Capital Stock - Schedule of Vesting Shares Subject to Repurchase (Detail) (Restricted shares subject to repurchase [Member])	Sep. 30, 2014	Dec. 31, 2013	Dec. 31, 2012
Amortization Expense [Line Items]
Total	1,343,764	1,456,987	1,156,078
1st quarter 2015 [Member]
Amortization Expense [Line Items]
Total	781,080
1st quarter 2016 [Member]
Amortization Expense [Line Items]
Total	395,716
1st quarter 2017 [Member]
Amortization Expense [Line Items]
Total	166,968