Organization and Summary of Significant Accounting Policies - Other Operating Costs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Other Operating Costs
Marketing costs, including advertising	$ 1.9	$ 3.8	$ 3.8
Grant Proceeds Under Cares Act	$ 24.0