Stockholders' Equity - Common Stock - Additional Information (Detail) - USD ($)	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019	Nov. 30, 2017
Options Granted [Line Items]
Common stock, shares issued	26,011,263		24,431,914
Proceeds from issuance of common stock, net	$ 3,330,366	$ 5,676,388
Warrants converted to purchase of common stock	393,084
Issuance of common stock from warrant exercise	158,494
Options Granted [Member]
Options Granted [Line Items]
Number of stock options granted	1,172,000
Options Granted [Member] | Gimoti [Member]
Options Granted [Line Items]
Number of stock options not begin vesting	437,500
Maximum [Member]
Options Granted [Line Items]
Weighted average exercise price of warrants	$ 3.12
Minimum [Member]
Options Granted [Line Items]
Weighted average exercise price of warrants	$ 2.41
FBR Sales Agreement [Member]
Options Granted [Line Items]
Common stock, shares issued	1,395,855	6,686,423
Common stock, weighted average price per share	$ 2.42	$ 0.87
Proceeds from issuance of common stock, net	$ 3,300,000	$ 5,700,000
FBR Sales Agreement [Member] | Maximum [Member]
Options Granted [Line Items]
Common stock, value of shares issuable				$ 16,000,000