Shareholders' Deficit - Changes in Shareholders' Deficit (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2022	Jun. 30, 2021
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	$ (466,413)	$ (743,009)	$ (278,155)	$ (392,189)	$ (743,009)	$ (392,189)
Repurchase of preferred shares in consolidated subsidiary		60,000
Issuance of common shares, net of offering costs				308,243
Issuance of common shares as part of acquisition	58,747			10,673
Issuance of common shares under equity incentive plan and employee share purchase plan	7,139
Issuance of common shares as payment for agreements		253,779		10,243
Issuance of common shares under equity incentive plan		(751)	7,261	1,382
Non-cash share-based compensation expense	40,267	82,790	25,586	48,726
Net loss	(441,885)	(116,897)	(211,159)	(265,328)	(558,782)	(476,487)
Other comprehensive income (loss)	(3,413)	(2,325)	(129)	95	(5,738)	(34)
Ending balance	(805,558)	(466,413)	(456,596)	(278,155)	(805,558)	(456,596)
Biohaven Shareholders' Equity (Deficit)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(462,286)	(739,380)	(275,976)	(390,370)	(739,380)	(390,370)
Repurchase of preferred shares in consolidated subsidiary		60,000
Issuance of common shares, net of offering costs				308,243
Issuance of common shares as part of acquisition	58,747			10,673
Issuance of common shares under equity incentive plan and employee share purchase plan	7,139
Issuance of common shares as payment for agreements		253,779		10,243
Issuance of common shares under equity incentive plan		(751)	7,261	1,382
Non-cash share-based compensation expense	40,267	82,790	25,586	48,726
Net loss	(441,387)	(116,399)	(210,619)	(264,968)
Other comprehensive income (loss)	(3,413)	(2,325)	(129)	95
Ending balance	$ (800,933)	$ (462,286)	$ (453,877)	$ (275,976)	$ (800,933)	$ (453,877)
Common Shares
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance (in shares)	70,540,802	66,933,531	65,066,468	60,436,876	66,933,531	60,436,876
Beginning balance	$ 2,112,686	$ 1,676,792	$ 1,604,021	$ 1,249,547	$ 1,676,792	$ 1,249,547
Repurchase of preferred shares in consolidated subsidiary (in shares)		1,232,629
Repurchase of preferred shares in consolidated subsidiary		$ 152,673
Issuance of common shares, net of offering costs (in shares)				4,037,204
Issuance of common shares, net of offering costs				$ 308,243
Issuance of common shares as part of acquisition (in shares)	493,254			115,836
Issuance of common shares as part of acquisition	$ 58,747			$ 10,673
Issuance of common shares under equity incentive plan and employee share purchase plan (in shares)	77,015
Issuance of common shares under equity incentive plan and employee share purchase plan	$ 9,965
Issuance of common shares as payment for assets (in shares)		2,037,921		110,998
Issuance of common shares as payment for agreements		$ 253,779		$ 10,243
Issuance of common shares under equity incentive plan (shares)		336,721	173,990	365,554
Issuance of common shares under equity incentive plan		$ 29,442	$ 14,173	$ 25,315
Ending balance (in shares)	71,111,071	70,540,802	65,240,458	65,066,468	71,111,071	65,240,458
Ending balance	$ 2,181,398	$ 2,112,686	$ 1,618,194	$ 1,604,021	$ 2,181,398	$ 1,618,194
Additional Paid-in Capital
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	129,580	169,656	123,731	98,938	169,656	98,938
Repurchase of preferred shares in consolidated subsidiary		(92,673)
Issuance of common shares under equity incentive plan and employee share purchase plan	(2,826)
Issuance of common shares under equity incentive plan		(30,193)	(6,912)	(23,933)
Non-cash share-based compensation expense	40,267	82,790	25,586	48,726
Ending balance	167,021	129,580	142,405	123,731	167,021	142,405
Accumulated Deficit
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(2,702,154)	(2,585,755)	(2,004,137)	(1,739,169)	(2,585,755)	(1,739,169)
Net loss	(441,387)	(116,399)	(210,619)	(264,968)
Ending balance	(3,143,541)	(2,702,154)	(2,214,756)	(2,004,137)	(3,143,541)	(2,214,756)
Accumulated Other Comprehensive Income
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(2,398)	(73)	409	314	(73)	314
Other comprehensive income (loss)	(3,413)	(2,325)	(129)	95
Ending balance	(5,811)	(2,398)	280	409	(5,811)	280
Non-controlling Interests
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(4,127)	(3,629)	(2,179)	(1,819)	(3,629)	(1,819)
Net loss	(498)	(498)	(540)	(360)
Ending balance	$ (4,625)	$ (4,127)	$ (2,719)	$ (2,179)	$ (4,625)	$ (2,719)