Stockholders' Equity And Stock-Based Compensation (Summary Of Stock-Based Compensation Expense By Type) (Details) - USD ($)	1 Months Ended	3 Months Ended			9 Months Ended
	Feb. 28, 2021	Sep. 30, 2022	Sep. 30, 2021	Mar. 31, 2021	Sep. 30, 2022	Sep. 30, 2021
Total stock-based compensation expense		$ 723,000	$ 1,577,000		$ 4,443,000	$ 10,990,000
Time-Based Options [Member]
Total stock-based compensation expense		562,000	2,072,000		3,814,000	5,758,000
Performance Options [Member]
Total stock-based compensation expense	$ 0	18,000	(625,000)	$ 4,200,000	233,000	4,903,000
ESPP [Member]
Total stock-based compensation expense		$ 143,000	$ 130,000		$ 396,000	$ 329,000