Annual report pursuant to Section 13 and 15(d)

Significant Accounting Policies - Computation of Basic and Diluted Earnings Per Share (Details)

v3.8.0.1
Significant Accounting Policies - Computation of Basic and Diluted Earnings Per Share (Details) - USD ($)
3 Months Ended 12 Months Ended
Dec. 31, 2017
Sep. 30, 2017
Jun. 30, 2017
Mar. 31, 2017
Dec. 31, 2016
Sep. 30, 2016
Jun. 30, 2016
Mar. 31, 2016
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Earnings Per Share [Abstract]                      
Net loss $ (10,693,690) $ (6,965,596) $ (7,296,887) $ (7,465,439) $ (7,570,275) $ (5,346,768) $ (4,189,391) $ (2,892,241) $ (32,421,612) $ (19,998,675) $ (8,850,739)
Weighted average shares of common stock outstanding 53,828,680 50,221,597 50,193,726 46,381,482 44,348,543 43,783,504 38,748,452 37,605,210 50,176,953 41,137,518 31,350,145
Net loss per share of common stock-basic and diluted $ (0.20) $ (0.14) $ (0.15) $ (0.16) $ (0.17) $ (0.12) $ (0.11) $ (0.08) $ (0.65) $ (0.49) $ (0.28)