CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Income Statement [Abstract]
Product revenue, net	$ 43,823	$ 1,151
Cost of goods sold	12,862	424
Gross profit	30,961	727
Operating expenses:
Research and development expense	107,111	56,070
Selling, general and administrative	159,523	95,601
Total operating expenses	266,634	151,671
Loss from operations	(235,673)	(150,944)
Other income (expense):
Interest expense	(7,731)	(56)
Interest expense on mandatorily redeemable preferred shares	(7,943)	(5,561)
Interest expense on liability related to sale of future royalties	(13,508)	(8,425)
Change in fair value of derivatives	(210)	(5,781)
Gain (loss) from equity method investment	5,261	(1,380)
Other expense, net	(1,700)	(96)
Total other income (expense), net	(25,831)	(21,299)
Loss before provision for income taxes	(261,504)	(172,243)
Provision for income taxes	3,824	694
Net loss	(265,328)	(172,937)
Less: Net loss attributable to non-controlling interests	(360)	0
Net loss attributable to Biohaven Pharmaceutical Holding Company Ltd.	$ (264,968)	$ (172,937)
Net loss per share attributable to Biohaven Pharmaceutical Holding Company Ltd - basic (in dollars per share)	$ (4.27)	$ (3.07)
Net loss per share attributable to Biohaven Pharmaceutical Holding Company Ltd - diluted (in dollars per share)	$ (4.27)	$ (3.07)
Weighted average common shares outstanding - basic (shares)	62,040,715	56,412,439
Weighted average common shares outstanding - diluted (shares)	62,040,715	56,412,439
Comprehensive loss:
Net loss	$ (265,328)	$ (172,937)
Other comprehensive income, net of tax	95	0
Comprehensive loss	(265,233)	(172,937)
Less: comprehensive loss attributable to non-controlling interests	(360)	0
Comprehensive loss attributable to Biohaven Pharmaceutical Holding Company Ltd.	$ (264,873)	$ (172,937)
Product revenue, type	us-gaap:ProductMember	us-gaap:ProductMember
Cost of goods sold, type	us-gaap:ProductMember	us-gaap:ProductMember