Stockholders' Equity and Employee Stock Option Plans 1997 Stock Plan (Details)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2014	Apr. 01, 2013	Mar. 31, 2013	Dec. 31, 2011
1997 Stock Plan [Abstract]
Common Stock, Capital Shares Reserved for Future Issuance			9,042,398	10,905,404	20,972,838
Options and SARS, Outstanding, Number	4,104,849	3,939,315	2,596,792		5,505,404	3,103,472
Share-based Compensation Arrangement by Share-based Payment Award, Additional Shares Authorized in 2013 Amendment				5,400,000
Number of Additional Shares Authorized	7,122,039	1,700,859
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	4,575,855	13,467,582	5,152,177		15,467,434	13,047,736