Income Taxes (Details 3) (USD $) In Thousands, unless otherwise specified					12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2012 Net Operating Losses [Member]	Dec. 31, 2011 Net Operating Losses [Member]	Dec. 31, 2010 Net Operating Losses [Member]	Dec. 31, 2012 Tax Credits [Member]	Dec. 31, 2011 Tax Credits [Member]	Dec. 31, 2010 Tax Credits [Member]
Summary of changes in valuation allowance
Valuation allowance at beginning of year	$ 727	$ 287	$ 249	$ 666
Increase (decrease) to valuation allowance					440	38	(132)			285
Valuation allowance at end of year	$ 727	$ 287	$ 249	$ 666