Net Loss Per Share - Calculation of Basic and Diluted Net Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
	Oct. 02, 2022	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Numerator:
Net loss		$ (408,168)	$ (570,279)	$ (213,796)
Denominator:
Weighted average common shares outstanding—basic	39,375,944	71,200,527	44,741,316	39,375,944
Weighted average common shares outstanding—diluted		71,200,527	44,741,316	39,375,944
Net loss per share attributable to Biohaven Pharmaceutical Holding Company Ltd.—basic (in dollars per share)		$ (5.73)	$ (12.75)	$ (5.43)
Net loss per share attributable to Biohaven Pharmaceutical Holding Company Ltd.—diluted (in dollars per share)		$ (5.73)	$ (12.75)	$ (5.43)