Income Taxes - Operating loss carry forwards (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Net operating loss carry forwards
Net operating loss carry forward	$ 7.3	$ 8.9
Foreign
Net operating loss carry forwards
Net operating loss carry forward	27.2
Net operating loss carryforward, not subject to expiration	22.9
Net operating loss carryforward, subject to expiration	4.3
Austria
Net operating loss carry forwards
Operating loss carryforward	22.9
Dutch
Net operating loss carry forwards
Operating loss carryforward	4.3
U.S.
Net operating loss carry forwards
Net operating loss carry forward	1.5
Net operating loss carry forwards expiring in 2017	1.0
Net operating loss carry forwards expiring in 2018	$ 0.5