X0306 4 2021-01-04 false 0001503274 Quanterix Corp QTRX 0001219039 CRANDELL KEITH 8755 WEST HIGGINS ROAD, SUITE 1025 CHICAGO IL 60631 true false true false Common Stock 2021-01-04 4 A false 2270.00 0.00 A 14229.00 D Common Stock 2021-01-04 4 A false 197.00 44.11 A 14426.00 D Common Stock 1905481.00 I See Footnote Common Stock 1214770.00 I See Footnote Stock Option (Right to Buy) 44.10 2021-01-04 4 A false 7900.00 0.00 A 2021-12-31 2031-01-04 Common Stock 7900.00 7900.00 D Represents restricted stock units that vest as to 100% of the shares on December 31, 2021 granted pursuant to the Quanterix Corporation 2018 Non-Employee Director Compensation Policy. Each restricted stock unit represents the right to receive one share of the Issuer's common stock. Includes 2,270 restricted stock units. Consists of stock granted in lieu of cash fees for service on the Company's Board of Directors and committees thereof for the fourth quarter of 2020. Closing price of the Company's common stock on the Nasdaq Global Market on January 4, 2021. These shares are directly held by ARCH Venture Fund VI, L.P. ("ARCH VI"). ARCH Venture Partners VI, L.P. ("GPLP"), the sole general partner of ARCH VI, may be deemed to beneficially own the shares held by ARCH VI. ARCH Venture Partners VI, LLC ("GPLLC"), as the sole general partner of GPLP, may be deemed to beneficially own the shares held by ARCH VI. The Reporting Person is a managing director of the GPLLC and shares voting and investment control with respect to these shares. The Reporting Person may be deemed to beneficially own the shares held by ARCH VI. The Reporting Person disclaims beneficial ownership of the securities reported herein, except to the extent of his pecuniary interest therein, if any. These shares are directly held by ARCH Venture Fund VIII Overage, L.P. ("ARCH Overage"). ARCH Venture Partners VIII, LLC ("ARCH VIII LLC") the sole general partner of ARCH Overage, may be deemed to beneficially own the shares held by ARCH Overage. The Reporting Person is a managing director of the ARCH VIII LLC and shares voting and investment control with respect to these shares. The Reporting Person may be deemed to beneficially own the shares held by ARCH Overage. The Reporting Person disclaims beneficial ownership of the securities reported herein, except to the extent of his pecuniary interest therein, if any. Represents non-qualified stock option to purchase 7,900 shares of common stock granted pursuant to the Quanterix Corporation 2018 Non-Employee Director Compensation Policy. /s/ Brian Keane, as Attorney-in-Fact for Keith L. Crandell 2021-01-05