Stockholders' Equity And Stock-Based Compensation (Summary Of Time-Based Stock Option Activity) (Details) - Time-Based Options [Member] - 2015, 2017 And Inducement Plans [Member] - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Beginning Balance, Number of shares	4,055,352
Options granted, Number of shares	1,023,333
Options exercised, Number of shares	(53,731)
Options canceled, Number of shares	(162,975)
Options expired/Redeemed, Number of shares	(65,263)
Ending Balance, Number of shares	4,796,716	4,055,352
Exercisable, Number of shares	3,018,902
Beginning Balance, Weighted average exercise price per share	$ 15.04
Options granted, Weighted average exercise price per share	22.04
Options exercised, Weighted average exercise price per share	11.47
Options canceled, Weighted average exercise price per share	16.94
Options expired, Weighted average exercise price per share	19.92
Ending Balance, Weighted average exercise price per share	16.44	$ 15.04
Exercisable, Weighted average exercise price per share	$ 16.38
Weighted average remaining life	7 years 18 days	6 years 4 months 13 days
Weighted average remaining life, exercisable	6 years 18 days