X0306 4 2019-08-12 false 0001459839 SI-BONE, Inc. SIBN 0001419187 Skyline Venture Partners V LP 525 UNIVERSITY AVENUE, SUITE 1350 PALO ALTO CA 94301 false false true false 0001434887 Skyline Venture Management V, LLC 525 UNIVERSITY AVENUE, SUITE 1350 PALO ALTO CA 94301 false false true false Common Stock 2019-08-12 4 S false 400000.00 18.25 D 4019985.00 I By Skyline Venture Partners V, L.P Shares held by Skyline Venture Partners V, L.P. ("SVP V"). Skyline Venture Management V, LLC ("LLC") is the general partner of SVP V and as such may be deemed to have voting and investment power with respect to the securities of SVP V. Dr. Freund, a member of the Issuer's board of directors, together with Yasunori Kaneko, are the managing directors of LLC and each may be deemed to have voting and investment power with respect to the securities held by SVP V. Dr. Freund disclaims beneficial ownership of such securities, except to the extent of his pecuniary interest therein. Skyline Venture Partners V, L.P., By: Skyline Venture Management V, LLC, Its: General Partner, By: /s/ Michael A. Pisetsky , Attorney-in-Fact 2019-08-14 Skyline Venture Management V, LLC, By: /s/ Michael A. Pisetsky, Attorney-in-Fact 2019-08-14