Revenues - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Capitalized contract cost, net	$ 2.7
Revenue recognized	25.0
Revenue, remaining performance obligation		$ 0.1
Prepaid Expenses and Other Current Assets
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Capitalized contract cost, net	1.8
Other Noncurrent Assets
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Capitalized contract cost, net	$ 0.9
Minimum
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Extended product warranty term	1 month
Maximum
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Extended product warranty term	3 years