Net Loss per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Numerator:
Net Loss	$ (18,753)	$ (2,986)
Net loss attributable to non-controlling interests		35
Accretion of beneficial conversion feature on series A preferred shares	(4,000)
Net loss attributable to common shareholders of Biohaven Pharmaceutical Holding Company Ltd.	$ (22,753)	$ (2,951)
Denominator:
Weighted average common shares outstanding-basic and diluted	13,088,861	11,776,429
Net loss per share attributable to common share holders of Biohaven Pharmaceutical Holding Company Ltd.-basic and diluted	$ (1.74)	$ (0.25)