Fostering Innovation Act of 2017 This bill amends the Sarbanes-Oxley Act of 2002 to establish a temporary exemption from the requirement that each registered public accounting firm that prepares or issues an audit report for an issuer of securities (other than an emerging growth company) shall attest to, and report on, the internal control assessment made by the management of the issuer. Specifically, this requirement shall not apply with respect to an audit report prepared for an issuer that: ceased to be an emerging growth company on the last day of its fiscal year following the five-year period beginning on the date of its first sale of common equity securities, had average annual gross revenues of less than $50 million as of its most recently completed fiscal year, and is not a large accelerated filer. An issuer shall cease to be eligible for the exemption at the earliest of: (1) the last day of the fiscal year following the 10-year period beginning on the date of its first sale of common equity securities, (2) the last day of the fiscal year in which its average annual gross revenues exceed $50 million, or (3) when the issuer becomes a large accelerated filer.