Selected Quarterly Financial Data (Unaudited) - Summary of Interim Financial Information on Quarterly Basis (Detail) - 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 |
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Quarterly Financial Information Disclosure [Abstract] | |||||||||||
Net Operating Loss | $ (17,568,845) | $ (11,589,319) | $ (12,394,490) | $ (9,214,375) | $ (6,247,048) | $ (7,234,204) | $ (7,572,638) | $ (6,228,452) | $ (50,767,029) | $ (27,282,342) | $ (46,573,093) |
Net loss | $ (18,255,896) | $ (11,573,273) | $ (12,126,152) | $ (9,050,773) | $ (6,620,102) | $ (7,210,591) | $ (7,294,245) | $ (5,999,699) | $ (51,006,094) | $ (27,124,637) | $ (46,515,956) |
Net loss per common share, basic and diluted | $ (3.68) | $ (1.37) | $ (0.67) | $ (0.50) | $ (3.22) | $ (0.86) | $ (0.41) | $ (0.33) | $ (3.68) | $ (3.22) | $ (8.03) |