Concentration of Credit Risk - Additional Information (Detail)	9 Months Ended
Sep. 30, 2015 Instruments
STA Instruments [Member]
Concentration Risk [Line Items]
Number of instrument on purchase agreement	12,000

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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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration