Fair Value Measurements - Schedule of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) $ in Thousands	Dec. 31, 2015 USD ($)
Assets:
Total assets	$ 97,366
Liabilities:
Total liabilities	5,520
Marketable securities [Member]
Assets:
Total assets	97,366
Derivative liability [Member]
Liabilities:
Total liabilities	5,520
Quoted Prices in Active Markets (Level 1) [Member]
Assets:
Total assets	97,366
Liabilities:
Total liabilities	0
Quoted Prices in Active Markets (Level 1) [Member] | Marketable securities [Member]
Assets:
Total assets	97,366
Quoted Prices in Active Markets (Level 1) [Member] | Derivative liability [Member]
Liabilities:
Total liabilities	0
Significant Other Observable Inputs (Level 2) [Member]
Assets:
Total assets	0
Liabilities:
Total liabilities	0
Significant Other Observable Inputs (Level 2) [Member] | Marketable securities [Member]
Assets:
Total assets	0
Significant Other Observable Inputs (Level 2) [Member] | Derivative liability [Member]
Liabilities:
Total liabilities	0
Significant Unobservable Inputs (Level 3) [Member]
Assets:
Total assets	0
Liabilities:
Total liabilities	5,520
Significant Unobservable Inputs (Level 3) [Member] | Marketable securities [Member]
Assets:
Total assets	0
Significant Unobservable Inputs (Level 3) [Member] | Derivative liability [Member]
Liabilities:
Total liabilities	$ 5,520