| Document and Entity Information | Feb. 15, 2022 |
| Cover [Abstract] | |
| Entity Registrant Name | ASPEN AEROGELS INC |
| Amendment Flag | false |
| Entity Central Index Key | 0001145986 |
| Document Type | 8-K |
| Document Period End Date | Feb. 15, 2022 |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 001-36481 |
| Entity Tax Identification Number | 04-3559972 |
| Entity Address, Address Line One | 30 Forbes Road |
| Entity Address, Address Line Two | Building B |
| Entity Address, City or Town | Northborough |
| Entity Address, State or Province | MA |
| Entity Address, Postal Zip Code | 01532 |
| City Area Code | (508) |
| Local Phone Number | 691-1111 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Security 12b Title | Common Stock |
| Trading Symbol | ASPN |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
