Summary of Significant Accounting Policies - Schedule of Assets Measured on Recurring Basis (Detail) - Fair Value, Measurements, Recurring [Member] - USD ($) |
Jun. 30, 2019 |
Dec. 31, 2018 |
|---|---|---|
| Assets: | ||
| Cash and cash equivalents | $ 48,157,010 | $ 62,614,010 |
| Total assets | 48,157,010 | 62,614,010 |
| Level 1 [Member] | ||
| Assets: | ||
| Cash and cash equivalents | 48,157,010 | 62,614,010 |
| Total assets | $ 48,157,010 | $ 62,614,010 |