Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Assets:
Cash equivalents	$ 63,194	$ 77,120
Liabilities:
Derivative liabilities	(2,471)	(862)
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1)
Assets:
Cash equivalents	63,194	77,120
Significant Unobservable Inputs (Level 3)
Liabilities:
Derivative liabilities	$ (2,471)	$ (862)