Stock-based Compensation (Details 3)	12 Months Ended
	Dec. 31, 2012
Shares of common stock reserved for future issuance under all of the stock incentive plans	12,458,000
Employee Stock Purchase Plan (ESPP)
Shares of common stock reserved for future issuance under all of the stock incentive plans	3,853,000
Discount from fair market value of the stock	85.00%
Shares of common stock reserved for issuance under the ESPP	5,000,000
Number of common stock shares issued	427,000