CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Operating expenses:
Research and development	$ 47,362	$ 34,996	$ 151,993	$ 66,755
General and administrative	7,574	4,571	24,495	12,527
Total operating expenses	54,936	39,567	176,488	79,282
Loss from operations	(54,936)	(39,567)	(176,488)	(79,282)
Other income (expense):
Interest expense	(12)	(239)	(33)	(906)
Non-cash interest expense on liability related to sale of future royalties	(5,633)	0	(6,134)	0
Change in fair value of warrant liability	0	(2,426)	(1,182)	(5,509)
Change in fair value of derivative liability	0	0	0	512
Change in fair value of contingent equity liability	0	0	0	(13,082)
Loss from equity method investment	(697)	(638)	(2,066)	(1,204)
Other	(2)	10	4	10
Total other expense, net	(6,344)	(3,293)	(9,411)	(20,179)
Loss before provision for income taxes	(61,280)	(42,860)	(185,899)	(99,461)
Provision for income taxes	161	55	273	647
Net loss and comprehensive loss	(61,441)	(42,915)	(186,172)	(100,108)
Accretion of beneficial conversion feature on Series A preferred shares	0	0	0	(12,006)
Net loss attributable to common shareholders of Biohaven Pharmaceutical Holding Company Ltd.	$ (61,441)	$ (42,915)	$ (186,172)	$ (112,114)
Net loss per share attributable to common shareholders of Biohaven Pharmaceutical Holding Company Ltd. — basic and diluted (in dollars per share)	$ (1.53)	$ (1.19)	$ (4.82)	$ (4.47)
Weighted average common shares outstanding - basic and diluted (shares)	40,147,735	35,930,698	38,636,072	25,102,920