ACHN 2017 Annual Report

Achillion Pharmaceuticals, Inc. Statements of Stockholders’ Equity for the Years Ended December 31, 2015, 2016 and 2017 (in thousands) Common Stock Additional Paid-In Capital Accumulated Deficit Stock Subscription Receivable Accumulated Other Comprehensive Income (Loss) Total Stockholders’ Equity Shares Amount Balances at December 31, 2014 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103,594 $104 $599,796 $(450,682) $(5,737) $ (12) $143,469 Net loss . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . — — — (5,030) — — (5,030) Other comprehensive income (loss) . . . . . . . . . . . . . . . . . . . . . . . . . . . — — — — — (33) (33) Stock compensation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . — — 10,072 — — — 10,072 Issuance of common stock upon exercise of warrants . . . . . . . . . . . . . 8 — — — — — — Issuance of common stock upon exercise of stock options . . . . . . . . . 835 1 3,730 — 126 — 3,857 Issuance of common stock under the employee stock purchase plan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 — 290 — — — 290 Issuance of common stock in connection with public offerings, net of issuance costs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13,800 14 132,509 — 5,611 — 138,134 Issuance of common stock in connection with the JJDC Stock Purchase Agreement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18,367 18 158,859 — — — 158,877 Balances at December 31, 2015 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136,640 $137 $905,256 $(455,712) $ — $ (45) $449,636 Net loss . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . — — — (61,706) — — (61,706) Other comprehensive income (loss) . . . . . . . . . . . . . . . . . . . . . . . . . . . — — — — — 196 196 Stock compensation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . — — 11,006 — — — 11,006 Issuance of common stock upon exercise of stock options . . . . . . . . . 41 — 108 — — — 108 Issuance of common stock under the employee stock purchase plan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 — 214 — — — 214 Balances at December 31, 2016 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136,722 $137 $916,584 $(517,418) $ — $ 151 $399,454 Net loss . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . — — — (85,236) — — (85,236) Other comprehensive income (loss) . . . . . . . . . . . . . . . . . . . . . . . . . . . — — — — — (540) (540) Stock compensation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . — — 10,573 — — — 10,573 Issuance of common stock upon exercise of warrants . . . . . . . . . . . . . 1,084 1 (1) — — — — Issuance of common stock upon exercise of stock options . . . . . . . . . 14 — 39 — — — 39 Issuance of common stock under the employee stock purchase plan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74 — 225 — — — 225 Balances at December 31, 2017 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137,894 $138 $927,420 $(602,654) $ — $(389) $324,515 The accompanying notes are an integral part of these financial statements. F-6