Consolidated Balance Sheets (Parenthetical) (USD $)	Jun. 30, 2013	Dec. 31, 2012
Statement of Financial Position [Abstract]
Preferred stock, par value per share (usd per share)	$ 0.01	$ 0.01
Preferred stock, authorized shares	5,000,000	5,000,000
Preferred stock, issued	0	0
Preferred stock, outstanding	0	0
Common stock, par value (usd per share)	$ 0.001	$ 0.001
Common stock, authorized shares	350,000,000	350,000,000
Common stock, issued	167,229,903	166,490,190
Common stock, outstanding	167,229,903	166,490,190