Consolidated Balance Sheets (Parenthetical) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Stockholders' equity:
Series A Preferred stock, par value	$ 0.01	$ 0.01
Series A Preferred stock, authorized shares	10,000,000	10,000,000
Series A Preferred stock, issued shares	0	0
Series A Preferred stock, outstanding shares	0	0
Series B Preferred stock, par value	$ 0.01	$ 0.01
Series B Preferred stock, authorized shares	10,000,000	10,000,000
Series B Preferred stock, issued shares	750,000	750,000
Series B Preferred stock, outstanding shares	750,000	750,000
Series B liquidation preference	$ 930,000	$ 922,500
Series C Preferred stock, par value	$ 0.01	$ 0.01
Series C Preferred stock, authorized shares	10,000,000	10,000,000
Series C Preferred stock, issued shares	177,904	177,904
Series C Preferred stock, outstanding shares	177,904	177,904
Series C liquidation preference	$ 97,847	$ 97,847
Series D Preferred stock, par value	$ 0.01	$ 0.01
Series D Preferred stock, authorized shares	10,000,000	10,000,000
Series D Preferred stock, issued shares	1,751,005	1,751,005
Series D Preferred stock, outstanding shares	1,751,005	1,751,005
Series D liquidation preference	$ 5,002,470	$ 4,961,324
Common stock, par value	$ 0.01	$ 0.01
Common stock, authorized shares	90,000,000	90,000,000
Common stock, issued shares	68,227,171	67,488,153
Common stock, outstanding shares	68,227,171	67,488,153