Stockholders' Equity, Employee Stock Purchase Plan (Details)	3 Months Ended	12 Months Ended
	Jun. 30, 2011	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
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)		117,533	79,221	84,082
Employee Stock Purchase Plan ("ESPP") [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee Stock Purchase Plan, available for grant (in shares)		683,000