Consolidated Balance Sheets (Parenthetical) - USD ($)	Jun. 30, 2015	Dec. 31, 2014
Statement of Financial Position [Abstract]
Series B redeemable convertible preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Series B redeemable convertible preferred stock, shares authorized	10,000,000	10,000,000
Series B redeemable convertible preferred stock, shares issued	8,290,353	8,671,040
Series B redeemable convertible preferred stock, shares outstanding	8,290,353	8,671,040
Series B redeemable convertible preferred stock liquidation preference	$ 14,053,000	$ 14,042,000
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	445,000,000	445,000,000
Common stock, shares issued	5,706,883	3,983,182