Investment in Silver Creek - Additional Information (Detail)	Sep. 30, 2017
Silver Creek Pharmaceuticals Inc [Member] \| Maximum [Member]
Consolidation Less Than Wholly Owned Subsidiary Parent Ownership Interest Effects Of Changes Net [Line Items]
Ownership interest percentage held by parent	50.00%

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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