Schedule II Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Allowance for doubtful accounts and returns
Changes in Valuation and Qualifying Accounts
Balance at Beginning of Period		$ 818
Charged to Costs and Expenses			$ 818
Deductions		818
Balance at End of Period			818
Deferred tax valuation allowance
Changes in Valuation and Qualifying Accounts
Balance at Beginning of Period	$ 9,133	8,327	6,835
Charged to Costs and Expenses	780	806	1,492
Deductions	2,224
Balance at End of Period	$ 7,689	$ 9,133	$ 8,327