Intangible Assets (Tables)

3 Months Ended

Mar. 31, 2018

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of Intangible Assets

(In millions)	Capacity Agreement			Developed Technology			Total
March 31, 2018
Cost	$	10.1		$	—		$	10.1
Accumulated amortization	(2.4		)	—			(2.4		)
Intangible assets, net	$	7.7		$	—		$	7.7
December 31, 2017
Cost	$	10.1		$	4.3		$	14.4
Accumulated amortization	(1.9		)	(1.6		)	(3.5		)
Impairment charges	—			(2.7		)	$	(2.7	)
Intangible assets, net	$	8.2		$	—		$	8.2

Schedule of Amortization Expense for Intangible Assets

Amortization expense for intangible assets consisted of the following:

	Three Months Ended
	March 31,
(In millions)	2018		2017
Amortization expense	$	0.5	$	0.5

Schedule of Intangible Assets Estimated Amortization Expense

Estimated amortization expense for the remainder of 2018 and each of the next four years ending December 31 is as follows:

(In millions)	2018 (Remainder)		2019		2020		2021		2022
Amortization expense	$	1.5	$	2.0	$	2.0	$	2.0	$	0.2