Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Income Tax Disclosure [Line Items]
Income tax expense (benefit)	$ 9	$ 6	$ 25	$ 23
Statutory rate			21.00%	21.00%
Net deferred tax assets	13,500		$ 13,500		$ 13,500
Operating loss and credit carry forward, expiration period			The Company’s federal NOLs generated in 2019 and 2018 have an infinite life, and the Company’s NOLs and credits generated as of December 31, 2017 have a finite life primarily based on the 20-year carry forward of federal net operating losses.
Net operating loss carry forward period			20 years
Domestic deferred tax assets ratable reversal pattern period			12 years
Deferred tax assets, valuation allowance	13,500		$ 13,500		$ 13,500
Cumulative terms of US book income turned to loss					3 years
Gross unrecognized tax benefit	800		800		$ 800
Deferred payroll taxes	300		300
Domestic Tax Authority [Member]
Income Tax Disclosure [Line Items]
Net deferred tax assets	13,000		13,000		13,000
Foreign [Member]
Income Tax Disclosure [Line Items]
Net deferred tax assets	$ 500		$ 500		$ 500