Discontinued Operations - Assets and Liabilities (Details) - USD ($) $ in Millions	Feb. 28, 2017	May 31, 2016	Feb. 29, 2016
Disposal Group, Including Discontinued Operation, Assets, Current [Abstract]
Current assets of discontinued operations	$ 0.4	$ 0.5	$ 0.6
Disposal Group, Including Discontinued Operation, Liabilities, Current [Abstract]
Current liabilities of discontinued operations	0.1	1.2	1.5
Discontinued Operations
Disposal Group, Including Discontinued Operation, Assets, Current [Abstract]
Accounts receivable, net	0.1	0.0	0.1
Prepaid expenses and other current assets	0.3	0.5	0.5
Current assets of discontinued operations	0.4	0.5	0.6
Disposal Group, Including Discontinued Operation, Liabilities, Current [Abstract]
Accounts payable	0.0	0.0	0.0
Accrued royalties	0.0	0.0	0.1
Deferred revenue	0.0	0.0	0.1
Other accrued expenses	0.1	1.2	1.3
Current liabilities of discontinued operations	$ 0.1	$ 1.2	$ 1.5