Other Income, net of expenses (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Component of Other Income, Nonoperating [Line Items]
Other income, net of expenses	$ 856	$ 264	$ 2,333	$ 1,037
Interest income [Member]
Component of Other Income, Nonoperating [Line Items]
Other income, net of expenses	332	207	866	685
Gain (loss) on Investments [Member]
Component of Other Income, Nonoperating [Line Items]
Other income, net of expenses	22	(103)	73	37
License fee income [Member]
Component of Other Income, Nonoperating [Line Items]
Other income, net of expenses	268	35	762	82
Other Nonoperating Income [Member]
Component of Other Income, Nonoperating [Line Items]
Other income, net of expenses	$ 234	$ 125	$ 632	$ 233