Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Income Taxes [Line Items]
Current state and local tax benefits	$ 21,000	$ 18,000
Current research tax credit receivable	21,000	18,000
Deferred tax assets, valuation allowance	52,696,000	42,829,000
Increase (decrease) in deferred tax assets valuation allowance	9,900,000	9,500,000
Unrecognized tax benefits or related interest and penalties accrued	0	0
Federal and State [Member]
Income Taxes [Line Items]
Net operating loss carryforwards	32,100,000	30,800,000
Operating loss carryforwards	$ 169,700,000	137,600,000
Net operating loss Carryforwards, limitations on use	Due to the Series A preferred stock financing in December 2012 and the shares issued in connection with the Company’s IPO in May 2019, the Company was subject to an “ownership change” under the Code Section 382.  As a result, the Company’s ability to utilize approximately $91.3 million of its NOL carryforwards and approximately $3.0 million of research tax credits is limited.
Limitations on use operating loss carryforwards	$ 91,300,000
Percentage of taxable income offset by operating loss carryforwards	80.00%
Federal and State [Member] | Earliest Tax Year [Member]
Income Taxes [Line Items]
Operating loss carryforwards expiration year	2031
Income tax examination year under examination	2011
Federal and State [Member] | Latest Tax Year [Member]
Income Taxes [Line Items]
Operating loss carryforwards expiration year	2037
Income tax examination year under examination	2020
Federal [Member]
Income Taxes [Line Items]
R&D tax credits	$ 702,000	671,000
Limitations on use tax credits research	3,000,000.0
Federal [Member] | R&D [Member]
Income Taxes [Line Items]
Tax credits carryforwards	$ 4,600,000	3,900,000
Federal [Member] | Earliest Tax Year [Member]
Income Taxes [Line Items]
Tax credit carryforwards expiration year	2032
Federal [Member] | Latest Tax Year [Member]
Income Taxes [Line Items]
Tax credit carryforwards expiration year	2041
State [Member]
Income Taxes [Line Items]
R&D tax credits	$ 149,000	$ 133,000