CADRA technology sale transactions (Details) (USD $) In Thousands, unless otherwise specified	May 31, 2014
CADRA technology sale transactions
Proceeds from the sale of the CADRA technology	$ 2,880
Fair value of the Holdback Payment and the Earn-Out Payments	922
Liabilities assumed by Mentor related to deferred maintenance obligations	607
Professional fees and other expenses related to the transaction	(448)
Goodwill allocated to the CADRA product line	(3,305)
Net book value of equipment transferred in the sale	(7)
Gain on sale of CADRA product line	$ 649