Summary of Significant Accounting Principles - Adjustment (Details) - USD ($) |
3 Months Ended | 6 Months Ended | ||||||
|---|---|---|---|---|---|---|---|---|
Jun. 30, 2019 |
Jun. 30, 2018 |
Jun. 30, 2019 |
Jun. 30, 2018 |
Mar. 31, 2019 |
Dec. 31, 2018 |
Mar. 31, 2018 |
Dec. 31, 2017 |
|
| New Accounting Pronouncements or Change in Accounting Principle [Line Items] | ||||||||
| Warrant liability | $ 15,876,415 | $ 15,876,415 | $ 1,822,819 | |||||
| Additional paid-in capital | 140,527,364 | 140,527,364 | 126,076,782 | |||||
| Accumulated deficit | (167,968,075) | (167,968,075) | (141,557,496) | |||||
| Total shareholders' deficit | (27,374,629) | $ (5,155,869) | (27,374,629) | $ (5,155,869) | $ (17,995,810) | $ (15,422,443) | $ (1,559,334) | $ 3,511,564 |
| Interest expense, net | 15,922,763 | 526,162 | 17,700,346 | 1,052,049 | ||||
| Net loss | (20,060,200) | (6,909,297) | (26,324,372) | (13,327,103) | ||||
| Net loss attributable to common stockholders | $ (20,146,407) | $ (7,674,476) | $ (26,410,579) | $ (14,092,282) | ||||
| Basic and diluted earnings per share (in usd per share) | $ (0.33) | $ (0.18) | $ (0.44) | $ (0.33) | ||||
| Change in fair value of warrants | $ 14,910,668 | $ 0 | ||||||
| Previously Reported | ||||||||
| New Accounting Pronouncements or Change in Accounting Principle [Line Items] | ||||||||
| Warrant liability | $ 33,529,599 | 33,529,599 | ||||||
| Additional paid-in capital | 139,670,292 | 139,670,292 | ||||||
| Accumulated deficit | (184,764,188) | (184,764,188) | ||||||
| Total shareholders' deficit | (45,027,814) | (45,027,814) | ||||||
| Interest expense, net | 32,718,876 | 34,496,459 | ||||||
| Net loss | (36,856,313) | (43,120,485) | ||||||
| Net loss attributable to common stockholders | $ (36,942,520) | $ (43,206,692) | ||||||
| Basic and diluted earnings per share (in usd per share) | $ (0.61) | $ (0.71) | ||||||
| Change in fair value of warrants | $ 31,706,780 | |||||||
| Restatement Adjustment | ||||||||
| New Accounting Pronouncements or Change in Accounting Principle [Line Items] | ||||||||
| Warrant liability | $ (17,653,184) | (17,653,184) | ||||||
| Additional paid-in capital | 857,072 | 857,072 | ||||||
| Accumulated deficit | 16,796,113 | 16,796,113 | ||||||
| Total shareholders' deficit | 17,653,185 | 17,653,185 | ||||||
| Interest expense, net | (16,796,113) | (16,796,113) | ||||||
| Net loss | 16,796,113 | 16,796,113 | ||||||
| Net loss attributable to common stockholders | $ 16,796,113 | $ 16,796,113 | ||||||
| Basic and diluted earnings per share (in usd per share) | $ 0.28 | $ 0.28 | ||||||
| Change in fair value of warrants | $ (16,796,112) | |||||||