Income Tax Matters - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Tax Credit Carryforward [Line Items]
Net operating loss	$ 94,600,000
Operating loss expiration period	Dec. 31, 2030
Increase (decrease) in valuation allowance	$ (3,500,000)	$ 1,500,000	$ (4,600,000)
Unrecognized tax benefits	3,800,000	4,100,000	1,500,000	$ 1,500,000
Amount that would be reflected in income tax provision if unrecognized tax benefits are recognized	1,500,000
Accrued interest and penalties on unrecognized tax benefits	300,000	300,000
Accrued interest and penalties on unrecognized tax benefits, current	0	0
(Decrease) increase in interest and penalty		$ 100,000	$ 100,000
Research Tax Credit Carryforward
Tax Credit Carryforward [Line Items]
Tax credit carryforward	$ 8,100,000
Tax credit carryforward expiration period	Dec. 31, 2040