| Document and Entity Information | Oct. 21, 2020 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Oct. 21, 2020 |
| Entity Registrant Name | CRISPR THERAPEUTICS AG |
| Entity Central Index Key | 0001674416 |
| Entity Emerging Growth Company | false |
| Entity File Number | 001-37923 |
| Entity Tax Identification Number | 00-0000000 |
| Entity Incorporation State Country Code | V8 |
| Entity Address, Address Line One | Baarerstrasse 14 |
| Entity Address, City or Town | Zug |
| Entity Address, Country | CH |
| Entity Address, Postal Zip Code | 6300 |
| City Area Code | 41 (0)41 |
| Local Phone Number | 561 32 77 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Security 12b Title | Common Shares, nominal value CHF 0.03 |
| Trading Symbol | CRSP |
| Security Exchange Name | NASDAQ |
