Use these links to rapidly review the document TABLE OF CONTENTS EXHIBIT INDEX One Kendall Square Bldg. 1400E, Suite B14202 Cambridge, Massachusetts 02139 (Address of principal executive offices) (Zip Code) Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-K (Mark One) ý ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2018 or o TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SEC ...