Stockholders' Equity - Additional Information (Detail) - $ / shares			9 Months Ended
	May 05, 2020	Feb. 08, 2017	Sep. 30, 2020
EWB Warrant
Stockholders Equity [Line Items]
Warrants issued to purchase common stock		40,000
Warrant exercise price		$ 3.64	$ 3.50
Warrant expiration date		Feb. 08, 2022
VLL7 Warrant
Stockholders Equity [Line Items]
Warrants issued to purchase common stock		290,000
Warrant exercise price		$ 2.00
Warrant expiration date		Feb. 08, 2022
Warrants or exercised received for common shares		193,494
VLL8 Warrant
Stockholders Equity [Line Items]
Warrants issued to purchase common stock		290,000
Warrant exercise price		$ 2.00
Warrant expiration date		Feb. 08, 2022
April 21 Funds Warrants
Stockholders Equity [Line Items]
Warrants issued to purchase common stock	275,000,000
Warrant exercise price			3.50
Warrants, term	3 years
Series B convertible preferred stock
Stockholders Equity [Line Items]
Minimum conversion price			$ 3.27
Dividend payment terms			Each share of Series B convertible preferred stock is entitled to a cumulative annual dividend of 5% for the first six (6) years following the issuance of such share and 3% for each year thereafter, with the Company retaining the option to settle each year’s dividend after the tenth (10th) year in cash. The dividends accrue and are payable in kind upon such time as the shares convert into the Company’s common stock
Cumulative annual dividend for first six years			5.00%
Cumulative annual dividend for each year after sixth year			3.00%
Price per share distributable to stockholders			$ 4.00
Series B convertible preferred stock | Common Stock
Stockholders Equity [Line Items]
Preferred stock shares convertible into common stock			5,673,281
Maximum | EWB Warrant
Stockholders Equity [Line Items]
Warrant exercise price	$ 3.50
Warrant expiration date	Feb. 08, 2023
Maximum | Common Stock
Stockholders Equity [Line Items]
Shares issued, price per share			$ 4.00
Minimum | EWB Warrant
Stockholders Equity [Line Items]
Warrant exercise price		$ 3.64
Warrant expiration date	Feb. 08, 2022