Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Statement of Financial Position [Abstract]
Accounts receivable, allowance for doubtful accounts	$ 714	$ 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
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	80,000,000	80,000,000
Common stock, shares issued	53,123,978	51,957,652
Common stock, shares outstanding	49,601,495	49,153,495
Treasury stock, shares	21,198,193	1,358,299