Goodwill and Intangible Assets - General Information (Details) - USD ($) $ in Thousands		12 Months Ended
Jun. 02, 2016	Dec. 31, 2017
Lesinurad transaction
Business Combinations
Payment for acquisition of lesinurad license	$ 100,000
Contingent consideration	$ 67,885
Licensing agreement \| AstraZeneca
Business Combinations
Royalty percentage per agreement	single digits
Milestone payment to be paid by company upon milestone achievement	$ 165,000
Milestone payment made		$ 15,000
Licensing agreement \| Post-marketing Activities
Business Combinations
Period for reimbursement amount of development activities (in years)	10 years
Licensing agreement \| Post-marketing Activities \| Maximum
Business Combinations
Reimbursement obligation	$ 100,000

Business Combination, Tiered Royalty to Acquiree, Royalty Rate Percentage

No definition available.

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- Definition

The amount paid by the company upon completion of a milestone by the counterparty.

+ References

No definition available.

+ Details

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- Definition

The amount to be paid by the company upon completion of a milestone by the counterparty.

+ References

No definition available.

+ Details

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- Definition

Period for reimbursement amount of development activities under the specific arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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- Definition

Amount of liabilities incurred by the acquirer as part of consideration transferred in a business combination.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 25
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6911189&loc=d3e6405-128476

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-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 30
-Paragraph 7
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-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 30
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=6911251&loc=d3e6613-128477

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- References

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- Definition

Minimum amount of other commitment not otherwise specified in the taxonomy. Excludes commitments explicitly modeled in the taxonomy, including but not limited to, long-term and short-term purchase commitments, recorded and unrecorded purchase obligations, supply commitments, registration payment arrangements, leases, debt, product warranties, guarantees, environmental remediation obligations, and pensions.

+ References

No definition available.

+ Details

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- Definition

The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3213-108585

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