Intangible Assets (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended	9 Months Ended
	Jun. 30, 2015	Dec. 31, 2014	Jun. 30, 2014	Mar. 31, 2015	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2013
Finite Lived Intangible Assets [Line Items]
Amortization of intangible assets	$ 114		$ 122		$ 345	$ 658
Cash received from amended supply agreement		$ 10,000		$ 2,300	$ 2,333	$ 10,000
Deferred credit amortization period					4 years
General Electric Company
Finite Lived Intangible Assets [Line Items]
Additional amount paid on execution of agreement					$ 7,000
Acquired finite-lived intangible assets, period					3 years
Deferred credit							$ 8,100
Supply Agreement
Finite Lived Intangible Assets [Line Items]
Useful life of intangible asset					15 years