Other Income, net of expenses (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Component of Other Income, Nonoperating [Line Items]
Other income, net of expenses	$ 627	$ 366	$ 1,477	$ 773
Interest income [Member]
Component of Other Income, Nonoperating [Line Items]
Other income, net of expenses	288	247	535	477
Gain (loss) on Investments [Member]
Component of Other Income, Nonoperating [Line Items]
Other income, net of expenses	(23)	69	51	141
License fee income [Member]
Component of Other Income, Nonoperating [Line Items]
Other income, net of expenses	67	48	493	48
Other Nonoperating Income [Member]
Component of Other Income, Nonoperating [Line Items]
Other income, net of expenses	$ 295	$ 2	$ 398	$ 107