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Stock-Based Compensation Plans (Narrative) (Details) | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2016 USD ($) plan shares | Jun. 30, 2015 USD ($) | Jun. 30, 2016 USD ($) plan shares | Jun. 30, 2015 USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Compensation expense for share-based payments | $ 3,811,300 | $ 4,728,949 | $ 7,833,682 | $ 9,574,999
Compensation cost capitalized as part of inventory |  |  | $ 282,786 | $ 249,581
Employee Stock Option Plan [Member] |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Number of shares available for grant (in shares) | shares | 24,000,000 |  | 24,000,000 |
Unrecognized compensation cost | $ 18,971,958 |  | $ 18,971,958 |
Employee Stock Option Plan [Member] | Minimum [Member] |  |  |  |
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 [Member] | Maximum [Member] |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Option vesting period |  |  | 5 years |
Option expiration period |  |  | 7 years |
Non-Employee Director Stock Option Plan [Member] |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Option vesting period |  |  | 6 months |
Option expiration period |  |  | 10 years |
Number of shares authorized (in shares) | shares | 1,000,000 |  | 1,000,000 |
Unrecognized compensation cost | $ 190,852 |  | $ 190,852 |
Options granted (in shares) | shares |  |  | 371,000 |
Employee Stock Purchase Plan [Member] |  |  |  |
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% |
Restricted Stock Plan [Member] |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Number of shares authorized (in shares) | shares | 9,000,000 |  | 9,000,000 |
Restricted period, maximum, in years |  |  | 10 years |
Unearned stock-based compensation | $ 12,088,592 |  | $ 12,088,592 |
Amortization expense | $ 991,674 |  | $ 1,943,745 |
Equity Incentive Plans [Member] |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Number of plans (in plans) | plan | 4 |  | 4 |
Stock Options [Member] |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Number of plans (in plans) | plan | 2 |  | 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://www.xbrl.org/2003/role/presentationRef -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=27013229&loc=d3e301413-122809 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5047-113901 Reference 3: http://www.xbrl.org/2003/role/presentationRef -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=6415400&loc=d3e5070-113901 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Staff Accounting Bulletin (SAB) -Number Topic 14 -Section F + Details
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