Supplemental equity information - Rights Agreement (Details) - USD ($) $ in Millions	Dec. 31, 2022	Apr. 06, 2020
Class of Stock
Operating loss carryforwards	$ 561.5
Rights agreement, percent of common stock owned required for exercise		4.99%
Rights agreement, additional percent of common stock owned required for exercise		0.50%
Exercise percent discount		50.00%
Preferred Stock
Class of Stock
Rights agreement, dividend declared (in shares)		1
Common stock
Class of Stock
Number of shares that may be exchanged per right (in shares)		1