Deferred Income on Shipments to Distributors (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Jun. 30, 2013	Mar. 31, 2013
Deferred Revenue Disclosure [Abstract]
Gross deferred revenue	$ 16,771	$ 17,581
Gross deferred costs	(2,809)	(3,042)
Deferred income on shipments to distributors	$ 13,962	$ 14,539
Discount from list price billed to the customer (in hundredths)	37.40%