Consolidated Balance Sheets [Parenthetical] (USD $)	Jun. 30, 2013	Dec. 31, 2012
Common stock , par value (in dollars per share)	$ 0.000001	$ 0.000001
Common stock , shares authorized (in shares)	50,000,000	50,000,000
Common stock , shares issued (in shares)	18,396,219	18,278,795
Common stock , shares outstanding (in shares)	18,396,219	18,278,795