Commitments and Contingencies - Additional Information (Detail) - USD ($) |
9 Months Ended | 34 Months Ended |
---|---|---|
Sep. 30, 2015 |
Sep. 30, 2015 |
|
December 7, 2012 Agreement [Member] | ||
Commitment And Contingencies [Line Items] | ||
Commitment towards investments in joint venture | $ 1,200,000 | |
Contribution to joint venture | $ 850,000 | |
December 9, 2014 Agreement [Member] | ||
Commitment And Contingencies [Line Items] | ||
Commitment towards investments in joint venture | $ 1,000,000 |