Concentration of Credit Risk - Additional Information (Detail)
|6 Months Ended|
Jun. 30, 2015
|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.