#1 The 609,090 common shares reported in Table I and accompanying warrants to purchase up to 609,090 common shares reported in Table II of this Form 4 were purchased together at a combined public offering price of $1.65 per share and accompanying warrant, which such combined public offering price included $0.01 per accompanying warrant.

#2 Includes 100,869 common shares held of record by ARCH Venture Fund VI, L.P. ("ARCH VI") and 942,423 common shares held of record by ARCH Venture Fund X Overage, L.P. (the "ARCH Overage"). ARCH Venture Partners VI, L.P. (the "ARCH GPLP"), as the sole general partner of ARCH VI, may be deemed to beneficially own certain of the shares held of record by ARCH VI. The ARCH GPLP disclaims beneficial ownership of all shares held of record by ARCH VI in which the ARCH GPLP does not have an actual pecuniary interest. ARCH Venture Partners VI, LLC (the "ARCH GPLLC"), as the sole general partner of the ARCH GPLP, may be deemed to beneficially own certain of the shares held of record by ARCH VI. The ARCH GPLLC disclaims beneficial ownership of all shares held of record by ARCH GPLP in which the ARCH GPLLC does not have an actual pecuniary interest.

#3 ARCH Venture Partners X Overage, L.P. (the "Overage GPLP"), as the sole general partner of ARCH Overage, may be deemed to beneficially own certain of the shares held of record by ARCH Overage. The Overage GPLP disclaims beneficial ownership of all shares held of record by ARCH Overage in which the Overage GPLP does not have an actual pecuniary interest. ARCH Venture Partners X, LLC (the "Overage GPLLC"), as the sole general partner of the Overage GPLP, may be deemed to beneficially own certain of the shares held of record by ARCH Overage. The Overage GPLLC disclaims beneficial ownership of all shares held of record by Overage GPLP in which the Overage GPLLC does not have an actual pecuniary interest.

#4 The reporting person owns an interest in ARCH GPLP but does not have voting or investment control over the shares held by ARCH VI, and disclaims beneficial ownership of such shares, except to the extent of any pecuniary interest therein. The reporting person owns an interest in Overage GPLP and may be deemed to have voting and investment control over the shares held by ARCH Overage as member of the investment committee of Overage GPLLC, but disclaims beneficial ownership of such shares, except to the extent of any pecuniary interest therein.