Quarterly report pursuant to Section 13 or 15(d)

Subsequent Events - Additional Information (Detail)

v3.19.3
Subsequent Events - Additional Information (Detail) - USD ($)
1 Months Ended 9 Months Ended
Oct. 11, 2019
Mar. 31, 2019
Jan. 31, 2018
Sep. 30, 2019
Sep. 30, 2018
Subsequent Event [Line Items]          
Proceeds of securities offerings   $ 23,319,156 $ 38,846,815 $ 23,319,156 $ 38,846,815
Subsequent Event [Member] | At-the-Market [Member] | Maximum [Member]          
Subsequent Event [Line Items]          
Proceeds of securities offerings $ 20,000,000