Option activity under the Plans for the year ended December 31, 2021 was as follows (in thousands, except as noted): | | | | | | | | | | | | | | | | | | | Weighted | | | | | | | | Weighted- | | Average | | | | | | | | Average | | Remaining | | Aggregate | | | | | Exercise | | Contractual | | Intrinsic | | | Options | | Price | | Term | | Value | | | (in thousands) | | | | | | | | | | | | | | | | | | | | | | Outstanding at December 31, 2020 | | 274 | | $ | 20.57 | | | 8.7 | | $ | 3,750 | Granted | | 213 | | | 7.02 | | | 9.3 | | | | Expired | | (1) | | | 72.67 | | | | | | | Outstanding at December 31, 2021 | | 486 | | $ | 14.58 | | | 8.4 | | $ | 7,800 | Vested and expected to vest December 31, 2021 | | 451 | | $ | 15.21 | | | 8.4 | | $ | 7,114 | Exercisable at December 31, 2021 | | 178 | | $ | 28.09 | | | 7.6 | | $ | 3,412 |
Option activity under the Plans for the year ended December 31, 2020 was as follows (in thousands, except as noted): | | | | | | | | | | | | | | | | | | | Weighted | | | | | | | | Weighted- | | Average | | | | | | | | Average | | Remaining | | Aggregate | | | | | Exercise | | Contractual | | Intrinsic | | | Options | | Price | | Term | | Value | | | (in thousands) | | | | | | | | | | | | | | | | | | | | | | Outstanding at December 31, 2019 | | 68 | | $ | 68.56 | | | 7.7 | | $ | — | Granted | | 211 | | | 5.01 | | | 9.4 | | | | Forfeited | | (4) | | | 7.19 | | | | | | | Expired | | (1) | | | 28.67 | | | | | | | Outstanding at December 31, 2020 | | 274 | | $ | 20.57 | | | 8.7 | | $ | 3,750 | Vested and expected to vest December 31, 2020 | | 238 | | $ | 22.66 | | | 8.7 | | $ | — | Exercisable at December 31, 2020 | | 66 | | $ | 63.95 | | | 7.2 | | $ | 3,070 |
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