Agreements with SK hynix and Micron (Details 2) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		12 Months Ended	3 Months Ended		12 Months Ended	3 Months Ended		12 Months Ended	3 Months Ended		7 Months Ended	3 Months Ended		7 Months Ended	3 Months Ended		7 Months Ended
	Jun. 30, 2014 SK hynix [Member]	Mar. 31, 2014 SK hynix [Member]	Jun. 30, 2014 SK hynix [Member]	Jun. 30, 2014 SK hynix [Member] Royalty revenue	Mar. 31, 2014 SK hynix [Member] Royalty revenue	Jun. 30, 2014 SK hynix [Member] Royalty revenue	Jun. 30, 2014 SK hynix [Member] Gain from settlement	Mar. 31, 2014 SK hynix [Member] Gain from settlement	Jun. 30, 2014 SK hynix [Member] Gain from settlement	Jun. 30, 2014 Micron [Member]	Mar. 31, 2014 Micron [Member]	Jun. 30, 2014 Micron [Member]	Jun. 30, 2014 Micron [Member] Royalty revenue	Mar. 31, 2014 Micron [Member] Royalty revenue	Jun. 30, 2014 Micron [Member] Royalty revenue	Jun. 30, 2014 Micron [Member] Gain from settlement	Mar. 31, 2014 Micron [Member] Gain from settlement	Jun. 30, 2014 Micron [Member] Gain from settlement
Accounts, Notes, Loans and Financing Receivable [Line Items]
Cash Received to date in 2014	$ 12.0	$ 12.0	$ 48.0	$ 11.8	$ 11.8	$ 47.3	$ 0.2	$ 0.2	$ 0.7	$ 10.0	$ 10.0	$ 25.5	$ 9.7	$ 9.7	$ 24.7	$ 0.3	$ 0.3	$ 0.8
Estimated to Be Received in Remainder of 2014	24.0		24.0	23.6		23.6	0.4		0.4	20.0		20.0	19.3		19.3	0.7		0.7
Estimated to Be Received in 2015	48.0		48.0	47.3		47.3	0.7		0.7	40.0		40.0	38.7		38.7	1.3		1.3
Estimated to Be Received in 2016	48.0		48.0	47.9		47.9	0.1		0.1	40.0		40.0	39.5		39.5	0.5		0.5
Estimated to Be Received in 2017	48.0		48.0	48.0		48.0	0		0	40.0		40.0	40.0		40.0	0		0
Estimated to Be Received in 2018	24.0		24.0	24.0		24.0	0		0	40.0		40.0	40.0		40.0	0		0
Estimated to Be Received in 2019 and thereafter										74.5		74.5	74.5		74.5	0		0
Total Estimated Cash receipts	$ 240.0		$ 240.0	$ 238.1		$ 238.1	$ 1.9		$ 1.9	$ 280.0		$ 280.0	$ 276.7		$ 276.7	$ 3.3		$ 3.3