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Subsequent Events Subsequent Events (Details) - USD ($) $ in Thousands |  | 1 Months Ended | 3 Months Ended | 6 Months Ended |  |
--- | --- | --- | --- | --- | --- | ---
Jul. 15, 2015 | Jul. 31, 2015 | Jun. 30, 2015 | Jun. 30, 2014 | Jun. 30, 2015 | Jun. 30, 2014 | Jul. 16, 2015 | Jul. 02, 2015
Subsequent Event [Line Items] |  |  |  |  |  |  |  |
Research and development |  |  | $ 490,728 | $ 447,273 | $ 951,277 | $ 976,157 |  |
AGTC | Subsequent event |  |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |  |
Research and development |  | $ 124,000 |  |  |  |  |  |
Purchase of common stock |  | 30,000 |  |  |  |  |  |
Prepaid research and development |  |  |  |  |  |  |  | $ 58,400
Total licensing and fees |  | $ 35,600 |  |  |  |  |  |
Potential future milestone payments |  |  |  |  |  |  |  | 1,000,000
Eisai | Subsequent event |  |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |  |
Term of lease | 10 years |  |  |  |  |  |  |
Swedish Orphan Biovitrum | Subsequent event |  |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |  |
Additional milestone payment |  |  |  |  |  |  | $ 10,000 |
Lead programs | AGTC | Subsequent event |  |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |  |
Potential future milestone payments |  |  |  |  |  |  |  | 472,500
Discovery programs | AGTC | Subsequent event |  |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |  |
Potential future milestone payments |  |  |  |  |  |  |  | $ 592,500

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- Definition The costs incurred in a planned search or critical investigation aimed at discovery of new knowledge with the hope that such knowledge will be useful in developing a new product or service, a new process or technique, or in bringing about a significant improvement to an existing product or process; or to translate research findings or other knowledge into a plan or design for a new product or process or for a significant improvement to an existing product or process whether intended for sale or the entity's use, during the reporting period charged to research and development projects, excluding in-process research and development acquired in a business combination consummated during the period. Excludes software research and development, which has a separate concept. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 730 -SubTopic 10 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6420194&loc=d3e21568-108373 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Research and Development -URI http://asc.fasb.org/extlink&oid=6523717 + Details
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