CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Operating expenses:
Research and development	$ 29,052	$ 21,019	$ 104,631	$ 31,759
General and administrative	9,064	4,199	16,921	7,956
Total operating expenses	38,116	25,218	121,552	39,715
Loss from operations	(38,116)	(25,218)	(121,552)	(39,715)
Other income (expense):
Interest expense	(13)	(362)	(21)	(667)
Non-cash interest expense on liability related to sale of future royalties	(501)	0	(501)	0
Change in fair value of warrant liability	0	(2,629)	(1,182)	(3,083)
Change in fair value of derivative liability	0	223	0	512
Change in fair value of contingent equity liability	0	(9,707)	0	(13,082)
Loss from equity method investment	(641)	(348)	(1,369)	(566)
Other	27	0	6	0
Total other income (expense), net	(1,128)	(12,823)	(3,067)	(16,886)
Loss before provision for income taxes	(39,244)	(38,041)	(124,619)	(56,601)
Provision for income taxes	25	399	112	592
Net loss and comprehensive loss	(39,269)	(38,440)	(124,731)	(57,193)
Accretion of beneficial conversion feature on Series A preferred shares	0	(8,006)	0	(12,006)
Net loss attributable to common shareholders of Biohaven Pharmaceutical Holding Company Ltd.	$ (39,269)	$ (46,446)	$ (124,731)	$ (69,199)
Net loss per share attributable to common shareholders of Biohaven Pharmaceutical Holding Company Ltd. — basic and diluted (in dollars per share)	$ (1.01)	$ (1.78)	$ (3.29)	$ (3.54)
Weighted average common shares outstanding - basic and diluted (in shares)	38,942,545	26,038,192	37,873,755	19,563,525