Property and Equipment, Net (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Oct. 01, 2017	Oct. 02, 2016	Oct. 01, 2017	Oct. 02, 2016	Jan. 01, 2017
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 126.1		$ 126.1		$ 106.2
Accumulated depreciation	(48.3)		(48.3)		(36.4)
Total property and equipment, net	77.8		77.8		69.8
Depreciation	4.7	$ 3.5	12.9	$ 10.3
Land
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	14.5		14.5		14.5
Buildings
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	8.6		8.6		8.6
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	16.0		16.0		14.0
Store equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	24.5		24.5		17.6
Office furniture and fixtures
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	12.9		12.9		11.1
Vehicles
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	44.8		44.8		36.1
Tooling
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	0.1		0.1		1.0
Construction in process
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 4.7		$ 4.7		$ 3.3