Shareholders' Deficit - Changes in Shareholders' Deficit (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	$ (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		10,673
Issuance of common shares as payment for assets	253,779	10,243
Issuance of common shares under equity incentive plan	(751)	1,382
Non-cash share-based compensation expense	82,790	48,726
Net loss	(116,897)	(265,328)
Other comprehensive income (loss)	(2,325)	95
Ending balance	(466,413)	(278,155)
Biohaven Shareholders' Equity (Deficit)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(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		10,673
Issuance of common shares as payment for assets	253,779	10,243
Issuance of common shares under equity incentive plan	(751)	1,382
Non-cash share-based compensation expense	82,790	48,726
Net loss	(116,399)	(264,968)
Other comprehensive income (loss)	(2,325)	95
Ending balance	(462,286)	(275,976)
Common Shares
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	$ 1,676,792	$ 1,249,547
Beginning balance (in shares)	66,933,531	60,436,876
Repurchase of preferred shares in consolidated subsidiary	$ 152,673
Repurchase of preferred shares in consolidated subsidiary (in shares)	1,232,629
Issuance of common shares, net of offering costs		$ 308,243
Issuance of common shares, net of offering costs (in shares)		4,037,204
Issuance of common shares as part of acquisition		$ 10,673
Issuance of common shares as part of acquisition (in shares)		115,836
Issuance of common shares as payment for assets	$ 253,779	$ 10,243
Issuance of common shares as payment for assets (in shares)	2,037,921	110,998
Issuance of common shares under equity incentive plan	$ 29,442	$ 25,315
Issuance of common shares under equity incentive plan (shares)	336,721	365,554
Ending balance	$ 2,112,686	$ 1,604,021
Ending balance (in shares)	70,540,802	65,066,468
Additional Paid-in Capital
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	$ 169,656	$ 98,938
Repurchase of preferred shares in consolidated subsidiary	(92,673)
Issuance of common shares under equity incentive plan	(30,193)	(23,933)
Non-cash share-based compensation expense	82,790	48,726
Ending balance	129,580	123,731
Accumulated Deficit
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(2,585,755)	(1,739,169)
Net loss	(116,399)	(264,968)
Ending balance	(2,702,154)	(2,004,137)
Accumulated Other Comprehensive Income
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(73)	314
Other comprehensive income (loss)	(2,325)	95
Ending balance	(2,398)	409
Non-controlling Interests
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(3,629)	(1,819)
Net loss	(498)	(360)
Ending balance	$ (4,127)	$ (2,179)