Stock-Based Compensation (Details)	Jun. 30, 2012	Dec. 31, 2011	Dec. 31, 2010
Schedule of Stock Options and Awards
Common stock shares available for grant	3,654,744
Common stock options outstanding	3,111,411	3,267,838	4,000,526
Stock Options [Member]
Schedule of Stock Options and Awards
Common stock options outstanding	3,111,411
Restricted Stock Awards [Member]
Schedule of Stock Options and Awards
Restricted stock outstanding	44,000	18,000	18,000
Restricted Stock Units [Member]
Schedule of Stock Options and Awards
Restricted stock outstanding	658,005	407,765	417,923