Equity Offerings - Additional Information (Detail) - USD ($)	Mar. 10, 2020	Feb. 10, 2020	Aug. 12, 2019	Mar. 31, 2020	Dec. 31, 2019	Apr. 28, 2017
Stockholders Equity Common Stock [Line Items]
Offering price (in dollars per share)	$ 0.68					$ 1.00
Preferred stock, par value (in dollars per share)	$ 0.01			$ 0.01	$ 0.01
Net proceeds after issuance costs	$ 13,500,000
2019 ATM Offering
Stockholders Equity Common Stock [Line Items]
Sale of common stock in an at-the-market offering			$ 25,000,000.0
Percentage of commission paid			3.00%
Purchase Agreement
Stockholders Equity Common Stock [Line Items]
Sale of common stock in an at-the-market offering		$ 25,000,000
Stocked issued in the period (in shares)		343,171
Number of awards authorized for grant (in shares)		171,585
Series C Warrants
Stockholders Equity Common Stock [Line Items]
Stocked issued in the period (in shares)	3,308,823
Series D Warrants
Stockholders Equity Common Stock [Line Items]
Stocked issued in the period (in shares)	3,308,823
Common Class A
Stockholders Equity Common Stock [Line Items]
Stocked issued in the period (in shares)	14,121,766
Offering price (in dollars per share)	$ 0.68
Common Class B
Stockholders Equity Common Stock [Line Items]
Stocked issued in the period (in shares)	7,937,057
Offering price (in dollars per share)	$ 0.68