Stockholders' Equity - Additional Information (Detail)					12 Months Ended
	May 05, 2020 USD ($) $ / shares shares	May 30, 2018 USD ($) $ / shares shares	Dec. 20, 2017 USD ($) $ / shares shares	Feb. 08, 2017 $ / shares shares	Dec. 31, 2020 $ / shares shares	Feb. 08, 2021 shares	Dec. 31, 2019 $ / shares shares
Stockholders Equity [Line Items]
Preferred stock, shares authorized					10,000,000
Preferred stock, par value | $ / shares					$ 0.001
Preferred stock, outstanding					0		0
VLL7 Warrant
Stockholders Equity [Line Items]
Warrants issued to purchase common stock				290,000
Warrant exercise price | $ / shares				$ 2.00
Warrants 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 | $ / shares				$ 2.00
Warrants expiration date				Feb. 08, 2022
Warrants or exercised received for common shares				193,494
EWB Warrant
Stockholders Equity [Line Items]
Warrants issued to purchase common stock				40,000
Warrant exercise price | $ / shares				$ 3.64	$ 3.50
Warrants or exercised received for common shares						27,599
Warrants and rights outstanding | $	$ 42,000
Legal and administrative cost | $	$ 92,000
EWB Warrant | Estimated Volatility
Stockholders Equity [Line Items]
Warrants measurement input	63.2
EWB Warrant | Risk Free Interest Rate
Stockholders Equity [Line Items]
Warrants measurement input	0.24
EWB Warrant | Dividend Yield
Stockholders Equity [Line Items]
Warrants measurement input	0
EWB Warrant | Expected Life
Stockholders Equity [Line Items]
Warrants outstanding term	3 years
April 21 Funds Warrants
Stockholders Equity [Line Items]
Warrants issued to purchase common stock	275,000
Warrant exercise price | $ / shares					3.50
Warrants outstanding term	3 years
Minimum | EWB Warrant
Stockholders Equity [Line Items]
Warrant exercise price | $ / shares				$ 3.64
Warrants expiration date	Feb. 08, 2022
Maximum | EWB Warrant
Stockholders Equity [Line Items]
Warrant exercise price | $ / shares	$ 3.50
Warrants expiration date	Feb. 08, 2023
Maximum | Common Stock
Stockholders Equity [Line Items]
Shares issued, price per share | $ / shares					$ 4.00
Series A Participating Preferred Stock
Stockholders Equity [Line Items]
Preferred stock, shares authorized					40,000
Preferred stock, par value | $ / shares					$ 0.001
Preferred stock, outstanding					0		0
Series B Preferred Stock
Stockholders Equity [Line Items]
Preferred stock, shares authorized					5,000,000
Preferred stock, par value | $ / shares					$ 0.001
Series B Convertible Preferred Stock
Stockholders Equity [Line Items]
Preferred stock, shares authorized					5,000,000		5,000,000
Preferred stock, par value | $ / shares			$ 0.001		$ 0.001		$ 0.001
Preferred stock, outstanding					5,000,000		5,000,000
Preferred stock, issued					5,000,000		5,000,000
Shares issued, price per share | $ / shares			$ 4.00
Total purchase price payable | $			$ 20,000,000
Convertible preferred stock, terms of conversion					Each Share shall be convertible into the Company’s common stock (i) following the sixth (6th) anniversary of the initial closing of the Private Placement or (ii) if earlier, during the thirty (30) day period following the last trading day of any period of three (3) or more consecutive trading days that the closing market price of the Company’s common stock exceeds $10.00. Each Share is convertible at the option of the holder of the Shares into such number of shares of the Company’s common stock
Convertible preferred stock, threshold closing market price of entity stock | $ / shares			$ 10.00
Percentage of beneficially ownership limitation in excess of outstanding common stock immediately after effect to applicable conversion			19.90%
Minimum conversion price | $ / shares					$ 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 | $ / shares					$ 4.00
Series B Convertible Preferred Stock | Common Stock
Stockholders Equity [Line Items]
Preferred stock shares convertible into common stock					5,742,188
Series B Convertible Preferred Stock | Private Placement at Initial Closing of Transaction
Stockholders Equity [Line Items]
Issuance of stock (in shares)			3,000,000
Shares issued, price per share | $ / shares			$ 4.00
Total purchase price payable | $			$ 12,000,000
Series B Convertible Preferred Stock | Private Placement at Second Closing of Transaction
Stockholders Equity [Line Items]
Issuance of stock (in shares)		2,000,000	2,000,000
Shares issued, price per share | $ / shares		$ 4.00	$ 4.00
Total purchase price payable | $		$ 8,000,000
Series B Convertible Preferred Stock | Maximum
Stockholders Equity [Line Items]
Preferred stock, issued			5,000,000