CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Operating expenses:
Research and development	$ 75,579	$ 10,740
General and administrative	7,857	3,757
Total operating expenses	83,436	14,497
Loss from operations	(83,436)	(14,497)
Other income (expense):
Interest expense	(8)	(305)
Change in fair value of warrant liability	(1,182)	(454)
Change in fair value of derivative liability		289
Change in fair value of contingent equity liability		(3,375)
Loss from equity method investment	(728)	(218)
Other	21
Total other income (expense), net	(1,939)	(4,063)
Loss before provision for income taxes	(85,375)	(18,560)
Provision for income taxes	87	193
Net loss and comprehensive loss	(85,462)	(18,753)
Accretion of beneficial conversion feature on Series A preferred shares		(4,000)
Net loss attributable to common shareholders of Biohaven Pharmaceutical Holding Company Ltd.	$ (85,462)	$ (22,753)
Net loss per share attributable to common shareholders of Biohaven Pharmaceutical Holding Company Ltd. - basic and diluted	$ (2.32)	$ (1.74)
Weighted average common shares outstanding-basic and diluted	36,793,090	13,088,861