Significant Accounting Policies (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Nov. 30, 2022	Nov. 16, 2022	Oct. 28, 2021	Apr. 30, 2020
Significant Accounting Policies
Impairment of long-lived assets	$ 0	$ 0
Impairment of in-process research and development	0
Unrecognized tax benefits	$ 0	$ 0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01			$ 0.01
Common stock, shares authorized	217,000,000	217,000,000
Lease liability	$ 48,815,000			$ 37,000,000.0		$ 11,700,000
Right-of-use asset	43,035,000	$ 35,852,000		$ 33,800,000		$ 11,000,000.0
Accumulated deficit	(239,774,000)	(202,857,000)
Goodwill, Impairment Loss	$ 0	$ 0
Estimated incremental borrowing rate (as a percent)			11.80%			12.89%