Segment Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2024 USD ($) segment	Dec. 31, 2023 USD ($)
Segment Information
Number of reportable segments | segment	2
Accumulated deficit	$ 902,861	$ 770,796
Total revenue	18,720	31,249
Cost of revenue	2,792	3,423
Total research and development	33,586	98,384
General and administrative	22,203	32,412
Licensing	12,666	14,658
Revaluation of contingent consideration	2,500	(26,900)
In-process research and development	86,905	6,629
Segment operating loss	(141,932)	(97,357)
Other income	9,867	8,509
Net Income (Loss)	(132,065)	(88,481)
Loss before income taxes	(132,065)	(88,848)
Operating Segments | Therapeutics Segment
Segment Information
Total revenue	16,179	28,214
Research and development project spend	17,974	67,614
Personnel	11,446	18,977
Other research and development expense	5,025	12,799
Total research and development	34,445	99,390
Licensing	12,666	14,658
Revaluation of contingent consideration	2,500	(26,900)
In-process research and development	86,905	6,629
Segment operating loss	(120,337)	(65,563)
Operating Segments | Contract Research Segment
Segment Information
Total revenue	2,541	3,035
Cost of revenue	15,349	18,960
General and administrative	4,035	4,561
Segment operating loss	(3,427)	(3,943)
Operating Segments | Bosakitug | Therapeutics Segment
Segment Information
Research and development project spend	299
Operating Segments | ATI-2138 | Therapeutics Segment
Segment Information
Research and development project spend	4,209	12,143
Operating Segments | ATI-052 | Therapeutics Segment
Segment Information
Research and development project spend	1,895
Operating Segments | Lepzacitinib | Therapeutics Segment
Segment Information
Research and development project spend	1,300	12,129
Operating Segments | Zunsemetinib | Therapeutics Segment
Segment Information
Research and development project spend	4,496	36,461
Operating Segments | Discovery | Therapeutics Segment
Segment Information
Research and development project spend	5,775	6,881
Intersegment Eliminations
Segment Information
Total revenue	(13,416)	(16,543)
Cost of revenue	(12,557)	(15,537)
Total research and development	(859)	(1,006)
Intersegment Eliminations | Contract Research Segment
Segment Information
Total revenue	13,416	16,543
Total
Segment Information
Total revenue	18,720	31,249
Cost of revenue	2,792	3,423
Research and development project spend	17,974	67,614
Personnel	11,446	18,977
Other research and development expense	5,025	12,799
Total research and development	33,586	98,384
General and administrative	4,035	4,561
Licensing	12,666	14,658
Revaluation of contingent consideration	2,500	(26,900)
In-process research and development	86,905	6,629
Segment operating loss	(123,764)	(69,506)
Total | Bosakitug
Segment Information
Research and development project spend	299
Total | ATI-2138
Segment Information
Research and development project spend	4,209	12,143
Total | ATI-052
Segment Information
Research and development project spend	1,895
Total | Lepzacitinib
Segment Information
Research and development project spend	1,300	12,129
Total | Zunsemetinib
Segment Information
Research and development project spend	4,496	36,461
Total | Discovery
Segment Information
Research and development project spend	5,775	6,881
Reconciliation of segment
Segment Information
General and administrative	18,168	27,851
Other income	$ 9,867	$ 8,509