| Cover Page | Jan. 11, 2021 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Jan. 11, 2021 |
| Entity Registrant Name | Acacia Communications, Inc. |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 001-37771 |
| Entity Tax Identification Number | 27-0291921 |
| Entity Address, Address Line One | Three Mill and Main Place |
| Entity Address, Address Line Two | Suite 400 |
| Entity Address, City or Town | Maynard |
| Entity Address, State or Province | MA |
| Entity Address, Postal Zip Code | 01754 |
| City Area Code | 978 |
| Local Phone Number | 938-4896 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, $0.0001 par value per share |
| Trading Symbol | ACIA |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0001651235 |
| Amendment Flag | false |
