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Compensation and Other Benefit Plans - Stock Option Plans (Details) - shares | 1 Months Ended | 12 Months Ended |
--- | --- | --- | ---
May 31, 2019 | May 31, 2017 | May 31, 2016 | Dec. 31, 2019 | Dec. 31, 2018
Share-based compensation |  |  |  |  |
Number of options outstanding |  |  |  | 1,839,623 | 1,624,746
2010 Plan |  |  |  |  |
Share-based compensation |  |  |  |  |
Increase in aggregate number of shares authorized for issuance | 450,000 |  | 170,000 |  |
Shares authorized for issuance | 3,029,062 |  | 1,108,560 |  |
2010 Plan | Minimum | Terminated employee |  |  |  |  |
Share-based compensation |  |  |  |  |
Expiration period |  |  |  | 3 months |
2010 Plan | Maximum |  |  |  |  |
Share-based compensation |  |  |  |  |
Expiration period |  |  |  | 10 years |
2010 Plan | Maximum | Terminated employee |  |  |  |  |
Share-based compensation |  |  |  |  |
Expiration period |  |  |  | 6 months |
2010 Plan | Options and Stock Appreciation Rights |  |  |  |  |
Share-based compensation |  |  |  |  |
Maximum shares per employee |  | 2,000,000 |  |  |
2010 Plan | Other Types of Stock Awards |  |  |  |  |
Share-based compensation |  |  |  |  |
Maximum shares per employee |  | 2,000,000 |  |  |
2010 Plan | Stock Options |  |  |  |  |
Share-based compensation |  |  |  |  |
Increase in aggregate number of shares authorized for issuance | 450,000 |  |  |  |
Shares authorized for issuance | 3,029,062 |  |  |  |
Shares available for grant |  |  |  | 525,020 |
2010 Plan | Common Stock |  |  |  |  |
Share-based compensation |  |  |  |  |
Increase in aggregate number of shares authorized for issuance |  | 1,470,502 |  |  |
Shares authorized for issuance |  | 2,579,062 |  |  |
2010 Plan | Common Stock | Stock Options |  |  |  |  |
Share-based compensation |  |  |  |  |
Increase in aggregate number of shares authorized for issuance |  | 2,004,087 |  |  |
Shares authorized for issuance |  | 2,579,062 |  |  |

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- Definition The highest quantity of shares an employee can purchase under the plan per period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901 + Details
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- Definition Number of additional shares authorized for issuance under share-based payment arrangement. + References No definition available. + Details
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- Definition Number of shares authorized for issuance under share-based payment arrangement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a)(3) -URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901 + Details
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- Definition The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901 + Details
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