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Stock-Based Compensation Plans (Narrative) (Details) | 3 Months Ended | 6 Months Ended | 12 Months Ended |
--- | --- | --- | --- | ---
Jun. 30, 2020 USD ($) plan shares | Jun. 30, 2019 USD ($) | Jun. 30, 2020 USD ($) plan shares | Jun. 30, 2019 USD ($) | Dec. 31, 2019 USD ($) | Sep. 30, 2019 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |
Share based compensation expense |  |  | $ 15,960,362 | $ 10,139,148 |  |
Compensation expense for share-based payments | $ 9,641,353 | $ 5,200,045 |  | 9,986,839 |  |
Employee Severance |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |
Compensation expense for share-based payments | 4,173,710 |  |  |  |  |
Omnibus Incentive Plan |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |
Number of shares authorized (in shares) | shares |  |  |  |  |  | 45,000,000
Shares issued under the Omnibus plan | shares |  |  | 8,458,942 |  |  |
Employee Stock Option Plan |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |
Unrecognized compensation cost | 6,882,606 |  | $ 6,882,606 |  |  |
Employee Stock Option Plan | Minimum |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |
Option vesting period |  |  | 1 year |  |  |
Option expiration period |  |  | 5 years |  |  |
Employee Stock Option Plan | Maximum |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |
Option vesting period |  |  | 5 years |  |  |
Option expiration period |  |  | 10 years |  |  |
Restricted Stock Plan |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |
Unrecognized compensation cost | 43,352,020 |  | $ 43,352,020 |  |  |
Restricted period, maximum |  |  | 10 years |  |  |
Amortization expense | 7,580,492 | $ 3,274,411 | $ 11,905,749 | $ 6,046,175 |  |
Restricted Stock Plan | Employee Severance |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |
Amortization expense | $ 4,148,477 |  |  |  |  |
Employee Stock Purchase Plan |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |
Shares approved (in shares) | shares | 2,000,000 |  | 2,000,000 |  |  |
ESPP discount rate |  |  | 85.00% |  |  |
ESPP discount rate recognized as compensation expense |  |  | 15.00% |  |  |
Shares granted (in shares) | shares | 1,269,603 |  | 1,269,603 |  |  |
Equity Incentive Plans |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |
Number of plans | plan | 2 |  | 2 |  |  |
Performance Shares |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |
Unrecognized compensation cost | $ 4,932,401 |  | $ 4,932,401 |  |  |
Amortization expense | $ 563,783 |  | $ 957,560 |  | $ 0 |

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