| Cover | Jul. 07, 2021 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Entity Registrant Name | Biohaven Pharmaceutical Holding Company Ltd. |
| Document Period End Date | Jul. 7, 2021 |
| Entity Incorporation, State or Country Code | D8 |
| Entity File Number | 001-38080 |
| Entity Address, Address Line One | c/o Biohaven Pharmaceuticals, Inc. |
| Entity Address, Address Line Two | 215 Church Street |
| Entity Address, City or Town | New Haven |
| Entity Address, State or Province | CT |
| Entity Address, Postal Zip Code | 06510 |
| City Area Code | 203 |
| Local Phone Number | 404-0410 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Shares, no par value |
| Trading Symbol | BHVN |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0001689813 |
| Amendment Flag | false |
