Segment Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Segment Reporting Information [Line Items]
Other income (expense), net	$ 39,424	$ 26,500	$ (1,909)
Provision (benefit) for income taxes	735	(1,383)	438
Net loss	846,422	408,168	570,279
Segment Reporting, Reconciling Item, Excluding Corporate Nonsegment
Segment Reporting Information [Line Items]
Net loss	0	0	0
Reportable Segment | Operating Segments
Segment Reporting Information [Line Items]
Preclinical research programs R&D Expense	57,181	35,911	18,116
R&D personnel expense (excluding share-based compensation)	73,644	60,058	53,743
R&D Share-based compensation expense	42,594	15,985	116,379
R&D Knopp amendment expense	171,850	0	0
G&A personnel expense (excluding share-based compensation)	24,894	21,087	20,164
G&A Share-based compensation expense	29,369	12,802	77,177
Other segment items	60,167	45,161	45,367
Other income (expense), net	(39,424)	(26,500)	1,909
Provision (benefit) for income taxes	735	(1,383)	438
Net loss	846,422	408,168	570,279
BHV-4157 (Troriluzole) | Reportable Segment | Operating Segments
Segment Reporting Information [Line Items]
Total R&D Program Expense	63,983	73,080	58,769
BHV-2000 (Taldefgrobep Alfa) | Reportable Segment | Operating Segments
Segment Reporting Information [Line Items]
Total R&D Program Expense	59,710	40,870	16,799
BHV-7000 & BHV-7010 (Kv7) | Reportable Segment | Operating Segments
Segment Reporting Information [Line Items]
Total R&D Program Expense	136,422	47,327	131,956
BHV-2100 (TRPM3 Antagonist) | Reportable Segment | Operating Segments
Segment Reporting Information [Line Items]
Total R&D Program Expense	29,044	12,865	8,255
BHV-8000 (TYK2/JAK1) | Reportable Segment | Operating Segments
Segment Reporting Information [Line Items]
Total R&D Program Expense	12,697	39,025	0
BHV-1300 (IgG Degrader) | Reportable Segment | Operating Segments
Segment Reporting Information [Line Items]
Total R&D Program Expense	30,078	22,239	0
BHV-1310 (IgG Degrader) | Reportable Segment | Operating Segments
Segment Reporting Information [Line Items]
Total R&D Program Expense	13,341	1,962	0
BHV-1400 (IgA Degrader) | Reportable Segment | Operating Segments
Segment Reporting Information [Line Items]
Total R&D Program Expense	19,572	1,810	0
BHV-1600 (β1-AR AAB Degrader) | Reportable Segment | Operating Segments
Segment Reporting Information [Line Items]
Total R&D Program Expense	14,650	254	0
BHV-1510 (Trop2) | Reportable Segment | Operating Segments
Segment Reporting Information [Line Items]
Total R&D Program Expense	28,540	0	0
BHV-1530 (FGFR3) | Reportable Segment | Operating Segments
Segment Reporting Information [Line Items]
Total R&D Program Expense	14,554	0	0
Other R&D program expense | Reportable Segment | Operating Segments
Segment Reporting Information [Line Items]
Total R&D Program Expense	$ 2,821	$ 5,615	$ 21,207