Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	9 Months Ended	12 Months Ended
	Sep. 30, 2012	Dec. 31, 2011
Condensed Consolidated Balance Sheets [Abstract]
Cumulative participating convertible preferred stock, dividend rate percentage	7.00%	7.00%
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	977,004	1,007,444
Preferred stock, shares outstanding	971,090	1,003,108
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	190,000,000	190,000,000
Common stock, shares issued	18,426,553	18,416,957
Common stock, shares outstanding	17,737,874	18,323,443