Kodiak Sciences Inc. Notes to Consolidated Financial Statements (in thousands, except share and per share data) 124 Stock Options Stock option activity under the 2018 Plan and 2015 Plan is summarized as follows (in thousands, except share and per share data): Outstanding Awards Number of Shares Available for Grant Number of Shares Underlying Outstanding Options Weighted Average Exercise Price Weighted Average Remaining Contractual Term (in years) Aggregate Intrinsic Value Balance, January 1, 2016.............................................. 1,814,560 102,937 $ 0.23 7.92 $ 86 Options granted............................................................... (1,209,595) 1,209,595 $ 1.04 9.53 Options exercised............................................................ — (10,674) $ 0.45 6.76 7 Options forfeited or canceled.......................................... 38,101 (38,101) $ 0.97 9.38 Repurchase of early exercised options............................ 51,689 — $ 0.12 RSAs granted(1).............................................................. (142,938) — Balance, December 31, 2016......................................... 551,817 1,263,757 $ 0.98 9.42 $ 100 Options granted............................................................... (137,500) 137,500 $ 1.06 Options exercised............................................................ — (5,603) $ 0.50 3 Options forfeited or canceled.......................................... 191,240 (191,240) $ 1.04 Balance, December 31, 2017......................................... 605,557 1,204,414 $ 0.98 8.49 $ 41 Shares authorized............................................................ 6,425,000 — RSAs granted .................................................................. (27,500) — RSUs granted .................................................................. (60,000) 60,000 $ 10.00 Options granted............................................................... (4,103,653) 4,103,653 $ 7.45 Options exercised............................................................ — (47,800) $ 1.03 290 Options forfeited or canceled.......................................... 185,000 (185,000) $ 5.19 Balance, December 31, 2018......................................... 3,024,404 5,135,267 $ 5.99 9.07 $ 10,681 Shares exercisable, December 31, 2017.......................... 863,791 $ 0.97 8.38 $ 30 Vested and expected to vest, December 31, 2017........... 1,204,414 $ 0.98 8.49 $ 41 Shares exercisable, December 31, 2018.......................... 1,766,385 $ 3.11 8.28 $ 7,182 Vested and expected to vest, December 31, 2018........... 5,135,267 $ 5.99 9.07 $ 10,681 (1) Reflects an adjustment to shares available for grant related to the issuance of restricted stock awards under the 2015 Plan. During the years ended December 31, 2018, 2017 and 2016, the Company granted 3,888,653, 107,500 and 1,205,940 stock options, respectively, to employees with a weighted-average grant date fair value of $4.36, $0.61 and $0.60 per share, respectively. Shares Subject to Repurchase The Company has a right of repurchase with respect to unvested shares issued upon early exercise of options at an amount equal to the lower of (1) the exercise price of each restricted share being repurchased and (2) the fair market value of such restricted share at the time the Company’s right of repurchase is exercised. The Company’s right to repurchase these shares lapses as those shares vest over the requisite service period. Shares purchased by employees pursuant to the early exercise of stock options are not deemed, for accounting purposes, to be issued until those shares vest according to their respective vesting schedules. Cash received for early exercised stock options is recorded as accrued liabilities and other current liabilities on the consolidated balance sheet and is reclassified to common stock and additional paid-in capital as such shares vest. At December 31, 2018 and 2017, 0 and 2,887 shares, respectively, remained subject to the Company’s right of repurchase as a result of the early exercised stock options.