Convertible 4.5 Senior Notes (Details) - USD ($) $ in Thousands		3 Months Ended	12 Months Ended
	Jul. 01, 2021	Jun. 30, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Sep. 30, 2020	Dec. 31, 2017	Dec. 31, 2016
Convertible debt
Convertible debt paid in cash	$ 1,100		$ 1,100
Interest rate (as a percent)			4.50%	4.50%
Interest expense			$ 47	$ 95	$ 95
Convertible 4.5% Senior Notes
Convertible debt
Convertible Notes Payable						$ 2,100
Principal amount of debt								$ 100,000
Convertible debt outstanding		$ 1,000
Shares issued with debt conversion (in shares)		238,777
Convertible debt paid in cash		$ 1,100
Interest rate (as a percent)			4.50%	4.50%			4.50%
Interest expense			$ 100	$ 100	$ 100