Stockholders' Equity, Employee Stock Purchase Plan (Details)	3 Months Ended
	Mar. 31, 2013
Employee Stock Purchase Plan [Abstract]
Number of shares reserved for issuance (in shares)	1,000,000
Term for Employee Stock Purchase Plan	10 years
Offering period of Employee Stock Purchase Plan	6 months
Minimum percentage of fair market value of the specified conditions used to determine purchase price of ESPP (in hundredths)	85.00%
Employee Stock Purchase Plan, shares issued (in shares)	0