarantors on a Combined Basis
Condensed Financial Statements, Captions [Line Items]
Service revenues	84.8	84.3	253.5	244.0
Product sales	99.3	67.8	256.6	195.8
Total revenues	184.1	152.1	510.1	439.8
Cost of service revenues	59.7	62.9	182.3	179.6
Cost of product sales	80.2	67.7	197.2	165.9
Total costs	139.9	130.6	379.5	345.5
Gross profit	44.2	21.5	130.6	94.3
Selling, general and administrative expenses	35.3	33.3	105.4	109.1
Research and development expenses	4.2	3.1	11.9	9.9
Operating income (loss) from continuing operations	4.7	(14.9)	13.3	(24.7)
Other income (expense):
Interest income (expense), net	0.0	0.0	0.1	(0.1)
Loss on extinguishment of debt			0.0
Other income (expense), net	0.1	0.1	0.2	(0.1)
Total other expense, net	0.1	0.1	0.3	(0.2)
Loss from continuing operations before income taxes	4.8	(14.8)	13.6	(24.9)
Provision for income taxes from continuing operations	(0.1)	1.7	2.8	6.4
Loss from continuing operations	4.9	(16.5)	10.8	(31.3)
Loss from discontinued operations	0.0	(0.1)	0.0	(0.1)
Equity in net income (loss) of subsidiaries	1.2	2.0	0.4	5.5
Net loss	6.1	(14.6)	11.2	(25.9)
Comprehensive income (loss)	6.1	(14.6)	11.2	(25.9)
Non-Guarantors on a Combined Basis
Condensed Financial Statements, Captions [Line Items]
Service revenues	1.9	2.9	9.8	14.0
Product sales	15.0	12.4	40.8	38.4
Total revenues	16.9	15.3	50.6	52.4
Cost of service revenues	1.1	1.8	7.3	9.8
Cost of product sales	11.9	9.1	33.3	29.9
Total costs	13.0	10.9	40.6	39.7
Gross profit	3.9	4.4	10.0	12.7
Selling, general and administrative expenses	3.2	2.2	9.3	7.0
Research and development expenses	0.0	0.1	0.8	0.2
Operating income (loss) from continuing operations	0.7	2.1	(0.1)	5.5
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	0.5	0.0	0.8	0.7
Total other expense, net	0.5	0.0	0.8	0.7
Loss from continuing operations before income taxes	1.2	2.1	0.7	6.2
Provision for income taxes from continuing operations	0.0	0.1	0.3	0.7
Loss from continuing operations	1.2	2.0	0.4	5.5
Loss from discontinued operations	0.0	0.0	0.0	0.0
Equity in net income (loss) of subsidiaries	0.0	0.0	0.0	0.0
Net loss	1.2	2.0	0.4	5.5
Comprehensive income (loss)	$ 1.0	$ 1.9	$ 0.3	$ 5.3