Intangible Assets - Schedule of Changes in Carrying Amounts of IPR&D Assets (Detail) - USD ($) |
3 Months Ended | 9 Months Ended |
---|---|---|
Sep. 30, 2018 |
Sep. 30, 2018 |
|
Indefinite-lived Intangible Assets [Line Items] | ||
IPR&D, Foreign currency translation adjustments | $ 0 | |
IPR&D [Member] | ||
Indefinite-lived Intangible Assets [Line Items] | ||
IPR&D Balance, beginning of period | $ 38,245,871 | |
IPR&D, Foreign currency translation adjustments | (376,894) | |
IPR&D Balance, end of period | $ 37,868,977 | $ 37,868,977 |