Condensed Consolidated Balance Sheets (Parenthetical) (Unaudited) (USD $) In Thousands, except Share data, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Condensed Consolidated Balance Sheets [Abstract]
Accounts receivable, allowance for doubtful accounts	$ 788	$ 571
Cumulative convertible preferred stock, at par value	$ 0.0001	$ 0.0001
Cumulative convertible preferred stock, shares authorized	100,000	100,000
Cumulative convertible preferred stock, shares issued	0	0
Cumulative convertible preferred stock, shares outstanding	0	0
Cumulative convertible preferred stock, liquidation preference	$ 300
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	80,000,000	80,000,000
Common stock, shares issued	52,872,524	51,957,652
Common stock, shares outstanding	49,678,844	49,153,495
Treasury stock, shares	1,404,994	1,358,299