Other Income, net of expenses (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Component of Other Income, Nonoperating [Line Items]
Other income, net of expenses	$ 752	$ 849
Interest income [Member]
Component of Other Income, Nonoperating [Line Items]
Other income, net of expenses	339	247
Gain (loss) on investments [Member]
Component of Other Income, Nonoperating [Line Items]
Other income, net of expenses	48	74
License fee income [Member]
Component of Other Income, Nonoperating [Line Items]
Other income, net of expenses	214	427
Other [Member]
Component of Other Income, Nonoperating [Line Items]
Other income, net of expenses	$ 151	$ 101