Stock Options (Details)	12 Months Ended			12 Months Ended									0 Months Ended						12 Months Ended		12 Months Ended
	Dec. 31, 2012 item	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 Maximum	Dec. 31, 2012 Minimum	Dec. 31, 2012 Preferred stock	Dec. 31, 2012 1995 Plan	Dec. 31, 2001 1995 Plan	Dec. 31, 1995 1995 Plan	Dec. 31, 2012 1995 Non-Employee Director Plan	Apr. 30, 2002 1995 Non-Employee Director Plan	Dec. 31, 1995 1995 Non-Employee Director Plan	May 17, 2012 2005 Plan	May 19, 2011 2005 Plan	May 20, 2010 2005 Plan	May 21, 2009 2005 Plan	May 29, 2008 2005 Plan	May 30, 2007 2005 Plan	Dec. 31, 2012 2005 Plan item	Mar. 17, 2005 2005 Plan	Dec. 31, 2012 2005 Plan Non-employee Board member
Stock Options
Number of stock-based compensation plans	3
Shares available for issuance								825,000	400,000		65,000	40,000	3,700,000	3,400,000	3,000,000	2,500,000		1,500,000		750,000
Options exercised (in shares)							67,365												297,001
Options outstanding (in shares)	2,779,000	2,691,000	2,380,000				188,175			17,500									2,573,500
Options granted (in shares)										62,500									3,259,500
Options cancelled (in shares)										45,000									388,999
Additional increase in number of shares available for issuance													300,000	400,000	500,000	500,000	500,000	750,000
Number of separate equity incentive programs																			3
Options that will be granted upon initial election or appointment to the Board (in shares)																					10,000
Preceding period within which individual has not previously been employed by the company																					6 months
Options that will be granted to purchase shares of common stock on the date of each annual stockholders meeting																					5,000
Period for which individual should serve as a non-employee Board member																					6 months
Shares available for future grant																			829,499
Common Shares Reserved for Future Issuance	4,773,000					1,164,000	188,000			18,000									3,403,000
Option exercisable period one	1 year
Option exercisable period two	3 years
Option exercisable period three	5 years
Exercise price as a percentage of the fair market value of common stock in case of optionees holding more than 10% of voting stock				110.00%
Voting stock percentage to be held by optionees					10.00%
Expiration term	10 years
Expiration term for incentive stock options granted to holders of more than 10% of the entity's voting stock	5 years