Summary of Significant Accounting Policies (Details 5) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Activity of accumulated comprehensive income (loss)
Unrealized gain (loss) on investments, net of tax	$ 505	$ (42)	$ (9)
Unrealized gain (loss) on currency translation	(8)	2	9
Ending Balance	$ 447	$ (50)