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Stock-Based Compensation Plans (Narrative) (Details) | 3 Months Ended
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Mar. 31, 2019 USD ($) plan shares | Mar. 31, 2018 USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Compensation expense for share-based payments | $ | $ 4,786,794 | $ 3,901,316
Compensation cost capitalized as part of inventory | $ | $ 295,973 | 258,651
Employee Stock Option Plan |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Number of shares available for grant (in shares) | 24,000,000 |
Unrecognized compensation cost | $ | $ 7,650,472 |
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 |
Non Employee Director Stock Option Plan |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Option vesting period | 6 months |
Option expiration period | 10 years |
Unrecognized compensation cost | $ | $ 4,302 |
Number of shares authorized (in shares) | 1,000,000 |
Granted (in shares) | 483,940 |
Employee Stock Purchase Plan |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Shares approved (in shares) | 2,000,000 |
ESPP discount rate | 85.00% |
ESPP discount rate recognized as compensation expense | 15.00% |
Shares granted (in shares) | 1,026,404 |
Restricted Stock Plan |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Number of shares authorized (in shares) | 9,000,000 |
Restricted period, maximum, in years | 10 years |
Unearned stock-based compensation | $ | $ 36,944,099 |
Amortization expense | $ | $ 2,723,579 | $ 1,643,060
Omnibus Incentive Plan |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Number of shares authorized (in shares) | 45,000,000 |
Restricted period, maximum, in years | 3 years |
Equity Incentive Plans |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Number of plans | plan | 4 |
Stock Options |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Number of plans | plan | 2 |

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- Definition Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5047-113901 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SAB Topic 14.F) -URI http://asc.fasb.org/extlink&oid=115993241&loc=d3e301413-122809 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (h)(1)(i) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
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- Definition The shares or units in an ESOP trust that have been assigned to individual participant accounts based on a known formula. IRS rules require allocations to be nondiscriminatory generally based on compensation, length of service, or a combination of both. For any particular participant such shares or units may be vested, unvested, or partially vested. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 40 -Section 50 -Paragraph 1 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=109244661&loc=d3e17540-113929 + Details
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- Definition The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested). + 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=109197908&loc=d3e5070-113901 + Details
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